Jump to content
Sign in to follow this  

Question About Valve Clearances

Recommended Posts

I've got about 800 miles on my '04 250X now, guessing about 80 hours and am checking valves again. (checked valves back at 500 miles, had about the same measurements)

If this was your bike, how would you proceed?

Exhaust spec per manual for .011 (+/- .001)

Both Left & Right Exhaust valves check the same:

.010 gauge fits loose (slips in/out with no friction)

.011 gauge fits snug (slips in/out with some friction)

.012 gauge fits tight (very snug fit and hard to move)

Intake spec per manual .005 (+/- .001)

Right Side:

.004 feeler gauge fits loose (no friction)

.005 feeler gauge fits snug (a little friction)

.006 feeler gauge --- (won't fit, too tight)

Left Side:

.003 feeler gauge fits loose (no friction)

.004 feeler gauge fits snug (a little friction)

.005 feeler gauge --- (won't fit, too tight)

I'm gonna guess that only the Left Side intake valve needs to be adjusted. Is that right?

Do my descriptions of how the feeler gauge fits make sense? The thin piece of metal (feeler gauge) SHOULD slip in & out with a SMALL amount of friction right?

Is it true that as time goes on, the valve clearances will tend to get smaller (tighter)?

Also, the Honda manual says to use "molybdenum disulfide oil solution". 1/2 engine oil and 1/2 molybdenum disulfide grease (containing 3% moly disulfide additive) to the valve lifters. Does this grease go by another name? What's it gonna be called on the shelf at the dealer? How important is this?

Any tips or advise you guys can throw my way would be muchly appreciated. 😢

Share this post


Link to post
Share on other sites

I saw 3% moly lube in my local auto parts store. Since my Yamaha manual didn't say how much moly should be in the lube, I wasn't sure if 3% was enough. Now that I read your post, I think I should have used it.

Here's some advice I recieved on this very same topic. Valve lubrication

I'm relatively new to the world of high performance 4-strokes, and I was told to expect the valve clearance to get tighter over time. Maybe this is common for bucket and shim designs because I once thought rocker arm designs get looser with age.

You might find it useful to know that CRF450R shims (0.375" diameter) fit into my YFZ450. I'm also told that DRz400, LTz400, and KXF400 shims are interchangeable as well.

If the CRF450R, CRF450X, YZ450F, WR450F, YFZ450, DRz400, LTz400, and KXF400 shims are all interchangeable, finding shims in stock should be less of a challenge.

Share this post


Link to post
Share on other sites

Thanks for the info....

Reshimmed the left intake valve. Had a 1.95 shim in there and went to a 1.925 Piece-o-cake. 😢

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...