Well i got the engine put into my quad and have startin tuning it. The problem im having is that the engine runs great with a 280 main jet in. mods are fmf slip on, uni filter and air box lid removed. when i do the plug chop the 280 jet is lean. i've gone all the way up to a 320 jet and it's still lean. when i put the air box lid on the 280 jet makes it so rich it wont even rev at wot. So i put a 270 in and still rich to the point that it wont rev. the smallest jet i have is the stock 230 but it runs lick crap with that jet in and the air box lid on. what gives?
difficult jetting
- Thread starter fesse
- Start date
check for air leak. make sure ur intake boot is in good shape and tight. take some water while running it and squirt it around there to see if the rpms change if the do then u have an air leak.
i have checked for air leaks using starting fluid/either. no leaks that i could find. have not messed with the needle at all, i was allways taught to set the main jet first then set the needle. also the quad runs strong at 1/2 throttle and falls on its face at wot when the air box lid is on. with the lid off it wants to pull the wheels in 2nd gear with anything from a 280- 320 jet. it seems wierd to me that it will run so well with a 280 jet and still be lean with a 320jet. i would think that 4 jet sizes would be a huge differance.
I feel your pain on this one. Other possibilities could be obstructed fuel line or maybe an issue with the timing being off. Good luck...
i had this problem the other day it end up being my reeds check it out i have a lil more work dun to my blaster but not much more i would trow that air lid out the window there no good i am runing a 35p 3clip and a 350 main try it out alll was go big then jet down I:I
Well put.You need to play around with the needle position.If it's rich move the needle clip down on increment at a time(which moves the needle up)and if it's lean you move the needle clip up(which moves the needle down).You also need to play with the air screw,start at 1 1/2 turns out and move it in 1/8 increments.Try that and report back.
needle will effect mid range jetting.. please read this it will help you out soooo much
http://www.blasterforum.com/engine-13/jetting-pe-pj-pwm-pwk-14934/
slip on?? as in just a silncer?? stock front pipe?? or afull fmf exhaust??? i ran a 280 main on a 2001 with boyseen reeds no lid and full fmf exhaust and ran great
if you have aslip on you really dont need to change the jetting, but takin off the air box lid you do
http://www.blasterforum.com/engine-13/jetting-pe-pj-pwm-pwk-14934/
slip on?? as in just a silncer?? stock front pipe?? or afull fmf exhaust??? i ran a 280 main on a 2001 with boyseen reeds no lid and full fmf exhaust and ran great
if you have aslip on you really dont need to change the jetting, but takin off the air box lid you do
I understand the concept of tuning a carb. The quad runs great at anything except wot. I would assume based on my experiance that it would be the main jet that needs changing. My problem is not that i need help with the basics it's that i can go from a 280 jet all the way up to a 320 jet with what seems like no change at all in a/f ratio. I'm guessing that there is not an air leak because if i put the air box lid on it runs pig rich. I also have checked for a vaccuum leak with starting fluid/ break clean the same way you would on a car. I feel that a 320 jet should make this thing bog pretty bad as it only has a slip on silencer and the air box lid removed although it has been pretty cold here in ohio. I hate giving up on this but i think i may just take it to someone with a little 2 stroke experiance as all of mine is in the automotive field.
so just asielncer and no lid... stock 240-250 for sold weather so with no lid.. one or 2 higher than that so... 270-280 no lid cold weather.. a some where in that area should work great for you...
Re: TRe: difficult jetting
if you are running lean on the topend yes, try moveing the needle down to the 4th clip, thats where mine was in my stock carb and the machine loved it.
if you are running lean on the topend yes, try moveing the needle down to the 4th clip, thats where mine was in my stock carb and the machine loved it.
Ok here's an update. I found that oil injection nipple on the carb was left open after. The previous owner removed the oil injection. I plugged that. Also I found that the air screw was apox three turns out, I set it at 1 1/2 turns out. I got to ride it once and it was still lean with a 270 jet. Unfortunately with the fading light and my test track being a flooded icy mess I don't think I'll be able to make any more progress tonight. I would still like a little advice on adjusting the needle though. I have the top of the carb apart with the slide out but its not obvious to me what I need to do and it don't want to screw it up.
I think i've finaly got this thing right. I ended up finding a airbox lid and putting it on out of frustration. I put a 230 main in, set the needle at the 3rd clip and have the screw set at 1 turn out. Now i got a stock engine with stock jetting and a good colored smoke ring. go figure. lol. I will say that it feels very weak on the topend of the rev range. is this just because the lid is on or because the jetting is richer? With the lid off it felt very strong on the topend. I guess i'll just try to ride it and have fun but i think the hot rodder in me is gonna want some more power soon. A big thankyou to everyone who helped me!
Yeah, having the lid on you will definately lose some power, especially in the upper rpms. That's when your motor wants the most air/fuel. Are you using the stock air filter?
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