sheared the shaft today Easy fix?

G

Gottohaveitnow

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Oct 11, 2015
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Ontario
Friend sent me this picture of the sheared shaft. Looks like he was left holding the starter flywheel/gear?
Anyone have any spare parts to fix a 2003 sx viper? located in Central Ontario.IMG_0655.JPG.jpg

Any help would be great
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That is the crankshaft that broke. Someone has some serious work ahead of them. New crank and full engine rebuild. I would also try to find the root cause. Motor mounts possibly, or over torquing the primary, or beating on it with a sledge hammer. Did the engine seize?
 
Newbb has some good bottom ends listed in classifieds. Probably has the parts you need...

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engine not seized! Can pistons rings etc still be used or does it have to be completely done from scratch. Apparently this sled just had a rebuild less than 2000km ago.
 
Pull it apart and if they are still within spec they should be fine to reuse. Probably just crank and lower bearings for sure.

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The clutch seems to be fine. The shaft sheared off and the engine rev just shot up like he blew a belt. Basically just dropped into the void! Had to shut down engine as usual.
The pics clearly show there was a crack in the shaft and it just gave up!
There was talk of bad motor mounts? He doesn't think the engine rocked on rev. to indicate a bad mount? Any other way short of pulling the block to see if this was the root of the problem.
I'm more inclined to go with over cranking on the bolt and not torquing it properly. Looks like bolt may have bottomed out causing the cracked shaft.
I'll check the classified for a part!

Thanks all that took time to view this thread!
 
I'm not sure you understand what you have there. The crankshaft output shaft is broken off. This could have been caused by many reasons and it's very possible you will never know. The only way to repair this is to remove the engine and take it 100% down. As for reusing the top end, if it was done recently, you can likely reuse it. Keep cylinders, pistons, pins, etc together. All new gaskets and a new or used crankshaft.
 
Gentlemen: if I recall correctly from a class that I took given by Olav Aaen years ago this is what happens when an engine is run with an out of balance clutch. Olav as you recall was a Polaris guru and he stated that the cause of crankshaft breakage and crank bearing damage was the direct result of either an out of balance clutch OR a clutch run with severely worn out bushings ect. In this condition the clutch will rattle and set up a standing wave of harmonic disturbance that will break a crankshaft. Makes sense.
 
JERSEYJOE said:
Gentlemen: if I recall correctly from a class that I took given by Olav Aaen years ago this is what happens when an engine is run with an out of balance clutch. Olav as you recall was a Polaris guru and he stated that the cause of crankshaft breakage and crank bearing damage was the direct result of either an out of balance clutch OR a clutch run with severely worn out bushings ect. In this condition the clutch will rattle and set up a standing wave of harmonic disturbance that will break a crankshaft. Makes sense.
Click to expand...

Yes, I have heard the same thing. Maybe even from the Aaen Clutch Tuning handbook (which I can't find right now). I have never experienced it myself though.

I agree with these guys, you will want to find your root cause or at least verify that the primary is in good shape. It might be a great time to rebuild it. New bushings and rollers/weights/pins/washers as needed.
 
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