Disappointed! Bike running slow


New Member
Local time
8:14 AM
May 29, 2008
Des Moines, Iowa
Trying to ride my bike this weekend to save some money on gas and all of a sudden it will hardly break 20 mph. Like it has a rev limiter that it is bouncing off of or something. It is a BGF 80cc and I just got it broke in (barely) was running good the other night and would zip right up to 35mph but was starting to notice that it seemed like it starved out a bit up there. Didn't do that when it was first broke in. Now it is gutless and even seems like it starves out at 20.:cry: Someday's it feels like I can't win for loosin'
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the plug was a descent med brown, not too rich or too lean. I cleaned it up on a wire wheel just to take the light carbon off it but it made no difference at all. It was in the rain a couple of times this week but I would not think that has affected it. It does run smooth up to that 20 mph mark, but again, it feels like it starts bouncing off a rev limiter or a governor.

Also, I am still running the original plug, it came with 2 but I can't find the other one at the moment. Does anyone know the AC equivalent # or of some brand interchange?
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Check your exhaust for any carbon buildup. That happened to mine earlier on then decided to do the DAX mod and opened it up. It's a bit louder now but the power is there.

(Dang. The Dax page with the muffler mod isn't there any more. Basically take off the cap,drill holes in the tube or just cut half of the tube off enough so that the tube doesn't go in that little hole anymore (You'll see what I'm talking about when you take that cap off),install just the cap back on if you cut it off. Then some people added some steel wool to muffle it somewhat. Mine's all open and loud. Remember to put that cap back on. Leaving the cap off is bad. The engine needs back pressure.)
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Have you taken your air cleaner off and made sure the throttle slide opens all the way?

Also Maybe you have a fuel constriction - or your tank is not venting.

Large has a good suggestion - exhaust blockage will give similar symptoms.
I blew out the coil and plug wire, test drive fine until 20 mph, took baffle out, test drive = fine until 20 mph. is there a pick up coil or something in the motor that I should blow out?
NGK B5HS or B6HS and currently I'm running a B7HS and it does just fine.