So I was thinking of doing some major work to my 400ex. It came with a hmf slip on and I have no idea if the guy re-jetted it. What would be a easy way to check? And if he didn't should I put a jet kit in it? Also what are some other easy but good upgrades I can do until winter when it will be overhauled.

 

Check the plug and see how she is running. Or open the bottom of the carb to look. You would know if it was not re jetted. It would run like crap and be smoking hot when running.
You could get a aftermarket air filter and remove the header to grind the inside welds down. Where it bolts to the head. Run it, then check the plug to see if the carb needs to be adjusted. Adjust the valves, chain and sprockets, brake pads. If you are going to build the motor next winter you can get a oversized oil tank, extra oil cooler, fan. The best thing you can do is adjust the rear shock.

 

It has a k&n on it now. I'll check the plug today after work.

 

Tan (brown) plug = jetted properly
Black plug = too rich - to large of main jet
White plug = too lean.

 

Hey, Sillymoose !!


check you PM....lol. sent you one a few days ago, dont know if you got it or not.