Carb Jetting

[bikewarrior350]

ive known that my warrior was jetted ritch but after the rebuild i just did its really clear that its extremely ritch. i know for a fact that the bike was jetted for flat track on the ice when i bought it. i dont know what jets are in the carb but ill will hopefully find that out tommrow. heres the engine mods i have currently...

-JE 366cc piston 10.25 to 1 compression
-hotcams stage 1
-K&N filter with no airbox lid
-Supertrapp pipe
-polished head
-RM Stator high preformance CDI

the bike runs amazing when its about 45 degrees out but today it was 75 and the bike stumbles around 1/4 to 3/4 throttle when i jab the gas then after a few seconds it clears out and runs fine. also when climbing steep hills at constant throttle it will stumble causing me to have to punch it to clear out the engine. i read some of the tutorials on carbs but im still lost as to which jets need to be changed. any suggestions for jet size would be great as well

 

[1998yamahawarrior]

Well find out what the jets are and where the needle is at and we can work from there, because each quad acts a little different to the same jetting. Do you know if its jetted with a kit or single ones from a dealer?

 

[bikewarrior350]

id guess that its just individual jets. i bought the quad from a neighbor and from what he told me the motor was done by trinity racing back aroung '98 ish so id assume that they just sent him the jets but i havent been able to find much information on what they actually sold in there kits as they dont sell them anymore. ill pull the carb off tommrow and get jet sizes and needle position. one thing i do know is that the idle air screw is basically unadjustable because the screw is sezed up and stripped but that shouldnt matter since there isnt a problem at idle

 

[bikewarrior350]

took the carb apart and its running a 152.5 main jet 42.5 pilot jet and the main needle is 5J18 position 3 down from the top. from what i can tell the only jet different from stock is the main jet. and what exactally does changing the needle position do?

 

[1998yamahawarrior]

the needle also controls some of the fuel delivery. Deadlast has a cool diagram in the tutorials section that shows what each thing does. Its called getting to know your carb. For the main id say get a 148 & 150, start w/ the 150 and see how it is. If its still rich go to 148.

 

[bikewarrior350]

i actually read that through several times. i definatly understand the principals of a carb from a physics stand point but am still lost on how to apply everything in the real world. im gonna get a 150 main from rocky mountan since im ordering other parts anyway but unfortunately they dont have a 148 so ill probably have to go to a dealer for that. just to confirm the main jet should be a Mikuni N100.604 Series correct? i measured the jet dimension wise and comparied with the info i found i think thats what it is just want to check

 

[miami1]

1/4 to 3/4 throttle is going to be your needlle try moving it around some and see where that gets you. lowering = leaner and raising = richer

 

[1998yamahawarrior]

Thanks for bringing that up miami it slipped my mind how that went

 

[bikewarrior350]

well i ordered a 150 main jet which im gonna put in as im pretty sure its running way to rich even at WOT. is there any specific specs for setting the main needle in a particular location? mabey baised on temp/altitude? just wondering

 

[1998yamahawarrior]

what is your altitude out there

 

[bikewarrior350]

im at like 1200 feet above sea level which shouldnt really affect anything. more just curious if theres a set rule about where the main needle should be placed

 

[1998yamahawarrior]

i was just tryin to think how that went. basicly if you move the clip up it leans it out down it richens it, by how far the needle goes in.