cannonball2
Well-Known Member
Yeah like off the MTD vari-drive lawn tractor system.
In frame Predator fricton drive build
- Thread starter wayne z
- Start date
wayne z
Active Member
Hey RC, top speed is about 38-40, maybe more, but I dont like to wind it up that tight. Was gtting 4500 rpm at 40 with the single belt drive. Prolly less now with the drag I'm getting from the idling low gear belt dragging the sheaves some.
That's a great idea about the vari pulley. Prolly could use one from a Comet drive.
It's hard to get the idling belt to not induce a lot of drag. Haven't spent enough time working on that with belt supports yet.
Other option I'm thinking about, is to use a sprag(freewheeling) bearing in the larger driven pulley, and use idler to engage hi gear and overun low gear
That's a great idea about the vari pulley. Prolly could use one from a Comet drive.
It's hard to get the idling belt to not induce a lot of drag. Haven't spent enough time working on that with belt supports yet.
Other option I'm thinking about, is to use a sprag(freewheeling) bearing in the larger driven pulley, and use idler to engage hi gear and overun low gear
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Dan
Staff
Wayne, amesome, kudos and hats off to ya!
That is one of the holy grails of motorized bicycle riding. I am doing a build with the Comet and should be purty awesome (according to the math, but untested as yet) But the thing is huge. The rear, driven portion of it sticks out 4". That is after how far the engine sticks out. On the back of the backing plate is a large shaft support and has to be angled down slightly to clear the slanted head of a HF/Predator engine. Other then a rack mount and as is, I don't see it working with pedals. Your manual shift seems so much better an option!
Yrs back I had toyed with the idea of a duel chain drive with 2 clutches. . So my thinking was low gear, use a freewheeling sprocket. When the higher geared clutch engaged, it would take over. Your build beats all the above! (my stuff)
Very, very cool!
That is one of the holy grails of motorized bicycle riding. I am doing a build with the Comet and should be purty awesome (according to the math, but untested as yet) But the thing is huge. The rear, driven portion of it sticks out 4". That is after how far the engine sticks out. On the back of the backing plate is a large shaft support and has to be angled down slightly to clear the slanted head of a HF/Predator engine. Other then a rack mount and as is, I don't see it working with pedals. Your manual shift seems so much better an option!
Yrs back I had toyed with the idea of a duel chain drive with 2 clutches. . So my thinking was low gear, use a freewheeling sprocket. When the higher geared clutch engaged, it would take over. Your build beats all the above! (my stuff)
Very, very cool!
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cannonball2
Well-Known Member
The MTD pulley is not spring loaded. The sheeve half will silde from side to side by gravity. It works by taking up the belt which makes the pulley smaller, The pulley only has to be spring loaded in the opposite direction of the drive, If lever operated, move the lever to lengthen the belt and you slow down tighten the belt and you speed up. Simple, one belt. I dont think the Comet would work as well, it not designed around a V belt like the MTD.
rustycase
Gutter Rider
CB2, you are a veritable fountain of knowledge! 
...so Wayne could then engage his drive in a slippy fashion with his lever, and tightening it further would progressively? move to a higher speed ratio???
and the spring would keep it engaged for engine braking maybe???
Where can we look at that mtd diagram?
I got a couple yard tractor/mowers out there in the yard I have never got around to messing with, yet. Maybe I could cannibalize them before they ever make smoke!
rc
...so Wayne could then engage his drive in a slippy fashion with his lever, and tightening it further would progressively? move to a higher speed ratio???
and the spring would keep it engaged for engine braking maybe???
Where can we look at that mtd diagram?
I got a couple yard tractor/mowers out there in the yard I have never got around to messing with, yet. Maybe I could cannibalize them before they ever make smoke!
rc
cannonball2
Well-Known Member
Here is a pic of the pulley. It spins on 1/2" Torrington bearings. I suspect the bore is 5/8 or close to it with out the bearings. So if I were going to use it I would weld it to the jackshaft, and use a spring loaded idler to take up or give out the belt along with a speed control idler maybe on a lever. In the mower the vari pulley moves. Easiest way might be a hand shifter on the top bar. Either gated for a given # of speeds or a heavy friction lock for infinate speeds. You dont want to buy one new($$$), there are used ones on ebay for as low a $20. The only thing that wears out is the bearings which arent going to be used any way.
Attachments
cannonball2
Well-Known Member
Left out the most important part. The pulley is modded by removing the(either) outer sheeve the shaft it rides on is extended and a strong compression spring is added and retained with a lock collar. I used this set up on a power wagon I built for my wife to haul her garden stuff around with. This was the transmission so to speak. I just made her a shift gate with 3 notches for low-med-hi.
cannonball2
Well-Known Member
What are you searching Dan the part?
wayne z
Active Member
Hey CB2, Do you have a part # for the MTD varidrive that you used? Is yours stamped steel?
There's a bunch of them on e-bay, some look kinda heavy. others the pics and description are not clear.
There's some new stamped ones, but they're pricey.
Edit: I looked at yer pic and see that it is stamped.
There's a bunch of them on e-bay, some look kinda heavy. others the pics and description are not clear.
There's some new stamped ones, but they're pricey.
Edit: I looked at yer pic and see that it is stamped.
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cannonball2
Well-Known Member
No Wayne I dont, the little power wagon is long gone. The gardening thing lasted about 3 years and it was sold at a yard sale. What is probably important to you is the size of the sheeve, thats your lowest ratio, and also determines if it will fit in you bike. Im thinking they were on average 5 or 6". The old rusty ones(with in reason) are fine as long as the pulley slides freely since your are ditching the bearings. Mine was stamped steel. I saw one for $20 on ebay, best thing to do is ask the seller to measure it for you. I honestly dont know if this can all be fit with in the confines of an MB, I had more room to work with. Figure if any body can you can! Now if you want to run 2 belts you will really have a set up, but it would probably be over kill, you would have a super low and a super hi. Dont think it could be made to fit anyway.
rustycase
Gutter Rider
I can't find any listed on the bay, either... but I found the driven sheave from a Comet drive listed for $74...
...IMO, stamped steel should do just fine for some extended period of time because there is really not a whole lot of power being applied here, and it is in a position for great cooling! lol
...trying to figger how to graft a 3" sheave onto a Max-torque spur geard clutch right now... so I can get a bearing in there like that fancy mod to replace the oilite bushing. One prob I got is that the sleeve the bushing runs on is wore out and Max-Torque doesn't really have an exploded parts diagram to order bits and pieces from.
Gotta go over to trikes and post a couple a pics to avoid bashing Wayne's thread here, too badly!
rc
...IMO, stamped steel should do just fine for some extended period of time because there is really not a whole lot of power being applied here, and it is in a position for great cooling! lol
...trying to figger how to graft a 3" sheave onto a Max-torque spur geard clutch right now... so I can get a bearing in there like that fancy mod to replace the oilite bushing. One prob I got is that the sleeve the bushing runs on is wore out and Max-Torque doesn't really have an exploded parts diagram to order bits and pieces from.
Gotta go over to trikes and post a couple a pics to avoid bashing Wayne's thread here, too badly!
rc
wayne z
Active Member
LOL, My thread is open to anyone to say anything that may halp or inspire someone. It's "our" MB community's thread far as I'm concerned.
Search E-bay for MTD vari pulley, or MTD mower parts.
I saw a pic of Lowracers clutch after modded. It's for sale on E-bay too. Search Maxtorque clutch. Looked like the sheave was machined to take the bearing, and it looked to be sweated to the clutch bell with brazing rod. Prolly the billet was brased on then the sheave was machined out from there.
Maybe you can buy the bearing from MT and figure it out from there.
Search E-bay for MTD vari pulley, or MTD mower parts.
I saw a pic of Lowracers clutch after modded. It's for sale on E-bay too. Search Maxtorque clutch. Looked like the sheave was machined to take the bearing, and it looked to be sweated to the clutch bell with brazing rod. Prolly the billet was brased on then the sheave was machined out from there.
Maybe you can buy the bearing from MT and figure it out from there.
happycheapskate
New Member
I don't know how you can use it on a bike, but I'll put in a good word for the MTD Yard Machines style self-propelled mowers! I used to work in lawn care, and had a couple of those! One had a 5.5 hp briggs , and it was my go-to mower for tall or wet grass. The plastic lever was the weak point in the system, and I got some cable stretch or belt stretch, but the drive system was tough! I used to run it wide open and mowed ditches and inclines with it, mowed with a bagger full of wet grass, and so on. I used to drive deck screws through the tires to keep them from rotating on the plastic wheels. haha
wayne z
Active Member
Ok, I worked out a few more bugs on my 2 speed fricton drive tranny. Still gotta work out some minor idler alignment issues and prolly need a stronger pivot mount for the idler lever and travel stop for the hi gear lever, and a way to operate it from the left side.
Also, after today's pix, I added small stiff, over center tension spring for the shift lever to keep it engaged .
Performance is real good. I can powershift on the fly. Must have the belt supports worked out pretty good, top speed hasn't been affected enough to tell, and either belt stops traveling when disengaged
. I have low gear idler adjusted so I can pop the clutch in low with a handfull of throttle and the belt slips just enough to not kill the motor, wind it out quickly to 20mph and jam it into high. No belt squeal at all like it did trying to take off in high like before.
I'm gonna refine it as far as I can, and see how long the belts hold up.
Also, after today's pix, I added small stiff, over center tension spring for the shift lever to keep it engaged .
Performance is real good. I can powershift on the fly. Must have the belt supports worked out pretty good, top speed hasn't been affected enough to tell, and either belt stops traveling when disengaged
. I have low gear idler adjusted so I can pop the clutch in low with a handfull of throttle and the belt slips just enough to not kill the motor, wind it out quickly to 20mph and jam it into high. No belt squeal at all like it did trying to take off in high like before.
I'm gonna refine it as far as I can, and see how long the belts hold up.
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cannonball2
Well-Known Member
Nice work Wayne I can truly appreciate all the thought and time you have working this out!
wayne z
Active Member
Thanks CB, after I get it going as well as I can, I want to build another with a Maxtorque dual sheave clutch with a freewheeling driven low speed pulley. Then it will be a lot simpler to build and operate. Twist the gas to go, and just one idler to engage high with the handlever for control. Squeeze for low, release for high. Sorta like the old Model T footpedal shift
Motorpsykler
New Member
Great build Wayne! Would it be possible to post a video of this thing running and shifting 1-2 while on a stand? I would LOVE to see this in action, and I'm pretty sure I'm not the only one!
happycheapskate
New Member
That's a lot of stuff to keep your pants legs out of, but it looks really cool!