1945 chief top end overhaul

[fizz]

Doing a top end overhaul on my chief, needs to be bored 30 over, guides, springs and valves. Ordered the parts from Jerry Greer. Found that my wrist pins were .004 oversize, but since the engine is in the frame, I am planning to oversize the pistons to take the old oversize pins. Really don't like the idea of pushing in rod bushings in the engine. Turns out, when the engine top end was rebuilt in 74', they put new pistons in a scored cylinder, and knurled the guides.

My question is, with the new import pistons, do I still follow the clearances in my original shop manuel, along with any other constructive comments. Cylinders will be getting machined towards the end of the week.

Should I worry about weighing the pistons to match what was in there, since they are old replacements anyway. Bike did run pretty smooth.

[T. Cotten]

...Should I worry about weighing the pistons to match what was in there, since they are old replacements anyway. Bike did run pretty smooth.

Fizz!

I wouldn't worry, even if they don't match each other.

If it ain't 'smooth', something else is wrong.

Honest.

....Cotten
PS: Caveat! Don't mix forged pistons in there anywhere...

[fizz]

Fizz!

I wouldn't worry, even if they don't match each other.

If it ain't 'smooth', something else is wrong.

Honest.

....Cotten
PS: Caveat! Don't mix forged pistons in there anywhere...

So I dug around a little because I was curious as why to not use forged pistons, and found Kiwi had problems with them seizing and went back to cast. Is this because a greater range in temperature happens with a side valve engine, or because of non-uniform distortion of the cylinders because of the extra casting on one side of the cylinders to accommodate the valves? just curious.