Juicy quick mods for xr650l???

7 replies to this topic
  • xlr8r

Posted April 01, 2005 - 12:22 AM


Hey guys,
I've got a nearly straight stock 2001 xr650l (i'm with the 'if it ain't broke don't fix it, just ride it' crowd). I know, I know, don't laugh. Anyways, now that it is broke and I am fixing it (I'm replacing the cam chain and clutch), I'm wondering about any quick power up tricks i can do while i've got the thing opened up and stripped down. I'm thinking in the range of less-than-$100-kind-of-tricks since I've already blown a couple hundred on not so fun things like gaskets and chains. Can anybody mention some things that I can look up as how-to's on the TT site? :D :naughty: :cry: :naughty: :D :D :D

  • roadcam

Posted April 01, 2005 - 05:28 AM


look for the "uncorking" mods listed in this forum frequently .. you should be able to find it just going back a couple of pages ... also may want to gear down a bit, stock gearing is way high ... I run 14/48 for 70% off-road, 30% on-road, works for me

  • ghoti

Posted April 01, 2005 - 08:10 AM


As long as you have the head off you could go with a thinner base gasket to increase compression, about $40.00. But you said you already bought gaskets. How about a port and polish on the exhaust side, slight port on the intake, the cost of some grinding stones? The clutch was gone already? And the cam chain? How many miles on the beast?

  • truck6driver

Posted April 01, 2005 - 08:21 AM


I'm with ghoti, Mild port job on the exhaust ports and header welds to smooth out the gas movement.

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  • DualSport650

Posted April 01, 2005 - 09:16 AM


Here's a list of things you can do to make your XR650L rip...

* Remove airbox restrictions - rip of the top snorkel, etc
* Get a UNI air filter - use No-Toil oil and grease
* Remove the EPA smog stuff
* Grind out the extra welds in the header inlets
* Get an aftermarket muffler - Yoshimura RS-3, etc.
* Get a cam http://www.thumperta...ad.php?t=239234
* Re-Jet the carburetor properly

That should be good for at least an extra 10 horsepower.


  • xlr8r

Posted April 01, 2005 - 12:22 PM


16k miles on it. I'm replacing the cam chain and friends because I'm trying to solve the mystery "chain-buzzing-cold-start-noise" that's getting worse, which i've been reading about on TT but found no solid answers on. I'm overly paranoid about mystery noise. As far as the mods go, how do I identify the "extra welds" on the port and/or header that i'm supposed to grind off? Is it just a smooth it out kind of deal? Does that require any attention to the jetting? By the way, thanks for all the advice guys!! :naughty:

  • DualSport650

Posted April 01, 2005 - 12:36 PM


Just un-bolt the header and look inside the holes. You'll see some nasty sloppy welds that make the holes smaller than they should be.

I did this with my old XR600 and it made quiet a difference in power. Not a huge difference, but definitely noticable. The welds on my XR600 were sloppy and made the header inlet holes way smaller than they should have been.

After you do all these mods, then re-jet it and your bike will rip. :naughty:

Get some...

  • ghoti

Posted April 01, 2005 - 01:18 PM


There was a post on the cold start-up noise. Seems like everyone's does it.

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