help with 1986 xr600r jetting and modding

2 replies to this topic
  • 77 chevy k30

Posted December 15, 2008 - 03:12 PM


I got a 1986 xr600r, so far no one makes an after market jet kit for this bike or anything else it seems off the shelf to increase performance. I have read of people "uncorking" a bike, does any one have any suggestions to make some mods to this bike. So far its completely stock and with stock exhaust.

Can i change jets?

Can i "uncork" it, and how?


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  • KAS

Posted December 15, 2008 - 04:23 PM


A lot of times in this forum you will read about people "uncorking" their XR650R's, which come from the factory with a number of odd restrictions.

The best way to "uncork" your 600 would be an aftermarket exhaust. FMF makes a Powercore IV, or a Q4 (more quiet version) for your bike.

Also, you could get an aftermarket air filter, like a Twin Air or Moose. They usually flow a little better than the OEM stuff. If the airbox has a removable snorkel in the top (I can't remember if the '86's do), pull it out and toss it.

I wouldn't worry about a "jet kit", you can just buy the jets individually. I can't tell you specifics since I have no idea what stock jetting on your bike is, but generally an XR with a different pipe & filter will at least need one or two steps bigger on the main, and maybe one size larger on the pilot. I believe your bike should be a dual-carb, so you would need to buy two main jets.

  • cleonard

Posted December 15, 2008 - 08:51 PM


The 86 XR600 is pretty "uncorked" compared to the later bikes. With the dual carbs it makes more power than the later bikes including the larger displacement XR650L. The main thing to mod is the restrictive exhaust. Do some searches to find what to do with the jetting.

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