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Discussion Starter #1
i have an 89 Evo with an S&S motor, the pinion gear shaft has sheared in 2 for no apparent reason, it was well lubricated, the rods and lifters,valves etc are all fine and working correctly the cam shaft has no signs of any abnormal marks, there are no metal filing in the crank case and all the gears are fine, the only explanation i can find is a fault in the shaft itself at point of manufacture at the time i was cruising at 125-135km on the express way with no pre noticable engine noise or clanking. Anyone know of this happening before???
 

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Retired citizen
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Pinion shafts can break when the clearence between the 2 gears is too tight.
How many miles on this EVO ???
By the way, welcome to the forum !
 

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Discussion Starter #3
Thanks mate, not that many, the original motor was replaced a few years back and Im im in the Philippines so its hard to do a lot of miles but I bought the bike second hand so cant say for sure how many miles exactly
 

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I {Heart} Hookers.
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Agreed. Did the engine seem to "whine" before the breakage? Cam gear and pinion gear mesh and there's pressure due to drive. If the gears are pitched too tight, it'll cause hard downforce on the pinion, and look at the nose cone bushing, at 12 o'clock, where the cam rides.

The cam's held at both ends, and tappet/valve spring pressure holds it well, in place. The pinion shaft is the weak point, as nothing suppoerts the hanging end with the gear.
 
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Retired citizen
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Also, did the oil pump seize up ??? Where did the shaft break, inside the pump gear or outside ?
 

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Retired citizen
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Ya gotta check with the Harley parts dept., those cranks were rebuildable. OR you can spend the big money on a S&S crank.
 

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Retired citizen
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When I get to my shop this morning I'll check my books to see if I can find ya the OEM part # for the pinion shaft.
RonniesPartsFinder has the pinion listed #24006-83.
 

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Any chance you could find out what flywheel or crankshaft will fit in my 1989 Softail custom case from a different model and year
 
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