Jetting a 2002 CR250

[murphy's law]

PHILIP,
I PRETTY MUCH RUN THE SAME SET UP AS YOU WITH THE EXCEPTION OF THE MAIN JET. I LIVE IN THE NORTHEAST SO I HAVE TO DEAL WITH DRASTIC TEMP DIFERENCES NO MATTER WHAT THE SEASON. HOWEVER IN THE SUMMER I FOUND THAT WHENEVER I WENT ABOVE THE 380 MAIN THE BIKE WOULD RUN SUPER RICH. I TOO RUN C-12 32/1 WITH MOTUL AT SEAL LEVEL. IT'S LIKE EACH BIKE IS CONSPIRING AGAINST US IN THIS JETTING BATTLE. SOME LITTLE JAPANESE TECHNICIAN IS SITTING SOMEWHERE LAUGHING HIS ASS OFF READING THESE ALL THESE POSTS.

 

[dodgeaspen]

Just put my S-8 nozzle in last night....what a difference!! The bottom is now very clean and responds to any jetting changes! If this didn't work I was going to buy a Kehin but no need for that now. Inital jetting for me in 40 degree weather is:

Pilot: 32.5
Main: 400
AS : 2
Needle: STK
Clip: 2nd

I may be jetting a little rich with the 32.5 pilot but I'd rather start out being conservitive....at least now I know the bike will respond to a leaner pilot if necessary.

 

[john stu]

i run a 32.5 with the needle in the second clip (with a s-8 nozzle)but i also run a mix of race fuel or it pings sometime down low

 

[sandflyz]

I'm just about to buy a 03 Cr. I'm in canada and my elevation is 3723'. Riding temps generally range from 15-25 DegreesC. I know these bikes are jetted for sea level so i figured i'd just do as the book recomends and buy a sj 30, clipip in the second position, a 6chy12-83, and a 410 main. I was going to do this before even riding the bike as i know it will be way to rich. Is this a good place to start? Has anyone else simply followed honda recomendations with jetting? What were the results?

 

[James Dean]

A #30PJ is working good in my '04CR. The stock needle needed to be in the #2 position.

I'm making jetting kits for the CR250R now. The kits are based off the '04CR with 2 custom made Mikuni needles. The bike dyno run came in at 47.5HP with a #400MJ. Send an email if any one is interested ( jdjetting@comcast.net ). The needles are not going to be as difficult to adjust the jetting with as stock.

James

 

[stroker]

aparently JD has his needles ready to sell now...