Jet question

[hooleyboy]

my problem is My YFZ450 seems to have developed a popping sound from the exhaust at steady throttle. It was running rather well for a bit. Do you think i could just adjust the fuel screw rather than rejetting to minimize the popping at the exhaust. IT does seem that im not getting enough fuel since i kinda have touch the throttle to start it up. Im not sure when my main jet is ( a friend jetted the carb and i cant get a hold of him) I think its a 160 or a 162 main any thoughts?

[Jeremy]

This start happening when it got cool out?

Yes, adjust the fuel screw a bit and it might take it away. Might have to adjust the needle too though and possibly the main if you want maximum performance.

Popping on constant throttle would make me think quite a bit of the needle though. Pilot is usually most noticeable when you let off the gas entirely to slow down.

[06YFZ45racer]

I have an 06 YFZ (hence the handle!)

I have a jet kit, cam mod, full GYT-R exhaust, K&N filter and lid rmoved. It runs VERY strong, but when it gets cool out like it is now i get the same popping. I adjusted the air mixture screw and it cleared up SOME, not entirely though. I didnt re-jet b/c i dont know that much about the carbs on the YFZ. When it warms back up your problem should clear up on its own.

[hooleyboy]

SO with your yfz do you have to give it a bit of gas when your starting it? I just slightly pushing the throttle in then pressing the start button and it fires up. Im running a yoshimura rs-7 full system and a gytr air filter (lid off) and gytr jet kit. My buddy who jetted the carb set it to the right elevation. I did notice after a few hours of riding i would get a bit of a pop in the exhaust. and now it just pops at normal riding.

[06YFZ45racer]

Yea i do press the throttle to get it going. In cold weather i use the choke with NO throttle applied. Mine is slightly harder to start now that I have done the cam mod, which if you havent done yet is a huge differance in mid power range!

I have only noticed the problem when it is colder outside, like this time of year. And i dont really adjsut aything to much to correct it.

And even though the eleveation is set correctly, the colder air is much more dense so it does affect how they run in cold weather, just as if you changed elevation in warmer weather.

[hooleyboy]

I just started it up and after some fooling around with the fuel screw i ended up giving it a 1/4 turn left and took it for a ride felt a bit better so i left it at that. I dont really no much about quads so i quess i will just deal with a little popping sound as long as it doesnt wreck my motor... It wont wreck my motor right?

[06YFZ45racer]

No, it will not do anything to the motor unless you have an extreme rich or lean condition! As far as i know you should be ok though.