I have an 84 K100RT with 127000km on it. When it first starts up its quite noisy, clattery almost. My first thoughts were the output shaft and I got a 12 rivet one off RickG to fix it. Before I go to the trouble of pulling it apart Im after some comments just in case its something else

OK, the noise is at idle and a bit above when it starts up from cold, but increasing the revs above say 2000+ rpm and it goes away. If I leave it on a fast idle to warm up, the noise can stop suddenly, but comes back if I reduce the idle speed. When its warm it runs smooth and and quiet.

My thoughts are that if it were loose rivets in the output shaft then it should rattle hot or cold.

I did balance the throttle bodies. This made little difference at cold idle, but it does run smoother at higher revs.

It sounds like uneven throttle bodies/fuel injection/ignition or something when cold to me, but Im open to suggestions.

I would guess a worn anti-backlash spring at the idler gear would have about the same symptoms.

Hi Rockman,

I am the purchaser of the other Rick G 12 rivet output shaft! Funnily enough, my '88100RT symptoms sound identical to yours.

I have been devouring every last post on output shaft noise and take this opportunity to thank all the many contributors.

My summary of the facts gleaned to date :-

Three sources of output shaft related noise:-

1) Worn anti back lash spring / retaining peg and or hole (as just mentioned)

2) Incorrect shimming/wear of the anti back lash gear end float control (new system) or shagged dished spacer / spring (old system)

3) Incorrect end float control of the output shaft / clutch basket assembly within the output shaft drum (so to speak). This would be due to the plastic washer / spacer (Item 10) having disintegrated or worn.

Above assumes that the end float of the output shaft drum as controlled by:-  
a) correct location of the big rear bearing outer race in the engine casing,
b) correct shimming of the inner race on the 'output shaft drum journal' by spacer (new system) or dished/castellated spring (old system).
So I guess this could be written as 4) Fourth possibility.

All clear as mud - specially for someone like me who has never seen the inside of a K engine other than as viewed past the crankshaft after removal of the right engine case!

Can't wait to get my eyes on (hands on) Ricks other 12 rivet shaft. Can someone post pictures of the individual components so I can try and move my "hypothesis" along the road towards being a "theory".

My hypotheses says that if you fit an item 10 that is too thick, all you do is inhibit the operation of the cush drive for a while until the arrangement loosens up (item 10 wears or falls apart). I suspect that if one starts with an item 10 that is too far out of spec, then it gets destroyed as one tightens the main clutch basket nut.

This hypothesis also explains (to me at least), why K75 machines do not have item 10. The output shaft and clutch basket do not require separate end-float adjustment as they are effectively integral with the output shaft gear and the shimming of the rear bearing inner race gives axial positioning of the whole assembly.

Go for it guys:- anybody sufficiently practiced in mental gymnastics out there, care to shoot me down before I take the time to try and elucidate with a labelled sketch.

So basically the output shaft has to come out, regardless of which of the possibilities it might be.

If I am right in the four different possibilities then there is potential for at least four sets of sounds emanating from output shaft problems. Trouble is there may be three other potential sources of the sound apart from output shaft problems, each with their own set of options!
I'm just sitting in an office in S E Queensland on the Coal Seam Gas Fields (dreaming of a K ride) playing with ideas Mate. If it's help you want, you've got to wait for the Gurus or give them a recording. Sorry

When I put in my 12 rivet shaft I also got a brand new clutch thrust washer of a bloke on ebay. He doesn't have them anymore though...

Figured it was worth doing as it was also a potential point of horrible noises and a bugger to get to again. Cost about $30 i think...

Hello Floyd,

If you are referring to the washer that goes between the clutch basket and the big nut, I cannot think of why that might be where it is (other than to provide a replaceable surface for the nut to bear against). My inclination would be to replace it only if it is obviously shagged as I cannot see it being a source of noise.

However.... As you say, it would be a bummer to be proved wrong!

I read all your posts with great interest. You write well plus I was impressed with the way you tore into it.... and the fact that it has borne good results. Well done Mate.

I want to put semi off road tyres (like you did on yours) on a bunch of K bikes for a planned trip through the Kimberlies with some mates middle of next year. I'll be hanging out for feedback in that respect as well as any general post rebuild shack-down issues.

Cheers mate,

You could be right in regards to the thrust washer. I just put my faith in those with more K-nowledge then my self, and figured $30 was just another number in my spreadsheet to give me piece of mind  When I first started my bike before doing any of the work to it, it had a HORRIBLE rattling clunking noise. No idea where it was coming from, but I more or less replaced/serviced everything it could have been (timing chain etc, sprag clutch, outputshaft etc, thrust washer, cush rubbers, alternator rubbers...miss anything?) - and there are no horrible noises at all now. 

As for the tyres, Im loving them. Mind you I am still 'learning' them, but so far so good. On hard downshiffitng the back end can skitter and slide a tad from compression, but no biggy. I havnt done any riding in serious rain (on tarmac) yet though. But in mud, dirt and gravel they are sensational. I was easily doing 80-100kms on muddy dirt roads slliding everywhere but just ploughing on through. good fun. In the dry on tarmac I feel pretty darn confident in them, for what they are.

Great stuff Mate - you are making me very excited both for planned rebuilds and off road adventures.

Please don't bin anything in the way of "evidence" from your teardown if you still have it available. I would appreciate the opportunity to inspect these at first opportunity along with bits that will come out of some of my K bikes in due course.

I bought one K75 with the Alternator drive rubber failure rattle so I know what that sounds like (in one particular case). It went quiet before I had ridden it 50km - discovered that all the lugs in the alternator coupling half had broken off due to the shock loading of metal to metal contact.

Posts on here indicate that timing chain noise will usually be associated with marks indicating contact between the stetched chain and timing cover internal surface.

Rockman
Charles99 is the one to talk to about possible wrattle sources. He appears to have done some serious interogation of his beloved "G"

So I've decided the output shaft needs to be changed as that seem the most likely source of all the noise. 

Can anyone who has done this give me a list of parts I should change while I've got it in bits.

I'll put an order in to the 'Bins' then and hopefully get it done in one session, not my usual pull it apart-wait for parts-reasemble a bit-wait for parts etc etc effort.

Hey Rockman.

Why not start by checking out that 12 rivet shaft you got from Rick G. How do the cushioning rubbers look?

When I asked the same question of Rick he said "change the output shaft seal to minimise risk of having to go back in" also "be prepared to do the clutch if it's anywhere up near 150,000km"

There is also the issue of which output shaft rear bearing is required in your machine. If yours is the old type it will be different from the one on the 12 rivet shaft and I believe you will need access to a press to change them over.

My '88K100RT has now clanked its way to Adelaide and after reading Charlie 99 posts etc I have decided it will make it to Perth. Hence I won't be doing what you are about to embark on, till early next year.

Good luck Mate - keep us posted

check out the bins whilst you in there ,
there are a few shims that may need replacing if you are exchanging the bearing on the back of the output shaft

the really early ones had a belville type washer that used to slop about after a time ...but if your using the later type shaft possibly just the different shim  might be needed ,,,from memory .5  , .75 , and 1 mm were available between the backlash gear and the bearing itself ???

the back lash gear tends to get some movement in a wobbly fashion if this is not right , which could add wear to the teeth of the crank gear to output gear basket assembly ....saw the teeth on those had lost a lot of profile on the crank and basket gears

don't forget to get the 5 ? rubber blocks that fit in the damper assembly ....just for piece of mind that it is a snug fit  ( mine are still loose I recon I should have had them on hand ...but didn't think about it till disassembled ...bugga )
doesn't cost much for the front most needle roller either .......but one would assume the 12 rivet model should still be ok (if not contaminated )

Ok, so Ive got: Damper rubbers x5, spacer ring (measure), seal, bearings (front & back), maybe clutch plate & o ring, sump gasket. Anything else?

The spacer rings are about 4.50 quid each so I dont want to buy a complete set of sizes if I can help it. Are there a couple of common thicknesses for these I could take a punt on, or is it just pot luck?

best I could figure .75 mm


sump gasket ??  no such thing ,,,get some driebond 1209 from the bins as well 10 quid lastS a long waY   IF YOU DO IT RIGHT

So you took of the right side engine cover and had a good look at the rivets and checked if they were moving or not, right?

wise idea rene

ReneZ wrote:So you took of the right side engine cover and had a good look at the rivets and checked if they were moving or not, right?

No I didnt, but by the noise its either the rivets or the anti backlash. Same solution both ways as I see it. I actually think its the anti backlash because it goes away when its warm and running smoother. To my mind loose rivets would be loose both cold and hot.

And yes Charlie. You are right about hte sump gasket. I have my 100gs in bits at the moment and the sump on it was in my mind when I typed that.

It's bad when you do that. I once very wisely told someone here about removing the pinion shaft and setting up new bearings to be told that is not how a BMW final drive works and then I realized that I was carefully explaining how a Z1300 Kawasaki works.