Jet Too Big?

[BlastersRfaster]

So i was riding my blaster today and noticed (its been doing it but i noticed alot today) that 1st through 3rd gear i dont have full power. it kind of sputters and i dont have all of my power. I think it may be my jetting. the motor is bored 0.060 over, has boyseen reeds, a full fmf exhaust, and the carb is a 32mm i believe. i just know its a big race carb. i think i need to go up in a few jet sizes but what confuses me is that 4th through 6th i have full power, no sputtering at all. any advice will be appriciated.

 

[Larry's Shee]

Start by cleaning carb and air filter. Unless you changed something, or had wrong jetting from the start, you shouldn't need to change. What does the plug look like now? Have you ever done a plug chop or leakdown test? Might also be good idea to do L.D. test now. How long have you been running current jetting?

 

[Blaaster]

Has the idle increased in speed as well?

 

[dksix]

How could jetting effect how it runs in low gears and not high gears? Wouldn't improper jetting be felt through an RPM range regardless of what gear the transmission was in?

 

[Blaaster]

How could jetting effect how it runs in low gears and not high gears? Wouldn't improper jetting be felt through an RPM range regardless of what gear the transmission was in?

Jetting goes hand in hand to load,

You should do a leak down test to see if it is airtight.

 

[dksix]

Jetting goes hand in hand to load,

You should do a leak down test to see if it is airtight.

I don't understand what you mean about jetting and load. Is there something about the description of the problem that makes you think specifically that it's sucking air?

 

[BlastersRfaster]

well it was rebuilt 2 rides ago and when we sealed the motor back up we did a leak down and it was all good. and its done this when i first got it too but i just didnt ride hard enough at the time to notice much. now that i rally the piss out of it, i notice it more. so it didnt just start. I havnt done a plug chop so i will do that. My carb and air filter are clean i clean them regularly.

 

[Larry's Shee]

If you can give carb size and all jets and settings would help. In general what does the plug look like? Tried new plug? Is sputter at WOT in low gears or as you are going from idle/whatever to wide open?

 

[BlastersRfaster]

If you can give carb size and all jets and settings would help. In general what does the plug look like? Tried new plug? Is sputter at WOT in low gears or as you are going from idle/whatever to wide open?

the main jet is a 270 i think. for some reason my brain wont tell me for sure but its either a 170 or 270 and im leaning twards a 270. its a keihin carb that to me (without pulling the carb off the boots) seems like its a 32mm. im not positive on that though. the other jets i have no idea.
The sputtering happens a little at whatever throttle but its pretty bad when i go WOT. And one thing i didnt mention is that when its not in gear (so neutral) it doesnt do it. it runs smooth. just 1st through 3rd is not quite right.

 

[Larry's Shee]

I would do another leakdown. 170 is pretty big, 270 would be huge. Knowing EXACTLY what you have for settings is the only way for anyone to help. In the meantime you could play with settings, raise or lower needle one clip and try, tweak air screw 1/8 each way see if that helps. Could even be you need a different needle. So next time you have carb apart, write ALL this info down for future reference.