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<  Performance issues  ~  DIY lightened alternator??

Deer Slayer
Posted: Tue May 27, 2008 4:58 am Reply with quote
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Joined: 30 Oct 2007 Posts: 15 Location: Howell Michigan
I have a spare alternator from another CB 750 motor, and was considering chucking it in the lathe to lighten it. I KNOW they're sold for $70, but WHY when I have a spare and a lathe? I remember seeing somewhere some instructions on how much metal to remove and where to cut. The only info in the clymer manual is the ammount of weight you can remove, and a pic. No specific info on where and how to cut. I have a lathe, and I'm not scared to ruin my spare alternator. I just wish I could find the site that shows that information again. If anybody can direct me to that site, it would be appreciated or just can give ma a better idea on how to go about this. Question
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Deer Slayer
Posted: Wed May 28, 2008 7:49 am Reply with quote
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Joined: 30 Oct 2007 Posts: 15 Location: Howell Michigan
This is the second dud thread in a row, not a single reply yet!!! I got a better response on a machinist's website. I was hoping for some approximate dimensions to aid in machining my flywheel. I dunno, somebody HAS to have done this before and can provide some info. Pictures are a good way to get an IDEA of how to proceed, but I really COULD use some specifics. Confused Rolling Eyes
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Satanic Mechanic
Posted: Tue Jun 03, 2008 6:15 am Reply with quote
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Joined: 04 Sep 2005 Posts: 309 Location: Munich, Germany
I have never done that myself, sorry. What you can do, if you want to sacrifice your starter is take off the starter sprocket torn off the flange at the back of the flywheel.

If you turn off material on the diameter, it will most probably also affect the charging. Rolling Eyes I need my electric starter, and therefore need the full charging power, which is why I stayed away from experimenting with lighting the rotor Mad

Cheers,
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Deer Slayer
Posted: Thu Jun 12, 2008 8:30 pm Reply with quote
Junior member Junior member
Joined: 30 Oct 2007 Posts: 15 Location: Howell Michigan
I removed 2.5 lbs from it, and it didn't affect the charging ability at all from what I can see. They say to remove 3, but I can't see how to do that without weakening it, or reducing the charging output. I use my elctric start too. You can remove a LOT of weight without affecting the charging ability. There's a ring of nothing but dead weight on the back of it that can be completely removed, then the back can be beveled @ 30 degrees all the way to just slightly bigger than the roller clutch doohickey. Anyways, I beveled mine 30 degrees on the front too, and removed just a little bit from the outside to clean up the face. Beveled the center post too @ 30 degrees. Pretty much made it look the same as what's in the clymer manual. Didn't reduce the alternator output any that I can tell. I get the same voltages I did before, turned on the high beam, blinker and put on the brake light all at the same time with a volt meter on it, and it's the same as before the mod. You can also just get a stock flywheel from a hondamatic, or 750F, they allready had a lighter rotor from the factory. Very Happy

Here's a pic of it:

http://www.practicalmachinist.com/vb/attachment.php?attachmentid=4347&d=1212548648
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