James Dean Carb Kit Installed ~ I Need A Little Fine Tuning

I was looking through my jetts and for some reason i don't have the stock pilot jet? So i installed my red needle #4th clip,42pj,170MJ,1-3/4 turn out on zyp-tye screw.The temp is a little to cold for proper test with red needle,68F.Should i have put a 48PJ instead of the 42PJ? i did ride it a little bit,it still has a bad bogg. :)

From the NCVQ#4/162 in your signature and 68F, try the 42 pilot with red needle #5 or blue needle #4 to have closer jetting, looking at where you started. Keep the 170 main jet with these settings.



I just found my 45PJ I think i will put it in and go from there,thank you for the reply.One more thing before i bought the jet kit from you i had already got a new starter jet 72SJ ,do you recomend i still use it with the new kit? The other thing is it has been very hot down here,High 90's to to low 100's,The reason i'm asking about the starter jet is i never use my hot start,it seams to start better with out it ! does that indicate a lean mixture? :)

I installed the 45PJ and i can not get the bike to run well at all. Red needle #4 170MJ 45PJ 1 3/4 turn on the fuel screw!! The temp is only 70F kind of humid.It's been 90 somthing all last week and i don't think the blue will work once it warms up again.Plus i'm going riding friday at elevation about 5000-7000 ft. anyone, anyone, bueler, bueler.Oh yeah the bike pops alot on decel. :) Does the popping indicate a lean mixture?

Drzphatkid- I tried a 45pj, 3out on the screw got rid of the popping but power was still soft. Went back to a 48pj(3/4turn out). Decel popping gone, bottom end grunt is awsome, and thats at 7000'+ and 90deg.

I have been riding in colorado for 11 days now at 10,000 feet and the 48 pilot at 1.25 turns works very well for me. Leave your pilot stock and play with the adjustable fuel screw to tune your bike.

The popping on deceleration is lean, turn the fuel screw outwards. I mentioned clip #5, did you try it? Clip #6 is very close NCVQ#4 off the bottom end if you need to go back that direction.


I have not tried #5 or #6 yet but i will next week . I got worried that i could not make it run right for my ride on friday! So i went back to my NCVQ needle.That set up is'nt that bad just not as snappy as i would like.The temp has been in the high 70s or low to mid 80s the last 5 days .Do you think i should try the blue needle first? :)

The Red marked needle #5 with a #42 or 45 pilot and 168 main should give the response you're looking for, 1 1/4- 2 turns out on the fuel screw. Use the fuel screw to keep it running clean at idle, too rich and the response will suffer badly. Different models have varied fuel screw settings with this.


I have been running JD blue #3 with 45PJ, 100PAJ, 170M. Bike runs awesome everywhere. Thing is, is in the morning when it is 55-60 degrees out it is incredible! A little lean on pilot but midrange on up is amazing! So to get those results at 90 degrees do I change to the red needle? Or maybe go down on the main? It's pretty close now at the hot temps but I definantly notice a differance between early morning and the rest of the day.


At 90F, the red needle #4 is going to run cleaner over most of the throttle range. (Florida and Texas riders take note :) )

The Red marked needle #5 with a #42 or 45 pilot and 168 main should give the response you're looking for, 1 1/4- 2 turns out on the fuel screw. Use the fuel screw to keep it running clean at idle, too rich and the response will suffer badly. Different models have varied fuel screw settings with this.


OK i did it but it still boggs right of idle when i whack the throttle open ! Is this a fuel screw problem or should i try the #6 position? The popping on decel is gone.The temp today is low to mid 80's.I really don't notice much differance in power compared to my NCVQ needle. I'm at 1 3/4 turn on the zyp tye. With the 45PJ 168MJ. :)

How did you arrive at a 40 PJ with NCVQ#4?

This is heading the same direction...

Yes, go to clip #6 on the red needle and drop the pilot jet to a #42 (or #40 if you were certain that NCVQ needed a #40).

This is not typical of most setups. Are you giving the bike a good ride period to warm it up? Snapping the throttle on the stand is not a true test of riding conditions.


I went with stock YZF450 jetting. NCVQ 40PJ 162MJ 1 3/4 turn on the screw. It worked better than stock with all my mods.This setup ran pretty well accept with a bogg right off idle,and in 3rd gear when i let full off and full on, it would stumble.I also put a 72 starter jet,it seems to start a lot better. I just did another test run around the block 3 or 4 times it seems a little better in the 3rd gear test,full off full on only a little stumble.Am i on the right track or should i test the BLUE needle per the kit recomendations? :)

The most familiar/popular settings are Blue #4(lower altitude & cooler), blue #3(mixed cond.), Red #5(crosses leaner to richer than blue #3) Red#4(warmer cond. & higher).

You are right in the zone of most riders and should be thinking of how it performs under normal riding conditions. Snapping the throttle open on an FCR carb is asking for problems, when the carb is not a CV type and has a relatively big bore. Careful tuning will allow it within limits.


Thank you James i will keep that in mind.I think i'm close,i just can't help but to compare it to my brother's DRZ which was mine at one time .When i say compare i mean the drz has no problem with the throttle snap test.The only thing i did to that bike is main, pilot and clip position and i did this in one try!I'am not suggesting that there is any thing wronge with you're kit,only that this WR is a little more sensetive to jetting.Again i thank you for you're time and testing with you're needles. :D



45 PJ

72 STJ

1 3/4 zyp-ty


I got my JD kit installed last night and had a few questions. #1) Does the fuel mixture screw richen or lean the mixture over the whole throttle range or just the initial throttle hit ? (i.e. Could you just jet the carb for ...say...3,000'-6,000' and then fatten the fuel screw when you ride at sea level?) #2) After installing the JD kit my bike still seems to have the same spudder from about 1/4-1/2 throttle....only when I'm holding the throttle stable, not accelerating. It should be noted that I set the carb up per JD's specs for 3,000-6,000' and I am getting this result at almost sea level (street test!!) That could very well be my problem except that isn't spuddering a sign of richness and wont it only run richer at altitude? Chuck :)

Rekless- The fuel screw adjusts the pilot circuit, closed to 1/4 throttle. Higher temps and humidity, as well as elevation, will also make your bike run richer.

Your profile says your bike is bone stock, have you pulled the grey wire yet? My bike stumbled and missed terribly at steady, low throttle openings until I did this.

The fuel screw only affects idle and slightly above. It won't help the overall jetting much for altitude changes.

The sputter is usually a sign of a rich condition. Try the next leaner (higher altitude) setting to see if it changes much, if any.




Can I simply raise the C-clip to the 3rd notch on the blue needle? Shouldn't that lean it out one step? Or should I leave the needle alone and go to the next leanest jet? Also, the bike has all the free mods with the GYT-R insert, which might change the recommendations. Actually I haven't done the grey wire mod Lip Skid. Maybe I'll give that a try next. :)

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