Need help jetting.

G

gabemoranblaster

Guest
i have a blaster bored out to a 240. it has a UNI air filter. I have FMF power core pro series 2. with open lid stock air box. 2003 blaster. i am 12 i dont have money to waste on a full kit.
 
jets flow the fuel through them, since your motor is now a 240 it is moving a lot more air and needs the fuel to mix with it, you can only go so far with a mixture screw so the larger jet flows more fuel, it is a really easy fix, all you do is pull of the carb and take of the bottom caled the bowl(4 screws holding it on), then in side be carefull not to hit or bend any thing, but u will see a brass fitting in the middle with a hol on it, that is your main jet, unscrew it an put in the new one, then reassemble the bowl and your done, u will need to adjust your mixture accordingly
 
u will see on the stock jet that there is a number on the bottom, some number smaller than your new 290, i dont remember the stock jet size, but the jets are for a mikuni carb if your carb is stock, i recommend taking in the stock one with you when buying the new jet, helps them find them easier
 
You never answered the question, is it a 240 sleeve in a stock jug or a .040" over piston and overbore? Do you just have the power core 2 silencer? or the head pipe as well? All bikes are diffrent, we can get you close but you will have to do some fine tuning and jetting for you're bike.
 
--to the OP.

Alot of people get confused because they bore their cylinder .040" over & assume that now the blaster is a 240cc.

If you did not actually purchase a 240cc big bore kit including a new cylinder head, and larger piston or had a new cylinder sleeve pressed into the jug, then your blaster is not a 240cc..

A 240cc Blaster will require a larger carb & at least a nice full exhaust to take advantage of the increased airflow.

When the # 290 was mentioned earlier- they were not referring to the size of the motor in anyway. It was in reference to the size of the main jet in the carb. A stock main is a 230. A 290 jet is obviously larger, and you'll need a larger jet to support any mods that increase airflow.

The people above were saying that w/ your light mods & bored .040" over, a 290 main jet would be a good starting point. This number will differ from quad to quad, riding styles, gas used, temperatures, sea level etc. Its up to you to dial in the jets to your specific needs.

If your Blaster is indeed a 240cc, then you'll need a larger carb & larger jets all together. And to be brutally honest, if you need to ask- you probably shouldnt have a 240cc Blaster.