R100GSPD '93 Noisy Valves..

[(RIP) Bin Ridin]

Hi:

Nice dry day here, so...(and big thanks to Gunner for the fab lift!)

Spent another 1 hour checking for the cause of noisy valves - clearances are set to a neat 0.10mm / 0.20mm at TDC. Rocker shaft bearings good, endfloat reduced to minimum using plastic shims, bike runs well, ticks over like a clock, but valve clanky noise is fierce..

What I noticed is that when the inlet valve is open, the exhaust clearance is much bigger than at TDC. Both sides the same. I did not measure it but it looks almost. Only 50K kms so bit early for cam or follower issues...

Anyone know what might cause this?

Bin

(aka. Puzzled, Blackrock)

 

[cookie]

some airheads seem to run like sewing machines, but i've had two where it is impossible to quieten the valve noise, and i've adjusted and replaced everything.

 

[electric_monk]

Mine is just like Cookies, rhs exhaust valve just continues to rattle after resetting, even after Dr Farkoff adjusted and re shimmed the thing. I'm trying to live with it as best I can.

 

[B Murr]

Assuming all cylinder head bolts are tightened to spec. The noise is definately coming from the rockers/tappets and not the actual valves themselves? Would worn guides give such a noise? Noise not coming from deeper down in cam/ followers area?

 

[flatdog]

Assuming all cylinder head bolts are tightened to spec. The noise is definately coming from the rockers/tappets and not the actual valves themselves? Would worn guides give such a noise? Noise not coming from deeper down in cam/ followers area?

I suspect that if the guides were that noisy, you would have noticed the wear a long time ago with the amount of smoke caused by oil leaking through.

 

[(RIP) Bin Ridin]

I posted same question on ADVRIDER, one suggestion is that the camshaft bushing might be worn allowing the camshaft to move laterally.

It could answer the question as to why the clearance is bigger off TDC, but seems unlikely.

Anyone seen this issue?

Interesting text:

http://www.bmwboxersupplies.com/camshaft-bearing-cast-ironbronze-lining-p-290.html?language=en

Bin

 

[cookie]

that's a possibility.

when i said i replaced everything, i didn't replace that.

 

[solidstate100]

I posted same question on ADVRIDER, one suggestion is that the camshaft bushing might be worn allowing the camshaft to move laterally.

It could answer the question as to why the clearance is bigger off TDC, but seems unlikely.

Anyone seen this issue?

Interesting text:

http://www.bmwboxersupplies.com/camshaft-bearing-cast-ironbronze-lining-p-290.html?language=en

Bin

Very interesting. Where does it actually GO on the camshaft - is it in the guts of the engine meaning a full stripdown or is it accessible with the engine in the frame eg in the timing chest?

 

[(RIP) Bin Ridin]

Good question, we need a grown-up to answer for us.

The bearing is behind the camshaft sprocket which is a tight fit on the camshaft. Not sure if it can be pulled off in situ (fnarr, fnarr). If the sprocket is removed, not sure how the flange / bush would be removed with camshaft in situ.

Anybody know the answers?

 

[DrFarkoff]

Part 4

IN theory can change in location Obviously will need the cam chain off but if its tight or the bush won't release then its barrels off, Cam followers out and withdraw the camshaft

and CAREFULLY Wiggle it to fit the Oil pump drive back on again on reinsertion

 

[B Murr]

I posted same question on ADVRIDER, one suggestion is that the camshaft bushing might be worn allowing the camshaft to move laterally.

It could answer the question as to why the clearance is bigger off TDC, but seems unlikely.

Anyone seen this issue?

Interesting text:

http://www.bmwboxersupplies.com/camshaft-bearing-cast-ironbronze-lining-p-290.html?language=en

Bin

But no noise coming from camshaft./followers area? I would imagine that if the bearing is worn and cam is rocking back and forth with each revolution that there would be a noise or vibration associated with that?



How about this. When both barrels are removed, push one follower in as far as you can with strong hand pressure, then go around to the other side and do the same and see if there is some sense of the cam shifting, only guessing here but to my logic that would seem to be a way to see if the cam is rocking back and forth without having to take the whole thing to bits.

Or then again do it with the heads on and push the pushrods as far as you can and then do same on other side, only would need to remove the rockers to do that I guess. Do pushrods ever get cracked?

 

[(RIP) Bin Ridin]

Thanks for that Jay.

I think first test is similar to BmMurr's suggestion, to push the camshaft sideways and see if it moves. Slacken all 4 tappets, then podge away at the pushrod on one side, while holding the one opposite to see if it shifts at all.

So many questions, so little time....

 

[cookie]

why not just take the timing case off and waggle the camshaft? in the unlikely event that you can detect any play, you can pull the sprocket and try to remove the bush?

probably have to slacken/remove the push rods, but it's easier than stripping the top end, rebuilding, then re-torquing.



... or just leave it alone



edit: my guess is that the cam followers are fucked, so probably best going with the top end strip

 

[Rob Farmer]

You can pull the cam without taking the heads and barrels off. To be honest it's no big deal to strip the top end off and a good oppourtunity to check it all out.

looking at the pictures theres plenty of dark oil on the exhaust side. My monies on the exhaust valve guides being shot. I know it's only 50k km but it also 22 years.

new exhaust valves and guides and a recut of the exhaust seats. Check out the cam followers while it's being done and the jobs a fish.

 

[(RIP) Bin Ridin]

Thanks Rob, I am out of time for now but will do this next time home. Very interested to see what is causing the noise in otherwise sweet engine. I would like to fix that first and then do the heads later if possible.

 

[(RIP) Bin Ridin]

Hi, so I ordered 4 cam-followers plus a gasket set..

Took it to bits, found heads very good, no leaks past valves and not recessed at all. Pistons and rings very good, zero blowby.

There is wear on 2 cam followers, I will fit 4 new ones. Lot of wear on gudgeon pins, will replace these. Quite slack in the small end, probably a lot of noise from this. Surprising wear. The unworn part of the pins feel ok in the small end bush so I hope new pins will be ok without replacing the bush. One conrod was slightly stiff on the crank, some wear on the bearing compared to the other side - will replace both shells.

Hope I will get the shells in time to reassemble this week.

 

[(RIP) Bin Ridin]

One thing I did spend time on was watching the valve clearances. When the inlet valve is open on either side, the exhaust valve clearance opens to huge. Likewise vice-versa when the exhaust valve is open. There is no reason for this other than the cam profile, so it must be "normal"..

The lh conrod was not as free on the crank as it should be. When I undid the bearing, one of the locating lugs on the shell fell out - a piece the size of a match-head. The bearing had not spun or worn out, luckily.

Awaiting gudgeon pins, shells and big end bolts and then button it up.

 

[solidstate100]

One thing I did spend time on was watching the valve clearances. When the inlet valve is open on either side, the exhaust valve clearance opens to huge. Likewise vice-versa when the exhaust valve is open. There is no reason for this other than the cam profile, so it must be "normal"..

Hmmmmm.

That doesnt sound like it should be normal......but I accept that it might be - just wondered if you had a "hot" cam of some sort in there, or maybe a replacement/refurbished cam which may have been reprofiled (possibly poorly) making the off ramp a touch to small in diameter?

If the clearance opens up to huge when the opposing valve(s) are closed, what (apart from gravity/weight perhaps) keeps the follower from potentially shuttling up/down and making all sorts of noise particularly when clearance is taken up as the on ramp starts??

Just a theory.

Anyway Im due a valve adjust session shortly on mine, I will have a play and see if mine replicates yours. I did replace the rocker train for the later plastic/shimmed type on mine as it was shocking noisy, and it made maybe 20% difference, but is now back to pretty much where it was before the mod - altho this will be the first adjustment since replacement so it may have bedded in and need a tweak on the shims......And also a short while back I fitted new gudgeon pins and pistons etc etc as part of the 1000cc conversion, and in terms on noise at least it made exactly zero difference, so my small end noise theory was wrong....however, in terms of power....

 

[(RIP) Bin Ridin]

A few pictures. Surprised at the wear on the bearings and gudgeon pins.

Solidstate100,
Would be very interested in whether yours behaves similarly cam-wise. When I say huge, I mean maybe 0.5mm, and you are right - what a clatter that will make..
A year or so ago, I lashed plastic shims into my rockergear to make sure they were quiet, no harm but not the full picture.
I can see the gudgeon pins (hopefully without new small ends) making a bit of difference.
Bin

 

[solidstate100]

Eek. Yep, all of those bearings/pins are toast!

Those Gudgeon pins are waaay worse than mine were, would be v surprised if you get away without a small end bearing change - since the rods are out anyway why not get it done, will be a cheap job from an engine shop. Peace of mind and all that?