650R re-jet w/ stock muffler? semi uncork?

5 replies to this topic
  • HC

Posted July 01, 2005 - 11:22 AM


just got a 2001 650R used, 350mi, bone stock not un corked. starts easy, 3X cold, 1X kick hot.

I am first going to get it street legal ( no small task here) then address the known issues, clutch bushing, etc....

I eventually would like to uncork it but I dont want it louder then stock ( or not much) any suggestions?

Great bike, thanks for the info,

  • HC

Posted July 03, 2005 - 08:59 PM


less sound = more ground

  • desmo900

Posted July 04, 2005 - 10:32 AM


hello.. I asked the same question a while back. but no one seemed to know what to do with the jetting for a stock exhaust but uncorked intake.

So I did a little experimenting and found that 1 size smaller jet for the main and pilot than what is recommended for your area seems to work.

just be sure to check you plug color and exhaust soot to be sure your not too lean.

If anyone knows of a better way to jet for a SemiUncorked bike, please let me know.

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  • GIANTac1

Posted July 04, 2005 - 10:46 AM


where are you in washington? I am moving up there in september.....near the Seattle area...

  • smashinz2002

Posted July 04, 2005 - 08:23 PM


Try drilling the stock exhaust tip to a diameter of 34mm or 36mm, what this does, is to open the exhaust slightly, but preserve the spark arrestor and internal baffle. And at the same time allow for richer jetting and less restrictive intake mods for much improved power. You have to work at pulling out the fiberglass wrapped tube in there, but it's worth the effort.
This mod is not loud, and you can then run a 160 main jet, or smaller for higher altitudes, like a 150 or 155. You can also include all the rest of the uncorking mods, the 40mm intake boot, the B3E jet needle in 3rd position, or stock needle in 4th position, and the airbox snorkel and restrictor plate removed. It's optional to change the pilot jet, I didnt, because my bike still starts just fine.

'00 XR650R/uncorked/jetted/street legal
'05 DR650SE
'04 KX500/fmfgnarly/vforce reeds

  • HC

Posted July 04, 2005 - 09:29 PM


thanks for the info,

man, starts 3rd kick everytime, easy.

giantac1, I'm 70 miles north of seattle, grew up there

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