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Anyone interested in a manual clutch for a horizontal shaft motor? It would be similar to a slide on centrifugal clutch, but would allow the user to operate the clutch manually with a cable. My brother and I are both engineers, and in our free time we designed and manufactured a clutch that could be used on a 3/4" PTO shaft. We originally designed these for use in the Motorsport recreation industry (go karts, mini-bikes, lawn mower racing, etc.), but we've started to consider that this unit might also have some industrial applications. We're about a month away from selling our first set of production parts, but we plan to offer a clutch that is usable on 3/4", 1" and 1-1/8" PTO bore. Just wanted to come on here and see what people thought. Feedback would be much appreciated.

Thanks,
D

Would not mind having one on my go-kart. About how much do you think this will cost?

Sent from my droid 4 using LMF

If you're looking to use our unit on a go kart, I will defer you to the following thread for all the current details and updates, including videos.

Custom manual clutch - DIY Go Kart Forum

Also for cost we're looking at somewhere between $100-150, and will have this figure finalized soon.

ddowns46 said:

Anyone interested in a manual clutch for a horizontal shaft motor? It would be similar to a slide on centrifugal clutch, but would allow the user to operate the clutch manually with a cable. My brother and I are both engineers, and in our free time we designed and manufactured a clutch that could be used on a 3/4" PTO shaft. We originally designed these for use in the Motorsport recreation industry (go karts, mini-bikes, lawn mower racing, etc.), but we've started to consider that this unit might also have some industrial applications. We're about a month away from selling our first set of production parts, but we plan to offer a clutch that is usable on 3/4", 1" and 1-1/8" PTO bore. Just wanted to come on here and see what people thought. Feedback would be much appreciated.

Thanks,
D

Click to expand...

would you please send me availability of this mechanical clutch and your contact info. Bilboy

Interesting.
Is there really a need for one ?
Working on a Ditch Witch from the 60's with a manual dog clutch
Got a roller from the 50's with a manual clutch
Just about every drum mower uses a cork clutch and the entire unit is about 1/2 that price.
Most reduction drives come with a clutch of some sort
And the local mower maker Cox has been using a simple cone clutch since 1962

bertsmobile1 said:

Interesting.
Is there really a need for one ?
Working on a Ditch Witch from the 60's with a manual dog clutch
Got a roller from the 50's with a manual clutch
Just about every drum mower uses a cork clutch and the entire unit is about 1/2 that price.
Most reduction drives come with a clutch of some sort
And the local mower maker Cox has been using a simple cone clutch since 1962

Click to expand...

To bertsmobile,

I was trying to find a source for a small engine manual clutch for a 4 cycle horizontal engine up to 30 hp. Small automotive type with dry disc, pressure plate, and adaptable driven disc such as a flywheel. I have several Cushman Motorscooter clutches that could be machined up to a 1" shaft to remove the driven disc taper bore. I think that they would handle up to about 8 hp. That type could be modified into a multidisc type to handle more hp, or a whole new one could be machined with larger dimensions. They work very well for changing gears in a manual transmission after the vehicle is moving, but still start out with centrifugal clutch type engagement at a certain speed above idle. Same as a standard centrifugal or Comet snowmobile or torque coverter drive. Wasted engine rpm and the finesse of an automobile type clutch. Motorcycle and atv clutches are wet multidisc coupled to a sealed manual transmission with only forward gears, no reverse unless you add a f-n-r gear box. 2 cycle engines can be reversed, like in some models of golf carts.
I have a Wisconsin 18hp THD engine with a SAE bell housing, with a heavy driven disc adapted to the Wisconsin horizontal shaft, a small standard auto type disc, Auburn type pressure plate, and throwout bearing. This is coupled to a 2 speed F-N-R manual automobile type transmission. Rare? Perfect setup!. With research I have only found similar drivetrains on 1960s thru early 1970s Bolen Grounds Keeper 9601-1 tractors and maybe rail road speeders. That's why I was trying to contact the people in the original Quote on this website. Simple mulitiple engine adaption.
Cone clutches are simple and easy to make, their only drawback is grabbing in engagement. They will effectually engage massive amounts of power depending on their size. But without modification they do not work well for often gear changes. They are great for slow speed engagement of rototillers, lawn mowers,etc. So are the industrial clutches that use a cam over or toggle engagement such as SAE or Twindisc that use a hand lever.
If I cannot find an off the shelf inexpensive type of dry disc clutch I can adapt Honda 3813 thru 5518 riding mower clutches. Only thing I would need to machine is the driven disc for each engine I want to use. Bilboy

This topic is quite old (2013).

A quick search reveal some existing manual dry clutches : https://3dmotorsport.net/products/3dma-racing-clutch-3-4
Dont know this kind of things and if it fulfill your requirements.

Mkala said:

This topic is quite old (2013).

A quick search reveal some existing manual dry clutches : https://3dmotorsport.net/products/3dma-racing-clutch-3-4
Dont know this kind of things and if it fulfill your requirements.

Click to expand...

Thank You for the reply Mkala,

After some more searching on the internet I found the 3D Motorsports web site, myself.

They advertise a dry 2 disc clutch for 3/4" engine shafts up to 20 hp and 25 ftlb torque. I would like a larger imput shaft size 1" or 11/8". I could work with an intermediate jack shaft to use the clutch on. I inquired if they could beef up the clutch for larger engines under 30 hp. Waiting to hear back from them. They show the clutch working on a 212cc Predator engine (Honda Clone from Harbor Freight) 6.5hp. Their 3/4" clutch runs $190 to $250.

Thanks Again,
Bilboy

There were lots of motorcycles that ran dry clutches and motorcycle clutches of the 20's to 80's ran on a 2" dia hub with a taper to fit the gearbox mainshfts.
Lots of old WM20's around with a clutch conversion to thrust race & over center lever.
To convert a motorcycle wet clutch to a dry one you simply strip the rubber off the driven plates & glue cork sheeting onto them.

Do you need the unit to be concentric with the end of the PTO shaft ?
Almost any small car clutch can be modified to fit.
The Triumph/BSA 3 cylinder engines ran a modified BMC Minni clutch.

If it is not a commercial secret what exactly are you trying to power.
Ransoms made some very large roller mowers still using a cork clutch.
We use them on cricket pitches down here.

bertsmobile1 said:

There were lots of motorcycles that ran dry clutches and motorcycle clutches of the 20's to 80's ran on a 2" dia hub with a taper to fit the gearbox mainshfts.
Lots of old WM20's around with a clutch conversion to thrust race & over center lever.
To convert a motorcycle wet clutch to a dry one you simply strip the rubber off the driven plates & glue cork sheeting onto them.

Do you need the unit to be concentric with the end of the PTO shaft ?
Almost any small car clutch can be modified to fit.
The Triumph/BSA 3 cylinder engines ran a modified BMC Minni clutch.

If it is not a commercial secret what exactly are you trying to power.
Ransoms made some very large roller mowers still using a cork clutch.
We use them on cricket pitches down here.

Click to expand...

Thank You Bert,

It is not a commercial secret. I have several projects that I have been collecting parts for. Most of them are small off road vehicles. Atvs, garden tractors. go karts, and scooters with manual transmission with manual clutches. I have several centrifugal drive trains, centrifugal clutches, comet type clutches, and comet type torque converters. I want to be able to change gears with a manual gear box, V belt drive won't work for moving and at the same time changing gears as it is hard keep from grinding gears. Cone clutches disengage well but it take great amount of practice to smoothly engage gears without grabbing instantly. I've modified them to allow a reasonable amount of slippage while engaging, engaged they are rock solid and you would have to work very hard to get them to slip under load. Cushman scooter clutches are great for changing gears while in motion they have a manual override throw out bearing but are centrifugal for beginning engagement, but are limited to about 8hp. Differntials will work by using a band brake one side and in the right configuration can be used as a reversing box. Motor cycle clutches are perfect but they are wet clutches and hard to seal in lube unless you are using the engine trans as a whole unit. I have used them several times but the engines can over heat working them at continued low speed. Water cooled motorcylcle emgines are no problem other than price. Dry disc clutches are the are the best for me. Now you have solved my problem with your suggestion to use cork to replace the wet disc linings. Thank You! If the cork has a short usage life I can use automobile used salvaged clutch, brake, or new friction lining material. I'm sure I can find high temp glue or I have tubular rivets and the manual brake relining rivet foot press machine. I can also use dry lawn mower clutches like on my 3813 Honda mower. I have a very large useable collection of machine tools turning, milling, planning, press and leaf brakes, sheet metal shears, rolling and forming machines. spot arc and gas welder, foundry, heat treating and forge. and first of all a large 215# anvil.
I am 72 but I'm not done yet.
As to having my future clutches concentric to the pto shaft; would be best but a jack shaft will work. small auto single disc clutches would work well, I would have to turn out a driven plate (flywheel) to fit pto shafts. Disc brake rotors might work with adaption, they are heavy and balanced.
I'll research dry clutch motorcycles as you have suggested. I am impressed with the ingenuity of Down Under people their ways to make do; some of our small farmers and people who work with their hands are the same, skilled workers here are hard to find. Our manufacturing needs a new supply of skilled workers and industry is trying to train them with new schooling in the manual arts. Hands on people can feel what works and lasts.

Thank You Again
Bill

The reason I asked about the position of the clutch as most of the motorcycle clutches use a pushrod through a hollow main shaft and these are easy to instal.
However you cant do that if like a centrifugal clutch it is on the crankshaft.
Them cranked pushrods are buggers to set right :confused2: .
Up till the 50's most UK motorcycles ran dry, cork lined clutch plates inside an oil filled chaincase ( only a British Engineer would try to do that ) :laughing:
Some Japanese clutches are reverse sprung so you dissengage by pushing from the pressure plate side rather than pushing from the sprocket side.
The BSA/Triumph triples ran a modified BMC mini clutch with a small flywheel.
Lots of parts books on line so you can see how they worked
That clutch would be way over the top for a 20 Hp Briggs, my single spring WM20 clutch would handle that Hp
The only thing to consider is when run dry the plates need more lift so if using a multi plate motorcycle clutch you might need to leave out one set of plates.
A clutch that handles 60+ Hp should handle 20Hp with one less set of plates standing on its head.
The racers who run dry chain cases replace the loose rollers with a double row sealed ball bearing

I don't know, belts and pulleys are cheap, easy, and can be bought about anywhere that sells that kind of stuff.
That said I would like one for the homemade garden tractor I've been building in my head :laughing:

I’m very interested in this as I’ve built a dune buggy that started as a mower. Weighs in at 1500lbs. Using belts as clutch don’t last long and get broken often. I’m using a 17.5hp Briggs opposed vertical shaft with an 8” pulley driving a 4” pulley on a mst205. Twin chain drive from trans to solid axle, 25” bear claw tires. 1st gear is a monster, pulled a 50’ JLG boom lift (4500ish lbs) though dry loose Florida sand. My understanding is the engine produces 17.5 hp and 45-47 ftlbs of torque. A better solution for a clutch is needed. I’m planning on building a newer version with a better frame design, would like a better clutch in the plans.