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Discussion Starter · #1 ·
I bought this engine recently and an alternator was not included. There is a spacer up against the sprocket. I've looked in my manuals, the rebuild video, and on the Net and I don't see it being used on any other engines. Anyone know what it is?

Thanks in advance.
 

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some times the rotor needs to be spaced away from the sprocket to get the magnets centered on the stator for better charging. no big deal.
 

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Just gonna throw this out there... In looking close at the pic, I see that the leading edge of the keyway is chewed up. I wonder if this has something to do with it? The reason why I say this, is because I had an issue on my 71, where the nut holding the rotor on backed off while I was riding it. Aside from scaring the crap out of me and rattling around inside the cover till I was able to stop... it sheared the key in half, and caused the rotor to spin on the shaft. In spinning around, what was left of the key chewed up the keyway pretty badly. Hard to imagine it's possible, but I have the pics to prove it.

Is it possible that the spacer you have was put there to hold the rotor in place? is there a hole drilled in the back of your rotor that corresponds to the peg on that spacer? I would think it would hold it in place pretty well.

Again, just a thought.
-BK
 

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Discussion Starter · #7 ·
This is all very good insight. The magneto and electronic ignition posts have me most intrigued. It seems like it is a spacer and locator of some sort. It doesn't seem like it is fastened to the sprocket. It does kind of seem like it is stuck on because of the pin. I plan to run a standard alternator so I guess this piece won't go back on during engine reassembly. Thanks for your input!
 

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i am thinking if the engine was a "race" engine in it's day and they ran a mag.....that the removal of the rotor would allow the engine to rev quicker.....
 

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The primary studs are removed ...were they regular bolts....the "normal" ones are mounting points for the "alt"....if they were removed and this was installed I have to go with all that say "racing" motor....weight elimination from the rotating mass. Sorta like drilling out the timing gears..
I am only going on a guess and common sense old "speed" ideas....i
 

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I use this spacer when using an alternator crankshaft in a pre unit motor using the generator primary covers. The pre unit alternator and unit crankshafts require this spacer or a piece of tubing between the nut and drive sprocket when assembled in a generator engine. Racers use it for same reason, to eliminate the alternator.
 

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This spacer, or distance piece, has 2 different numbers in the parts books, one is for all models, and one is for "AC" ign. When used with corresponding sprocket and rotor, and without key, different timing positions were used via 3 holes in rotor. That's what this is. The one you normally find is smaller diameter but same thickness. I wouldn't dare leave it out, I'm not sure the rotor would tighten up, or if it would cause primary chain interference. I wonder if the ET setup, used with conventional stator, would secure rotor when keyway is damaged? Just thinkin.... As far as racers losing the alternator, they used a long spacer ( the center knocked out of a rotor works well), or cut the end off the crank, drilled and threaded for a bolt. Some race primary covers won't fit till this is done. My .02.
 
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