Anyone used one of these?

#1
I have the opportunity to get a nice used Comet 108C clutch cheap off a high power sled that blew its motor. I want to put it on my GX390, but since the motor shaft is 1" straight, and the clutch is 30mm tapered, I have an issue.

I did some looking around and found this.

Seems like a simple solution. The golf kart guys that put big blocks in have used them and are happy, so willing to give it a try, especially since the bike will weight much less than a golf kart.

One other thing I noticed on the 390 is the crank is 30mm above the step from 1" straight.

Any thoughts on this?
 
#6
Well, getting a complete sled 108c driver/driven/jackshaft/etc. for $100, yeah, I think it may be worth it. The sled it came from it a good freind and I know he takes care of his stuff. That sled had been clocked at 82mph on an ice lake. He thinks his kid didn't put enough oil in the gas and it seized.
 
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#8
Yeah, me. I have access to a lathe and know how to use it.

That was not the point of this thread. I wanted to know if anyone had tried this kind of adapter and if it worked. If the adapter had just spun on the crankshaft, then it is worthless. Wanted some real world input.

Thanks though. :thumbsup:


On Edit: On further thought, I could make my own and have it with the keyway......

I amaze myself with my brilliance sometimes. :eek:ut:

:laugh::laugh::laugh:
 
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#10
gettin the shaft

If you would feel so inclined remove crank and have it machined.If thats not in your budget try the do with what you got method and start motor and run it at low rpm and sand and grind till you acheive 1".Good luck.Sorry didnt realize you are dealing w/ atapered clutch and not tapered crank.The sleeve method may work.But Just the same a machine shop may be able to help you out.
 
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rmm727

Active Member
#11
If you feel so inclined to make one of these. Go make a 3/4" version for me. 3/4" ID would make the sleeve beefier. The 1" version would only have a wall thickness of less that 2.5mm.
 
#12
If you feel so inclined to make one of these. Go make a 3/4" version for me. 3/4" ID would make the sleeve beefier. The 1" version would only have a wall thickness of less that 2.5mm.
That is what concerns me, but also makes me feel good. Thin because it will probably deform, but good in that as it deforms it will grip the crank and clutch even tighter. Make it a few thousandths long and crush it in to lock it together. So much for ever getting it off.

Clutch springs/weights are cheap on Ebay, and the clutch is coming with some spares. The sled was rated at 85hp, so yeah a bit more than my big block will ever put out.
 
#13
Any non-buddy machine shop is going to charge more than $50 to make that part. Setup, turning and likely grinding, 2-3x the asking price, easy. And to be able to use legit Comet clutch that'll last forever, I'd just buy the adapter. I have the ability to make one, and would order instead.


Or, maybe open the clutch to straight and make a keyed bushing, straight wall.


Or, sell the 390 and rebuild the sled motor.
 
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