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After my 25 mile ride home the other night from work I sat outside my garage for a little while listening to my BA and watching the tach. It sounds to me like one of the cylinders is missing just once about every 3-4 seconds. The tach drops a few hundred RPM just for an instant and then goes back up. Like a few others here my bike idles around 1100 until it warms up and then it seems to like to idle at about 1600 but otherwise it runs great and I haven't noticed any hesitation or power loss when riding.

Any comments or suggestions?

Thanks,

Keith

Sounds like a vacuum leak to me.....

check those carb ballance vacuum caps. another guy had the same problem and his rubber cap was cracked or missing.

cat

Running a vacuum line from one carb to the other can help even out an unsteady idle. Of course, if it's actually missing that won't fix it.

Matt

Sorry it took so long to get back - had a few gigs this weekend.

That's an interesting idea Matt. I checked the rubber caps and they all look fine, are pushed all the way on and tight. I removed the AI system long ago so I don't have that line to worry about. I'm wondering if it may be electrical somehow or possibly an artifact of the bike running slightly lean?
I'm guessing it's running a little lean since I haven't drilled the plugs and set the adjustment screws. Likewise, in some ways my BA exhibits the same behavior the Trophy did with the fast idle. Adjusting the air adjustment screws on the Trophy fixed that problem.

Keith