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I am wondering if anyone can shed light on an issue we are having with this particular bike. Basically, the bike starts fine cold and warms up and drives perfectly for about 15 minutes ( responsive to throttle, idles great) . But, after this time period the bike then seems to run lean and then will barely start. Any throttle applied after it falls into this condition stalls the engine. If you let the bike cool off, it will again be perfectly operational.

We took the carb completely apart and cleaned it. Everything looks good inside - floats look like they are working etc. We opened the gas lid to activate vacuum, no response. Can anyone throw some recommendations at us? I'd be happy to post a video of the the bike operating if needed. Thanks for any help.

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When it starts running lean and all that, does the way it runs improve when you open the fuel filler cap? – Timo Geusch May 15 '12 at 1:18
Are you sure its running lean? what colour are the sparkplugs when the engine stalls? is there a lot of soot at the exhausts? – Mauro May 15 '12 at 7:06
No, opening the fuel cap doesn't help. Doesn't seem to be any soot or anything. We assume its running lean because it seems like it needs gas - when you open the throttle it stalls. I can post a video of this on youtube or something i think that might help. I'm not sure what other information can help at all. – user190084 May 16 '12 at 18:20
its odd because it starts up and runs seemingly perfectly for 15 or 20 minutess then it just doesn't work – user190084 May 16 '12 at 18:22

1 Answer 1

If it has an automatic choke then make sure that is operating properly i.e., turning off after a minute or so. If it's a manual choke then disengage it once the motor is warmed. Riding a mile or two is sufficient.

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