Downshifting and the bike dies?

[NJ Pilot]

I bought an 06 X last year in great shape. The bike ran really well last season except when I down shifted in tight corners, the bike would cut out. I just put in the JD kit this summer. I just ran it up and down the street today and the thing is still cutting out when I downshift. The bike idles well and has good acceleration. Where should I start?

Thanks for any help

[IvanCRF]

Make sure the ignition coil isn't loose from when you did the JD kit.

The pilot jet may be partially clogged.

[FORMA MOTO]

Does it die from chopping the throttle, or from down shifting?

[NJ Pilot]

When im riding the dez at high speeds I can chop the throttle and grab the clutch wth no problems. When I was riding McCain Valley in tight single track, 1 2 3 gears it would cut out immediately. It would really only happen when I was really hard on the gas and then off. Moderate throttle and it was not really a prob. Yesterday I was mid throttle in second gear and right when I let off the gas and grabbed the clutch it kicked off again???

I'm gonna pull the carb and do a full cleaning and rebuild. I will also check the ignition coils as well

[FORMA MOTO]

When im riding the dez at high speeds I can chop the throttle and grab the clutch wth no problems. When I was riding McCain Valley in tight single track, 1 2 3 gears it would cut out immediately. It would really only happen when I was really hard on the gas and then off. Moderate throttle and it was not really a prob. Yesterday I was mid throttle in second gear and right when I let off the gas and grabbed the clutch it kicked off again???

I'm gonna pull the carb and do a full cleaning and rebuild. I will also check the ignition coils as well

If this issue only occurs at speeds where you are allowing lots of engine braking, then it's most likely carb related.

I would 'pull the carb', but just loosen it, twist it, and remove the jet access screw on the bottom of the float bowl (or the float bowl).

Replace the pilot jet with a new one

Then check your fuel screw to make sure the o-ring isn't damaged,

Then replace the 'slide vacuum plate seal' on the front of the slide.

[NJ Pilot]

If this issue only occurs at speeds where you are allowing lots of engine braking, then it's most likely carb related.

I would 'pull the carb', but just loosen it, twist it, and remove the jet access screw on the bottom of the float bowl (or the float bowl).

Replace the pilot jet with a new one

Then check your fuel screw to make sure the o-ring isn't damaged,

Then replace the 'slide vacuum plate seal' on the front of the slide.

I'm not seeing a pilot jet in the shop manual. Pilot screw is all im seeing. Can you post a pic of the slide vacuum plate seal as well. Thanks Krannie

[FORMA MOTO]

I'm not seeing a pilot jet in the shop manual. Pilot screw is all im seeing. Can you post a pic of the slide vacuum plate seal as well. Thanks Krannie

It's usually called a pilot or 'slow' jet. They clog extremley easily with modern fuels. Even a partially clogged jet the bike can run ok in certain stiuations, and terrible in other.

Read this:

http://www.dirtrider.com/tech/141_0707_keihin_fcr_carb_rebuild/index.html

[roadglider]

Do you use the clutch when downshifting? Just a thought but could this have anything to do with the clutch lever starter safety switch?

[NJ Pilot]

It's usually called a pilot or 'slow' jet. They clog extremley easily with modern fuels. Even a partially clogged jet the bike can run ok in certain stiuations, and terrible in other.

Read this:

http://www.dirtrider.com/tech/141_0707_keihin_fcr_carb_rebuild/index.html

Thanks for the info. I pulled the pilot jet and it looks a little cruded. Are you still running a 48 pilot jet? I have the JD with a 165 main. I have a stock 42 in there now. Would you recommend sticking with the 42 or move up to 45 or more? Im in San Diego and ride mainly the dez and mtns locally.

O-ring on the fuel screw looks good

[FORMA MOTO]

Thanks for the info. I pulled the pilot jet and it looks a little cruded. Are you still running a 48 pilot jet? I have the JD with a 165 main. I have a stock 42 in there now. Would you recommend sticking with the 42 or move up to 45 or more? Im in San Diego and ride mainly the dez and mtns locally.

O-ring on the fuel screw looks good

45 or 48. 48 usually with internal motor mods.

[roadglider]

I looked at the schematic and it looks like all the clutch safety switch does is close the circuit for the starter switch. It doesn't apear to have any ignition interlock function. Hope you find the problem soon.

[NJ Pilot]

I looked at the schematic and it looks like all the clutch safety switch does is close the circuit for the starter switch. It doesn't apear to have any ignition interlock function. Hope you find the problem soon.

Thanks for looking. Appreciate the input.

[Nayther]

I think you found the answer. Just a small amount of crud in the pilot jet will cause issues, on top of that the stock one is too small. JD really should include a larger PJ in their kit. If it were me I'd buy a larger PJ, then soak/clean that one and keep it for an emergency spare.

[NJ Pilot]

I took the bike out yesterday and really hammered it. Going to the jd and changing the slow jet to a 45 really improved the throttle response. And best of all, the bike didn't stall when i downshifted.......ahhhhhhhh I love this bike. Thanks everyone for the help, especially you Krannie:thumbsup: