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Discussion Starter · #1 ·
I admit its an oddball question---
I have a Sachs moped with many drive train issues ( don't give up, keep reading). I am thinking about repowering with a small 4 stroke engine, and then using a variable belt drive to drive the rear wheel. I have seen lawn tractors that use a variable belt drive. Is it possible to adapt that to a moped configuration? I would appreciate as much detail as possible--as well as a source for parts.
 

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Some mopeds did use a variable belt drive, I am not sure which ones. May be worth more to retrofit with a scooter engine, unfortunately, most scooters incoprporate the swingarm into the engine/tranny drive train.

Paul
 

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We used a centrifugal belt clutch and a torque convertor that would gear up from (3 to 1) to (1 to 1) on minibikes. Then used a jack shaft and sprockets to the wheel. These were industrial units made by Morse Chain Co. that are no longer available. These units were bought in 1968 or 1969 for around $70 per unit.
 

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Rupp minibikes used a salisbury clutch setup (just like a snowmobile) into a jackshaft and then chain and sprockets down to the rear wheel. They had around a 5hp engine for power.
 

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Discussion Starter · #9 ·
That northern tool variator looks great, but my goal is to do this on the cheap.

I originally posted this on the lawn tractor roundtable because I was hoping to get some input from the guys who have tractors that use a variator to drive the transmission. I think MTD did a million of them. I was looking for specifics about how those systems work, and how I adapt one of them for my moped.

The cheapest solution is probably to rebuild what I already have, but I can get a Harbor Freight engine for much less than rebuilding my Sachs. That's what piqued my interest.
 

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I have a few variator pulleys off some 80's Craftsman tractors--but to use them would be rather difficult in your application,you will need 2 belts and arranging the pulley sheave operating setup would be pretty complicated and judging by how poorly they worked on the tractors ,I wouldn't bother wasting the effort and expense to use one...the torque converter would be easier to rig up......

But on a light weight moped,I think using a centrifical clutch alone would be more than sufficient--all my mini-bikes and go-karts had just a centrifical clutch with a 6 to 1 reduction in the sprockets or pulleys to the rear wheel,and with a 3.5 to 5 HP engine,they climbed some pretty steep hills and topped out at 25-30 mph wide open...the ones I had were "Comet" or "Mercury" clutches that engauged at 1800 rpms,you can swap different springs into them to alter the speed they'll start engauging too...
 
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