Belt drive disaster

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King
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Belt drive disaster

#1

Post by King » Mon Aug 22, 2005 12:40 pm

Hi All

A cautionary tale. A few weeks ago I snapped my front chain so while I waited for some new parts I installed a belt drive I had sitting around to keep the bike up. Saturday I was on a club run when suddenly I heard a ping down in the primary case and then lost all motive power.
Peeping though the space in the primary case we could see the belt turning then stopping when the clutch was engaged. It was assumed the belt teeth had stripped. But, when I got her back in the barn and pulled off the primary cover I found that the nut on the sprocket shaft had slipped just enough (about a thread) to allow the sprocket shaft key to get some wiggle room and it then proceeded to carve up the aluminum drive pulley and finally spit itself out. I would expect that same thing would eventually happen with the splined sprocket shaft, given enough time.
I had torqued the nut to about 60 ft lbs using the jam bar and had intended to take the bike over to a buddy to torque it to the specified 80 ft lbs with the air impact wrench. But that never happened (Mea Culpa). So the lesson is; make sure your front pulley nut is regulation snug.

Good Rides

King



57pan
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Re: Belt drive disaster

#2

Post by 57pan » Mon Aug 22, 2005 3:52 pm

Thanks for the heads-up.

I know that my sprocket shaft nut is not anywhere near 80 ft. lb. - I just did not have a good way to hold the front pulley while tightening it. On mine, though, the pulley was a light press fit on the splines and I Loc-Tited the nut on the shaft.

I did have to take the front pulley off after about 1000 miles to replace the engine sprocket shaft seal and the fit of the pulley on the splined shaft was still good.

I'll have to keep an eye on it though.

mbskeam
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Re: Belt drive disaster

#3

Post by mbskeam » Tue Aug 23, 2005 2:43 am

hello,

RED LOCK TIGHT, is your friend.
mbskeam

PanPal
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Re: Belt drive disaster

#4

Post by PanPal » Tue Aug 23, 2005 2:44 am

Does anyone make a belt drive that incorporates a compensator?

mbskeam
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Re: Belt drive disaster

#5

Post by mbskeam » Tue Aug 23, 2005 11:47 pm

hello,
belts, being belts tend to absorb the vibration that is in the drive.after you put on a belt set up you will feel the diff.
mbskeam

Wrencher
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Re: Belt drive disaster

#6

Post by Wrencher » Mon Aug 29, 2005 9:22 pm

Yeah, Harley-Davidson made a belt drive with a compensator sprocket. They used it on the FXSB Sturgis and FXDG "Willie G" models. It is a two piece thing with rubber dampers inside of it. You are supposed to lube it with a special lubricant called "Poly lube" every 10,000 miles or so to keep it from squeaking. It was a real piece of junk. Most people that had them threw them away and bought a solid replacement pulley. I think Primo used to make the replacement pulley.

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