I was cleaning the carbon off my piston and while scraping, noticed that the piston can rotate ±5 degrees in the cylinder. Shouldn't it be completely constrained, except for up and down?
Is my wrist pin wearing out? Thanks for any help
oh man, no no no. if it is twisting, you need a new gudgeon pin and bearing. its ok if it has a slightly side to side perpendicular to the rod, but twisting is a sign tht wrist pin ( gudgeon) bearing is bad or not the right one. i use a wrist pin bearing made for stihl chain saws. it's slightly wider and thicker than the stock bearing. i get it from a small engine and power tool shop a few miles from my house. they cost me like 5 bucks each. well worth the money when you compare to a new jug, pin, piston and rings.
Sorry to bring up an old thread but I finally have my engine apart. The play isn't as bad as I thought before, but the main wear seems to be the crank bearing. Significant side to side play, but only about 0.1mm end play.
Not joking. The generic 66cc engines are really that bad, right from new. I laughed for ten minutes when I unboxed and opened up mine.
Idk what else you can do with it, unless you're actually set up for pressing cranks apart and back together.
Well hey, if it's been that loose from factory, it's definitely served me well.
Nope haha definitely do not have a press, I've only just bought a Dremel LOL.
I'll keep this crank then and put it back when I've finished port matching. Thanks for the help!