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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Filmcamera on November 23, 2018, 02:51:45 PM
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I hope I do not know the answer to this question already but fear I might.
My 1991 16v K100RS has been back on the road for about two years now. I ride it fairly often and fairly hard. Yesterday for example I did 150 miles to the beach and back on mountain roads over four hours or so. All in all I average around 500 miles a month.
It has always ran a little hot, something I put down to be in Costa Rica where is it seldom less than 27 C or 80 F and humid. There is also always quite a lot of slowish speed twisties and climbs through mountains etc.
It has also always used a lot of oil. Take yesterday's ride for example, I checked the oil level and it was bang in the middle before I left. When I checked again this morning it was just touching the bottom of the sight glass, what is that 3 fl oz?
Now the issue at hand. It seems to be running hotter and hotter. At least half the time yesterday the needle was just below the red, the kind of temp where the fan would kick in if it was not already on from the manual switch I have. Without the fan it would boil for sure, with it it JUST stays out of the red. The funny thing is that maybe one ride in three is stays just above half or maybe just below 3/4 the whole time with no issues except when doing a long slow climb when it will rise but then come back down again as soon as I have a few minutes of sustained speeds of 50 mph+. On the way back from the beach yesterday it absolutely poured with rain, a real torrential downpour, the first time I have ridden in raid that bad and I have to say I was very impressed with how sable the bike was and how (relatively) dry I stayed. Needless to say the engine temp was fine all the way home since it was getting a nice soaking!
Here are the things I have done to try and remedy the problem so far.
New thermostat, I soaked the radiator in vinegar for fours days before flushing carefully and refilling with racing coolant. The temperature sensor is also new as is the oil sensor. The radiator itself seems in good condition.
So what else can I try? Are there any other options apart from and engine rebuild with new rings etc? Could there be an issue with the oil/water pump? (I have never touched that since I got the bike).
Last piece of info is that when I checked the valves they were nearly all a little tight, I have not fixed that as of it.
Riding season is just arriving here and I really do not want to take if off the road for months to strip the engine down, not to mention the cost, especially since I would have to buy a bunch of special tools from what I can see.
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FC what was the condition of the water when you first drained the radiator. Sometimes vinegar won't shift all the scale and what scale it loosens can end up clogging the galleries. A compatible proprietary cleaner along with reverse flushing is sometimes needed or have it professionally cleaned and checked. You also need to remove the thermostat and check that it's fully opening. Just because it's new doesn't mean that it is working correctly. A corroded impellor vane in the pump will allow it to over heat as will a impellor slipping on the shaft as it heats up. What was the brand and specifications of your coolant. Long shot incorrect ignition timing will also cause it to run hot as will too lean a mixture. Do your valve clearances.
Regards Martin.
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FC you might also want to check that your temperature gauge is calibrated correctly. I have seen a few people chasing supposed problems when all that was wrong was a gauge or test equipment reading wrong. I had a car with a standard temperature gauge that read high. I fitted an auxillary temperature gauge and it read low. I took both into work and had them recalibrated. Are you using coolant?
Regards Martin.
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Hi Martin,
The coolant is Bel-Ray moto chill racing coolant. This is some of their blurb
Bel-Ray® Moto Chill Racing Coolant is an engine coolant that uses a special non-toxic propylene glycol formula designed for better heat transfer and cooler running engines. Protects from corrosion and extends the life of all motorcycle cooling systems including those using magnesium and aluminum components
The water that came out of the radiator was not too bad, I had already flushed the radiator with just water a number of times when I got the bike, I had also squeezed the tubes multiple times because they sounded 'crunchy' when I first got the bike. After the vinegar soak I flushed the radiator a few times with water but will take your advice and see if I can find a special cleaner to try again. There are no professionals for that kind of thing here I am afraid.
I will also check the thermostat. I can check the valve clearances again but fixing them is a pain on the 16V bikes, if I have to do that I might do the whole thing and do the rings at the same time.
Do you think I should crack open the water and oil cover to have a look at it then?
The bike doesn't run lean if anything it runs rich.
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The coolant is supposed to be used undiluted but I diluted it, partly because it is so damn expensive here, $30 a liter. Originally I had it 50/50 and this time after doing the vinegar etc I went 2/3 collant 1/3 distilled water.
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The radiator itself seems in good condition.
So what else can I try?
Last piece of info is that when I checked the valves they were nearly all a little tight, I have not fixed that as of it.
The coolant is supposed to be used undiluted but I diluted it, partly because it is so damn expensive here, $30 a liter. Originally I had it 50/50 and this time after doing the vinegar etc I went 2/3 collant 1/3 distilled water.
An engine shouldn't be run with tight exhaust valves regardless of whether they're a little tight. All valves should be set to spec. It's a more complex process in a 16V moto but it must be done. Brichbk's thread shows what can happen when valve clearances are ignored.
The moto isn't overheating until the temperature light is lit. On a long, slow mountain ascent, the engine will be warmer than on the flats. Even with the fan operating, the gauge will be toward its upper range. I'd like to know if the fan cycles when you don't have it activated by the bypass switch. Try flipping the radiator cap gasket to perhaps seal it better. If it isn't sealing well, the boiling point of the coolant is lowered. Your moto should work well with long-life coolant in a ratio of 60% distilled water:40% coolant. How does your racing coolant differ from long-life?
As far as oil consumption goes, according to BMW, maximum permissible oil consumption is 1.5 liters per 1000kms. Of course, some motos consume less than others, but thou shalt not covet. :oldguy:
Don't let your imagination run wild. Adjust the valves; flip the radiator cap gasket. Verify the coolant level. Follow manufactuers' instructions. Your cost-cutting and avoidance of maintenance can lead to the parting out of your moto.
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Yes the fan does come on automatically if I do not have it manually turned on. I will try leaving it to do its thing and see if it turns OFF as well and how often. The coolant level if fine, I just checked it. I will flip the radiator cap to see if that helps.
I have no idea what the difference is between long life and racing coolant, here you have limited choices to say the least and that seemed to be the best option I could find.
I guess this weekend I will be rechecking the valves and seeing how they are, first though I am off to see Roger Waters in concert tomorrow night with my two sons. I can't wait!
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When I flush radiators I try to run it through a cloth. A cloth can be cable tied over the inlet pipe forming a bag so that you can see if there is any scale. If your hoses sounded crunchy it would more than likely be scale. When you flush it is better to reverse flush as this stands more chance of dislodging scale. Forward flushing can result in pushing scale into the galleries. Previously you just cleaned the radiator I would in order first use a compatible cleaner and run the bike the required amount of time then reverse flush and check what is in the water being flushed out of the radiator and the block. If scale ,crap or debris is encountered I'd do it again. The water in both the block and the radiator needs to run clear. Scale coating the inside surface of the block inhibits the transference of heat from the block to the water, and can lead to overheating. I would also check to see if the cooling fins are clear of bugs and crap. Do not use air or high pressure water to clean the cooling fins. Bent cooling fins need to be straightened gently. There are tools available cheaply of Ebay or use popsicle sticks cut and sanded to size , don't use anything sharp. If there was signs of corrosion in the water I would pull the pump to check for corrosion. For peace of mind you might want to check the impellor. Electronic immersible thermometers are available from Ebay and can be used to test the gauge and the thermostat as well as checking your coffee. Are there signs of leakage at the weep hole.
Regards Martin.
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Jonathon, Have you ever pulled the radiator out and cleaned out the fins? Doing that did more to lower the running temperature than almost anything else I did to the Moby Brick.
Is your replacement thermostat an OEM part? The OEM thermostat has a shutoff for the radiator bypass that may not be on an "equivalent" thermostat. If that bypass isn't being closed off when the engine gets warm and opens the thermostat a large portion of the circulating coolant will go around the radiator and not do any heat removal. Even if you have an OEM thermostat, it's possible that it is not closing off the bypass.
Last, regarding oil consumption, try putting a quart of Marvel Mystery Oil in the crankcase when you do the next oil change and run on it for a couple thousand miles. Moby Brick used a lot of oil before the MMO treatment by the guy who bought it from me. He now reports that oil usage is down to less than a quart in 1500 miles.
As far as valves, I would at least do the exhaust valves. They are the ones most likely to burn when they get too tight. Intake valves have the fresh charge cooling them.
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Yes it is an OEM thermostat, it came from Max BMW.
The fins are in pretty great shape, I just checked them and though they are a few that are slightly bent overall it seems ok, I will try and post a photo soon. One of the funny things about CR is that there are NO bugs when you ride or drive. I did 150 miles yesterday and did not have a single bug splatter, I have often wondered why, it is the same with cars, windscreens stay clean. We never have salt on the roads and I try not to off road much so the fins tend to stay in pretty good condition.
I will get a cleaner and try the reverse flush though, I am pretty sure the radiator has not had distilled water in it before I got the bike and the water here can be super hard.
Marvel Mystery Oil, ok let me jump on the right now, my missus happens to be in the US to celebrate Thanksgiving with her family so she might be able to bring some back because it is not available here for sure.
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Is this is the stuff?
Marvel Mystery Oil (https://www.amazon.com/d/Engine-Oil-Additives/Marvel-MM12R-Mystery-Oil-Pack/B0725JQXKS/ref=sr_1_1_sspa?ie=UTF8&qid=1543011634&sr=8-1-spons&keywords=marvel+mystery+oil&psc=1)
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If it hasn't been run on distilled water and the water is hard, it could be the problem. Built up scale can sometimes be hard to dislodge in both the block and the radiator. If it is severe you might have to flush a few times. And scale can also build up in the pump leading to restrictions. While the missus is in the US you might want get her to get you a few other things. A digital thermometer, a laser temperature gun all can be had cheap at Harbor Freight are invaluable and have multiple uses.
Regards Martin.
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Luckily I have both of those - well the digital thermometer is a digital meat thermometer but I guess it can do the job - I just have to use it without her indoors finding out...
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That's the stuff.
Even if the fins look good, there could be a lot of crap in between them. I know I flushed out enough bugs from mine to feed a family of four for a week. The only way I know to get them out is to soak the radiator in vinegar and run water from behind through the fins. The only way to do it right is to take the radiator off the bike.
Your bike has a lot of years and miles on it. Don't assume the fins are clear.
Cooling is a function of the coolant's specific heat. Distilled water probably has the highest specific heat of any coolant you can easily get. The trouble is, it has no corrosion preventives or anything to raise the boiling point. I'm inclined to believe that BMW's recommended 60/40 mix is probably the best coolant mix for our bikes.
I suspect that "racing" coolant has additives to raise the boiling point so that it can safely run at higher than normal operating temperatures. I also suspect that it's heat transfer ability at a given temperature may be lower than BMW's recommended mixture. This may cause the engine to actually run hotter in order to achieve the required heat removal. It's a case of the capability to run hotter causing it to run hotter. Also, bear in mind that racing machines are running at high speed and have lots of airflow for cooling.
Remember that temperature equilibrium will occur at the temperature where the difference between the air temperature and the coolant temperature in the radiator allows the heat removal to equal the heat generated in the engine. If you want to reduce the engine temperature you need to increase the heat transfer in the radiator. Unless you go to a larger radiator, the only other thing you can do is increase airflow. If you are running with a wide open thermostat and seeing high coolant temperatures, you need to look at radiator size and airflow. It's all you have to work with.
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Ok that all makes perfect sense, thanks.
Let me get the radiator off and try a flush or two and also source a different coolant and go 60/40 disttilled water v coolant.
Marvel Mystery Oil ordered...
She is gonna kill me, all the stuff I send means less clothes etc she can bring back... lol
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I just think that the cooling system is a bit small compared to modern systems. My '05 (and the '02) K12Lt don't run the fans like the '85 and '91 at the same air temps. 80F and humid, is that all =-} add 20 more degrees for here in the summer for months on end. I hear the fans kick on once I get home, but it is friggin' hot. Got stuck one Friday afternoon in stop and go traffic over 95F, damned hot. Tempted to split lanes to get the temps down, as much for me as the RS! If you are not seeing the temp light come on, I think it is working as designed.
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I've never had trouble with overheating in the cooling system on my 75s even on the hottest days in traffic that QLD can come up with. Fuel system overheating is another matter, currently dealing with it. However my cooling system has only ever run with BMW coolant ( It is the same price if not cheaper than aftermarket coolants) and distilled water. And even then it has been flushed out a couple of times and the fin cleaned out.
I use a slightly different method to .75 I soak it overnight in hot water and dishwashing liquid then vacuum with my shop vac. You could still be running in the correct temperature range if the light is not coming on and it's not regurgitating coolant. Hence the need to check the accuracy of your temperature gauge. Laser temperature guns are now cheap as chips and have other uses. I also use mine to check that my cylinder temperatures are even.
Regards Martin.
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The coolant is Bel-Ray moto chill racing coolant.
I can check the valve clearances again but fixing them is a pain on the 16V bikes, if I have to do that I might do the whole thing and do the rings at the same time.
The Bel-Ray MotoChill instructions clearly state Do not dilute. By diluting it, you lessened its effectiveness. Incorrectly diluted coolant won't work well just because you want to save money. You've compromised cooling by doing that. All you need to use is long-life coolant—OAT-type—in the correct proportion with distilled water, or may Bel-Ray MotoChill as it was designed to be used. Long-life OAT-type coolant should be common, even in Costa Rica.
The whole thing that you're considering doing is a far reach from just adjusting valve clearances. If you knew that you'd avoid it like the plague. If you want to find out whether the rings are a problem, do a compression test. Give us the values. Follow classic compression test methods; brichbk explains the process in one of his posts. It was how he discovered one of his exhaust valves was near self-destruction and you can use it to determine if a rings in a cylinder might be faulty.
The distance between the top of the sight glass to the bottom represents approximately 0.6 liter. Be certain the crankcase ventilator assembly isn't clogged. A clogged crankcase ventilator can increase oil consumption.
Your moto should function well in the highlands of Costa Rica without a larger-capacity radiator but that's always an option if all other systems check out ok and overheating is proven to be a problem. Clean the cooling system thoroughly. Mix long-life OAT coolant with distilled water carefully in the recommended proportion. Measure the valve clearances carefully and use the correct size cam followers (buckets) to set them to their specified clearances. You want the intake valves correctly set too. It might get costly but those exhaust valves will only get tighter with more riding. If one of the valves break, then will be the time to contemplate the whole thing.
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I will do what I can, I have done a compression test in the past, if memory serves I got a fairly consistent 120 - 125 on each cylinder though 3 may have been down at 115 - certainly no zero readings like in the thread you mentioned.
I will search for the coolant you mention, believe me it is not as easy as you think. I might end up going to BMW and seeing if they will take my right arm for some OEM stuff.
I think you may be wrong about the top of the sight glass to the bottom being 0.6 liter. I have had to fill it up many times and it has never been anywhere near as much as 20 fluid ounces to make up that. Granted normally I am filling from the bottom to the middle of the sight glass but that is generally 3-4 fluid ounces.
The valves I will check and look into again, last time I checked the general consensus of the forum was to leave them alone and ride, if they have got tighter that might change.
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A cylinder leak down test would also be helpful for evaluating valves and rings.
Andy
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I will search for the coolant you mention, believe me it is not as easy as you think.
I think you may be wrong about the top of the sight glass to the bottom being 0.6 liter.
The valves I will check and look into again, last time I checked the general consensus of the forum was to leave them alone and ride, if they have got tighter that might change.
Anybody who advises that tight exhaust valves should be left alone is mistaken.
OAT coolant is used in most modern cars. It's the most common along with Hybrid Organic Acid Technology (HOAT) coolant. It's called Long life coolant.
As far as my being mistaken about the sight glass values, take it up with BMW. That value is published in both the K75 and K1100 BMW Rider's Manuals.
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I am looking into the procedure to change the buckets on the bike. Clymers says I need two special BMW tools to get the camshafts out, they are $225! Add to that the buckets are $35 each, meaning I am looking at nearly $800 before tax and shipping to get them ehre.
Has anyone taken the camshaft out of a 16v engine without the special tools?
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Not the K100, but yes on the K1200. Basically, you zip tie the timing chain to the camshaft gears and then release the timing chain tension. Then remove the camshaft gears and the nuts holding the camshaft to the motor. The gears are keyed to the shaft with a pin to realign it on reassembly. Torque everything to spec. on reassembly. You should be able to find a youtube video of the procedure.
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I've had the head off my engine which involved removing the cams. Reinstalling the cams is a kinda fiddly job, getting things lined up, but not really that hard. I did it without the special tools and didn't have any problems. As far as I can tell, the special tools just make it a quicker, no-brain kind of job.
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Great thanks to both of you. That saves some cash at least
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I am looking into the procedure to change the buckets on the bike. Clymers says I need two special BMW tools to get the camshafts out . . .
What the Clymer manual actually indicates is that you need those tools if you want to remove the camshafts without removing the timing chain cover and the timing chain. The tools were developed for production purposes. As Gryph mentions, it is perfectly possible to do the task without the tools; it's just more involved.
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A quick update
I found a new coolant
(http://www.motobrick.com/gallery/1/3823-241118162226-18661028.jpeg)
(http://www.motobrick.com/gallery/1/3823-241118162226-18662162.jpeg)
it says to use it instead of water so I will not dilute it, there is no need for anti freeze here so it will be 100% the new coolant.
I checked the thermostat and it does open correctly, it is not a snap open but more of gradual opening starting at 85 C and ending by 90 C. If left to cool it closes again. I tested it various times and it opened and closed every time.
I took off the radiator to check the cooling fins better
(http://www.motobrick.com/gallery/1/3823-241118162241-18731561.jpeg)
(http://www.motobrick.com/gallery/1/3823-241118162239-1872272.jpeg)
There is some dirt in there and a pretty good ding in one corner but all in all I would say it is not too bad.
I did notice a rust like deposit on the inside which is probably a mix of limescale and corrosion, hopefully a flushing agent will get rid of it. The coolant that came out was almost totally clean though, very few extra particles in it at all.
(http://www.motobrick.com/gallery/1/3823-241118162235-18711767.jpeg)
Tomorrow I going to check the valve clearances again but attached is a chart showing what they were when I last checked them about 2500 miles ago.
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The coating that is in the radiator will also be in the block and will be reducing the ability of the cooling system. You will see what happens after you use a good flushing agent, the water will not be running clean when you first drop the mixture. You need to clean and straighten any bent fins on the radiator. This is a tedious and time consuming activity which gives you the opportunity to connect with you inner being. Sanded and shaped popsicle sticks are ideal, be patient and gentle. Soak the radiator overnight in either water and detergent or vinegar to loosen the crap. Then use a hose to gently wash out the crap. Never use high pressure you can also use compressed air but you need to turn the pressure right down.
Regards Martin.
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greetings...
if you are gonna f with that rudson snake oil you may wanna getts the yellow bottle...
all my bricks run hot... if you aint blowing the cap you are gňod to go...
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j o
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All in all, the fins don't look bent. I would not screw with them. Soak the fins in detergent or vinegar and gently flush them from the BACK side. You might have to do it a couple of times to be absolutely sure all the crap is out of there. When I did mine I flushed by pouring hot water from a gallon jug held about a foot above the fins.
That red coating in the radiator is something I've never seen in a cooling system. I have a well and from time to time we are confronted with iron bacteria that turns everything a rusty red like what you have. I suspect that someone before you might have been running well water in your bike. Normally vinegar gets that crap out, but those rust stains can be pretty tough. You probably need to get something stronger.
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I have a well and from time to time we are confronted with iron bacteria that turns everything a rusty red like what you have. I suspect that someone before you might have been running well water in your bike.
+1
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greetings...
iron has good thermal conductivity...
j o
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are there any vacuum leaks, that can cause overheating
or a compression test, eg head gasket leaking between adjacent cylinders
overheating only sometimes could be caused by either of those causes
in vacuum case by movement or lower revs than usual
leaking head gasket could be worse on shorter trips before the engine has heated or worse on longer trips, depending on where the leak is.
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... I had a car with a standard temperature gauge that read high. I fitted an auxillary temperature gauge and it read low.
"A man with one watch knows the time; a man with two is never sure."
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Looking at that valve chart, all i can say is wowza.....If I read it correctly you have 10 of 16 that are too tight, granted not by much, but still outside of the tolerance range, 4 that are at the bare minimum and 2 that are fine.
#3 intake and #4 exhaust both a&b are right at the bare minimum.
#3 exhaust, both are just right.
All the rest are out of spec on the tight side.
BMW says not to(they want to sell you new ones), some riders here will also say not to, yet some riders have, and I have, "re-used buckets" or "moved buckets around" as needed to meet specs, with no ill effects.....
In my case I was able to move a bucket from a valve that was too loose and use it on a valve that had been too tight. It all depends on the thickness of your buckets and where they are at if you can re-use them or not.
The only way you are going to know what you need for new buckets is to pull the cams and inventory exactly what buckets you have and do the math. It may be possible to read the bucket spec, or you may have to measure it with a micrometer.
Re the radiator/engine cooling system, like others have mentioned, do a chemical flush to get as much of that scale out as possible as it does/will inhibit heat transfer, both in the block as well as in the radiator.
We have similar issue where I work, with our industrial chiller air conditioning system. Steel pipes and tap water cause a rusty scale inside the copper tubes of the chiller bundle. Even with continuous chemical treatment we still have to brush out the tubes every year to minimize/reduce/remove the coating inside the tubes that inhibits the heat transfer.
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Exactly, 10 of 16 too tight - and the great Chris Harris said in his 2v video if you are doing this on a 16v boke you are wasting your time, they never go tight...
That is partly why I plan to redo the measurements today.
Meanwhile I have been working on the outside of the radiator, having soaked it overnight. I swear it has not been this clean since it rolled of a West German production line in July 1990!
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FC, do note that the smallest bucket is a 2.50..... if you have a tight valve and the bucket is already a 2.50 you are NOT going to be happy as you will be looking at a head off valve job to replace the valve and seat...
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I just rechecked all the valve clearances and though there is some good news overall the picture is pretty much the same.
Number one cylinder intakes are the worst, 0.10 mm was a go but 0.13 mm was a no go, 0.15 mm is minimum so way tight
2 and 4 were also slightly tight 0.15 mm was a go but 0.18 mm was a no go so on the very limit and 3 was in the middle 0.18 mm go .20 mm no go
The exhaust side was better all four cylinders are in spec but 1 and 2 are at at the min, 0.25 mm was a go but 0.28mm was a no go. 3 and 4 were 0.28 mm go 0.30 mm no go.
So not one loose valve in the whole 16. Obviously number one intake is the main concern.
Before I can take the valves out to see what buckets I need to buy I have to buy a valve spring compression tool (at least I think I do). Does anyone have a specific make or model they have used and liked on a K bike?
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Before I can take the valves out to see what buckets I need to buy I have to buy a valve spring compression tool (at least I think I do).
Where in the instructions did you get that idea?
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The only tool I needed to remove the buckets on Moby Brick was a magnet.
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In Clymers in the section about how to remove a valve but now you mention it I read the part again and it seems you can take the lifters out without removing the whole valve or cylinder head etc.
So all I have to do is take off the valve cover and timing chain cover, remove the timing chain, remove the crankshafts and then I can pull out the lifters using a magnetic tool?
Then I just need to measure them, do some math, order new ones and wait for them to arrive. Then reverse the whole process. Is that more or less correct?
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I think you meant camshafts, but yes, that is about what is required.
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Oops, yes I did. OK thanks, that is slightly less daunting than I had thought.
I am going to wait a bit though, I want to try and ride during at least part of the season and also this is an expensive time of year to be doing fairly major repairs. Either way if the valve clearances have not changed in over a year a month or two more will be probably be ok.... famous last words I know.
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I'll add a little tip, before you remove the lower/exhaust camshaft, have your clean spots ready for the buckets as some may literally "fall" out from gravity(being at an upward angle in the head). The oil viscosity may provide enough resistance to keep them in place long enough to use a magnet on them, but I have had some not stay put.... just FYI.
The intake ones will stay put as they will be at a downward angle and you will want a magnet to help remove them.
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This morning I added some radiator flush and ran the bike at idle for twenty minutes, once it had got up to normal temperature, as the product instructions indicate. During that time I noticed the fan came on at the correct temp indicated on the temp gauge - ie just under half way between 3/4 and the red line. It also went off again at the correct place, just a hair over half way. I allowed it to do two cycles and it did the same both times.
I think that shows the temp gauge is approximately accurate.
Now I have to let the engine cool down then drain the flushing agent and run through with water until it runs clear. I did buy a second bottle of radiator flush in case it is needed.
Whilst the bike was idling I took the time to take a few digital temperatures using my laser temperature gauge. I noticed that the number one cylinder exhaust pipe was quite a lot cooler than the others. I took the readings about one inch from where the header connects to the engine. Number one was 175C and all the others were between 210C and 220 C.
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when was the last time the TB's were balanced?
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About six months ago or so. I have ordered a leak down tester so when it gets here in a couple of weeks I was planning to do a compression test as well as a leak down test, I can easily enough add a TB balance as well.
So looking again at the valve clearance results, all the exhaust valves are either in the middle of the range or at the low end, none are out of spec. Can I get away with just doing the intake valves meaning I only have to remove one camshaft or should I replace the exhaust valves that are in range but at min? What am I aiming for? Mid range, or max acceptable without be considered loose? I think Clymer uses midrange ie 0.18mm for intake and 0.28mm for exhaust but given that Chris Harris said loose is ok is it maybe better to go for 0.20mm and 0.30mm?
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Valve clearance doesn't normally increase over time. What you are adjusting for when you do the valves is the wear on the seat in the cylinder head, which as it wears closes up the gap between the valve and the cam. For this reason, I always adjust for the maximum clearance so I have the maximum safety margin. The valves on the 16v engines are such a pain in the ass to do, if I found one that absolutely needed a new bucket I would adjust it to the maximum clearance. Since the damn buckets are so friggin' expensive I would just do the ones that are at the absolute minimum.
Since you have several that are close but still in spec, and you're looking at riding season, you might want to just do the valves that are definitely out of spec and make a point of checking and keeping a record of clearances going forward.
You mention letting the bike idle and seeing the fan and the temperature gauge work properly. Did the fan lower the temperature enough to shut off? Was this after you cleaned the fins? If so, it might indicate that you are making some progress on the overheating issue.
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Yes the fan did lower the temp enough to shut off - at least the first time I did the radiator flush when it was a mixture of racing coolant and radiator flush in there. I have just done a second flush with just water and the flush - this time the temp went into the red and although the fan cooled it enough to come out of there it stayed just under the 3/4 mark at which point the fan shut off again, the temp started to climb rapidly again so I left he fan turned on manually and it kept the temp at the just under the 3/4 mark for the rest of the time needed for the fush to do its stuff.
Now I am just waiting for the engine to cool enough to drain the radiator and run the engine with flowing water for a bit before refilling with the new OAT coolant I purchased.
On the valves I think you are right, I will do cylinders 1 and 4 on the intake side now and monitor the situation. That means just one camshaft needs to come meaning I could even take the old buckets out to work out what ones I need to order then but them back in again to keep riding until they get here. With Max BMW and the time of year and customs etc I anticipate a minimum of three weeks from ordering the buckets to having them here to ready to install.
When I do order them is there anything else I need to replace at the same time? Is it just the buckets or do people typically change the springs or collars etc at the same time?
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When I did them on Moby Brick I just changed the buckets. When you put everything back together, use plenty of oil on all the working surfaces. Don't be like me and use an assembly paste with molybdenum in it. The moly got into the engine oil, made the sprag clutch slip and required that I do a flush to get it out.
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If you are going to have the cam cover off and 1 cam out, I'd suggest you go ahead and pull both cams(1 at a time.....) and go ahead and check/measure your buckets, record them on paper, for your future reference.....save yourself some time and grief later on when you do the next check, but that's just me.
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If you are going to have the cam cover off and 1 cam out, I'd suggest you go ahead and pull both cams(1 at a time.....) and go ahead and check/measure your buckets, record them on paper, for your future reference.....save yourself some time and grief later on when you do the next check, but that's just me.
Great idea!
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Sounds good, I will do that, I like the idea of taking the camshafts off one at a time as well!
I finished the second radiator flush process and buttoned everything up again. A quick test ride was inconclusive but I did get all the way up my hill without the fan coming on until the very end, normally I turn the manual fan on as a matter of course at the bottom and the temp still hits auto fan on temps by the top so I would say that is an improvement. I plan on leaving the manual fan switch alone for a few days to get a better feel for how hot it gets how quickly.
Thank you to everyone for all the help, believe me I will need more when it comes to taking the buckets out!! yawl yawl
Until then time to go and get some miles in while she who must be obeyed is out of the country...
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I went for a ride today to see how the bike was doing after all the radiator work and the new coolant. I purposefully left the manual fan switch alone to see how it went. the bike ran great, the fan only came on right at the end of the ride after a few minutes in a car park at sub 5 mph speeds. It does seem though that the temp gauge is failing - the fan kicked in when the temp gauge was reading less than half way! I could feel the bike was hotter than that from the brick tell tale toaster properties on my leg...
It is a matter of replacing the temp gauge or is there some maintenance I can do to it?
Apart from that the bike does seem to running a little cooler. Again the fan did not come on until right at the end on the way up my hill.
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What did you use to flush the cooling system clean water or did you use a flushing agent. The flushing agent needs to be compatible with alloy block. When you flushed it did you get any scale or muck in the water.
Regards Martin.
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The temperature gauge and the sender work on a negative coefficient, that is, the higher the temperature the lower the sender resistance. That your gauge is reading low leads me to suspect a dirty/bad connection somewhere. You should go through the entire signal path from the sender to the gauge cleaning the connections.
Check the resistance of the sender body to the main ground at the battery. It should be very close to zero.
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What did you use to flush the cooling system clean water or did you use a flushing agent. The flushing agent needs to be compatible with alloy block. When you flushed it did you get any scale or muck in the water.
Regards Martin.
Yes, you never mention what has come out when you cleaned the various parts of the system. Did much come out of the fins? How mucky was the flushing liquid when you drained it. Did a lot of muck come out when you did the system flush after you cleaned the radiator?
While it's important to flush the block, overheating the coolant indicates that the problem is in heat REMOVAL ie, the radiator. There are only two reasons why the heat is not being removed. First, there is not enough coolant flow through the radiator. This could be caused by blocked passages in the radiator, or a bad water pump that is not flowing enough, or there is too much flow in the bypass caused by a thermostat that is not sealing it off effectively.
Second, there is not enough heat transfer between the coolant and the air. This is due to air blockage in the fins, or mineral coating in the coolant passages.
Since you have done a lot of cleaning, we can assume for now that heat transfer in the radiator from coolant to air is not the problem. That leaves the coolant flow as the source of the overheating. Let's also assume that the radiator passages are clear and not restricting flow. That just leaves pump flow and the bypass as the remaining suspects.
You might want to pull the water pump cover to check the impeller and internal passages of the pump. Beyond that, I have no ideas on how to test it. Perhaps someone else can offer some suggestions.
I have worked on a lot of marine engines, many of which, especially older ones had raw water cooling with block bypasses to allow the engine to warm up faster while allowing flow to cool the exhaust. I have seen a lot of old engines overheat because the bypass does not seal completely when the thermostat opens, allowing a lot of cooling water to not flow through the block. My experience is that it doesn't take much bypass leakage to overheat an engine.
I can vaguely recall that there was a brick owner who had an overheating problem that I think was caused by the way the thermostat was installed in the thermostat housing. I can't remember exactly, but it may have had something to do with how a gasket was installed. Again, maybe someone more knowledgeable may be able to supply more detail.
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Also some thermostats have a togglethingy that goes through a hole.
The thermostat should be installed with the hole uppermost to allow any air bubbles to pass through.
Also if the bottom hose is too soft it could collapse from pump suction when accelerating.
It is easy to check, look at the hose under revs when it is hot, ideally the hose wouldn't pass through the crank cover.
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Another easy check when the engine is cold does the fan spin easily when pushed with your finger.
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FC, also note that there are 2 temperature sensors at work here....
The sensor for the gauge is mounted at the bottom of the water pump, and the sensor for the fan and engine fuel control is mounted in the riser pipe behind the radiator, bolted to the top of the block.
Like was mentioned check the electrical connections, you may also want to remove each one and see how much scale is on them as well.
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I went for a spirited 90 minute ride in the twisties on Sunday morning and am glad to report the fan never came on once except as I pulled to a stop at my house at the very end. The temp gauge is still out of whack but I will clean up the sensor this week when I do a leak down test (the tester arrived on Saturday) and see if that helps.
Thanks for all the suggestions, the bike is definitely running cooler than it was.