Show us your DIY belt drive

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Otero

Member
Feb 1, 2010
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Well here are pics of the build refined. At a glance they're little
different than the first set. #1 used a 5/8" bolt for a shaft, the
shank of which was actually 9/16" thus loose fitting in the bearings.
For this build I used a 10" x 3/4" bolt laboriously filed it down to a
tolerance of .7mm at the clutch end to allow for heat expansion.
and .3mm at the pulley end. So now no wobble in the 5/8" bearings.
the 10" bolt was the only one I could find with a long enough shank.
The Staton friction channel mounting arrangement is far more
exact though I did shave back the drum shroud as it kept the drum
reaching the last 1/16" of the clutch shoes.
The belt tensioner is slotted & adjustable. you'll note a second belt
zip tied to the seat stay. These 2 belts are interchangeable &
represent 2 ratios. The 68" 3L belt is 17.7 to one; the 71" 3V
is 20.6 to 1. They can be changed without removing the wheel.
The pic of the under side shows bearing,spacer, shaft collar--
collar ,spacer, bearing. this keeps the collars from binding
against the bearings. the notch in the shaft is for a wrench to
grip when changing the pulley or clutch drum.
The crash guard telescopes for maintenance like a trombone
and steadies vibration; the main mount is backed with thick
rubber, and there are also plastic washers where the struts mount
that serve to dampen vibration. It's not noticeable even at
22 mph. That's as fast as I've gone yet at scarcely more than
half throttle.
 

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MEASURE TWICE

Well-Known Member
Jul 13, 2010
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I think I understand. You use a larger pulley on the shaft with a slightly shorter belt and get more speed and less torque. This is the lower ratio. Then there is the other belt just being kept out of the way with straps, this so you need not take the wheel off to change belts. You have enough room for the larger pulley and just keep it on hand to swap with the one on the threaded shaft. The back idler I guess did not have enough to make up the difference in swapping pulley sizes?

Swapping in the shorter or longer chain on my jackshaft sprockets to change ratio is much more of a pain as it set in a position surrounded by the back wheel.

I was wondering what the weight of the bike was before and after adding all the motorized stuff to it.

I know I have about 110lbs (60lbs back wheel and 50 lbs front wheel) on my muli-use motor bike now.

I realize that the training wheel brackets which one side is so far welded in place adds to the weight. This is only for the infrequent use as an art vehicle. And also the rest of the added weight should be able to be modular and dis-attach when back to OHV trail riding.

I have to look and see what a JC Penny Foremost bike used to weight back when they were produced maybe in the late 60's.

I just mention this as it looks like you ingenious transmission is not to heavy. No welding I think too?

MT
 
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Otero

Member
Feb 1, 2010
782
17
18
wa
I don't need to swap pulleys. Because the V-belt seats more deeply
into the pulley it give a lower ratio. The L-belt sets further out on the pulley
for more high end. actual belt length is irrelevant as i can use anything from
68 to 74. The tensioner simply adapts to whatever length is there.
 

MEASURE TWICE

Well-Known Member
Jul 13, 2010
2,775
1,274
113
CA
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