Valve clearance....

[planedick]

My model F has always had a noisy top end and I just assumed that the valve clearance was too great. Recently I went for a ride with my half helmet which allowed me to actually hear the engine while running and it was so bad it scared me. So I decided to "bite the bullet" and adjust the valves. Imagine my surprise to find that the clearances were not too much, but rather, too little. The intakes are all .004 inch (.105 mm), two exhaust were .007 inch (.178 mm) and two were .006 inch (.15 mm). According to Clymers the intake is supposed to be .006 to .008 inch (.16 to .20 mm) for the '78 - '79, the '80 - '82 should be .004 to .006 and the exhaust should be .008 to .010 on all models. It would seem to me that being too close it should be less noisy. GGRrrrrrr I had a chance to listen to and ride Mason's machine a little while back and it wasn't as noisy as mine. I wonder what could making so darn much noise. Chain is new and tight.
Anyone have any ideas?

[prometheus578]

"Chain chain chain... chain of fools."

I've heard noisy bikes with adjustable lifters, but the bucket and shim design is rather quiet. Barring the odd possability of worn cam journals, I'd recheck your timing chain/tensioner again.
When you set it last, was the crank in the "C" position?
Go to Harbour Fright, or wherever, and pick up a cheap mechanic's stethoscope. Probe around a little... touching on the tensioner and the areas of the cylinder and head where the chain lives.
Leaking exhaust gaskets can sound like a tapping or rattle, too.

[trbig]

Also, when turning your timing plate CLOCKWISE to line up the "C", if you go slightly past this mark, DO NOT turn it back counter-clockwise... go completely around again clockwise. This keeps any slack in the chain to the front of the motor so the tensioner can pull it out.
I also have better luck pulling the tensioner completely out, pushing the plunger all the way in and locking it with the screw lightly, installing it back in, and then loosen the screw holding the plunger. You will hear it give a good smack to the chain guide. Then torque the adjuster screws to spec.


Tod

[planedick]

The real question is...

I have the valve cover off, so checking chain adjustment is not the problem for sure. I recently installed a new chain and it was still tight when I took the valve cover off. I guess the question now is: Does the gap between the cam and valve bucket get less or more when the engine is hot. The clearances now are just a little tight when the engine is cold which is the right time to measure.

[trbig]

Just poking the chain between the 2 cam sprockets is definately not a good way to check for tightness. You would somehow have to get your fingers down the front of the head between the long stretch between the cam and the crank... somewhere in the middle I suppose... anyway. It's only 4 screws on the left sidecover and 2 on the adjuster to do it right and know for sure. Chains will stretch the most when brand new.

As for the clearances you stated, the book says "Valve clearance (Cold)" Exhaust .21-.25mm (.008-.010 in) Intake .11-.15mm (.004-.006 in) You do want some clearance due to everything sweeling up when it gets hot. (Notice the bigger gap on the hotter exhaust valves) If your valves are too tight, when the engine is at operating temps, it could be letting a valve stay slightly open and burn it or the valve seat. Since you are this far into it, I would shim it up correctly.

Tod

[trbig]

Well.. I see that the gaps are a tad different. I am sorry. My book is for an XJ.... Go with what your book says.

Tod

[John]

The valve clearences were made smaller in 80 to help quite down the valve noise that the earlier models had. It is best to use a metric feeler guage instead of a standard feeler gauge with metric equivalents printed on each blade.

[planedick]

Both...

I have both standard guages with metric on them and metric guages and the standard are easier because I can measure between what the matric ones do. Forget the cam chain thing. I have meen mechanikin for over 50 years and I have taken the adjuster out and set it up reall tight and there is no difference. You can rest assured that the cam chain is NOT the problem, nor is there any sign of wear on the cam lobes. I'm thinking maybe piston slop. I have an even 150 lbs compression all accross and that's at idle without touching the throttle during the test. The bike runs really good, it's just noisy on the top end. It's got 60,500 and I'm pretty sure the engine has never had anything done except what I've done to it. PO never did anything except ride to work, change oil and basic PM.

[trbig]

I have an even 150 lbs compression all accross and that's at idle without touching the throttle during the test

If you do a search, you can find the proper way to check compression on these bikes. It's done with the engine warm, but not running.
If your chain is tight, your compression is good, and you are getting good oil to everything, I wouldn't worry about it right now. Some of these bikes are noisier than others. You might even try another oil. Some people say it quieted theirs down considerably when they found the right one that their bike liked. What one persons bike likes may be totally different than what yours likes.
When I put my fairing on, all of a sudden I could here all kinds of things off that motor.... scared me too. It was making them all along, it was just funneling them to where I could here them now. Same thing when I rode without a helmet a couple times.

Tod

[mro]

I'm thinking maybe piston slop

piston slap, and also rod bearing and would imagine wrist pin noise seam to like transmitting there sound to other than where it originates. .

flat out would have lost a bet on piston slap noise (#3 piston hitting back of cylinder), sounded like coming from primary shaft area (Loudest) (can not remember last time lost a bet) Even seemed louder in head!!!


mro
compression test!?
warm up engine, pull plugs, disconnect tci