Quick Question

[Kos92]

My question is: What size of main jet would you use to jet a 2003 Yz 125? I want to buy an FMF fatty with a shorty silencer. Would you just use the stock jetting?

 

[tjscott]

jetting varies drastically depending on temperature, elevation, all of that good stuff. and if you are altering intake or exhaust in any way the jetting will need to be different

 

[Kos92]

i have jetted before, except it was my blaster. I live in mass and right now the weather is in the 40's and as low as the 20's. I am just wondering what maybe FMF's jetting requirements are. I am not modifying anything else but the exhaust. The weather conditions i am mainly concerned about is the summer when its in the 80's -90's.

 

[tjscott]

well look it up on fmf's website.
fmfracing.com i believe.
but that will only give you a starting point.
heres a good rule of thumb for jetting...
http://www.mototips.com/how-articles/2173-jetting-your-ride.html

 

[Kos92]

alright thx man, i appreciate it

 

[tjscott]

no problem.
let me know if you still have any questions