pro circuit T4

Just got hold of a s/hand T4 muffler for my 01 WR400.Anybody got any ball park jetting specs.Currently got 42 pilot,1 clip richer on standard needle, 172 main, standard was 165. Bike was near perfect with this jetting with stock Aussie muffler.Any help would be good



2001 wr400. still setting up

Forgot to to put in that I ride mostly between 0 to 500 meters above sea level

Fitzy, I have the same version of the WR426 that you have that came with that Euro/Canadian muffler. I bought my pipe from Pro-Curcuit at a race for a discount (not really) and had them install it. They told me not to change my jetting at all and to leave it stock, I too ride at sealevel. But like most guys I wanted to make sure that I was getting the most out of my bike so I tried every combo of main and pilot jets and different clip positions only to find out that nothing worked for me, I mean I foulded plugs, the bike popped and spat up and never wanted to start. Alot of guys on this site have spent countless hours of testing different configurations for the bike and for the life of me I can't get my bike to work any better than stock!!

Best of luck to you!!

Cheers, Dan

Dan. Thanks for the reply. Rode the bike on the weekend with the pro circut and just like you I found the standard jetting just fine. Might just richen up the needle one clip , just to be safe for a while.

Thanks again


Fitz, If you do rejet please let me know what you find. Thanks


Hope to get out in the next week or so. Will let you know what I find




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