Took the engine out of my sons 2001 Quadsport 80 because there was a knock of some sort. I don't know if the knock was from the connecting rod bearing or the wrist pin. I don't have a shop manual. So I haven't tore it down yet. How difficult is it to remove the connecting rod from the crankshaft? I've rebuilt dozens of SBC's. Never rebuilt a little two cycle engine though.

Take all the help I can get, thanks, NYH1!

 

It's nothing like a SBC. The big end does not come apart. The crank comes as an assembly and it's pressed together. Pretty much a non serviceable part.

If the rod is the problem you buy the rod and crank as an assembly.

 

Thanks for the reply. So I guess I should just go ahead and take the head and or jug off and go from there? Is it easier to tell if it's the wrist pin or bad rod/crank bearings?

Thanks, NYH1!

 

Yep, should be easy to tell when the jug is off. Good luck man, and let us know how it went.

 

The knocking may be a wore piston and yes, get the top end off and see what the piston to wall clearance is.
Wiggle the rod side to side and up/down. Try to notice any movement with the exception of minimal side to side motion. That's normal.
I've not ever seen a piston pin brg go bad on these.
FYI: the good dr.turbo is correct in recommending a new crankshaft. By the time you buy the rod kit and get it installed, the new crank is only a few dollars more...And it's straight.
Splitting the cases (apart) is easy. Getting it together without binding the crank is the trick.
I use alot of heat.

 

You've never seen wrist pin bearings go bad? So chances are it's the rod/crank bearings then?

 

I'm sure a pin brg could go bad but the odds are it's another problem.

 

Thanks.