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With the upcoming riding season soon to be here it was finally warm enough and I felt like doing some wrenching, so no better time to check the valve lash. While doing the job I also took some pictures and will post a step-by-step process for this. Starting with my DVX and then moving to a Honda TRX250, which has a more similar valve adjustment process to the AC 4x4's.

---- The first step is to remove all fender, coulings, sheilds, gas tank, etc so that you can easily work on the valve train. Also be sure to start with a clean machine so you wont have to worry about dirt falling into the head.
[attachment=67654:100_0839.jpg]

---- Next step is to remove the valve cover, lossen and remove the 3 bolts that hold it on. Be sure not to loose the rubber o-rings under the bolts.
[attachment=67655:100_0843.jpg]

---- With the valve cover off you can now set the engine to top dead center by removing the timing inspection cover and slowing turning the engine over until the timing marks line up.
[attachment=67656:100_0841.jpg]

---- Now to get proper valve lash measurement the engine must be on the compression stroke. With the DOHC motor of the DVX to tell this the cam lobes will be facing in opposite direction.
[attachment=67657:100_0845.jpg]

---- To check the valve lash take a feeler gauge and slide it between the bottom of the cam lobe and the valve shim. Using different blades on the feeler gauge to determine the valve lash by working your way up or down to one blade that will not fit, then cross reference that to the specs. Luckly on my DVX all the valves were still within spec, one close to beign tight but still in spec.
[attachment=67661:100_0848.jpg]

---- Now if valve lash was out of spec, one would have to remove the cams and shim to see what size shim is currently in there. Then with some math fiqure out what size shim would be needed to put the valve lash back into spec.
 

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Discussion Starter · #2 ·
Now here is the pictures and directions for adjusting the valves on my Honda TRX250, which would be used for working on your AC 4x4 motor.

---- Again start with a clean ATV and strip everything down so the work can be done easily. Set engine to TDC (removing the spark plug will make it a little easier to turn engine over) and remove the valve cover.
[attachment=67664:100_0850.jpg]

---- To tell if the motor is on its compression stroke or not the rocker arms should be a little loose and have a slight amount of play.
[attachment=67665:100_0854.jpg]

---- Checking the valve lash is the same idea, slide feeler gauge between the bottom of the rocker and top of valve. Both valves on my honda were loose and needed to be adjusted.
[attachment=67667:100_0851.jpg]

---- Adjusting the valves is a much easier job though then the DVX. Start by loosening the lock nut, while holding the adjuster screw secure.
[attachment=67668:100_0856.jpg]

---- Next tighten (or loosen) the adjuster screw until the valve lash spec is ment, when tighten you can jsut leave the feeler gauge in place and tighten until snug. While holding the adjusting screw firmly, retighten the lock nut and then double check the valve lash to be sure it is correct and didn't change.
[attachment=67669:100_0860.jpg]

---- Once all the valves are now in spec and everything is done, clean up the valve cover and head surfaces, apply a small amount of sealant and install the valve cover and tourque to spec. If possible now start the engine and listen for any off sounds, then finish putting your quad together :thumbsup:
[attachment=67671:100_0861.jpg]
 

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Nice work GoFastCat. The Cat sohc engines have inspection covers to allow access to the valves. Saves removing the entire valve cover. Your instructions and pics are excellent.
 

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Very nice write up!
 

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How can I tell if my 05 500 is TDC? Nice write up.

Thanks

WC
 

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OK I was thinking of attempting this on my 650H1. Same question as WC. How do I check for TDC and what do I need to remove (as far as body panels go)?
 

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650 v2

im looking at doing my valves on my 2005 650 v2 and was wondering if theres a write up or manual of sorts that i can get so i can attempt this,thanksClap
 
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