i set valves to spec..go for ride and out of spec again....why?

[remainincognito]

1975 engine..setting inlet at .004 and exhaust at. 006. Ride for a day and not at spec. I set cam tensioner first then valves. Any ideas

 

[5twins]

Did they get tighter or looser?

 

[remainincognito]

They get looser

 

[5twins]

Getting tighter could be valve recession problems but looser, I don't know. You should rotate the motor a few times and re-check after setting. Sometimes you don't get them right the 1st time around.

 

[OakBehringer]

Are you consistently setting them at TDC of the compression stroke?

 

[remainincognito]

Yes..set at tdc compression stroke..rotate..do exhaust side..go to other cylinder..set to tdc on compression etc

 

[remainincognito]

Just reset and will go for ride and check again

 

[jchrisk1]

Are the lock nuts loosening up?

 

[nj1639]

Are the lock nuts loosening up?

That's where I was going to go due to having that issue in the past.

 

[angus67]

did you say you do the intake on one side at tdc, then rotate to do the exhaust on the same side? dont rotate the motor untill you are ready to do the valves on th e other piston.

 

[kvanderploeg]

Aren't valves supposed to be checked and adjusted only on an overnight cold engine?

Kent

 

[ippytattoo]

+1 to angus and knvanderploeg yes cam chain when engine is hot valves when engine is cold.

 

[1974jh5]

It's not unusual for a cam to have a base circle that's not dead round. That means that you have to check carefully to be certain you are checking it at the same point each time. But if the valves really are loosening up, it's probably the locknuts not holding or possibly the rocker shafts are worn.

 

[remainincognito]

Yes I check when engine is cold. It is fine now. Made sure to to set on same point each time. You rotate just a touch past then it changes. Did not realize how touchy it was. I'm set for .003 on intake and .006 on exhaust for my 1975. How much noise should one expect from valves at spec? Valves at spec but kinda noisy. Thanks for the help.

 

[5twins]

Well, depending on the amount of wear, what you're measuring and what the gap actually is may not be the same. The adjuster screw ends get all pitted and worn and the valve stem tops sometimes get dimples worn into them. You can't measure down into those dimples so the actual gap may be larger than what you're measuring.

 

[angus67]

any news?