Mods/conversions for maxtorque clutch
- Thread starter dtv5403
- Start date
- Tags clutch maxtorque mods/conversions
Yes - buy a 40/41 clutch sprocket & swap it out. https://www.OldMiniBikes.com/?target=product&product_id=38003&category_id=3541
Here's how they come apart & go back together. You don't need the board for reassembly but it's a cool trick.
https://youtu.be/htE8-IcFcxU
Here's how they come apart & go back together. You don't need the board for reassembly but it's a cool trick.
https://youtu.be/htE8-IcFcxU
OK one more question. I know I can Google this, but if anyone KNOWS the answer, it will be a whole lot easier than sorting through a hundred or more results, most of which won't even be relevant to the actual search terms. Does anyone KNOW if there is such a thing as a 28t freewheel sprocket for a jackshaft input? The jackshaft is 5/8" keyway and the sprocket must engage counter-clockwise. A freewheel sprocket would eliminate the engine braking, as the freewheel would disengage when letting off the throttle. I am going to Google it as well, just want to see if anyone knows and has a link to what I am looking for.
They make them but they are going to be for a bicycle chain.
I understand your concept and it should work but I think your only chance is buying a 5/8" freewheel adapter (Google it) and then have a 40/41 sprocket drilled out to fit the adapter so that it can be welded on.
We like pictures around here. Why not post some up?
I understand you are working on a motorized Bike. It would be nice to see why you don't just put the clutch on the engine so that it operates normally.
I understand your concept and it should work but I think your only chance is buying a 5/8" freewheel adapter (Google it) and then have a 40/41 sprocket drilled out to fit the adapter so that it can be welded on.
We like pictures around here. Why not post some up?
I understand you are working on a motorized Bike. It would be nice to see why you don't just put the clutch on the engine so that it operates normally.
The clutch is on the crankshaft. I misspoke when I said it was on the jackshaft, but there is a jackshaft. What I experienced on my last bike with the same setup is that even when the bushing is well lubricated, I still experienced some engine braking. I found a website that sells all different kinds of stuff for motorized bicycles, including freewheel setups and I emailed him to see if he has or can make what I need and I explained it in as much detail as possible. A bicycle freewheel will not work, as they all engage clockwise and the PTO of the engine is counter clockwise. Unless the make a 9t freewheel, which would actually work because the jackshaft output sprocket spins clockwise, but I doubt I can find a freewheel that small, and even if I did I don't think it will stand up to the speeds it would need to spin. I have seen clutch sprockets that freewheel, but they don't make them in 9t or 28t, which would be one of the two sizes I need, 28t for the input and 28t for the output. I don't see how they can work on the crankshaft itself either, because they are a ratcheting freewheel which means anytime the crankshaft spins, they would engage, even at idle.
Are you using a small two-stroke? I've owned a couple of two cycle engines that ran CCW. They usually had a gear reducer that changes the PTO to clockwise. Could you just mount the engine 180 degrees and run it Clockwise? Then you could use a bicycle / adult trike freewheel adapter with the right sprocket welded on.
Freewheel Adapter, Sick Bike Parts
Or, for a second, let me be "that guy" - Don't worry about engine braking...just keep your foot on the gas!
Freewheel Adapter, Sick Bike Parts
Or, for a second, let me be "that guy" - Don't worry about engine braking...just keep your foot on the gas!
My 1980 Kitty Cat has a max torque clutch 5/8 bore on a 60cc two cycle with a 2-1 gear reduction. Lots of small two strokes that will fit a max torque clutch.
If you are using a jackshaft it doesn't matter if the engine runs clockwise or CCW. You just flip the sprocket over and it locks the other way. It's reverseable.
Something like this but with the right chain pitch http://pages.ebay.com/link/?nav=item.view&id=191645748760&alt=web
If you are using a jackshaft it doesn't matter if the engine runs clockwise or CCW. You just flip the sprocket over and it locks the other way. It's reverseable.
Something like this but with the right chain pitch http://pages.ebay.com/link/?nav=item.view&id=191645748760&alt=web
Cool.
Let me try to answer your original question.
For ease of explanation, here is a diagram of a max torque clutch:
The bushing #3 rides between the sleeve #12 and the sprocket #2
In order to replace the bushing with a bearing it would have to be the same size dimensionally as the bushing. One thing you could try - is take apart the clutch and bring the bushing in to a Motion Industries (formerly Bearings and Drives) or maybe even a Fastenal and see if they can match up a bearing to the bushing. Probably a needle style bearing as you suggested as most ball bearings would be wider than the space allows (the article you posted makes it look like there might be options with roller bearings though).
I'm not sure I buy the whole heat failure argument if they are kept oiled with a heavy weight 80-90 gear oil or even lithium grease it should stay fairly well lubricated and cool. Debris is another matter - and oils and grease attract debris so that may be true. I just can't imaging that a needle bearing can handle 8500 rpm on a two stroke piston wrist pin at 200+ degrees but fail at 3600 rpm in a 4 stroke PTO. I'm no expert though so perhaps I am missing something.
As others have suggested you could make the space between the sleeve wider by using a smaller sleeve or a larger diameter sprocket but the work it would take would hardly be worth the effort.
Let me try to answer your original question.
For ease of explanation, here is a diagram of a max torque clutch:
The bushing #3 rides between the sleeve #12 and the sprocket #2
In order to replace the bushing with a bearing it would have to be the same size dimensionally as the bushing. One thing you could try - is take apart the clutch and bring the bushing in to a Motion Industries (formerly Bearings and Drives) or maybe even a Fastenal and see if they can match up a bearing to the bushing. Probably a needle style bearing as you suggested as most ball bearings would be wider than the space allows (the article you posted makes it look like there might be options with roller bearings though).
I'm not sure I buy the whole heat failure argument if they are kept oiled with a heavy weight 80-90 gear oil or even lithium grease it should stay fairly well lubricated and cool. Debris is another matter - and oils and grease attract debris so that may be true. I just can't imaging that a needle bearing can handle 8500 rpm on a two stroke piston wrist pin at 200+ degrees but fail at 3600 rpm in a 4 stroke PTO. I'm no expert though so perhaps I am missing something.
As others have suggested you could make the space between the sleeve wider by using a smaller sleeve or a larger diameter sprocket but the work it would take would hardly be worth the effort.
Cool.
Let me try to answer your original question.
For ease of explanation, here is a diagram of a max torque clutch:
The bushing #3 rides between the sleeve #12 and the sprocket #2
In order to replace the bushing with a bearing it would have to be the same size dimensionally as the bushing. One thing you could try - is take apart the clutch and bring the bushing in to a Motion Industries (formerly Bearings and Drives) or maybe even a Fastenal and see if they can match up a bearing to the bushing. Probably a needle style bearing as you suggested as most ball bearings would be wider than the space allows (the article you posted makes it look like there might be options with roller bearings though).
I'm not sure I buy the whole heat failure argument if they are kept oiled with a heavy weight 80-90 gear oil or even lithium grease it should stay fairly well lubricated and cool. Debris is another matter - and oils and grease attract debris so that may be true. I just can't imaging that a needle bearing can handle 8500 rpm on a two stroke piston wrist pin at 200+ degrees but fail at 3600 rpm in a 4 stroke PTO. I'm no expert though so perhaps I am missing something.
As others have suggested you could make the space between the sleeve wider by using a smaller sleeve or a larger diameter sprocket but the work it would take would hardly be worth the effort.
Let me try to answer your original question.
For ease of explanation, here is a diagram of a max torque clutch:
The bushing #3 rides between the sleeve #12 and the sprocket #2
In order to replace the bushing with a bearing it would have to be the same size dimensionally as the bushing. One thing you could try - is take apart the clutch and bring the bushing in to a Motion Industries (formerly Bearings and Drives) or maybe even a Fastenal and see if they can match up a bearing to the bushing. Probably a needle style bearing as you suggested as most ball bearings would be wider than the space allows (the article you posted makes it look like there might be options with roller bearings though).
I'm not sure I buy the whole heat failure argument if they are kept oiled with a heavy weight 80-90 gear oil or even lithium grease it should stay fairly well lubricated and cool. Debris is another matter - and oils and grease attract debris so that may be true. I just can't imaging that a needle bearing can handle 8500 rpm on a two stroke piston wrist pin at 200+ degrees but fail at 3600 rpm in a 4 stroke PTO. I'm no expert though so perhaps I am missing something.
As others have suggested you could make the space between the sleeve wider by using a smaller sleeve or a larger diameter sprocket but the work it would take would hardly be worth the effort.
I am just trying to help with a sense of realism and practicality, but dtv5403 seems to know a lot about these. Seems to want to argue every suggestion offered in the spirit of helping!
Also he is spinning a little tiny engine (the torque monster 79cc Predator!) to 6K without the proper billet parts. In the spirit of safety, we should not continue to try and talk all this nonsense about things we don't apparently know!
Also he is spinning a little tiny engine (the torque monster 79cc Predator!) to 6K without the proper billet parts. In the spirit of safety, we should not continue to try and talk all this nonsense about things we don't apparently know!
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