Jump to content
Sign in to follow this  

01 xr400r compression

Recommended Posts

Hey guys, I got a xr400r, cranked this morning, cranked fine but choked down before I could take off, went to crank it again & had no compression, took the decompression cable loose, still no compression, cam chain tensioner went out end of last year had to replace it & a bent valve, been running fine since then, had plenty of compression when I cranked it to start with this morning, don't understand it, can anyone help???

Share this post


Link to post
Share on other sites

Sorry man, fast loss of compression is usually a bad deal.

I'd start out by checking valve crearances. You can then back off the decompression adjuster and do a compression test too. That's several kicks at WOT and we'd like to see it over 150psi or so. If you can get ahold of a cylinder leakdown gauge I can talk you through the process of figuring intake, exhaust or piston leak so you know where to focus.

Share this post


Link to post
Share on other sites

Check the basics first, valve clearances, compression, auto decomp and the ever faithfull.... Broken choke butterfly then go from there. Engines are simple, don't think too much or it will get complicated.

Share this post


Link to post
Share on other sites

Thanks for the input, took the valve adjustment plugs off to check adjustment, valves aren't moving at all, doesn't look good, just my luck time to start ridin & i'm broke down, any other suggestions???

Share this post


Link to post
Share on other sites

Complete valve cover off & slowly wind the engine over (easier with the spark plug out) if nothing is moving up top but you cannot see why, the problem is down stairs, possibly in the lower timing gears.

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  

×