Late 90's Jetting - Yamaha Pro Circuit

[Crazy]

Could anyone tell me what jets they are using with a 1996 yamaha yz250 with a Pro Circuit Platinum pipe. The bike ran perfect before the pipe, then after installing it, the bike really hesitates in the low rpms then comes on strong but not like the original pipe. If you have this type of combination of bike and pipe plz help I saw FMFs jetting guide but pro circuit doesnt have one.

[Aus_Rider_22]

Sorry I don't have model specific help, I would just go with what the FMF site says.

Both the PC and FMF exhausts will do the same thing and allow a better exhaust flow, so this would create a slightly leaner mixture. I would increase pilot jet size and see if that has any effect on bottom-end performance.

I bolted on FMF Fatty pipe and FMF silener to my bike and did not require to change jet sizes or fiddle with carb settings.

The only adjustment I made is moved clip up one position to give crisper jetting across whole range.

It's funny how you can never really recommend the exact specifications. Too many variable involved in jetting. Mods, altitutude, temperature, season, and general mechanical condition of bike effect the jets that allow optimum performance.

[Crazy]

Alright Ill try those off of FMF. I couldnt believe it either that the bike changed that much just from changing the pipe.

[KXYZ Guy]

Let me know if you figure it out. I just got a 98 YZ250 with a PC Platinum and it does the same thing. It would be nice to know where to start.

Also, can somebody point me out what size jets I have? They are all stock. I bought a Clymer but it says I have a Mikuni carb so thats obviously not going to help. I need to figure that out before I can start messing with the jetting.

[Crazy]

Im going to try taking it apart in the next few days, Ill let you know how it goes.
And I believe stock was 175main 38pilot 3rd clip

[zuki]

Originally Posted by KXYZ Guy

Also, can somebody point me out what size jets I have?

Take apart your carb, and then take out the jets. The numbers are stamped on the jets