[Trudeau89]

Hi guys,

Just wanted to get some opinions on my current situation. I have an 09 CRF250R that I have been having issues dialing in the fuel mixture.

I have had a JD Jet kit installed for about 2 seasons running great with no issues. However, This past season I got to the point where I had a serious bog under initial hit of the throttle and I found myself going all the way in on my fuel screw attempting to lean it out to acceptable level.

Today I took out the needle and it appears to have damage or wear on the needle tip.

Obviously this is a problem and I will replace the needle, but do you think this is what has caused my recent rich mixture issue?

It bogles my mind knowing it was running great and then over the span of about 4-5 races took a drastic turn for the worse. Becoming rich to the point where I had no more adjustment in my fuel screw to keep it running good, even though I had made no new adjustments or changes to the bike.

Any advice or comments would be appreciated.
Thanks, Nick

[crfsonly]

between the time it was running well and now was it sitting with fuel in the carb? normally the bogging off idle is a lean condition not a rich condition. have you pulled your emulsion tube (needle jet holder) and inspected it? also, it have seen carbs where jets are actually rolling around in the float bowl. i'm assuming you've checked the jets as well. also, do you have the floating valve plate and seal installed correctly? you may also need to replace the seal. i would like to see a photo of the needle wear.

ken

[Trudeau89]

between the time it was running well and now was it sitting with fuel in the carb? normally the bogging off idle is a lean condition not a rich condition. have you pulled your emulsion tube (needle jet holder) and inspected it? also, it have seen carbs where jets are actually rolling around in the float bowl. i'm assuming you've checked the jets as well. also, do you have the floating valve plate and seal installed correctly? you may also need to replace the seal. i would like to see a photo of the needle wear.

ken

No it was not sitting during the change in performance. It would continue to improve while turning the fuel screw in I just eventually ran out of adjustment. I have not inspected any of the other items you mentioned, I was originally just going to check the clip position on needle and thats when I noticed the 'damage' to the needle.

This is a picture of the Needle (top) the lower needle is the spare blue needle provided by JD as a comparison.


http://imageshack.us/photo/my-images/535/img3638o.jpg/

Also I will add another strange occurence I have never noticed before, around the same time this all started happening I noticed a drastic increase in the amount of fluid found in the crankcase breather..

[Trudeau89]

By trudeau89 at 2012-02-26

[crfsonly]

definitely pull the float bowl and check the float height, jets and emulsion tube. report back.

[Keith72]

definitely pull the float bowl and check the float height, jets and emulsion tube. report back.

Your float level should be 6.0 mm.

[Trudeau89]

Sorry it took so long, float level was good. Took the carb apart and cleaned everything and replaced the jet needle. (Props to JD Jetting for sending me a replacement)

The problem has not been resolved.

I have another symptom to add to the mix, not sure if it is relevant. At about the same time this all started happening I also noticed a drastic increase in the amount of fluid found in the crankcase breather / drain.

I went from about 2 years of never having to empty the drain, to it filling up about every two weeks.

Any possible cause of such a problem?