K75 doesn't seem as smooth as it should be

[TimTyler]

My clutch parts each had a few small holes drilled in them apparently for no other reason than to remove extra weight. The holes did not always correspond with the installation markings, so I suspect the parts are balanced a second time and then marked before leaving the factory. Whatever imbalance remains in the shipped parts must be really minimal.

[Elipten]

I agree Tim. 

[F14CRAZY]

I have also noticed holes drilled into the clutch cover and the "housing cover," obviously for balancing reasons.

Didn't pick up a clutch cover O ring when I got the disc at the dealer. Being that you have to destroy it to get the clutch cover off, I had to go to an auto parts store and find one close enough last night. Evidently, "close enough" isn't and I found a decent puddle from the bellhousing weep hole :musicboohoo: ...so I'll have to take the trans and clutch off again. It's only the 4th time...

Regardless, today I took the bike out for an hour or so, mostly around 5500 rpm (or 80 mph) and it's vibrating as bad as ever. I don't think I made it 30 minutes without having to take a break due to numbness in my hands. I'm about at the end of the line trying to figure out this vibration.

I can either get a new "pressure plate" and "clutch housing" from the dealer, which will have new, easy to see balance marks (my clutch housing's mark is still good and can't be mistaken for any other marks that anyone else has added. And it's over $400), or I can have a machine shop balance it. Not sure of the cost on such a service.

If that doesn't work out I'm going to cut my losses. I bought this bike to take day trips and to commute from Grand Rapids to East Lansing for college but I can't be going numb on a bike from a manufacturer that's renown for their touring motorcycles.

[TimTyler]

Regardless, today I took the bike out for an hour or so, mostly around 5500 rpm (or 80 mph) and it's vibrating as bad as ever.

I thought you said you got rid of the vibration on June 1?

I went for a 45 minute ride, keeping it at 75-80 mph (around 5400 rpm) and it seems that I fixed the problem

What about 5400rpm in 3rd gear? I think that any clutch imbalance should present itself at the same RPM regardless of MPH. (?)

Like Johnny suggested, I'd be looking at suspension / wheels / tires.

[Elipten]

I just put a new clutch all parts in to my K75 as I did not to want to screw around.  Money I have a fair bit, time is extremely precious.  I tell you there are various marks on my new components but nothing that stood out.  Obvious drill holes that were to balance.  I talked to senior techs at Bobs and local dealership and they said BS on balance as parts are mix and match, which only makes sense given modern world of manufacturing. 

Anyway mine runs as smooth as can be and no special offset of parts applied.

I would look elsewhere as others stated.  How is that joint on the driveshaft as a start?

My old car vibrated so bad and it was the u joint, wheels?

There are lots of sources on a vehicle.

[F14CRAZY]

June 1st: it was better, but I don't think it was "right."

I'd say the vibration feels the same various speeds but the same RPM, it's just that I haven't been able to cruise for like half an hour in 3rd gear @ 5500 rpm to see if I go numb or not. But in other gears, in neutral and on the stand...I'd say it vibrates the same at those rpm.

If I'm at 80 mph and I pull the clutch and let the engine idle the vibration goes away. If I pull in the clutch and hold it at 5500 rpm (or there abouts) it still vibrates. I truly don't think it's in the wheels or tires. Driveshaft U joints are tight.

[Elipten]

Is it vibrating when on center stand and revved?  Or only when driven on the road.  Try in neutral and in gear on center stand.  Use care when in gear as no Darwin Award is given for an accident.

[F14CRAZY]

Yup it vibrates when in neutral and on the center stand at w/e RPM (like 5500)

[wmax351]

How else could BMW sell you the parts separately?

Each part is marked at its heaviest point, thats why they should be mounted 120^o apart.

Exactly as Inge says. They are all within tolerance, and the heaviest parts offset, the net variation in balance is far smaller than the tolerance for individual parts.


Motrocycle Tires have the same deal: there's a spot for the lightest part, which you put at the Valve.

[Elipten]

Guess I got lucky, with my clutch so sounds like clutch or something else in the engine.  At least you are isolating the problem.

Take the clutch out.  Get the bolts, nuts and o ring.  Maybe local shop will be kind enough to show you marks.  I sure could not see them on my new ones and I spent plenty of time looking.  Hard to find knowledgable Kbike tech these days though.

I would pull alternator and check it as that is a spinning mass also while you have tranny out.

[F14CRAZY]

I ordered the "clutch housing," pressure plate, and the O ring from the dealer this morning...will be in Friday and I plan on tearing the bike down again on Sunday

[TimTyler]

Since when are dealers open on Monday? :)

[F14CRAZY]

Heh the BMW dealer here is open on Monday's in-season. The one none-BMW dealer in town isn't but the other big dealer is...which sold and installed my new rear Dunlop...snooze ya lose

[F14CRAZY]

a'ight...

Picked up the new pressure plate, clutch cover, and O ring from the dealer today:



The balance marks are on the outside and oriented toward the camera though the pressure plate caught a reflection. Considering they're from BMW, they're expensive, and that it's important, the balance marks are pretty half-ass. The right thing for me to do would be to get a stamp kit and make some better, more permanent marks.

Just in case mine is screwed up for w/e reason, I bought a clutch housing from an '88 K75 with 36k miles on ebay for $57.99. Made sure it had a good balance mark. These are over $400 new and that's beyond the scope of this project. On the dinner table I oriented the clutch housing's mark at 12 o'clock. The mark is a bit dirty so I pointed at it





Then the pressure plate's mark is roughly at 4 o'clock



Or at least the marks are as close to 12, 4, and 8 as they can be. With there being only 3 positions that they can be in there is one "ok I think this is where it should be" position and two "nope" positions.

I'll be tearing the bike down this Sunday, hopefully for the last time in a long time and will report back with my findings

The housing is around 8 o'clock

[pdg]

So, is it possible to fit the crank out of phase with the balance/output shaft? 

[F14CRAZY]

Put the new clutch parts in today...same crap. Don't know what to do now.

He said to line up the factory marks...which is NOT what the clymer manual suggests.

From the factory manual...print out...show to the service manager...don't forget to slam the door.

Why does it say to arrange the clutch disc with the whole 120 degree thing? The clutch housing (the flywheel type thing) has a mark and should be included in the 120 degree thing, from what I understand. The clutch disc's position in relation to the rest of the parts changes whenever the clutch is disengaged  :dunno

I have the day off of work tomorrow so I'm going to do some more tinkering. I removed the alternator and will take an extended drive without it to be sure it isn't the alternator (but as I've said the monkey nuts and all seem to fit just fine and the bearings seem fine when its spun manually).

About the only thing I haven't done yet is a check of the valve clearances. I'll throw some more money to the dealer and get a valve cover kit and make sure none of them are tight (Chris Harris insists that loose is okay)

[Motorhobo]

I hope your dealer is trustworthy...valve adjustment is labor intensive and I have heard so many stories of dealers billing for work not done....make sure you ask them to keep all the old parts and shims including valve cover gaskets and valve cover bolt grommets...have them note the clearances before and after and what shims were used to make the adjustment. Sorry -- I'm just not a very trusting person and I have reused the gaskets and shims with success so you might as well ask to have them, better in your parts bin than theirs.

Wrt smoothness -- I got my 94 k75 on the road today -- first time I've had both k75s running side by side since I got the 94...it's amazing how much smoother with less vibration at the bars the 94 is with 70k than the 95 with 97k...I am suspecting throttle body balancing at this point...pretty sure the clutch went in correctly...valve adjustment just done 3k miles ago...throttle bodies rebuilt not too long ago...new plugs and wires...will send video comparison soon...in the meantime, can someone explain how throttle body balancing can affect the smoothness of the engine at mid-rpms of 5500 or so?

Btw the only other difference is that the 94 has an exhaust gasket that I fashioned from a beer can and some high temp RTV. The 95 has no gasket. The beer can version seems to be working great -- no smoking, noise or backfiring in first 100 miles. How would the absence of an exhaust gasket affect  'smoothness' of the engine,if at all. Btw I know smoothness isn't a moto technical term but it's the title of the thread so might as well stick with that.

[F14CRAZY]

I hope your dealer is trustworthy...valve adjustment is labor intensive and I have heard so many stories of dealers billing for work not done....make sure you ask them to keep all the old parts and shims including valve cover gaskets and valve cover bolt grommets...have them note the clearances before and after and what shims were used to make the adjustment. Sorry -- I'm just not a very trusting person and I have reused the gaskets and shims with success so you might as well ask to have them, better in your parts bin than theirs.

Wrt smoothness -- I got my 94 k75 on the road today -- first time I've had both k75s running side by side since I got the 94...it's amazing how much smoother with less vibration at the bars the 94 is with 70k than the 95 with 97k...I am suspecting throttle body balancing at this point...pretty sure the clutch went in correctly...valve adjustment just done 3k miles ago...throttle bodies rebuilt not too long ago...new plugs and wires...will send video comparison soon...in the meantime, can someone explain how throttle body balancing can affect the smoothness of the engine at mid-rpms of 5500 or so?

Btw the only other difference is that the 94 has an exhaust gasket that I fashioned from a beer can and some high temp RTV. The 95 has no gasket. The beer can version seems to be working great -- no smoking, noise or backfiring in first 100 miles. How would the absence of an exhaust gasket affect  'smoothness' of the engine,if at all. Btw I know smoothness isn't a moto technical term but it's the title of the thread so might as well stick with that.

Reminds me that I have to get some exhaust gaskets too. I've been able to put the header/muffler back on and not have it leak until this time. I can hear it leaking a little under load.

I plan on checking the clearances myself, then if necessary, taking it to the dealer and having them adjust the valves. From my reading the tools are like $100 and dealers seem to charge an hour to do it anyway. And it isn't very common for them to need adjustment.

I meant to mention too that I also rode the bike in 55 mph zones and was able to run it for a while in 3rd gear @ 5-5500 rpm. Same vibration with decreased ground speed.

Bike is nice and smooth until you get to around 4500 rpm regardless of gear. 5500 gets me numb after a while. Much above that and it seems like it'll shake apart before too long.

[Motorhobo]

Ken Lively sells the valve tool for 24 bucks. It's an exact replica of the BMW tool. Watch this video to see how to use them.



Get digital caliper on Amazon or HF for $20. Get feeler gauges at Sears for cheap. Take gauges you need out of gauge set and put a paper clip and heat shrink on the end to make them easier to manage. Get used dental pick from a dentist to dislodge the shims.  Use 19mm wrench to turn crankshaft. Post  questions here. Save $$ and hassle since once you have the valve cover off you're going to have to either trailer the bike to the dealer or have them remove the valve cover and seal again. Those gaskets and the rubber grommets really aren't designed to be taken off and put on repeatedly. Plus -- you know it's done right -- priceless.

If you've got that kind of shaking at 5500+ something's not right ... Maybe get thicker gloves and ride till runs no more or get someone to have a good look at the engine. Has anyone ever put a frame gauge on it?

[F14CRAZY]

Had the valve adjustment done at BMWMC of Grand Rapids today. I haven't taken it on an extended ride yet but it's got to be better...

than the owner's R1100RT-P they gave me as a loaner...it was interesting to try a boxer and compare it to my K, but I'd say that at all RPM, the R vibrated and shook (and surged!) at least as much as my K75 does (or did). I didn't like take it on an extended ride but I don't know how R guys can stand those things, and who keeps buying them? I know it's all about heritage but I wasn't about to trade my bike for it.

[F14CRAZY]

I ran it to Lansing and back on Thursday and didn't go numb...I'd say the bike is performing normally (especially after that oilhead experience...why do people keep buying those boxers...)

[Motorhobo]

I ran it to Lansing and back on Thursday and didn't go numb...I'd say the bike is performing normally (especially after that oilhead experience...why do people keep buying those boxers...)

 Because you can grill hamburgers on them while you ride.

[MEZ]

... on page 8.87 of the BMW technical manual

I think "8.87" is the manual's print date.

Try page 11.97.0 of the 8.87 tech manual.

This and tips like this I like.... :2thumbup:

just for the record what is the consequence of failure to adhere to this procedure..???

[TimTyler]

The bike will vibrate .000001% more than what the designers expected.

[wmax351]

Ken Lively sells the valve tool for 24 bucks. It's an exact replica of the BMW tool. Watch this video to see how to use them.



Get digital caliper on Amazon or HF for $20. Get feeler gauges at Sears for cheap. Take gauges you need out of gauge set and put a paper clip and heat shrink on the end to make them easier to manage. Get used dental pick from a dentist to dislodge the shims.  Use 19mm wrench to turn crankshaft. Post  questions here. Save $$ and hassle since once you have the valve cover off you're going to have to either trailer the bike to the dealer or have them remove the valve cover and seal again. Those gaskets and the rubber grommets really aren't designed to be taken off and put on repeatedly. Plus -- you know it's done right -- priceless.

If you've got that kind of shaking at 5500+ something's not right ... Maybe get thicker gloves and ride till runs no more or get someone to have a good look at the engine. Has anyone ever put a frame gauge on it?

You don't need the wrench to turn the crankshaft. Just bump the starter button, and it will move to the next position.