2 speed clutches

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BigBlue

BigBlue

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While surfing the Internet, I've found an updated version of the 2 speed Max-Torque clutches that were custom made for Rupp minibikes by Max-Torque.

Since the Rupps produced 4hp or more, then I understand that this setup would only be suitable for those who use bigger engines (212cc predator). They won't work on smaller hp engines since this shift points won't be correct.

http://www.blackwidowmotorsports.net/_13132r_two_speed_transmission_kit_68_69.html

Here's a link to a forum that gives more information on the design and how they work:

http://www.oldminibikes.com/forum/mini-bike-parts/47746-rupp-2-speed-clutches-exact-copys.html

Chris
AKA: BigBlue
 
wayne z

wayne z

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Very interesting! I think they would work on the smaller 79 or 99cc engines also since they are controlled by rpms not power.
 
Russell

Russell

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I posted a similar article on these in te past. The primary clutch has two sprockets oh the same tooth count. The jackshaft has a larger freewheel sprocket(first gear). The jackshaft has a second clutch with a smaller sprocket (second gear)that kicks in when RPMs are high enough. This setup is ideal for MBs as all you really need is two speeds. The hard part is finding a primary clutch with two sprockets. However max torque would probably make it up for you on request. Building your own just wouldn't be that expensive. I made one years ago for my son, it left the honda 50's in his dust.
 
wayne z

wayne z

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Hmmm I guess one could use a dual sheave centrifugal primary clutch to build this and have a belt primary. The 3" comet dual sheave is a tad over $100
 
Ibedayank

Ibedayank

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wayne z said:
Hmmm I guess one could use a dual sheave centrifugal primary clutch to build this and have a belt primary. The 3" comet dual sheave is a tad over $100
Click to expand...
not the way the clutches are set up...
better look at the pics

one sprocket on the jackshaft is a freewheel the other is the clutch


operation is....
spin to about 3600 and the clutch locks up and the first chain aka low freewheels on the jackshaft. When that happens now you have your second gear


http://www.bmikarts.com/item/Max-Torque-Dual-Sprocket-Clutch-400905-354

as I said $60


can find the jackshafts on Ebay for about $150
 
BigBlue

BigBlue

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I guess either I don't understand the concept or some people failed to look at the items for sale or the forum. Maybe they are confused themselves.

The Rupp unit is different from the Comet unit.

The primary clutch (engine clutch) and the driven clutch (jackshaft clutch) are included in the price.

First gear is the one-way clutch/Sprag bearing that mounts on the jackshaft and second gear is the centrifugal clutch. The second gear kicks in when the jackshaft reaches 1800 RPM. On the minibike, that's between 20 - 25 mph. http://www.oldminibikes.com/forum/ebay-craigslist/62174-2-spd-jack-shaft-doesnt-look-right-3.html

Dual chains? Maybe the Comet 2 speed clutch does. Why would you need dual chain? Maybe two separate #35 chain. How much does #35 chain cost?

Chris
AKA: BigBlue
 
Ibedayank

Ibedayank

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BigBlue said:
I guess either I don't understand the concept or some people failed to look at the items for sale or the forum. Maybe they are confused themselves.

The Rupp unit is different from the Comet unit.

The primary clutch (engine clutch) and the driven clutch (jackshaft clutch) are included in the price.

First gear is the one-way clutch/Sprag bearing that mounts on the jackshaft and second gear is the centrifugal clutch. The second gear kicks in when the jackshaft reaches 1800 RPM. On the minibike, that's between 20 - 25 mph. http://www.oldminibikes.com/forum/ebay-craigslist/62174-2-spd-jack-shaft-doesnt-look-right-3.html



Dual chains? Maybe the Comet 2 speed clutch does. Why would you need dual chain? Maybe two separate #35 chain. How much does #35 chain cost?

Chris
AKA: BigBlue
Click to expand...
from your OWN link
Every part of the 2-speed set up is identical to the original Rupp set up used in 1968 and 1969 TT500 and Roadsters, except for the modern day clutch internals. I even used roll pinned on the gears and and added the the original vintage Max Torque decals to it. Any more questions please let me know.
post 23
 
wayne z

wayne z

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Ibedayank said:
not the way the clutches are set up...
better look at the pics

one sprocket on the jackshaft is a freewheel the other is the clutch




Well, I had contemplated and commented about this idea way before I saw these pictures, and I don't see why it couldn't be pulled off with belts. Just hafta figure out how to adjust them independatly.
The dual sheave primary clutch would replace the dual chains one that is mounted on the engine.
On the jackshaft, smaller solid sheave for high gear, and a larger spragged sheave for first gear.
Secondary clutch don't hafta be set up exactly like the pic , it could be chain or belt drive conventional clutch, mounted anywhere nessasary on the jackshaft.
The idea I actualy had before was a simi-automaticdrive. Eliminate the dual tension adjustment problem too. Just use a manual belt idler clutch for 2nd gear, and automatic clutch for take-off and low gear.
Squeeze the handlever to keep high belt idler loose, and accellerate with 1st gear cent clutch drive then release handlever for high.
Click to expand...
 
Ibedayank

Ibedayank

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Wayne not insulting or anything but without the low side being able to freewheel how would you stop the belt from getting burnt spots? Yours is not a new idea as was used in garden cultivaters back before I was even born. Not a garden tiller but a small walk behind plow. I could not have belts on both speeds without one of them burning from friction of the pulleys.
 
wayne z

wayne z

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Well, in my previous post I mentioned that the low speed pulley has a sprag bearing. That would allow the freewheeling needed.

My previous post was so jumbled up without spaces that it was sorta hard to read without missing something LOL
 
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