20 Most Recent 2000 Yamaha WR 400 F Questions & Answers

I would change the spark plug this is probably not the problem but I have had them look alright but give me some of the same issues. To me it sounds like a carb issue. If it starts and idles but won't run good at higher rpm's then it could be the main jet getting clogged or the float bowl sticking and not letting enough fuel in. You may need to add a fuel filter to the line. You may want to check your timing also.

milky oil tells me you have water in oil , change oil then check fluids level

Sounds like a broken drive shaft.

silly question but have you checked air filter

Check the carb. If it bogs, it could be running lean. If it stalls, it could be an electrical issue. For the carb if it is stock I would recommend a jet kit.JD Jetting Dirt Bike Jet Kits

Shoul be on on side of motor. Same as dip stick.

The 400's are virtually bullet proof, much more reliable then the new generation. It is the pick of the WR-F's. The most problems i have heard off is lack of grease in the steering head bearings and swing arm bearings. Check these for notchiness. All japanese manufacturer's seem to put very little grease in these areas. Also any rattles from cold, could mean the timing chain is starting to waer and valves need shimming. Good things to do first up if has a few kilometers on it. But other than that just general bike checks, spokes, chain & sprockets, changes through all gears, clutch free play, frame conditions paying special attention to the footpeg mounts for cracks, hopefully the bike will come with a service history and you will score yourself a great bike!