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XVS250 rev issues

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Brooksy08, Jun 29, 2014.

  1. G'day all! I'm a 35yo rider from Darwin and my daily commuter my Yamaha XVS250 2006 has been having some rev issues lately. I've had this bike for a while now and makes a great cheap commuter. When I first got it it would quite happily sit on between 110-120kms all day without an issue. In the last month to 1 1/2 months it gets to 100 km/h and within a few minutes it starts to struggle, like it's struggling to get enough fuel or it's being choked. Once it starts struggling the only way to make it stop is to pull the bike over, at which point it stalls then re-start it. On re-starting it, it struggles for 5-10 seconds then it's back to normal. I have had several mechanic look at it, have replaced the manifold/carburettor joint (under the carbie) as the old one had cracks in the rubber. I'm thinking there may be a air leak in the carbi, such as a missing O-ring. The jets have been cleaned several times and this has no effect on fixing the issue?! Has anybody else had a similar issue?! Would love some help if you might know what the problem might be.

  2. It does sound like a fuel restriction. There are a couple of things that can cause this. You first need to determine if the problem is in the carburettor, or in the fuel supply system. Disconnect the fuel line at the carburettor and place a container under it, then start the engine. There should be enough fuel in the carburettor to run it for 30 seconds or so for this test. You should see fuel pulsating out of the line at a good rate.
    If it barely pulsates & only just drips out then you know it is a fuel supply issue. If so then it could be a faulty fuel pump or vacuum hose fault going too fuel pump. Could have blocked fuel tap, blocked fuel line fitting in tank, blocked filler cap breather.
    If fuel supply is good, then inside the carb there is a filter on the back of the float needle seat. This could be blocked restricting flow into the fuel bowl. Also check that the fuel bowl vent pipe is clear.
    • Agree Agree x 1
  3. I have also seen a faulty voltage regulator / rectifier cause a CDI unit failure / running issue. These were a common problem on the XV/XVS 250. Check your charge rate to make sure it is not going above15v.