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Old 04-21-2010, 11:07 PM
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Motorized Bicycle Elite Member
Join Date: Mar 2010
Location: Central Texas
Posts: 5,379
Question Engine temporarily locked down but piston and cylinder are fine?

I got my new bike going today and took it for a little road trip, I had run the engine on it before on another bike so it was not the first time it had ran but it only had maybe 30-40 miles on it.

Ok.... now to my problem, I was going along fine and then I ran it at WOT for about 200-300 yards going up hill and down and then back up another hill, when I got leveled off again I backed off the throttle to a comfortable slower speed, after about an 1/8th mile or so the engine started choking down but not like 4stroking or anything like that, it was more like it was seizing up, so I back off the gas and pulled in the clutch and tried to rev it up a little but it would just barely rev and then it died on me, I stopped and let it sit for a minute and then it started back up and I got going again and then after about 1/8th mile or so it started seizing again and this time it was for keeps.

I had to peddle the darn thing back home up all those hills about 7 miles, woo wee I aint in shape for that....! but I made it home just the same.

I pulled the engine off the bike earlier and took the head off to look at the cylinder & piston, it all looks fine no scoring and the spark plug was a good dark brown color too, this engine has a pull start so I pulled it and wala, it just spun over just like it should, but I could hear a squeaking noise in the bottom end of the engine like it was dry, I checked everything I could see or try to wiggle and all seems good and tight, I pulled all side covers off and checked everything and seems good , I then turned the engine over until I could see the intake gap below the piston through the intake port, I sprayed a little silicone spray into the engine and spun it over again and the squeaking stopped and it spun very easy with no noise, I cant help but think that it leaned out real bad for a short time causing the lower end to dry out.... but, I have not run into this problem before so I'm unsure what to think about it, I'm gonna put the engine back on the bike in the morning and see what it will do now, I am also gonna mix my fuel with more oil instaed of the 70:1 full synthetic I'm running in my other engine and maybe go with about 32-40:1.

Anyone else ever had this happen?

Was I running to lean and is this the cause of the problem?

Sorry this is so long but I wanted to get all the details in here.

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