Jump to content
Sign in to follow this  

02 yzf250f running really rough

Recommended Posts

Hey guys I bought a 02 250f last year recent top end and recent overhaul of suspension sprockets chain etc so was running really nicely. A couple months ago I went to a big organized trail ride and started the bike up as usual let it warm up but when I went to ride it just bogged really bad backfiring etc. It still starts and idles fine. Anyway its been in the local yamaha mechanics for two months now and they just can't figure out whats wrong, first they re shimmed and adjusted the valves which probably was due to be done but didn't fix the issue. Next they decided it was the carb and replaced a needle and did some tuning still the same issue. They then tried a donor carb which didn't fix it. Now they think its the CDI unit but they can't find another one to try out in it as apparently only one from another 02 will work? Anyone know if other cdi's would work or have any other suggestions on what the problem could be? I have pretty much missed out on a whole summer of riding so I'm kinda pissed.

Share this post


Link to post
Share on other sites

That's really Weird bro. I don't have a yz but I read a whole bunch bout em. But did yamaha jet carb? Because it could be getting too much gas or maybe not enough gas. Also maybe check ur timing marks on your cams maybe they are off timing. How bad of a bog is it?

Share this post


Link to post
Share on other sites

Yea they did play with the jetting and couldnt get it running right, i think its running lean, it basically idles fine but wont rev past what i would guess is about 3000 rpm and just has no power at all. I'm really surprised that they have no idea what it is after 2 months, are they incompetent? I've been thinking of getting it back from them and taking it to another mechanic. And yes it had brand new fuel when this happened.

Share this post


Link to post
Share on other sites

The CDIs from 2001 to 2010 will work, they are basically the same engine.

Share this post


Link to post
Share on other sites

Typically if the bike ran good ONCE with the jetting in it, it should run good a year later with the same jetting (Jets don't change) That is is everything is clean... So I kinda would rule out jetting as a problem. What does the plug look like? How much cranking pressure does it have.....And does the bike back fire when you try to give it the throttle? I'm sure your shop has checked for all the normal stuff....Kinda weird that they have had it this long though....You might consider taking it to another shop

Share this post


Link to post
Share on other sites

your problem sounds like its electrical, in the magneto there is a sensor its small squared and black tell the guys in the shop to try the bike with a new one I think thats your problem

Share this post


Link to post
Share on other sites

Probably wouldn't start easy if it was a pick up coil.....I would get out your timing light and see what your advance sequence is like....

Share this post


Link to post
Share on other sites

I just re-read your original post and noticed you said it did backfire......I would check the coil

Share this post


Link to post
Share on other sites

As mentioned it does sound like electrical....

Share this post


Link to post
Share on other sites

Hey thanks for the suggestions guys, will give them a call tomorrow and see if they have checked the pick up coil.

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  

×
×
  • Create New...