Flapdoodle
Member
I was not real pleased to find my roller cage sliding back and forth either. Next time it is apart I will put 2 short lengths of brass tubing on either side.
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Needle Bearing on Wrist pin Loose?
- Thread starter Russntustin
- Start date
Russntustin
New Member
Well, the piston and con rod will be held in place in the cylinder but that bearing cage still has the ability to shift either way on the wrist pin. My con rod has two oiling holes. This just doesn't seem right but i don't know these things. I will look into the wavy washers. Or the tubing spacers maybe. I'm anxious to get it back together but......
Sorry for the bad picture....but you can see what I mean.
Sorry for the bad picture....but you can see what I mean.
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Skyliner70cc
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I had to install a new top end and put new bearing in it. I don't idle my engines anymore with the bike on its side kickstand.
Flapdoodle
Member
After some though and the possibility of dropping the short brass tubes I though of earlier into the crankcase, I think this might be better. It would be made from piano wire (spring steel wire) say .020-.032" diameter. It could simply be pressed into place using needle nose pliers.
arceeguy
Active Member
I'd be afraid that the piano wire would let loose from the heat or reciprocating motion and get caught in a port.
My only concern with the wavy washers was that the extra weight would throw the engine off balance, but it turns out it doesn't vibrate any more. Chances are, these engines aren't "precision balanced" to begin with anyway.
There is probably no need to do this at all, because even if the bearing is all the way to one side, the rollers are still contacting the entire rod surface. The picture shows something that cannot happen in the engine, and that is having the rod not centered in the piston. I threw the washers on just to make myself feel better.
My only concern with the wavy washers was that the extra weight would throw the engine off balance, but it turns out it doesn't vibrate any more. Chances are, these engines aren't "precision balanced" to begin with anyway.
There is probably no need to do this at all, because even if the bearing is all the way to one side, the rollers are still contacting the entire rod surface. The picture shows something that cannot happen in the engine, and that is having the rod not centered in the piston. I threw the washers on just to make myself feel better.
Russntustin
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Skyliner70cc
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You should cut the rest to size and sell the "spacers" to us for 5 bucks shipped
heathyoung
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Nice - chopped up on a lathe I assume?
The clearances on these engines are abyssmal - sloppy engineering at its best. I wonder if a longer (wider?) bearing would be a solution as well?
The clearances on these engines are abyssmal - sloppy engineering at its best. I wonder if a longer (wider?) bearing would be a solution as well?
Mountainman
Active Member
what was that THING falling off ?
I like your idea -- but I wouldn't want to try that on mine
we don't wish for our THING to fall off at high rpm
she asked "what was that"
noTHING dear !!!
ride that THING
I like your idea -- but I wouldn't want to try that on mine
we don't wish for our THING to fall off at high rpm
she asked "what was that"
noTHING dear !!!
ride that THING
arceeguy
Active Member
It's not "sloppy engineering" - the engineering is what it is. Sloppy fit and finish? Yes. But remember that for an internal combustion engine to even run, there must be a fairly high amount of precision in the manufacturing. No doubt these engines could be a lot better if more attention were paid to the little details.
