Valve adjustments on 400EX

[Chillyboarder]

I am looking to start regular maintenance for my bike.

Probably going to buy new battery, change oil to 20w50 and buy the k&n oil filter cleaning kit.

I reading and am wondering if valve adjustments need to be regularly adjusted. I don't know what it is exactly, saw the guide on here though. Is it just a one time thing when you break it in? Or something you should do every so many rides?

Any help would be appreciated, thanks!

[cnl83]

I dont think it should be in the regular maintenance category. If they are not rattling, then you are still good. If they were out of tune, then you would hear them.

[GPracer2500]

Originally posted by cnl83
I dont think it should be in the regular maintenance category. If they are not rattling, then you are still good. If they were out of tune, then you would hear them.

Not necessarily. Out of adjustment valves aren't always noisy. As a valve recedes into its valve seat the clearance between the stem and the rocker can disappear. That can actually make them quieter than a correctly adjusted valve.

You cannot rely on the sound of a valvetrain to determine if it is within specs or not. Noise (both the presence AND absence) can be a clue--but only an actual measurement of the clearances can provide absolute answers.

Personally, I would run away from the seller of a quad that believed valve clearance checks are not part of regular maintenance.

There is little reason to not follow the recommended maintenance schedule for a stock engine, which is: inspect and adjust as necessary after the first 20 hrs (or 100 miles) and then every 100hrs (or 600 miles) thereafter.

[cnl83]

either way its pretty easy to do.

[GPracer2500]

Yes, it is pretty easy.

I do a valve tune up/check every few months. They dont go out of adjustment that quick they stay in line pretty well. Half the time I check my valves they are still perfect maybe I did a tiny bit of tightening or no tightening at all. It just keeps your HP up and stuff.