Hi. I'll start with the problem. Dropping a new top end in my '74 RD350. Left side slides right on.
Right side won't go into the case without some pressure (without rings.) When on and torqued, the right piston drags in spots. The outside bottom piston skirt was contacting the cylinder. I re-checked the bore clearance (.003.) I'm suspecting a PO over rev.
Bent fucking con rod, right? What else could it be?
Everything fits great till U put the wrist pin in.
You could rotate the crank, with the cylinder off, so the rod is at BDC and look to see if the rod is evenly spaced between the crank flywheels and not leaning towards one side.
as stated check position at bdc and tdc if possible. bent rod typically won't cause problems with rotation believe it or not, but a warped cyl liner will, especially if it was bored incorrectly.
Yes, did some research and the Harley guys have a wrist pin sized rod to check against case deck.
A guy also got 2 machinist quality beams (below or above the wrist pin) to raise or drop onto to check alignment against the case. Also, I was able to check old 250cc piston for wear marks and found a lot of blow by on one side of the piston. So, it was running before with the bent rod but seems the tolerances were larger and piston clearance was not an issue. Doubt I'll be able to straighten.
Why do you think that over revving would have caused a bent rod?
if the rod is indeed bent its fucked. throw it away.
I bent a conrod once, pushing too hard on the piston pin to get it out. I had the crank was rebuilt to fix the problem. Use a piston pin puller to remove stuck piston pins.
I don't know if that was the cause of your problem.
I'm a cause and effect kinda guy so I want to find out what happened.
I have never seen it personally but, I have heard over-reving can cause
rods to bend. The banging on the wrist pin thing could have happened too,
not by me, the top end was 3 over.
Now that it's out, I'm not sure both of them aren't bent.
You can also see how crooked the piston was riding.
Pictures aren't working today, I'll try later.
is it bent to the side or front to back? if its to the side it was from a ham fisted repair IMHO. I've spun the motors and others wayyyy past where they should be. so far on one motor I actually cracked a piston in half across the top of the dome wrist pin hole to wrist pin hole, only thing holding it together being the rings. I'm dead serious. but the rod was fine. .02