need help on clutching drr90

[madnoodle]

I just bought a drr 90 for my son he weighs 73lbs quad has pcs exhaust wondering if anyone can give me ideas where to start on clutching and gearing. He wants to race motorcross. thank you

[CRBOGGAN]

Stock cylinder pcs pipe 24 carb.
19/35 or 19/32 sprockets
stock 787 belt

ztr 1500 t spring
stock v 4.25 to 4.50 or mixs of the two.
jetting= 55degess or close to it needle 3 from top main 122 pilot 42 air screw 2 1/2 out and this should be plenty rich to go colder.

[madnoodle]

thank you what does 55degree mean

[CRBOGGAN]

outside temp

[madnoodle]

use same set up at normal temps just different jetting.also do you recommend using slipper front sprocket or solid one.

[madnoodle]

koso 1500 ok

[Hetrick Racing]

is there something wrong with the way it is working right now? before you make changes to the clutch,i would make a list of issues and go after that list rather than just changing parts.