Valve clearance varies after head installation

Towner · Nov 9, 2013

Hello,

I had a strange incident with my inlet valves after head installation. While remounting the head after renewing the gasket, I noticed that there was no clearance at both inlet valves. Exhaust valves have been ok. I turned the engine several times, but it didn't get better. So I adjusted as specified in the manual. During the test ride I noticed, that the valve train was noisy. Next day I retorqued the head and checked the valve clearance. Both inlet valves were very loose (both 0,50mm) again. What happened ? Has someone experienced the same ?

Ralf

rvich · Nov 9, 2013

Perhaps the pushrods where not completely seated?

Towner · Nov 9, 2013

rvich said:
Perhaps the pushrods where not completely seated?

Yes I supposed that too. But shouldn't they get seated after turning the engine several times ?

Or is that a known appearance ?

EDit: I' am pretty sure that the are correctly seated at the top and at the bottom it cannot be checked - or ?
Wouldn't it effect more than 0,5mm ?

Ralf

Hobot · Nov 9, 2013

No One will ride out of their home with a push rod off lifter with the insane noise it makes, often just on kick over snaps a distinct sharp ring in head. Valve seated wearing cause loss of lash gap. Worn cam lobes tend to increase it. Crush down of base plate and head gassket would tend to close lash up.

Towner · Nov 9, 2013

Don't know. I adjusted the primary chain before I started it. Maybe it got seated then. But I didn't hear any extraordinary noise while turning the engine.
I'll check the valve clearance after the next ride, hoping it won't change anymore. But that could be next year. Weather is turning bad now here in Germany.

Ralf

les ward · Nov 9, 2013

I had this once after taking the head off. The edge of the pushrod was caught on the centre of the rocker ball. I went to a rally about 100 miles away for the weekend and torqued the head down when I returned, but had no more adjustment for the tappets. That's when I found that the pushrod wasn't seated properly. However it had run OK and in my youthful ignorance thought it sounded OK. Certainly nobody at the rally mentioned it.

Hobot · Nov 9, 2013

Ok then - its possible to ride around w/o alerting to noises, ugh, means must dig back in or just run until fault becomes really obvious show stopper.

Biscuit · Nov 9, 2013

Is it possible when rotating the engine to check intakes you stopped not on the heel of the intake lobe but rather on one side or another? This would have taken up any clearance there and when readjusted to specs in this position would have been too loose.

debby · Nov 9, 2013

I had the same exact thing happen on my 750 last year when I put the motor back together after a rebuild. It started second kick but made a horrible clattering noise and didn't seem to be running right. I only ran it for about a minute, then shut it off. Tore the motor back down, couldn't find anything wrong. I had the same symptoms with the valve clearances, so I'm guessing the pushrods weren't seated properly on the lifters even though I could have sworn they were.

I'm putting the motor back in tomorrow and will be extra careful with the pushrods when I get around to refitting the head (might be a couple of months until I get around to finishing things up though...)

Debby

Hobot · Nov 9, 2013

aw don't be silly - we are all always extra careful puzzling the push rods in, each and every time as only way to get em in and so easy to pop one out before head snugs down no matter how many times prior it worked out fine. I was on NOC INOA and Brit Iron list for some years getting hand holding on various things like Cdo head installs, never heard of the rubber band over head method to keep rockers pressed on push-rods, till after I mentioned my happiness trying it in '03. Very very rare to have more than one p-rod off at once while able to run so if more than one lash gap at issue here, it ain't likely push rod related. Ride to wrench then wrench some more to ride.

Biscuit · Nov 9, 2013

I would think, as hobot suggested, two push rod that were adjusted to specs whilst their ball ends were riding on their respective cam follower edges, would make a hell of a "shut me of immediately" kind of racket when they decided to self index where they belonged. Towner said the rechecked clearance was around .50mm. That would make for a loudish valvetrain but I'm guessing a pushrod dropping down into the follower where it belonged would open up it's 'correct' clearance of .20mm to around 3.2mm to 3.5mm. That would be way louder than "a loud valvetrain".

Towner · Nov 10, 2013

Biscuit said:
... you stopped not on the heel of the intake lobe but rather on one side or another..

Unlikely, I rechecked it several times, especially after having this situation.

What I did: I took the head off to renew the gasket due to a leak. I used the same gasket type (flame ring composite) as before. I renewed one
intake pushrod.
pushrod-question-t17646.html
I don't care to reinstall the pushrods at the same cylinder as before. After reinstalling the head the valve clearance usually has to be
corrected a bit, as the outlet valves needed only a little correction. But both inlet valves had no clearance. I thought it was caused by the
new pushrod and the other not on the same place as before.
It lasts further 2 weeks, before I started the bike, because I overhauled the oil pump, adjusted the timing chain and the primary
(and drive chain) as well.

When I started the bike, it was a bit noisy, but no unusual sound. I wondered that the performance was not such good. While riding I became
aware that the noise was caused by too much valve clearance. First I thought that is the new pushrod, which has run in. But the other side
was the same. I never thought, that 0,5mm clearance would have such little effect.

Ralf

Biscuit · Nov 10, 2013

Well it's obvious all your pushrods were indexed correctly from the start. .5mm is too loose but not as loose as pushrods that had slipped from the cam follower's rim into the socket would be. Flame Ring gasket, is that the term given to what was once called a composit or fiber gasket? A gasket made from an organic type material with a pressed steel rim crimped around the combustion champer area? If so, it's also currently what's on my engine. When I install these, I torque the head once to specs then let the engine sit overnight. Next day re-torque always yields more turn neccessary to get back to spec. Then two more torque sessions after running engine up to temp (then cooling). It's not unusual to show reduced valve clearance after installing a new, particularly composite, head gasket and after each re-torque. Increased clearance is hard to understand though. I know you'll say "no way" to this but could you have mistaken a 0.20mm feeler gauge for a 0.50mm. for adjustment? Please don't take this the wrong way. I try to look at these kind of problems as my own "what could could I have done to cause this" problem.

Fast Eddie · Nov 10, 2013

When I took the top end off my recently bought Commando, and cleaned everything up, I found a piece of (what I believe to be) very squashed head gasket material in one of the cam follower cups, where it had sat between the pushrod and cam follower for who knows how long.
I thought, what fun the PO must have had trying to work out why the tapper clearance kept changing as the material squashed!
FE.

Towner · Nov 10, 2013

Biscuit said:
Well it's obvious all your pushrods were indexed correctly from the start. .5mm is too loose but not as loose as pushrods that had slipped from the cam follower's rim into the socket would be. Flame Ring gasket, is that the term given to what was once called a composit or fiber gasket? A gasket made from an organic type material with a pressed steel rim crimped around the combustion champer area? If so, it's also currently what's on my engine. When I install these, I torque the head once to specs then let the engine sit overnight. Next day re-torque always yields more turn neccessary to get back to spec. Then two more torque sessions after running engine up to temp (then cooling). It's not unusual to show reduced valve clearance after installing a new, particularly composite, head gasket and after each re-torque. Increased clearance is hard to understand though. I know you'll say "no way" to this but could you have mistaken a 0.20mm feeler gauge for a 0.50mm. for adjustment? Please don't take this the wrong way. I try to look at these kind of problems as my own "what could could I have done to cause this" problem.

Yes, it is the genuine AN composite gasket and I did it the same way. First retorque after sitting overnight, next retorque after running the engine. It was the third time that I removed the head and until now the clearance always decreases a little after retorque. So I am sure that the increase of clearance is not caused by retorquing. I am beginning to believe that I did something wrong during the first adjustment, but can't imagine what. Perhaps I had a mental black-out and checked the clearance when the outlet valve was completely opened instead of the other inlet valve. Or something in the valve train gets seated.

Towner · Nov 10, 2013

Fast Eddie said:
When I took the top end off my recently bought Commando, and cleaned everything up, I found a piece of (what I believe to be) very squashed head gasket material in one of the cam follower cups, where it had sat between the pushrod and cam follower for who knows how long.
I thought, what fun the PO must have had trying to work out why the tapper clearance kept changing as the material squashed!
FE.

I took this into account too, but it is very unlikely, that this happened on both sides and only at the inlet cups.

Valve clearance varies after head installation

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