Clutch

[copyman]

Hi

I took apart this Max-Torque clutch and had a question since I never had one apart. Is there suppose to be like a brake pad material on the spring loaded side or bare metal like in picture? I would think metal to metal would slip?

Also can I put this whole thing in an ultrasonic cleaner? Is there anything inside that gets cleaned / lubed needing to take apart further?

Thanks

 

[ole4]

They are metal to metal.

 

[SAS289]

There's no need to take anything else apart unless you want to change the spring. The shoe side can get a few shots of brake clean and you're done. I wouldn't use ultrasonic cleaner or brake clean on the clutch drum and it's bushing. Wipe it clean with a rag then use a few drops of oil on the bushing smeared around it's surface.

Metal to metal does slip and you should be able to see the slip area on the clutch drum. The slip that happens during engagement is brief and not a concern as long as the rider engages and goes. The engagement slip can get the clutch very hot from slow speed on and off the clutch riding.

 

[copyman]

There's no need to take anything else apart unless you want to change the spring. The shoe side can get a few shots of brake clean and you're done. I wouldn't use ultrasonic cleaner or brake clean on the clutch drum and it's bushing. Wipe it clean with a rag then use a few drops of oil on the bushing smeared around it's surface.

Metal to metal does slip and you should be able to see the slip area on the clutch drum. The slip that happens during engagement is brief and not a concern as long as the rider engages and goes. The engagement slip can get the clutch very hot from slow speed on and off the clutch riding.

Great info! Thanks!

 

[I74]

Looks like that has the stock 2200rpm ''silver'' spring in it.

If that is going to be used as a straight clutch on a Mini, I & others,, highly recommend going with the Max torque ''green'' 2600rpm spring.

Way smoother engagement, & will also help against premature engagement when going around corners.

Real spooky when the front end tries to lift when taking a turn.

Also helps with spooling up the motor more before engaging, which ''especially'' on lower HP ''smaller'' engines,, puts less stress on the crank & rod ect.

I

 

[copyman]

Looks like that has the stock 2200rpm ''silver'' spring in it.

If that is going to be used as a straight clutch on a Mini, I & others,, highly recommend going with the Max torque ''green'' 2600rpm spring.

Way smoother engagement, & will also help against premature engagement when going around corners.

Real spooky when the front end tries to lift when taking a turn.

Also helps with spooling up the motor more before engaging, which ''especially'' on lower HP ''smaller'' engines,, puts less stress on the crank & rod ect.

I

Also great info! This was clutch that came with fox mini bike but was not on engine. Was in a box with some other parts and not all for the Fox so it was probably from another model. Going to be used on a TEC HS40 .
Are the clutches readily available with the green spring? Does it have to be a max torque or is there other brands recommended?

Thanks again

 

[I74]

Also great info! This was clutch that came with fox mini bike but was not on engine. Was in a box with some other parts and not all for the Fox so it was probably from another model. Going to be used on a TEC HS40 .
Are the clutches readily available with the green spring? Does it have to be a max torque or is there other brands recommended?

Thanks again

There is places that sell the Max torque SS clutch with the ''green'' spring in them, but think they are like around 60+ bucks,, which is still ''really cheap'', compared to what you can spend for some of the other clutches.

The Max torque ''green'' spring by itself,, is only around 11 bucks.

I personally like these clutches with this set up ''a lot'',, especially for what they cost,, & have never had any troubles.

Another trick is to file or grind ect. the sharp edges of the shoes a wee bit.

It helps in from cutting grooves in the drum, & also helps in even more smoother engagement.

Looks like the edges of your shoes ''definitely'' need dressed.

 

[copyman]

There is places that sell the Max torque SS clutch with the ''green'' spring in them, but think they are like around 60+ bucks,, which is still ''really cheap'', compared to what to can spend for some of the other clutches.

The Max torque ''green'' spring by itself,, is only around 11 bucks.

I personally like these clutches with this set up ''a lot'',, especially for what they cost,, & have never had any troubles.

Another trick is to file or grind ect. the sharp edges of the shoes a wee bit.

It helps in from cutting grooves in the drum, & also helps in even more smoother engagement.

Looks like the edges of your shoes ''definitely'' need dressed.

Man there is some really good input for this subject. Not only going to help me but many others in the future!

Thanks!

 

[copyman]

I was looking online for a Max-Torque clutch with green springs and didn't see any. I did see the green replacement springs. Are springs hard to replace?

Also I'm assuming the standard minibike chain is a #35. How many teeth on the clutch sprocket would be recommended for a 1970 Fox?

Jumped the gun with this post. I just checked and the sprocket on Clutch is for #40 chain but the sprockets on jack shaft & rear wheel teeth are #35 so guess I need the whole clutch?

Thanks again

 

[Charles S]

 

[copyman]

Thanks very helpful video!

 

[copyman]

Ok. I found this one in picture. Only one I could find with green springs.


Max-Torque Racing Centrifugal Clutch, 3/4" bore
Max Torque Racing Clutch 3/4" bore 10-15 tooth available for #35 chain. This clutch will engage around 2800-3000 RPMs.

It has a choice of how many teeth. Can someone explain what the different number of teeth on sprocket does? From searching the internet looks like 12T is most poplar?

Thanks

 

[Charles S]

Can someone explain what the different number of teeth on sprocket does?

The tooth count determines your reduction ratio. A high ratio (AKA: low gearing) provides more torque at the wheel for quick acceleration, hill climbing, etc., at the cost of reducing top speed. A low ratio (AKA: high gearing) provides higher top speed (assuming the engine can reach max rpm) but will reduce wheel torque which, if the ratio is too low, may cause the bike to struggle accelerating, climbing a hill, or even just to get moving from a stop. Most vehicles have a transmission that provides multiple ratios while most minibikes have only one fixed ratio (unless a CVT / torque converter is used), that ratio needs to be a compromise, you can't "have it all" when you have only one ratio. When choosing your clutch sprocket tooth count, you first need to determine how you intend to use your bike. If you intend to ride it on relatively level paved surfaces, you could run a lower ratio than what you would need to ride hilly trails, for example. Rider weight is another factor. Before trying to consider what sprocket would be good, we need more information (I could search your other threads but I'm not going to spend my time on that). What engine? What is the tooth count of your rear (wheel) sprocket? Does your bike have a jackshaft? If so, what are the jackshaft-in and jackshaft-out sprocket tooth counts? What is the OD of your tire (affects "effective gear ratio", search it)?

 

[copyman]

The tooth count determines your reduction ratio. A high ratio (AKA: low gearing) provides more torque at the wheel for quick acceleration, hill climbing, etc., at the cost of reducing top speed. A low ratio (AKA: high gearing) provides higher top speed (assuming the engine can reach max rpm) but will reduce wheel torque which, if the ratio is too low, may cause the bike to struggle accelerating, climbing a hill, or even just to get moving from a stop. Most vehicles have a transmission that provides multiple ratios while most minibikes have only one fixed ratio (unless a CVT / torque converter is used), that ratio needs to be a compromise, you can't "have it all" when you have only one ratio. When choosing your clutch sprocket tooth count, you first need to determine how you intend to use your bike. If you intend to ride it on relatively level paved surfaces, you could run a lower ratio than what you would need to ride hilly trails, for example. Rider weight is another factor. Before trying to consider what sprocket would be good, we need more information (I could search your other threads but I'm not going to spend my time on that). What engine? What is the tooth count of your rear (wheel) sprocket? Does your bike have a jackshaft? If so, what are the jackshaft-in and jackshaft-out sprocket tooth counts? What is the OD of your tire (affects "effective gear ratio", search it)?

I will report back with that information...Thanks

 

[copyman]

The tooth count determines your reduction ratio. A high ratio (AKA: low gearing) provides more torque at the wheel for quick acceleration, hill climbing, etc., at the cost of reducing top speed. A low ratio (AKA: high gearing) provides higher top speed (assuming the engine can reach max rpm) but will reduce wheel torque which, if the ratio is too low, may cause the bike to struggle accelerating, climbing a hill, or even just to get moving from a stop. Most vehicles have a transmission that provides multiple ratios while most minibikes have only one fixed ratio (unless a CVT / torque converter is used), that ratio needs to be a compromise, you can't "have it all" when you have only one ratio. When choosing your clutch sprocket tooth count, you first need to determine how you intend to use your bike Just regular riding. If you intend to ride it on relatively level paved surfaces, you could run a lower ratio than what you would need to ride hilly trails, for example. Rider weight is another factor. Before trying to consider what sprocket would be good, we need more information (I could search your other threads but I'm not going to spend my time on that). What engine? TEC HS40 What is the tooth count of your rear (wheel) sprocket? 72Tooth Does your bike have a jackshaft? Yes has a Jackshaft . If so, what are the jackshaft-in and jackshaft-out sprocket tooth counts? Both 15T What is the OD of your tire The wheels are 10" and the tires are 15" (affects "effective gear ratio", search it)?

Both short & long Chains are 35T.

1970 Fox Trail Tramp


Please expand quote above and see bold answers. Appreciate any advice on drive setup, especially the clutch with what I have. Like I posted previously someone suggested the Max-Torque green springs and I posted pic of only one I saw, confusing because ad shows green springs as a "racing clutch".

Thanks again for the help

 

[Charles S]

Both short & long Chains are 35T.

1970 Fox Trail Tramp


Please expand quote above and see bold answers. Appreciate any advice on drive setup, especially the clutch with what I have. Like I posted previously someone suggested the Max-Torque green springs and I posted pic of only one I saw, confusing because ad shows green springs as a "racing clutch".

Thanks again for the help

Disclaimer: I am not an expert!

With what you have, I would suggest the smallest clutch sprocket you can find, which I think will be 11T. With the 72T rear sprocket, that would give you a 6.545:1 ratio. Since both jackshaft sprockets are the same tooth count, the jackshaft doesn't affect the overall ratio. That may work for you but I think that ratio may be a bit low for your large OD tire. I would try it and if it doesn't work for you, you can alter the overall ratio by replacing one, or both, of the jackshaft sprockets. A larger jackshaft-in sprocket (which you may or may not have room/clearance for), or a smaller jackshaft-out sprocket, would give you a higher overall ratio (AKA: lower gearing). A smaller jackshaft-in sprocket, or a larger jackshaft-out sprocket (which you may or may not have room/clearance for), would give you a lower overall ratio (AKA: higher gearing). This may seem confusing (I'm having trouble just trying to make this understandable), but don't worry about the jackshaft for now, get a clutch and see how it works for you.

If the ratio doesn't work for you, then you can consider the jackshaft. There are jackshaft calculators (BMI Karts has one on their site) but it's just simple math.

If your jackshaft-out sprocket were 13T, your overall ratio would be 7.554:1 (with 11T clutch, 15T jackshaft-in & 72T rear)

The math
15/11=1.364
72/13=5.538
1.364x5.538=7.554 for a 7.554:1 overall ratio

You can easily plug in other numbers and do the math (or use BMI's calculator). Again, don't be concerned about the jackshaft for now, I just wanted to give an example of changing a jackshaft sprocket.

As far as tuning a clutch (springs, etc.), I can't advise you on that. If none of the experts on here help you, you could contact Jim at Max-Torque.
http://maxtorque.com/contact.php

https://www.bmikarts.com/go-kart-how-to-guides

 

[copyman]

Disclaimer: I am not an expert!

With what you have, I would suggest the smallest clutch sprocket you can find, which I think will be 11T. With the 72T rear sprocket, that would give you a 6.545:1 ratio. Since both jackshaft sprockets are the same tooth count, the jackshaft doesn't affect the overall ratio. That may work for you but I think that ratio may be a bit low for your large OD tire. I would try it and if it doesn't work for you, you can alter the overall ratio by replacing one, or both, of the jackshaft sprockets. A larger jackshaft-in sprocket (which you may or may not have room/clearance for), or a smaller jackshaft-out sprocket, would give you a higher overall ratio (AKA: lower gearing). A smaller jackshaft-in sprocket, or a larger jackshaft-out sprocket (which you may or may not have room/clearance for), would give you a lower overall ratio (AKA: higher gearing). This may seem confusing (I'm having trouble just trying to make this understandable), but don't worry about the jackshaft for now, get a clutch and see how it works for you.

If the ratio doesn't work for you, then you can consider the jackshaft. There are jackshaft calculators (BMI Karts has one on their site) but it's just simple math.

If your jackshaft-out sprocket were 13T, your overall ratio would be 7.554:1 (with 11T clutch, 15T jackshaft-in & 72T rear)

The math
15/11=1.364
72/13=5.538
1.364x5.538=7.554 for a 7.554:1 overall ratio

You can easily plug in other numbers and do the math (or use BMI's calculator). Again, don't be concerned about the jackshaft for now, I just wanted to give an example of changing a jackshaft sprocket.

As far as tuning a clutch (springs, etc.), I can't advise you on that. If none of the experts on here help you, you could contact Jim at Max-Torque.
http://maxtorque.com/contact.php

https://www.bmikarts.com/go-kart-how-to-guides

Damn! Some good stuff on this forum. If you need information or advice for mini bikes & related what a better place than this.

Being new and my limited experience with minibikes has only been with torque converters with a belt, jackshaft & chain driving rear wheel. Last time I had any experience with a centrifugal clutch was when a kid and got a cheap $59 minibike from a dept store! Showing my age

Thanks

 

[pomfish]

 

[Charles S]

Damn! Some good stuff on this forum. If you need information or advice for mini bikes & related what a better place than this.

Being new and my limited experience with minibikes has only been with torque converters with a belt, jackshaft & chain driving rear wheel. Last time I had any experience with a centrifugal clutch was when a kid and got a cheap $59 minibike from a dept store! Showing my age

Thanks

As I said, I'm no expert. You have more experience than I do! (see my signature)

 

[toomanytoys]

I usually shoot for 6:1 ratio. Seems to give the best of both worlds.