Cylinders misfire when RPM low

[legeboka]

I have new Yamaha XLT 1200 (2 stroke, 3 cylinder engine) Engine runs perfect except when I run it around 3000-3300 RPM's one cylinder misfire for a few seconds.<br />With all other RPM’s and in idle engine runs stable with all 3 cylinders. Is it normal or I have to take it to the shop for check up?

 

[Jeff Walkowiak]

Re: Cylinders misfire when RPM low

does it just miss or pop through the carb if it just misses try a new plug may just be a defective one, if it coughs through the carb its too lean and the cyl is in need of a bit more fuel

 

[ronskal]

Re: Cylinders misfire when RPM low

All two strokes are jetting sensitive with regards to temp./altitude.<br /><br />All two strokes tend to stutter, lope, misfire at some point due to this.<br /><br />It's most likely a minor carb adjustment for a pro, but not an easy adjustment for the average DIY type.<br /><br />My PWC also runs a little rough in the midrange from being a little rich (too much fuel) but this is better than being too lean.<br /><br />Throw a new set of plugs in her to rule out that.

 

[Jeff Walkowiak]

Re: Cylinders misfire when RPM low

ronskal if your 800 is acting a bit funny around 3000rpm see if your raves are a bit loose, the red caps should be all the way down, on those engines if the raves open too soon they get a bit funny around the 3000rpm range, sound like they are running a little rough, then they smooth out.

 

[ronskal]

Re: Cylinders misfire when RPM low

Jeff-I'll check the RAVES as you suggest. I usually pull them out and clean them during my winter maintenance chores.<br /><br />I believe they are rigged all the way in, but I will go check them. I was told that they should be rigged all the way in, unless you get a performance decrease.