ok i just put a used yoshimura pipe on my bike , has twin pod filters but new carb i know is factory.. has weak spot when given gas... wanna get a lunch box filter

What jets should i get???

We have a FAQ that is amazing.  It has a jetting matrix that would answer your questions.

http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/Rejetting

-Turd.

would i just use the performance listing...every pipe is listed except yoshi....and only list the 40 not the second jets??

alan

All pipes are the same for jetting. They differe in where they make power and where and how much noise they make.
I had a WFO, D&D can on one bike and it was a much better runner up high - 8K and up than the other pipe which was a Yosh. I put the yosh on and it promptly started behaving more mid range 6-8K than 8-10. It even lost 3-500 rpm up high. This was the same bike, back to back runs on the same day 2 way average on the 407 in ontario canada where you could do WFO runs without traffic interference.
I'd run 150 mains, 40 pilots, 1 washer under needle and 3 turns out on mix screws. They are too close to really be different for jetting, but you can fiddle and fine tune either with washers, float levels and air screws etc.
Cool.
Srinath.

will try , gonna get jets tomorrow fingers crossed... Thanks