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Valve Clearance Question

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I just finished adjusting my valve clearance for the first time and have 2 questions.

1. When aligning the "T" by rotating the flywheel CCW there is also an "F".

What is "F" used for?

2. How critical is following the torque spec? Is there a trick when torqueing

down the jam nut? ,I tried to snug the nut while holding with a

screwdriver and then using the torque wrench but the gap seemed to

close slightly without the screwdriver backup.

I would not have even attempted this without the info and help I've already gotten from TT. What a great resource.

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I've never heard what the "F" is for so I can't help you there.

When tightening up the lock nut I just snug it good with a box end wrench while holding the adjuster with a screw driver (I do not torque the nut, never have on anything including cars, and have never had a problem). It takes a little trial and error when tightening the lock nut to find the right spot so your finished clearance is correct.

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Start out with the feeler gauge feel on the loose side and hopefully by the time you tighten it down properly it will be more like just right. It's alot of trial and error and sometimes they seem to have a memory of their old position, which can be quite frustrating. Thank goodness there are only four!

I never used a torque wrench on automobile valve adjusters either, but on a 10,000rpm motor I do. I'm sure someone can share a story about what happens when one of these works loose. It can't be pretty.

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The "F" is the firing point, ignition timing.

As far as torque, I bought a 1/4in drive torque wrench, after I adjusted the valves on my daughter's XR100...... She's racing a junior enduro, all reports had her at a good pace, hit the reset, bike started having no power, I was riding sweep, came up on her very upset.

It seems the lock nut had backed off, and the adjuster pin backed off, and the exhaust valve was barely opening......

Sheer luck allowed the pin and lock nut to lodge safely in the head, instead of making its way to the bottom end where who knows what could have happened!

Robert

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Red Snapper's right.

When torquing to spec. they will tighten up everytime, so as already said, torque when they are a little on the loose side and after practice it won't be very hard to get them to be just right.

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Thanks for all the info. I feel much better now. I probably adjusted each one 4-5 times before I was satisfied with the gaps. I spent nearly an hour and a half by the time the bike was all buttoned back up. I guess 20-30 minutes was a little optimistic for my first time. No pun intended. :cry:

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F is for checking timing firing mark

adjust the valves for a tight fit on thefeeler gage. when you tighten the nut and remove the back lash from the threads the clearance should be just right. takes awhile to develop te feel.

never torque the adj. nuts just nice and snug.

many years ago was working on two bikes at once and did not tighten down one of the nuts on my xr 250. fired it up and whacked the throttle, in about 5 seconds real bad noises from the top end. shut it down and took off the round caps. missing one nut. took off the valve cover and found the nut laying in the oil resovoir for the cam up against the peak of the lobe.

no damage whatever. put it back togehter and made sure all of the adjusting nuts were real snug

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