Crank knock

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Postby detroit » Tue Aug 31, 2004 12:44 pm

In rebuilding, re-assembling a 185, I rotated the crank by hand thru the bottom of the cycle and going from down to up I get a small knock noise. Guess my questions are:
1. Am I SOL with this crank or will it still work reliably..?
2. Is separating the crank for new connecting rod a pain and or expensive..?
3. What are my (reasonable) options..?
4. Any used cranks for sale out there..?
Any other comments are appreciated. Thx
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Postby ozzie » Tue Aug 31, 2004 5:16 pm

before you go pulling the crank apart check the piston pin for wear. more common than failed crank bearings. if you have not fitted the piston yet check the side play on the conrod. roller bearings usually rumble when worn piston pins rattle. and slipper bearings knock.
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Postby Guest » Tue Aug 31, 2004 5:33 pm

The piston does rock longitudally (the wrong way) over the pin but the wrist PIN is very tight in the piston. All the way thru putting it in. This tells me either needle cage bearing worn or top hole in connecting rod worn. If so, options..? Are there oversized needle bearings around.
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Postby Guest » Tue Aug 31, 2004 6:20 pm

Doesn't sound as if you have a problem at all. If you are rocking the prop back forth quickly with your hand and hearing a slight "tock tock" noise it's entirely normal. Being unfamiliar with the engines could lead you to the conclusion you have drawn however. Not saying something isn't wrong with the engine its just that the engines do make a noise if you rock the prop.

What exactly are you doing with the prop (crank) to produce this noise.
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Postby Guest » Wed Sep 01, 2004 7:29 am

I just put the jug and head back on, no prop yet, and by hand rotate the crank thru the bottom of it's travel and then up just a little. Turning the crankshaft by hand back and forth, back and forth thru the bottom of rod travel. As it changed direction (from traveling down to up) is when I hear this little knock.
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Postby ozzie » Wed Sep 01, 2004 4:44 pm

yes this sounds normal can you compare to other engine. with wrist pins and bearing usually replace piston ,pin and bearing as set.
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