MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Custom Motobricks => Topic started by: Shiny on August 06, 2016, 03:51:20 PM
-
Hi all,
This thread will be about my 1986 K75 and it's journey from craptacular to somewhat decent. I bought it back in May after selling my 2000 KLR 650 for $2k. I wanted a project bike that wouldn't take a lot of work to get to the look I was after, that might be rough cosmetically but mechanically sound. I read about the bulletproof brick and impulse bought the first K I saw.
This is it. My 1986 K75. Says 35k on the odo but the odo doesn't work... I believe it started life as a T-model due to the drum rear brake and k100 standard headlight fairing. (http://i.imgur.com/FijiBvz.jpg)
Took it for a test drive at the buyers house. Was blown away by how smooth the engine was. Not a huge fan of the bars on it, pretty tall and laid back, looking for something "sportier". There was a pulsing in the front when braking. Unbeknownst to me at the time, the coolant reservoir was missing. The seller was asking $1600 firm, so that's what we agreed on. Yes, I paid too much.
Got it home and ordered the Clymer manual and set to work. First thing was to lube the shaft input splines. I don't think they looked too bad, I hope?
(http://i.imgur.com/XIMf663.jpg)
(http://i.imgur.com/7NmEUIL.jpg)
Saw horse method of support worked a treat for anyone out there worried about it. Got it on there by myself. Only dropped the bike on my foot once.
(http://i.imgur.com/7vLKmeO.jpg)
Getting the transmission back on was a bear.
The clutch cup was torn and had leaked transmission oil all over the swingarm. Starting to figure out how much BMW replacement parts will cost...
Oil change, coolant flush, brake bleed, and we're ready to hit the road! Not so fast, bike won't start. It cranks but there's no fuel. I had cleaned out the tank when I first got the bike and the pump had sat dry for 1.5 months. Bench tested it hooked to the battery and yup it was dead. One off brand pump later and it started! Running a little raggedy, so I pop the valve cover off and holy hell all the valves were tight. Intakes were around 0.125mm and exhausts were 0.215! I'm currently waiting on the valve shims. (Shout out to Ken Lively at polpenhollow@yahoo.com for his valve tools) Bought some 4 hole injects from Ebay so we'll give those a try this week as well.
Wait you ask, it took 1.5 months to lube the splines? Not exactly. When I was taking off the exhaust for the first time one of the studs cracked off flush with the head. Thus began an odyssey: I drilled a pilot hole through the stud and tried a spiral extractor. The extractor cracked, also flush with the head. Tried using a dremel to grind the extractor out, no luck, those things are seriously hard steel. Bought a clever bit called the Rescue Bit which chewed through the extractor and remaining bolt like butter. Got another screw extractor and.... cracked the head. Sort of. The embossed hole the stud goes in.
(http://i.imgur.com/NZX7Xwh.jpg)
Well shit. Got some permatex high heat gasket maker and slapped that exhaust back on minus one bolt. No leaks yet... I'll either swap a new head on there or build a new boss with jb weld if it does start leaking. I can't even describe how much effort went into that bolt, but it nearly soured me on the whole project. Getting it started again has warmed me to it again, especially now that the worst of the summer heat (fingers crossed) is over.
Tried painting a piece orange, wasn't a fan:
(http://i.imgur.com/gr8jDnm.jpg)
Stripped the tank. Some dipshit had covered it in spray truck bed coating. Wasn't exactly tough though, was peeling all over the place. Think I'll leave the tank bare for now, I really like the grinder swirls.
(http://i.imgur.com/FQiU27e.jpg)
(http://i.imgur.com/I47YTRB.jpg)
Things to come:
Paint!
Handlebar swap
Instrument cluster?
Naked headlight conversion.
-
Keep at it and the bike will definitely reward you. They are a extremely tough reliable bike, but they don't like sitting, bad electrical connection can be the root of a lot of problems Deoxit will be come one of your best friends, the 4 pin fuel pump connector (under RH side of tank) is often a problem. Rubber bits need to be checked eg : the Z hose, the rubber caps on the throttle bodies. Rubber fuel hoses in the tank need to be fuel proof ( submersible)and you need to check the fuel pump damper, it can disintegrate. Alcohol in the fuel should avoided where possible.
Regards Martin.
-
Thanks Martin.
I didn't detail it but I've been hard at work (literally working overtime to pay for my hobby) replacing all the rubber doodads. The crank case breather hose was split, the submersible fuel lines were cracking, the external fuel lines were shot. Honestly the only rubber that looks good on the bike was the fuel pump damper, not turning to goo at all.
-
:2thumbup:
-
EDIT: wrong thread
So here was my math:
(http://i.imgur.com/mWLaiRA.png)
-
Where in Nova did you pick that up? Alexandria?
-
Actually got it from a guy down by Charlottesville. Not one of my wisest purchases. Seen a few on craigslist since I bought it in better condition for cheaper. Such is life.
-
Hi Shiny,
Great to see another committed bricker.$1600 still ain't bad for what you got.I know you could cry over spilt milk but,your on ya way now.Clutch splines all good.Its the back drive shaft (female)spline that gets shagged 'cause that's where the stretch ocures.Hope that's good.
35,000 miles.Is that the original seat cover?or aftermarket?I've just started my forth recover after 250,000km as a guide...but there's still skin quality variation involved.
Oh yeh,"The bastard bolt"!You can always expect one of those.It's just the shit happening.Good chance one's enough.If it isn't you'll get a lovely crackling backfire on the overrun.
No expansion tank!Probably stable coolant fluid volume with resident air volume and won't have been catastrophic but,for how long?
I liked the Orange....'Seventies.Laverdas,Ducati's...
All the best.
-
Thanks dude.
Yeah I think thats the original cover. I'm actually selling that seat on ebay right now and in the motobrick marketplace.
-
New shims arrived and were installed. What a pain get those things to seat without falling out while you remove the holder.
New handlebars also arrived. I ordered these:
https://www.amazon.com/gp/product/B0050HC2NQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B0050HC2NQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1) Emgo Street Handlebar - Drag Bend
Started taking off the old LT bars and encountered what many have: 22mm is not 7/8". Sand off the paint of the ends of the bars and started going to town on the controls with my trusty rat tail file. Got through the clutch perch and throttle perch, but not the throttle tube, before I had to quit for the evening. Planning on loosening the banjo bolts in order rotate them to make the hose to the steering stem work until I can get new brake lines fitted.
Got a big box from Max BMW in the mail with new rubber bushings for the valve cover and submersible fuel line for inside the tank, then we should be road ready.
-
Got a big box from Max BMW in the mail with new rubber bushings for the valve cover and submersible fuel line for inside the tank, then we should be road ready.
You are installing a coolant expansion tank before you head out, to which the venerable Dude alluded, right? You could be having plenty of corrosion and precipitates in there with the current setup. A coolant flush, new coolant and an expansion tank would be helpful.
-
No worries, bought and installed a reservoir a few weeks ago. Flushed the coolant too, it's a lovely shade of swamp green.
(http://i.imgur.com/M5x2CQ0.jpg)
While I was taking apart the throttle tube, this little dot of red paper fell out along with this rusty washer. The throttle chain and gear was packed full of murky grease. Cleaning it out made it feel better, and I couldn't figure out where this washer came from.
(http://i.imgur.com/oECGgtf.jpg)
New handlebars are on and all controls hooked up! The cables are a bit long, so some creative routing was utilized. Anyone want to trade a brand new high bar clutch cable for a s-cable?
Before
(http://i.imgur.com/1f5XWC1.jpg)
After
(http://i.imgur.com/AGcHDYj.jpg)
(http://i.imgur.com/MH8mmmR.jpg)
-
FML my new Chinese knock off fuel pump isn't working.
-
Bars look good.'Hope they pass the thousand mile test.Takes some dedication with that rat's tail file.
Spare cable,ya never know.Keep it?
All good,so far....
-
Okay so the pump does work, when hooked to my gf's ninja 250 battery directly... All connections under the tank to the pump check out, multimeter on the pump leads only reads 9v while cranking... Got the battery on the charger now, will give it a try tomorrow evening. It's always something!
-
Flaky battery was the culprit. Charged overnight and she started right up. Valve adjustment didn't fix my throttle hesitation, so I took it for a short ride to get it warmed up and then tried syncing the throttle via the bypass screws. Got it synced, but still has some hesitation...
Riding it around town felt great, it's shifting well and so smooth. It's gonna take some getting used to coming from the KLR, where all the power was down low. I was shifting way too early. And those darn turn signal controls are going to be the death of me; I kept indicating right while trying the cancel. One thing that has me slightly concerned is that it feels like the wheels want to track every little crack in the road, "tar snakes". Just the new tires?
While I was playing with the vacuum ports, I noticed the one going to FPR had some oily residue in the end, any thoughts?
Gonna start painting up my plastics, gotta figure out how to fix the cracked tail wedge while I'm at it.
-
One thing that has me slightly concerned is that it feels like the wheels want to track every little crack in the road, "tar snakes". Just the new tires?
Some tires models do that more than others. What are you running? If a tire has a straight central sipe, it might tend to track along a snake. I'd think, tar snakes are troublesome to some degree for most riders
-
I practice intentionally riding on tar snakes in the Spring when it's cool just to get used to them, but in the heat of the summer that tar melts and causes a little lateral skip at times. :yow
I think any tire can slip on tar snakes when it's really hot. I try to avoid them, but that's impossible all the time.
Ride safe.
-
Nice to know we have new inmates coming in all the time :hehehe. Keeps the discussion going...welcome!
-
Got brand new Bridgestone S11 Spitfires on it.
Any input on the throttle? Like when I give it a good twist the RPM drops for half a sec before rising.
-
Fuel, fire, air... Sounds like you have the fuel situation under control. Fire most likely not the problem, Leaves AIR. Have you checked the rubbers/gaskets around the bases of the throttle bodies for leaks? Perhaps the airflow meter??? Real good description of the system basics here http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm (http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm)
-
Yeah the rubber boots look to be in good condition, likely replaced in the last decade. Propane torch (unlit) waved around the boots while running produced no change in rpm. I'll look into the airflow meter.
-
One last pic before some painting! I'm going with industrial gray.
(http://i.imgur.com/GNzz49A.jpg)
Think I found my idle/hesitation issue? The idle bypass plug on the airbox? Missing.
(http://i.imgur.com/AJeUGs8.jpg)
Found that while checking the fan, think it's toast. Gotta get that fixed before I can risk commuting on this thing. Stop and go traffic is a fact of life around NoVA. What's the latest intel on a cheap replacement fan that doesn't take any fabrication? I'm mad that I have to drain the coolant, it's brand new... Extra flushed I guess.
-
I'm mad that I have to drain the coolant, it's brand new... Extra flushed I guess.
Drain the coolant into a clean container. You can pour it right back into the radiator.
-
Drain the coolant into a clean container. You can pour it right back into the radiator.
Huzzah! Still have the coolant jug. Should probably replace the drain plug while I'm at it since the damn thing is nearly stripped.
-
What's the latest intel on a cheap replacement fan that doesn't take any fabrication?.
Huzzah? They're still shouting that in N. Virginia? Must be to charm the tourists. :giggles
Anyway, regarding a replacement fan:
A replacement that isn't OEM will take some degree of fabrication to mount it. Read this (http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/fans/fans.htm) about fan replacement, and look through both the Technical Library Index (http://www.motobrick.com/index.php/topic,666.0.html) and this (http://www.kbikeparts.com/classickbikes.com/ckb.tech/ckb.tech.tocm.htm) to learn about solutions for future challenges.
-
How bad of an idea would it be to wire a new fan so that it's always on? The temperature sensor at the pump should stop the flow of coolant at the engine if it's getting too cold. I guess mileage could be negatively effected.
Looking at getting a SPAL puller fan and ordering an Eastern Beaver headlight relay and an SPST switch for the fan.
-
How bad of an idea would it be to wire a new fan so that it's always on? The temperature sensor at the pump should stop the flow of coolant at the engine if it's getting too cold.
It's a just plain bad idea to have the fan running all the time. The bike's engine has an optimal range for efficient operating temperature. A fan running all the time will interfere with it. When an engine is not running efficiently, it develops problems.
The fan is a device to help the engine stay within its optimal temperature range. A fan switch is installed by owners who want to activate it temporarily when riding during hot temperatures in slow-moving traffic or hill-climbing with loads to insure themselves that their engine will be less likely to overheat.
The thermostat is the device that diverts coolant from the radiator to help with warmup and to keep the engine within its optimal temperature range.
You should consider learning how some of your engine's components operate. The information and illustrations following this diagnostic flowchart (http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm) may help you.
-
Second time for Bert V.'s link :bmwsmile, Laitch. Bad idea running the fan all the time...In cool weather my fan never kicks on. The situations Laitch describes are the only time it runs. The engine does not have a heat problem when the bike is moving. My bike has gauge which indicates very well when the fan should run (approaching 3/4 mark). How would you know when to run the fan?? Better to go through the diagnostic and figure out how to make the current system work and THEN wire up an over-ride if there are concerns. http://www.motobrick.com/index.php/topic,6702.msg45871.html#msg45871 (http://www.motobrick.com/index.php/topic,6702.msg45871.html#msg45871)
-
Second time for Bert V.'s link :bmwsmile, Laitch.
I'm in Calvin Coolidge's (http://www.brainyquote.com/quotes/quotes/c/calvincool414555.html) camp, Jack :giggles
-
I'm in Calvin Coolidge's (http://www.brainyquote.com/quotes/quotes/c/calvincool414555.html) camp, Jack :giggles
Thank god somebody :hehehe is or nothing would ever get solved on this forum!
-
Jeez guys, just a thought. Still, theoretically, the fan only cools off the coolant in the radiator. The thermostat controls the amount of that coolant which reaches the engine. If the fan was running all the time, the thermostat would have to stay open not as long.
Thermal stress is one issue I could see, as the extra cold coolant hits the first cylinder, you could possibly wear one wall more than the other. The KLR650 is notorious for that, hence why they all burn oil.
In any case I ordered a SPAL 6.5" fan, looks easy enough to install. Going to wait on the headlight relay until I get a chance to clean out the handlebar switch. Noticed that the high beam doesn't work. It's going to be crazy hot here the next few days so we'll see if I can bear to be out in the garage.
-
Still, theoretically . . .
There is no progress without experimentation and sacrifice, Shiny. Be the one on point concerning this. Leave your fan on during all your rides and keep us updated.
-
There is no progress without experimentation and sacrifice, Shiny. Be the one on point concerning this. Leave your fan on during all your rides and keep us updated.
...I do have a spare cylinder head (that I picked up for cheap after the exhaust stud fiasco).
Speaking of that stud, the exhaust is definitely leaking a little. I'm planning on trying to use high-heat jb weld to stick a new stud in the remnants of the boss and see what happens. Otherwise a head tear-down is in my future.
-
Speaking of that stud, the exhaust is definitely leaking a little. I'm planning on trying to use high-heat jb weld to stick a new stud in the remnants of the boss and see what happens. Otherwise a head tear-down is in my future.
Before you do the cylinder head swap, Shiny, you might find instructive this thread (http://www.motobrick.com/index.php/topic,7717.msg54835.html#msg54835) in its entirety
-
Oh the stud is out of the cylinder head, it's just that I broke the cylinder head raised boss that it threads into in the process. See the pic in my first post. That cracked part fell of entirely.
Swapping the head will wait for the winter, I'm just hoping my jb weld stud will get me through the rest of this season.
-
Did a little work this afternoon. Required some beer in the 100 degree garage:
(http://i.imgur.com/1TkideJ.jpg)
Did some wet sanding on my plastics to take care of a couple runs, will repaint in a few days.
Drained the coolant. Remember how I said the plug was stripped? Well it really didn't want to come out. Ending up using the dremel to cut some flats on it.
(http://i.imgur.com/hRgYjwy.jpg)
Got the new fan in. Wired it up, tested it at the relay and it works! The high temp late on the dash isn't functioning though.
(http://i.imgur.com/Eh4Jbnn.jpg)
My soldering is serviceable at best.
(http://i.imgur.com/rM8leCE.jpg)
Gotta wait a few days for the new coolant plug, in the meantime, got a few questions:
What the heck is this tube, and should it be connected to something?
(http://i.imgur.com/sBdnaXU.jpg)
What is this wire? I'm guessing it shouldn't be frayed like that. :mbird (looks like it goes to the ignition control module)
(http://i.imgur.com/jiG3L1P.jpg)
(http://i.imgur.com/aeoidCY.jpg)
-
crankcase breather on the tube...mine is plugged...several threads here
-
So what did you have to sand down? I have ran into the same probelm with my bike.