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Discussion Starter #1
Hey guys, I've got a weird problem that the mechanic is having a hard time duplicating. I'd love to hear some advice as to what I should do.

I've got a 2010 Buell Blast (I know, I know...) and it's been great as a starter bike, but over the months it's gotten a bit harder to ride for longer periods.

Basically, here's what I know happens:

1. When I first start the bike, it starts right up but if I give it much throttle after the automatic choke reduces the idle speed it will backfire and die. Since the bike's got a carb instead of FI, I think this is normal. Is it?

2. After riding for a few minutes (maybe 5-10 at 45mph or so), the bike will feel like it's losing power periodically. Every once in awhile it will even cut out entirely and leave me gliding to the side of the road. It feels better when I throttle the bike up a bit, but if I let the RPM go down it sputters a bit more.

The mechanic says they can't reproduce the issue (especially not the second). I had to get it to a licensed H-D dealer since I don't know anywhere else that wants to work on a Buell. People seem to be afraid of them.

Any advice? I can't get a new bike until after I move, and I really don't want to miss out on a riding season because I'm afraid to take longer rides on the Blast.
 

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Intermittent problems could be the CDI unit - had similar happen to me - kept having to bump start a 750 - I was younger and fitter back then - see if you can borrow one to see if it fixes the problem
 

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The symptoms seem to say restricted fuel supply; the idle jets are often the first to stop working as the level drops in the carb. Over-filling can cause similar issues, so a sticking float valve could be causing it. Look at your spark plug - white is hot, or too little fuel, black and soft is too much, black and wet is WAY too much. Do this as soon after a stall as possible, without starting it again.

But, electrical problems often mimic fuel problems. Check the battery Voltage, while riding, if possible. It should never go below about 13V. If that's OK, then have a close look at the ignition, as DBB suggests.
 

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Discussion Starter #4
The symptoms seem to say restricted fuel supply; the idle jets are often the first to stop working as the level drops in the carb. Over-filling can cause similar issues, so a sticking float valve could be causing it. Look at your spark plug - white is hot, or too little fuel, black and soft is too much, black and wet is WAY too much. Do this as soon after a stall as possible, without starting it again.

But, electrical problems often mimic fuel problems. Check the battery Voltage, while riding, if possible. It should never go below about 13V. If that's OK, then have a close look at the ignition, as DBB suggests.
I'll give the mechanic some better instructions and see if they can reproduce the stall and diagnose it, otherwise I'll get them to check the fuel supply to the carb and make sure there's nothing simple there (like a bad filter or water getting into the carb).

Thanks for the help!
 

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Discussion Starter #5
I'll give the mechanic some better instructions and see if they can reproduce the stall and diagnose it, otherwise I'll get them to check the fuel supply to the carb and make sure there's nothing simple there (like a bad filter or water getting into the carb).

Thanks for the help!
I got the bike back today, they say they spent an hour and a half trying to duplicate the problem but I'm a little doubtful. As soon as I got it back and roe it off the lot it started surging a little while I held the revs steady.

Once the rain lets up and I get a little time, I'm going to go ride it for awhile and then check the spark plug as soon as it starts showing problems. Hopefully that will lead me down a better road and I can go to a mechanic with a "Hey, please do this exact thing." rather than a more generic "I don't know what's going on.".

They did adjust the idle revs to be a bit higher, which seems to help keep the bike from dying. But what I've noticed is that it doesn't seem to address the problem - which is that there are periodic misfires. It feels like something isn't getting into the carb right - fuel or air. But if I keep the revs up high enough I either don't notice the misfires or they don't happen.
 
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