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I'm stripping down my 1987 K100RS for some TLC. The fuel pressure regulator seems to have gone south by leaking fuel into the vacuum hose and diluting the oil, so I need to swap that out, check the valves, do the splines and figured I'd give it a good once over with new injector o-rings, fuel hoses, etc. while she's in bits.
I really love this bike and it's in great condition, so I'd like to also fix the rattly output shaft. I already changed the alternator monkey nuts and this did not cure the rattle, it seems very clear to me that the output shaft is the problem - a pretty good rattle when cold, goes away mostly once warmed up, but you can hear it a bit getting on/off the throttle. It's not the cam chain. Reading through the manual, it looks like a lot of work to get the shaft out, but it's also pretty straightforward.
My question for the gurus is whether it's worth all the effort to replace the split gear spring, or is the rattle likely to come right back in another few thousand miles? Or, is it possible to swap the output shaft for a later one from a 16V bike, with a possibly better design?
Thanks guys for any advice.
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The output shafts on the K100 from about 89 on have a shaft with 12 rivits and not 6 as yours does. The 6 rivit shafts were not strong enough and after about 100,000miles or so gave out. There are a few who have tried to replace the rivits with bolts and extra rivits but they don't seem to be successful.
My advice is to get a 12 rivit shaft from a late model K100 engine and use it. But be carefull if you buy a complete engine, I have seen 2 engines recently one a 90 the other 91 and both had 6 rivit shafts. They had either been robbed out or never had them in the first place.
I don't know for sure if a shaft from a 16v engine fits as BMW are in the habit of making changes at any time during a model. A K75 is not the same and cany be used.
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The fuel pressure regulator seems to have gone south by leaking fuel into the vacuum hose and diluting the oil,
How do you know? (Just curious)
... so I'd like to also fix the rattly output shaft.
How are your valve clearances, and are your throttle bodies balanced?
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Thanks guys for the replies.
As for the FPR going bad - I noticed last time I did an oil change that the oil level slowly climbed from halfway up the sight glass to past full after a few weeks of riding. In addition, the oil became dark fairly quickly. Somewhere I read about the pressure regulator failing and allowing raw fuel to be sucked into the #4 intake vacuum port. I checked mine and sure enough, the vacuum hose was full of a small amount of liquid gas and has become soft and "sticky" as they do when exposed to fuel. It wasn't enough to noticeably affect fuel economy and the engine runs normally, but it's clear that at least some gas is making its way into that hose.
Tim you are probably right about checking the valves and TB balance, I am certain that at least the TBs are probably long overdue for attention. I suppose it's possible that getting things tuned up will make the rattle go away, just thought I'd check in for people's experience with that while I had the bike pretty well torn apart. On the other hand, the bike runs like a dream and has a rock steady idle already. It sounds like finding a 12 rivet output shaft is a bit of a crap shoot, so maybe I'll just do the big tuneup first and see if it helps.
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I noticed last time I did an oil change that the oil level slowly climbed from halfway up the sight glass to past full after a few weeks of riding.
My oil level also rises about a half inch after the first few hundred miles following an oil change, but it stops rising at that point. I attributed it to the oil's reaction to heat but I'm no scientist.
I had a similar rattle sound that was more prominent at idle and with a cold engine. Fine tuning the engine completely eliminated it. My exhaust valves were very tight.
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I had a similar rattle sound that was more prominent at idle and with a cold engine. Fine tuning the engine completely eliminated it. My exhaust valves were very tight.
Music to my ears, Tim! I believe I'll let the output shaft alone.
Love your profile pic, the back of that motobrick looks like Darth Vader's gatling gun.
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Good progress tonight stripping things down...this bike is 100% unmolested. I love that.
Sent off the injectors to Mr. Injector to be cleaned and checked, just because she deserves it.
While the valve cover is off I thought I might remove and re-seal the cam chain cover, it seems to have a weep along the bottom, and I can check on the cam chain guides. Can this be done without disturbing the timing? It sounds like a dealer-only proposition to reset the timing. I sure wish they'd put in a timing window somewhere for us home garage hacks.
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Can this be done without disturbing the timing? It sounds like a dealer-only proposition to reset the timing. I sure wish they'd put in a timing window somewhere for us home garage hacks.
From the Haynes manual:
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Just what I needed, thanks Inge.
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Got the final drive, swingarm and transmission off without any fuss tonight. The K vs. an airhead reminds me of my Vanagon vs. an old Bus. The air cooled machines are simpler but I am certain that the water pumpers are easier to work on!
EXCEPT...where the heck is the circlip that's holding the drive shaft on? Is it at the front of the shaft or in the middle of the universal joint?
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It's on the transmission output shaft I believe, you don't see it but it'S there.
Grab the drive shaft gently with vise grips and a rag and tap it with a hammer - it will pop out easily. Reassembly is the opposite, give it a firm tap and it will click back in.
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By the time you buy the parts to refit the injectors, you may as well send them out for cleaning. For a few bucks you finish the job and may not need to take them out later for cleaning
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Thanks again guys.
As for the injectors, I agree, they are enroute for cleaning, I was going to just re-seal them but they were looking grungy, so I figured it was cheap insurance against another tear-down!
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My brick is doing its best impression of a Star Wars snow speeder.
I think it's come apart about as far as it's going to, and now it's starting to go back together. Today I removed the calipers and fettled them, and pulled the triple clamps out for re-greasing. There was a lot of preload on the bearings and the steering was stiff, although the old grease was in good shape, even though it had pretty clearly never been apart before. Also pulled all the wiring plugs apart and shot the contacts with Deoxit.
The fork sliders were looking faded so I sent them off for a fresh coat of paint at my friend's paint shop. Those forks are easy to get apart, just remove the bolt at the fork bottom and the sliders come right off, no need to fool around with the caps and spring stack as far as I could tell. I think you could replace fork seals just by removing the wheel and brakes.
I have my injectors back from Mr. Injector and they look great. I was going to put the fuel rail in tonight but I have a question. The injectors came back with new o-rings but I had a pack of o-rings from EME that I wanted to install. There are two different colors, brown and blue, four of each. Does anyone know which goes where? I'm guessing one tolerates heat better than the other...? Link below:
http://www.euromotoelectrics.com/Fuel-Injector-O-ring-13-64-1-437-474-p/boinj-oring474x8.htm (http://www.euromotoelectrics.com/Fuel-Injector-O-ring-13-64-1-437-474-p/boinj-oring474x8.htm)
(http://farm9.staticflickr.com/8049/8107726543_fa884aea9a_b.jpg) (http://www.flickr.com/photos/38874353@N05/8107726543/)
photo (http://www.flickr.com/photos/38874353@N05/8107726543/#) by jetpoweredmonkey (http://www.flickr.com/people/38874353@N05/), on Flickr
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Nice bike, clean shop, can I trade you shops?
I am working on another spline lube, darn there are alot of pieces to take off.
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Found the answer - the blue o-rings go on the fuel rail side, brown to the cylinder head.
Next question - valve shims - where do you guys get 'em?
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Next question - valve shims - where do you guys get 'em?
My local BMW dealer service manager let me trade in my old three for new three. :2thumbup:
I think there are some Japanese bike shims that'll fit too if that's easier.
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Thanks Tim, I'll try there first. Someone is selling individual shims on ebay too.
Got a little more work done today. The rear main seal was leaking, a new one is on the way. In hindsight I think the leak was due to my rising oil level issue, when I parked the bike, the oil level was at the top (probably above) the sight glass. When I pulled the clutch assembly off the output shaft, oil poured out of there. I don't think that seal is supposed to hold oil back at rest, it will migrate through eventually. Still, no way to know for sure, so a new one will go in once it arrives. I spent some time cleaning the grunge off the inside of the bellhousing, I'm running out of stuff to do while waiting for parts, why not! I also made some guide pins to reinstall the transmission, dead easy, hacked the heads off a couple of bolts and slotted them for a screwdriver.
To install the new seal to the correct depth (not flush like the original), I'm going to try cutting a circle spacer out of an old yogurt tub lid. I should be able to use the old seal as a template and just tape it up to the back of the crankcases to act as a stop. Looks like it is about the right thickness.
Another task for today was installing a battery cable kit from Euro Motoelectrics. When I bought the bike, the battery was three years old and I had a big trip coming up, so I replaced it because it seemed to crank pretty slow. The new battery was not much better. Looking at the wiring, especially the pitiful ground wire, they looked like they would be hard pressed to run a turn signal, let alone a starter. The EME kit looks like it would have no trouble powering a welder! The new cables were a little fiddly to get through the rubber grommet into the electronics box, but otherwise easy to install. You just run them parallel to the existing cables, and throw away the old grounding cable. Can't wait to see how she cranks now!
Man, this bike is in good shape.
(http://farm9.staticflickr.com/8052/8111676422_cf41939ccf_b.jpg) (http://www.flickr.com/photos/38874353@N05/8111676422/)
Got my valve adjusting tools ($28) and clutch pilot tool ($18.50) in the mail from Kenneth Lively a few weeks ago. They are really well made and a real bargain for the price. If you need a set, Ken's email is polepenhollow@yahoo.com.
(http://farm9.staticflickr.com/8048/8111676500_c3a2f072de_b.jpg) (http://www.flickr.com/photos/38874353@N05/8111676500/)
(http://farm9.staticflickr.com/8047/8111668945_44be2d9ef3_b.jpg) (http://www.flickr.com/photos/38874353@N05/8111668945/)
Got my injectors and rail reinstalled too. The blue o-rings go toward the fuel rail, brown toward the cylinder head. Mr. Injector cleaned these for me and they came back looking like new.
(http://farm9.staticflickr.com/8049/8111676362_f3c02008b1_b.jpg) (http://www.flickr.com/photos/38874353@N05/8111676362/)
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I think you could replace fork seals just by removing the wheel and brakes.
That's the way I do it. :2thumbup:
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Got the fork lowers back from the paint shop today. Looking good! Also got a big expensive box of mostly tiny little parts in the mail!
(http://farm9.staticflickr.com/8327/8140898820_2b85159e7b_b.jpg) (http://www.flickr.com/photos/38874353@N05/8140898820/)
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Stayed up way too late and got a lot done tonight. Installed the new pressure regulator, rebuilt the forks and got the front end together with new seals and gaiters. I'm glad I hassled with getting the forks painted, they look like a million bucks!
Hit a snag. I'm getting ready to put the clutch back in, and I see in the Haynes that there is a thrust washer that's supposed to go between the clutch housing and the output shaft. I can't remember removing this part for the life of me, I have things well organized and it's nowhere to be found. Is it possible that some bikes don't have it? The fiche says it is either 1mm or 1.25mm thick. That is a big gnarly washer, I can't imagine misplacing it. It doesn't seem to be stuck to the back of the clutch housing or the end of the shaft.
(http://farm9.staticflickr.com/8054/8144176300_c0eae3001a_b.jpg) (http://www.flickr.com/photos/38874353@N05/8144176300/)
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Today I discovered my missing thrust washer. When I pulled out the old output shaft seal, chunks of plastic fell out from behind it. The remains of the washer. It looks like it somehow self destructed and has been kicking around behind the seal for some time. Some parts of it must have stayed in between the clutch housing and output shaft, because the nut was still tight. I was surprised to see it was made of plastic, but this has to be it, you can see it in the photo on the flanged part of the clutch housing where it lives. It's exactly 1.0mm thick as the fiche indicated it should be. So, I feel better because it turns out I didn't lose it after all!
Unfortunately it is not complete, there are some small pieces missing, I suppose they must be down in the sump, or maybe they were pulverized by the output shaft bearing, who knows. The bits that did come out are kind of rounded on their broken edges as if they've been washing around in there for a while.
I was surprised to see this washer is plastic, I will be curious to see if the new one is too, I hope not, because BMW wants $25 for it! For anyone going in to do a spline lube, I sure think it would be worthwhile to pull the clutch housing off, replace the o-ring under the outer nut/washer and look to see if your thrust washer is still intact.
(http://farm8.staticflickr.com/7252/8152052705_b33f3b035c_b.jpg) (http://www.flickr.com/photos/38874353@N05/8152052705/)
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The thrust washer is part 9 here: http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51752&catID=21&catname=Clutch&bindName=Clutch&bindCat=21_0251 (http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51752&catID=21&catname=Clutch&bindName=Clutch&bindCat=21_0251)
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The thrust washer is part 9 here:
Trust washer is part # 10.
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I always thought that was the name for the washer in front of the clutch nut. Learn something new every day...
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Already got a new washer on the way thinking I'd lost it!
Here's my poor man's output shaft seal installation jig. It's a yogurt tub lid, cut out with a circle cutter. The plastic is .46mm thick, as opposed to the .5mm spec on the factory tool. Close enough for me. Now all I need is to drill a hole in a block of wood and mash the seal in while this spacer is taped up to the back of the crankcase.
The new and old seals are dimensionally exactly the same but the design of the seal is different. Does anyone know why BMW changed the install depth spec? It seems like the seal is going to be awfully close to rubbing on the back side of the clutch housing.
(http://farm9.staticflickr.com/8343/8153032366_7a8b39e174_b.jpg) (http://www.flickr.com/photos/38874353@N05/8153032366/)
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I think there is a change in diameter (IIRC) that the seal almost runs off on, therefore having a reduced pressure on the seal. If you are worried about the rear of the flywheel, why don't you fit the thicker spacer? 1.25 mm instead off the 1mm one?
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I thought about that, I wonder if the 1.25mm washer is made for the revised seal depth...but then again, the book says to replace the washer with whatever thickness was in there to begin with. I haven't heard anyone else chime in about their seals getting wiped out on the back of the clutch housing, so maybe I shouldn't worry about it!
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Lots of progress this week! I got my new "stop disk" (thrust washer) from A&S and had a fun time putting the gearbox and rear end back on this weekend, cleaning every part to perfection, lubing and obsessing the whole way. New clutch cable and cleaned out bearings, ohhh maaaan that is a smooth pull! Shop therapy. But holy $H!T, the thrust washer is $23.11, made of plastic! I swear someone messed up when they entered it in the BMW fiche, and it's supposed to be $2.31. Oh well...
Unexpected setback - could not get the dang oil filter out. The wrench just skipped over it. Took off the sump plate, cleaned out all the old grunge, manhandled the stupid filter out, resealed. Grrrr.
Tonight I managed to get the tank back on, all of the plugs reconnected, for once everything worked right first try, and although the rear end is still flying with no wheel attached, I had to have a go at starting up. A few cranks to prime the fuel lines and PURRRR...no more output shaft rattle! AWESOME!! She's never sounded so good, I'm sure of it. AND, I haven't even synched the throttle bodies or checked the valves yet. That's for tomorrow night.
Unexpected bonus #1 - the EME starter cable kit I put on is SWEET. The starter cranks 100% faster now! Totally worth it.
Unexpected bonus #2 - THAT NEW ENGINE SMELL. :2thumbup:
I'm hoping someone can do a spot check on their bike for me. I got the exhaust back on and *barely* clearing the sidestand, but it's still not quite right. I was having trouble before with the stand banging/rattling on the muffler. I see on the fiche that there are four washers, one for each bolt that holds the centerstand bracket to the bottom of the gearbox. I have no washers at all. It looks like they are supposed to be between the gearbox and the bracket rather than under the bolt heads. That would probably give me my missing clearance. Could someone verify that these are on your bike?
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Too late for you but if your oil filter wrench is skipping over the flutes on the oil filter what I've found works to get a good purchase on the oil filer is to put some steel wool in the oil filter wrench and then pound it onto the oil filter.
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Looking good, jpm. And thanks for the info on the spendy plastic washer. That is one piece I accidentally left off the shopping list for my planned clutch inspection, seal and o-ring replacement. It looks to be the same part numbers and thickness options for the 1100 models too. I suppose I will just wait to measure the existing one since the price isn't conducive to just ordering both to be safe.
Enjoy the wrenching.
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Does anyone know why BMW changed the install depth spec?
I understood it was to have the new seal's wiper contact a new area on the shaft, as there was the possibility that the area swept by the old seal may be worn (allowing oil leakage).
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Good input guys, thanks.
Got her all back together and rode to work yesterday. Man, what a difference! I think that broken thrust washer was really putting some sand in the vaseline. The bike had a pretty unpleasant band of vibes at 60-65. Luckily it was smooth at my normal 80mph cruising speed. Now it's smooth everywhere! The mirrors are crystal clear at all speeds and really no vibes at all in the bars. I think I have a good one.
I replaced the o-rings on the throttle body air bypass screws and put the screws back where they were. I wish I'd checked the balance before I took the bike apart, just to see if it made much difference. They needed very little adjustment to be in sync.
I had new tires mounted while I waited and ogled new bikes at A&S (actually, I'm always more excited to see what's in the used section!). Stared at an R1100S for a little while. I bet it's fun, but I like my K. Tires are Michelin Pilot Activ in the OEM sizes, it's hard to compare them to the old, cracked Dunlops they replaced...1000% better, of course.
Rebuilt forks, slick clutch, way nicer gearchange thanks to those clean splines...she feels like new again. I swear I can't feel a single bump through the forks, it's amazing what an oil change can do. Can't wait to see if I picked up any MPG benefit with the cleaned injectors.
Before the tear-down, the handlebar was really mushy in its mounts. I took things apart and compared them to the fiche, and found that there was supposed to be a washer on top of the upper rubber mount (under the handlebar clamp), mine were missing. Maybe someone took them out to try to tame some vibes, maybe the factory forgot. I bought new ones and the bars are so much more solid, no flex, much nicer steering response and the vibration is less than before, if anything.
I flushed the brake fluid but could not get more than a few drops out of the rear caliper. I played around with it for a while only to discover that the dealer-installed reservoir update (mounted behind the side cover) was done wrong. The reservoir has two outlets, one is blocked, the other isn't. The feed hose to the master cylinder was connected to the blocked outlet! Whoops. Fixed that and had the brake bled in two minutes. If you want it done right...
(http://farm9.staticflickr.com/8478/8188864675_5334d832f9_b.jpg) (http://www.flickr.com/photos/38874353@N05/8188864675/)