XR650 Jetting with Big Gun exhaust system?


Can anyone tell me the jetting set-up for a 2001 XR650R that has been uncorked, air box cover drilled and has a Big Gun pipe and silencer?

I have a 175 Main and 65s pilot now and the bike runs way too lean throughout - it is slow and pops when decellerating.



68s, 70 or 70s pilot, b53e neddle 3rd clip, 180~185 main sea level California.

I ran 70s main, b53e, 185 main with header and free flowing muffler, holes in the side cover. 70 without the 's' is leaner then a 70s.


These are some of the things I started way back when I had the stock carb in 2003. Jetting a little rich sure does help get rid of the off idle dead spot when you whack the throttle real quick.

I ran 70s pilot, b53e needle 3rd clip, 185 main, UNI air filter fully oiled, Holes in the air filter side cover, XR's Only header, R4 muffler, AJCV disengaged, Choke flap removed (it also allows just a little more flow), HRC intake boot (carburetor insulator) sea level to 4000'.


I found the bike to start easier when full chock was needed. I was running a 70s pilot so, a little more air would be needed then would be needed for a 68s or a stock 65s. I really liked the 70s with the idle mixture screw a little more then half a turn out. My bike was a one rarely a two kick to start bike. LockTite the screws.

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