Jump to content
Sign in to follow this  

trouble shooting 99 wr 400

Recommended Posts

so a while back i got a used wr400f motor and threw it into  my street legal yz400f i thought a wide ratio transmision and the wr stator was a big plus. i had it run and stall out in the past never to run again, i did things like put a yz450 carb and shim the valves- no start and no bump start worked, it had spark and i dumped fuel in the plug hole it would not fire. yesterday my kid brought over his new leek down tester it took less than 5 min to figure out air was getting past the piston because we could hear air in the timing chain galley , cam caps off and cams out we could hear air in the intake and the exhaust. what a great tool to have if your trying to figure out if a motor is any good without tearing it down.

i guess 175 bucks i got what i paid for lol, i have new valves , guides and seals on hand so here i go again to the machine shop.

is the difference between a 400 and a 426 noticable? my 400 cylinder looks ok but measuring will tell for sure, are the 444 big bores reliable? what to do its old and i dont want to dump more into the motor than the bike is worth

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  

×