jetting, and gearing

[baker250r]

I am rebuilding my 4wheeler this winter and goin all out.... i sent my cylinder out to get decked, and the head shaved. ported, polished, im goona be runnin 86 style piston with spacer plate, duncan paul turner and fat boy 2 cr250 boysen reed cage, and reed spacer. the question, is where do u guys think i should start with jetting... it was only jetted for a old paul turner pipe and lrd silencer before. i will also be running 110 octane turbo blue in it to, and i guess u have to jet for that too... any ideas?

also, what do you guys have for gearing for MX?

[ESR250R]

it depends on what carb your using, i am using a 38mm stryker and my main jet is a 188. its a little rich but thats how i always run it. as for gearing, i went with 14/38 on 18" klaws and i like the gearing. it's a little more clutch work but you dont have to shift as much.

[beerock]

you should be around 175-190 depending on the porting.

14/38 is good but i learned that the motor will bog in 6th if your running a 86 tranny. with this in mind you can run 13/37 and be like a 14/40.

you can run a gear higher and still have power and be able to hit 6th with confidence of pulling it. but for track 14/38 is good but if you do all sorts of riding the other combo may work better for you.


another suggestion would be to NOT buy aluminum sprockets, DONT waste your money!!! all they do is wear out fast and they cost like 30 bux. buy 3 steel sprockets 37,38, and 39 buy a 143 and a 14 and play with the combinations

265's are powerful and if there geared right with a fiull port job can hang with 310's

[baker250r]

well, i put in a 180 jet.... and for the time being, its a dog... im goona play with the needle tomorrow.... do u guys have any reccomendations on pilot jet? if i dont need to change that.... what about mixture screw and air screw settings?

[baker250r]

alright guys. I had the 180 jet in there, and a 170 jet. it bogs in the midrange... and i run it for a while, and i take the plug out both times, and the plug is wet, but no carbon buildup or anything. is that a sign of lean? it also backfires. I know u guys are probly goona laugh at me for this. but i dont know much about carbs, and what is rich and lean and all that. all i know is i had to go up 20 sizes for my raptor just for a slip on pipe. thats about all i know about carbs.