2002 CR250 Jetting

[soulmate33]

Aloha from Honolulu, Hawaii Guys (& Gals)<----politically correct.

I just bought an '02 CR250 and would like to rejet it before taking it to the track & trails. Being that we have a lot of tight 1st gear only kinda trails (with 51T rear), I don't want to foul any plugs.

I've read a bunch of threads on rejetting the pilots , needles, mains, and nozzles for '02-'03 CR250.

I ride @ sea level, temps about 75-90 degrees, from 70-90 percent humidity.

I plan to mix 50/50 pump premium with C-12 and Amsoil racing @ 50:1. (the reason for the race gas is because I can hear some slight pinging while riding it on the road with just pump gas and Amsoil @ 50:1).

Do you guys (& gals) get your pilots, needles, mains, nozzles from the Honda dealer? Or an after market source.

Any other feedback on this rejetting will be greatly appreciated, as I'm used to rejetting Keihins.

Much Mahalo,

Tracy <-------Guy.....LOL

 

[Sandy Whoops]

The infamous S8 nozzle is from a YZ125. The PN is 3TC-14141-S8-00 and can be obtained from your local Yamaha delaer for about $25.

Generally, the '02 CR250 is too rich on the idle circuit and too lean on the main. Also, there is a lean spot at 1/8 to 1/4 throttle. The needle taper is not very suitable, and little info is available regarding needles from other years & sources. The C-12 should take care of the penchant to detonate, though.

 

[trout]

The infamous S8 nozzle is from a YZ125. The PN is 3TC-14141-S8-00 and can be obtained from your local Yamaha delaer for about $25.

Generally, the '02 CR250 is too rich on the idle circuit and too lean on the main. Also, there is a lean spot at 1/8 to 1/4 throttle. The needle taper is not very suitable, and little info is available regarding needles from other years & sources. The C-12 should take care of the penchant to detonate, though.

I have been thinking of that nozzle as well, however I am not as picky as some so i have just left it alone so far out of fear of screwing it up. I hear its a finicky carb as far as jetting goes so i have left 'well enough' alone for now.

 

[soulmate33]

The infamous S8 nozzle is from a YZ125. The PN is 3TC-14141-S8-00 and can be obtained from your local Yamaha delaer for about $25.

Generally, the '02 CR250 is too rich on the idle circuit and too lean on the main. Also, there is a lean spot at 1/8 to 1/4 throttle. The needle taper is not very suitable, and little info is available regarding needles from other years & sources. The C-12 should take care of the penchant to detonate, though.

Thanks for the reply.
Looks like you are from Florida, you must have the same weather/altitude conditions as me.
What other jetting changes have you made?

 

[Sandy Whoops]

S8 nozzle, 400 main, 30 pilot, stock needle with the e-clip in the 3rd position. I think I was about 2 1/4 turns out on the air screw, but I set it where it needs to be and don't think much in terms of "turns out".
Before installing the S8 nozzle, I used a "1 size leaner" needle. I think the e-clip was in the 2nd notch from the top.
Suggest that you check the float height before making any changes. A few folks have found theirs set incorrectly from the factory.

The 400 main is a bit fat. A 390 may be a better choice for you as you have access to elevation changes. Not sure how much the C-12 will impact these settings, though. And if you install other engine mods, then all bets are off.
Honda sells a kit that includes all the available jets and needles. It's a bit pricey @ $110 from Service Honda, but I've probably spent half that amount buying individual pieces. Something to consider.

Hey Trout - jetting your carb is easy and rewarding. Once you've done it, you'll kick yourself for not having done it sooner.

 

[mtk]

Actually, the full jet kit is $150 from Service Honda, at least for the 2002. I bought one myself, but from another vendor I deal with regularly. It came with mains from 320-440, a half-dozen or so slow jets, and a dozen or so optional needles (basically all the needles listed in the Owner's Service Manual under carb tuning). I also got the S-8 nozzle for the YZ125 as has been mentioned.

I'm currently in the process of getting my jetting sorted out, so don't bother asking for the final specs. :)

 

[James]

I ran the same as Sandy basically but my main got as low as 360 in the hottest/most humid part of the summer. I found that the S8 allowed me to run a bigger main as I think I was using the main to fix some of the richness at lesser throttle openings with the stock nozzle.

The best it ever ran was one cool fall day with the stock jetting at 700 ft or so. Was scary fast!! Next weekend was a jetting exercise again.

 

[bedell99]

Right now this is my jetting using C-12 at 5500 ft. This is a setting that runs very good thru out the throttle range.

360, 76 needle 2nd notch, S-8 nozzle, 30 pilot 1 1/2-2 turns. It runnign real good now the temps are in the 60's and the gas is perfect for my application.

Erik

 

[taksx]

em i the only dork that goes by the manual? i've got my carb set up for sea level on the 2002 model
with a pro circuit pipe and v force cage. bike runs great no hick ups or sloppy throttle.
i've got to check the S8 nozzle that's news to me, i've only had the bike for a month.
cheers :cool: