Jump to content
Sign in to follow this  

05 CRF250R cutting out

Recommended Posts

I've got a 05 CRF250R. It's got Lexx exhaust, quick shot, aftermarket rev box, and it's been dyno tuned. Power is AWESOME.. Runs perfect until I hit whoops or jump. Once I start hitting whoops, the bike cuts out, and acts like someone hits the kill switch, so I have to pull in the clutch and rev it up to pick up the Rpm again. When I jump, it does the same thing when I land. It seems the bike does this in negative or 0 G situations, whoops, jumps, heavy brakin bumps, etc. I have NO CLUE. Any help? The valves are in spec, carb has been professionally pulled apart and replaced all gaskets and cleaned, and reassembled. What y'all think? And yes I've had bikes before, so I'm not new to this stuff. Thanks guys any help is appreciated.

Share this post


Link to post
Share on other sites

Pull off the tank and number plate and seat

Inspect all electrical connections, especially the plug cable, and coil ground

Pull the stator cover off and clean the sender/pick up of any metal debris

 

Still does it?

 

Pull the float bowl and set your float height to factory specs

  • Like 1

Share this post


Link to post
Share on other sites

I think its your carb float. Be sure to set its minimum drop to book spec. Its the maximum amount that the float is allowed to drop that can cause your problem.

On rough terrain, g-outs and jump landings, the float can be forced downward into the fuel level. That displaced fuel has to go somewhere, usually shot up thru the jets into the carb, making the engine stumble, and/or out the carb overflow.

The float should have a max drop stop tab adjustment. After setting the book minimum spec, set max drop to 5mm over that. That is plenty of drop to allow the inlet needle to unseat fully to keep the carb full, but keep the float from flopping excessively between stops on rough terrain.

If you do this, post your results.

  • Like 1

Share this post


Link to post
Share on other sites

The float was just reset, still Doing it. I'm thinking its electrical. I unhooked my kill switch, still does it. I'm gonna pull of the seat and tank and clean all connections and see what happens. Thanks guys ill report back

Share this post


Link to post
Share on other sites

I had a shop reset the carb and float for free since they did all the original work, now I'm going to adjust it by myself and play with it and see what happens

Edited by lil_thumper250

Share this post


Link to post
Share on other sites

Okay so valves are in spec, carb float is reset, all fluids changed, carb redone, still doing it. I'm lost. It's not the kill switch, I ruled that out.

Share this post


Link to post
Share on other sites

Fixed it!!!

Okay so my rear brake pads were squeezing the rotor a bit. Adjusted those, and at the same time I removed my quickshot and went to stock. Runs amazing now. No cutting out. It was just too much fuel from the quickshot and my brakes rubbing.

Share this post


Link to post
Share on other sites

I thought I fixed it, guess not. Doesn't donut anymore with whoops but I hit the local track today and it still cuts out hard when I jump.... Here we go again

Share this post


Link to post
Share on other sites

Whenever I jump. It seems to cutout in zero g situations when I land. I think my back brake might be rubbing still, but I'm pretty sure it's too much fuel.

Share this post


Link to post
Share on other sites

Back brake will not cause any change in engine operation. If... you are on the brake when landing and sense that deceleration as an engine issue is entirely different.

 

If your brake caliper is sticking, you need to fix it first. Simply spreading the pads will not do  it. you must service the cailper sliders.

 

I also suggest you lower the deal height some and also increase the free play, if only to test it and confirm that it is not a rider issue.

 

BTW, zero G only happens at the apex of a jump (peak of a jump, in mid-air), not a landing. On landing is when a fuel issue usually occurs, if at all.

Share this post


Link to post
Share on other sites

I've had multiple people ride it and it does the same thing. I've been riding myself for 12 years so rider error is not the problem ( I hope) hahaha. Okay I'll check it out. I'll play with float height and a few things. I've got some very good dirtbike mechanics on it right now so let's see what happens

Share this post


Link to post
Share on other sites

Took it back. They pulled the carb completely apart, and found a very small o ring missing, put it back together, made 28hp/18tq on the dyno. Very happy for just a slip on pipe, and being @ 5,000ft altitude.

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  

×