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2-stroke "gurgle"

Joined
Apr 12, 2007
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#1
I noticed that after I warm my 93' RT180 up and begin to ride it's very gurgly and poppy. The throttle is very responsive, but it just runs rough. I know it's a 2-stroke, so it's not going to be the smoothest motor in the world, but this is striking me as simply too rough.. almost jerky.

I was thinking of checking the reeds to ensure they're operating freely and close tightly, I have been getting some deal of backfire lately, but it happens so infrequently I can't tell whether it's out of the tailpipe or the carburator.

Any suggestions?

Dan
 
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Mar 30, 2006
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#2
If it's only the first minute after you warm it up and start riding thats just the motor clearing itself out. Most bikes tend to be a bit boggy but they usually clear out pretty quick.
 
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#4
Well, it's poppy, it backfires now and again, and at 1/4 throttle just putting around under the power band, it's really jerky and has a lot of hard vibration, making the front fender bounce up and down like crazy.

Once I open it up it smooths out a bit, but once I try to just cruise around it gets jerky-vibration again.

This is a reed-valve bike, and I'm almost tempted to check the reed cage to make sure the reeds are snapping shut tight enough.

It idles fine, and runs OK in the power band and on the high-end, it's just under the power band is HORRIBLE... and this is after a half-hour of riding, it still does it.

I just didn't know if it was supposed to be THAT rough, because it's kinda bothersome.

Dan
 

BSWIFT

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N. Texas SP
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#6
I would suggest that you check the top end. The rough running at start up is common with Yamahas, they're cold natured beasts. Being a 93, I would suspect some wear on the piston and cylinder and possible the rod bearings. Checking this is pretty simple on the RT and would cost you rings and gaskets at minimum. If your reeds were the issue, I would suspect that showing up more in the higher RPMS than lower but I could be wrong, I've never experienced bad reeds and I've had 15 Yamahas over the years.