I recently ordered a big gun exhaust and they told to to use a 145 main jet but that sounds huge compared to the jettingadvise I've read here. has any one used a big gun and the 145 jet

 

That may be a dyno jet number.

 

yea thats way big.... also dont forget the big gun is designed for the 300.... little bit more displacement... i have a 125 in..... alot have the 128 in though....

 

Hasy anyone compared the 125 to 128 on same bike? I have the 125 w/ my Two Brothers slip on, have always wondered if I should have done the 128. I don't want to miss out on any potential power gain! I am about 2000 feet here in Spokane.

 

What bike and what mods have you done. I have a bill blue pumper with all the free mods and am using 45 pilot and a142.5 main.
before the pumper, i had a 128 in the cv carb
cheers hatto

02 klx300
Staintune Header
Std Muffler, but plug removed
No air box lid
34 mikuni pumper 45 and 142.5 jets a/f 1 3/4 turns
Crank case breather
Tommaselli Bars
Barkbusters
Uni filter
Peg extenders
13 tooth counter - 48 tooth rear

 

I had the #128 and live at 2500'. After riding with it for 200 miles, it seemed a tad bit rich with some light popping. I went to the #125 and it runs hard and strong with no popping.