wrist pin needle bearing

joek · #1 (**permalink**) 10-02-2009, 04:00 PM

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?

**Norman** · #2 (**permalink**) 10-02-2009, 05:59 PM

unfortunately some are worse.

joek · #3 (**permalink**) 10-02-2009, 09:22 PM

Quote:

Originally Posted by Norman

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

**Norman** · #4 (**permalink**) 10-03-2009, 05:10 PM

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.

donuts31 · #5 (**permalink**) 10-03-2009, 11:40 PM

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.