Originally Posted by Jumpa
Very true Map different size pistons as well.
Is it the Gurbee that has the piston hole higher than the rest ? I found that out the hard way . Good thing I tested it out before I put any type of torque on the motor. I had my piston bottom out on me on one 66/cc
I had grabbed the wrong piston it was about a ¼ inch to high on the center con-rod hole on the piston making the piston bottom out on the crank So no they are not all interchangeable parts. I've even seem completely round cylinders even ..I meant to ask someone on here about that too.
How about the 66cc motors with the 6 mm head bolts , I got one of those in the mail and was not happy
As a rule if the cylinder, or the cooling fins have a more round, or cylindrical appearance that is one indication of it being the smaller, 48cc engine. The cylinder stud diameter is another 'general' indicator. The 6mm stud engines were almost exclusively the lesser displacement while those having 8mm studs were the larger.
Keep in mind that we're dealing with quality control and manufacturing practice that differs from what we are used to in American made products. There are no hard and fast rules that apply but again, generally speaking, if the cylinder fins are round, it is a 48cc. If the studs are 6mm, it is a smaller engine. That said, the ONLY way to be sure is to measure the bore and stroke of whatever engine you have to be certain.