CRF's Only Forums

- 2007 CRF250
- Stock Carb

Situation:
I had a JD jet kit to make a FMF full exhaust run. Also had a quickshot on it. Bike ran fine but I moved those over to my 2009 so I put everything back to stock....or so I thought.

Problem:
Bike starts and runs fine on choke and it even revs up okay on choke. As soon as I take it off of choke and attempt to rev it, it bogs down and kills. It will idle off of choke for a while but it will not rev off of choke.

Thoughts?

Clogged Pilot Jet

Thanks, I tried to clean it but didnt really have anything that could go through the hole and didnt have any contact cleaner (was at the track). I'll give that a shot again tonight.

If that doesn't work, any other ideas?

That is THE issue.

Remove it and clean it or replace it with a new one.

roger that.....thx guys!

I had the same problem with my 08 450R I used WD40 to spray mine out and then just dried it off before reinstalling it and presto all better.

Update:

I tried cleaning the slow jet last night and it looked like there was something in there that makes the hole smaller than the larger hole that the jet is made up of. Anyway, when I tried to put something small enough through there to clean it out it seems to clog it up and I couldn't see through it. If I blew it out, I could then barely see through it so I don't know if that's how it is desinged (with a small washer or something in there) or if it is a bad part so I will be ordering a new one today.

Same thing though, when I start the bike it runs perfect on idle and on choke. Take it off of choke and try to rev it and starts to bog and then will kill unless you just let it idle.

I will be ordering the slow jet today and will keep you guys posted.

One more question...

The new slow jet will take a few days to get to my local dealer, is there a chance my stock 2009 slow jet will be the same as my stock 2007 slow jet? I would like to try the 2009 jet just to see if that gets it running correct if it will fit.

Should be the same just look to see what the sizes are they are stamped

First off, you were right about the 09 pilot jet being the same size as the 07. They were both 42's. When I looked through each one they looked the same and had the same size hole so my theory on the other being jacked was off I guess. I put the newer pilot jet in the 07 bike and got the same result.

Let me try to further explain the problem with a little more detail.

The bike starts fine, as if it were going to run perfect. 1st or 2nd kick and it idles perfect.....even off of choke. When I start to rev it OFF of choke it starts to rev and then sounds like it's running out of gas because it starts to sputter and will die unless I let it idle again and then it will idle just fine. Same thing, rev it up and it appears to run out of gas unless I go back to idle.

The weird part is that I can rev it ON choke and while it doesn't run perfect, it does in fact rev up like normal.

My question is; is there some other control that feeds the carb when the throttle is engaged off of choke? Could it be an air fuel mixture that is really off and causing it to mix wrong when the throttle is engaged? I'm wondering if maybe I put the long needle jet in wrong....maybe that's jacking with it. I made sure the main jet is not clogged and the pilot jet is pretty much new. The air screw is turned out 2 and 1/4 turns out.

Thoughts?

The plate that attaches to the slide has a hole in it. The plate looks like the hole should go to the top, it doesn't.
It goes to the bottom.
Did you have the slide out of the carb during the swirch around ? Doug

[email protected] wrote:The plate that attaches to the slide has a hole in it. The plate looks like the hole should go to the top, it doesn't.
It goes to the bottom.
Did you have the slide out of the carb during the swirch around ? Doug

Cause of the exact symptoms described...

I didn't take out anything but the needle just put in the stock back in from a JD kit needle. Maybe the hole is clogged?

Maybe the needle is in incorrectly.

Take off the top plate on the carb and ensure that the needle rises and falls with the twisting of the throttle.

Thx everyone for the advice. I pulled the needle out and noticed the clip wasn't even on there. I guess me and my buddy overlooked that part when we were rushing to get the parts swapped from my 07 to my 09. Anyways, I put the clip on the 3rd notch and it run fine on the stand.

I'll be taking it to the track on Wednesday but the problem mentioned here is def fixed.

Thanks again!