help with Older thumper

5 replies to this topic
  • groovatic

Posted April 25, 2002 - 03:56 AM


Hey I have a wonderfully restored 85' XR600 with the pesky two carb. config. The bike ran great up untill I was riding around 50-60mph on an old railroad bed, (was a little whoopy hard to keep the bike on the gound) and every time I hit a whoop, the bike would quit for a sec and then come out of it. It was realy annoying. Then My buddy caught up to me and we stoped for about 5 minutes. It restarted fine and then I went to take off again. No power and it skipped and sputtered. I have fine comp. and the comp. release was off. No smoke 'cept the usual small amount of blue from an older engine. It idles great starts great but it doesn't like getting on the throttle. Wazupwitthat?

  • Matt96xr6

Posted April 25, 2002 - 04:53 AM


Sounds like the floats need adjusting and maybe a new needle spring also.

  • ossagp1

Posted April 25, 2002 - 08:39 AM


I have owned two of the twin carb machines and i agree with Matt. Make sure that the crossover from the side with the float is flowing free too. Otherwise the side that should come in at higher throttle settings wont. The downside to this setup was that it was expesnive to produce,,,heavy and hard to tune. The upside is that it is worth a couple of more hp than the single is when it works right and you will never need to buy bigger if you hop way up. You can bore them oversized if you like.

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  • johnsxr

Posted April 26, 2002 - 03:34 AM


have you checked the fuel system for water ? pull the 17mm caps on carb bottoms - catch what comes out and check it for water contamination!!!
john 84 xr500r!

  • sixr500

Posted April 26, 2002 - 07:10 PM


Hellloo, Groovatic, I would agree with my buddy johnsxr! Did you have fresh gas in the tank?? I am in bangor and I am interested in places that are cool to ride, and palmyra is only 45 minutes away. I would like to hear from other riders in maine for some good woods trails/pit rides!!
si 83 xr500R

[ April 26, 2002: Message edited by: sixr500 ]

  • groovatic

Posted April 27, 2002 - 04:36 AM


Palmyra is a great place, but I just moved here myself just a while ago and am still exploring the places around here. Thanks for the tip about the water- somehow I dont think that is the problem though, I opened up both the jets on the bottom of the carbs and found fresh gas comming out, I did fire it up for a spin around the field and it seems to be running better, but it still skips and pops at the high end, Ittl still pull great from the bottom like a truck! Palmyra has an old railroad bed that crosses through to Pittsfield and you can realy cruse on it. I even goes through the middle of the towns, so gas is not a problem.-but I dont know how far it goes yet- still not ready untill my bike is running better - Ciao~Ed

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