Sheared pinion shaft
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Intermediate
Joined: Mar 2008
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Sheared pinion shaft
Just bought a Sputhe motor with 500 miles on it. Previous owner started it up, pushed it from the garage and it stopped. With gearcase cover off you can see pinion shaft has sheared in line with the crankcases. Anybody know what might have caused it and what I'm likely to find on a stripdown or what to look for ? I take it the crank needs to be split to replace the pinion shaft ?
Luckey me ?
Luckey me ?
HDF Community Team
Joined: Dec 2005
Posts: 5,402
Likes: 2,605
From: NC USA
Yep, it's got to come all the way down...
It's no scary thing. In fact, that's my favorite part of a bike to rebuild - especially if someone else pulls it out
About the only thing that will cause that other than a defective part (which IS RARE) is that whoever trued the flywheel assembly hammered on the wheels while it was still in the stand. Or, it didn't pull up correctly when torqued into the wheel and someone hammered on it too hard to true it to the wheel.
It's no scary thing. In fact, that's my favorite part of a bike to rebuild - especially if someone else pulls it out
About the only thing that will cause that other than a defective part (which IS RARE) is that whoever trued the flywheel assembly hammered on the wheels while it was still in the stand. Or, it didn't pull up correctly when torqued into the wheel and someone hammered on it too hard to true it to the wheel.
HDF Community Team
Joined: Dec 2005
Posts: 5,402
Likes: 2,605
From: NC USA
I don't know exactly what you have... they stopped making removable pinion shafts circa 1989 and removable shafts on the drive side disappeared before that.
With the engine out, heads and cylinders removed... if all you did was replace the shaft and true it and slam it back together... about 2.5 hours and most of that would be cleaning and truing. BUT, there's other stuff needs attention that will add to the time - pinion bushing lapped and/or replaced (have to lap a new one just the same) replacing the thrust washers in the wheels (if needed) and I'm assuming everything else is OK so far as rod bearing races, oil pump, wristpin bushings main bearing etc.
PS Yes, if it's a removable type flywheel, you can buy them, but only in std. size. (1.25) they're about 125.00, but I see brand new ones on ebay all the time for less than half that. And if it's NOT removable, you can send them to Truett-Osborne and they can cut the shaft out and machine it for a replacable pinion (or) drive side shaft.
With the engine out, heads and cylinders removed... if all you did was replace the shaft and true it and slam it back together... about 2.5 hours and most of that would be cleaning and truing. BUT, there's other stuff needs attention that will add to the time - pinion bushing lapped and/or replaced (have to lap a new one just the same) replacing the thrust washers in the wheels (if needed) and I'm assuming everything else is OK so far as rod bearing races, oil pump, wristpin bushings main bearing etc.
PS Yes, if it's a removable type flywheel, you can buy them, but only in std. size. (1.25) they're about 125.00, but I see brand new ones on ebay all the time for less than half that. And if it's NOT removable, you can send them to Truett-Osborne and they can cut the shaft out and machine it for a replacable pinion (or) drive side shaft.
Last edited by t150vej; May 5, 2009 at 05:04 PM.
4th Gear
Joined: Sep 2010
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Sportster evo pinion shaft
Redoing an 86 883 sportster as my 1st HD enterprise. The broken off pinion shaft which turned this motor into a basket case is the most major hurdle for me to overcome. I intend to make it a plus rather than a minus by installing or machining a sturdier one on and mating it with a better than factory matched set of cams either S+S,Andrews or Screamin Eagle. In addition I want to balance the rotating assembly better than stock in the best way possible. Not sure I understand bob-weight balancing or the procedure "BalanceMasters" does or even with the knife and fork setup which components need to be matched weight wise as in a car engine. I have 02 1200 "take-off" heads and new HD 1200 .010 pistons as well as a pretty pair of 90 883 cylinders to bore. Hoping to get some input on various options for Pinion shaft replacement and balancing. Thanks Keith
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