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View Full Version : ATC 110 Engine Breaks Up At High RPM



Badbmwbrad
12-30-2012, 06:26 PM
This is my first 3-wheeler (purchased 12/23/12) and I'm becoming more skilled at riding it. It snowed overnight here on the southeast coast of Massachusetts. After clearing my raceway... er, gravel driveway with the snowblower, the "track" is coated with a layer of ice and snow. This is prefect for skidding and sliding the ATC 110 in turns and gassing it on the straight (driveway is ~ 100' wide and 200' long).

So I'm leaning it on two wheels while making a sharp U-turn then launch out of the corner down the straight; allowing engine revs to quickly build up. As the engine revs up (>5000RPM) in 2nd gear, I pin the throttle full-open. Immediately, engine firing breaks up and cuts out like there's a rev limiter circuit built into the CDI ignition. When the throttle is partially closed, engine response returns immediately.

I'm certain the carburetor pilot and main jets are clean. There's no obstruction in the air cleaner element. The sparkplug gap is OK. I haven't checked the CDI timing (not sure whether it's adjustable or not). Valve tappets are adjusted to 0.002" clearance (Thanks to 3WW, I now know it's supposed to be 0.003").

What is causing the engine firing to break up when throttle is pulled full-open at a higher RPM?

PS The 3-wheeler riding experience is unlike anything on two (or four) wheels. I'm really liking how it feels to lift the inside rear wheel in a sharp corner then gas it to spin the outside wheel and slide it sideways in the snow! :D