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Norm's 2 stroke repair center Having problems with you 2 stroke motorized bicycle engine? Just ask Norm. he loves to tinker and troubleshoot engines.

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  #1  
Old 10-02-2009, 04:00 PM
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joek joek is offline
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Question wrist pin needle bearing

also posted in 2 strokes, could not figure out how to move it here

I have a BGF Z50SL that I pulled the top end to clean out swarf from the crankcase and cylinder. the wrist pin
bearings radial freeplay feels ok, but the axial play seems excessive, the piston, wrist pin and bearing will rock side to side in the rod jounal about 5 to 10 degrees. is this normal for these engines?
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Old 10-02-2009, 05:59 PM
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Default Re: wrist pin needle bearing

unfortunately some are worse.
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Old 10-02-2009, 09:22 PM
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Default Re: wrist pin needle bearing

Quote:
Originally Posted by Norman View Post
unfortunately some are worse.
should I expect bearing failure? think I prefered a bushed small end. had a '55 motobecane with bushings I sold to a neighbor that still runs like new. Joe
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Old 10-03-2009, 05:10 PM
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Default Re: wrist pin needle bearing

you should see how sloppy my bushed wrist pin engines are compared to the needle bearing ones. I was going to replace the bushing then decided to go for it over a year ago still going strong look at the total tear down post that is the engine I was worried about I rode it today its still running great. I have been running all my engine lately on an oil sold at walmart polan syn 2 stroke oil at 40 to 1 runs better than on the 32 to 1 mix I've been using I also run the cheap regular gas with the ethanol for me its working great. this oil don't seem to leave any smoke either.
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Last edited by Norman; 10-03-2009 at 05:13 PM.
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Old 10-03-2009, 11:40 PM
donuts31 donuts31 is offline
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Default Re: wrist pin needle bearing

I miss my Kingsmotorbike bushing engine (purchased 4 years ago). It was the most powerful engine I've ever owned and I traded the bike it was on for a 25 year old Jeep. It was a mistake that I regret each time I ride one of the newer engines.

Point being is that I never had a HT bushing engine fail on me but I've had a roller bearing cage disentegrate taking the top end with it.
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Old 04-16-2010, 04:54 PM
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Default Re: wrist pin needle bearing

had a mate bring his bike to me saying it was a bit rattly took it apart ! no bush in the piston at all was still running! got a machine shop to turn a new one up,couldnt find the standard size one,going great now.
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