Can a maxtorque bushing type clutch be made to freewheel/converted to one way

[butterbean]

Well, the qmatic has a maxtorque clutch, but the qmatic and 7G are completely different.

 

[KCvale]

Since when have you ever heard of a maxtorque clutch on a kit transmission?
This is for a 79cc predator with jackshaft plate.
The clutch is on the crankshaft.

You're supposed to be some kind of expert or something.

MaxTorque is just a brand name not some different cent clutch system.
You don't need to be 'some kind of expert' to know how they work.

In fact they claim their bushing clutch bells are better than bearings.
http://www.maxtorque.com/html/clutches.html

"Oil Impregnated Bushing - The oil impregnated bronze bushing rotates on a ground sleeve. This configuration, utilizing a high-grade specially formulated oil or grease for bushing lubrication, considerably increases clutch life in high heat conditions over assemblies that use needle bearings. A bushing is more "forgiving" to both heat and contamination than a needle bearing."

That does not answer your freewheel question, and neither does pointing out the SS in the clutch you mention is for Six Shoes.

As mentioned in above posts a freewheel sprocket on the back wheel would be ideal, like a bicycle, it freewheels at the wheel so even the chain doesn't move when coasting.

 

[butterbean]

I'm using a moped hub, and the sprocket bolts directly to the hub, so I'm not sure if a freewheel sprocket is possible, but perhaps a freewheel sprocket on the jackshaft input or output. That would require either a 28t freewheel sprocket for 35 chain (input) or 9t freewheel sprocket for 41 chain (output). Either one would have to fit a 5/8 shaft with keyway, and I'm not sure where to find those but I'm about to start looking. I think that would be a lot easier on the clutch, and would definitely eliminate the engine braking. Side note, the clutches on the kit transmissions, except for the qmatic, are all 3 shoe clutches. They all work the same, but I doubt a maxtorque six shoe clutch would fit on any of them. For one, the smallest bore the maxtorque comes in is 5/8. The clutch shafts on the kit transmissions are what, 15mm? Actually that might be pretty close but the drum on the maxtorque is pretty big, and from what I've seen there isn't much extra room in the kit transmissions for a larger clutch drum. You call it a bell, I call it a drum, same thing. Maybe I'm wrong, but I doubt the maxtorque would fit any of the kit transmissions due to the size of the drum, excluding the qmatic.

 

[butterbean]

For the record, eliminating engine braking was always my main goal. Bump starting was just an option. Some centrifugal clutches will bump start, but a bushing clutch cannot. It must have a one way needle bearing in it in order to bump start. After talking to some people on a minibike forum, it is actually possible to do a bearing conversion on a bushing clutch however, it requires welding and machining of the crankshaft and part of the clutch drum. It is expensive, difficult, time consuming and not worth the cost and effort.

 

[HeadSmess]

all centrifugal clutches engine brake...

the shoes are forced out until the crankshaft speed lowers enough to disengage. crankshaft speed.

even with no throttle...the shaft that WAS spinning at full throttle is now being spun by the bell...and the shoes are still being forced out.

so yes, stick a freeweheel in there, and presto...no more engine braking. this means the sprocket cannot drive the bell, cant drive the shoes, end of story. engine cant even drive the sprocket...until its spinning FASTER.

and then chain drag is still there.

final sentence was the one...not worth the time and effort (plus much easier to use a freewheel in the rear sprocket on the wheel, if at all...)


what is NOT possible is to have a freewheel, engine braking free clutch that will ALSO bumpstart.

think about it....

bell one ways on shaft. turns shaft when motor not running.

shaft can spin inside bell when running.

shoes transfer to bell to sprocket.

put a freewheel on sprocket.

sprocket freewheels when clutch is rotating slower or stationary. can only grip when bell is faster than sprocket or bike is rolled backwards.

engine braking is nothing more than starting an engine, really... you turn it over. to the point that diesels cut the fuel entirely and start using the engine as a compressor.

i always found the maxtorque cutches were expensive, time consuming and not worth the effort... rattle themselves to pieces and that was only wid a HS50

 

[KCvale]

all centrifugal clutches engine brake...

the shoes are forced out until the crankshaft speed lowers enough to disengage. crankshaft speed.

even with no throttle...the shaft that WAS spinning at full throttle is now being spun by the bell...and the shoes are still being forced out.

And THAT is exactly where your whole logic falls apart!

The clutch pads engage by shaft RPM.
You drop to idle and those puppies retract in by their springs and don't touch the bell.

The bell just freewheels along happy regardless of the shaft it is on's speed, or the speed of it being spun by something else.
It won't move until the pads fling out with throttle RPM and grab it inside.

If you have a clutch bell attached so tight to the shaft it is suppose to spin free on that it can actually spin the whole engine shaft with the engine off or even at idle and make the pads fly out you have major issues because if the clutch bell can turn the engine it is simply a fixed sprocket.

I really just can't believe this is such a hard concept to grasp for some.

The bell, drum, whatever you want to call it, is passive, period.
It can simply NEVER turn the clutch pads itself by design.

If the shaft it is on spins, it don't care or move anything else.
If you spin the bell around the shaft it is on it still don't care or move anything else but the output like the back wheel sprocket it connects to.

Sure you can make some kind of freewheel sprocket for the output from the clutch bell, the thing is, the bell is already a freewheel with just bushing drag, bushing issues come with wear and they darn sure don't drag enough to start an engine.

It is everything between the rear sprocket and automatic drive freewheel that cause coast drag.

It starts at your rear wheel sprocket.
If it freewheels like your pedal sprocket all is good.

If the chain has to spin then you want a nice easy to spin ratcheting (freewheel) input on the other end.

The farther back up the drive train you have to go like belts or chains, the more drag you get until you get to the cent clutch, you know, the part that lets the engine start and rev a bit before it engages the drive train but a freewheel itself when the engine is off or idling?

This has gone on a bit beyond silly don't ya think?
Simple mechanical design fact science.

Regardless of the configuration of the drive train, I took the time to detail everything with pics and facts here.
Grasp them now, or dink around with your own theories and call me a stupid **** when it works ;-}

 

[butterbean]

Kc, you're missing where the problem occurs. When you have a bushing riding on a shaft, there is always a possibility of friction between the bushing and the shaft. No one is saying that the shoes still make contact with the drum after the throttle is released. The problem I have found is that no matter how well that bushing is lubricated, there will be friction between the bushing and the shaft. Therefore, the drum is still tied to the motion of the crankshaft as the rpms begin to cycle down and compression slows the engine. This is why engine braking occurs in a bushing type clutch. Bushings and bearings are two entirely different things and they do not work or perform the same. You may understand how these clutches work, but its apparent to me now that you haven't understood a single thing I've said about engine braking this entire time. Engine braking in a centrifugal clutch has nothing to do with the shoes making contact with the drum.

 

[KCvale]

Kc, you're missing where the problem occurs.
Engine braking in a centrifugal clutch has nothing to do with the shoes making contact with the drum.

I understand entirely and why I don't like to work with output shaft mounted clutch bell systems, especially a bushing that has additional lateral tension from whatever it is chained or belted to.

Even a Q is the same, the bell just isn't mounted to the engine shaft.

It has a pulley on the engine out, to a belt, to another combined clutch and bell shaft mount.

It is just after the engine which is a pulley that always spins the belt when the engine is on, to an the output sprocket to the wheel, leaving the clutch bell, on a bushing, to be your freewheel, under chain tension.

Either put a freewheel drive sprocket on the transfer case output, or do it at the wheel sprocket so even the chain don't move.

This is exactly why I go with 4G transfer cases.
The clutch is on the engine output shaft, but the bell/pulley is on its own transfer case bearing shaft, completely isolated.

The belt transfers power to a bigger bearing mounted pulley for the needed reduction and the output sprocket that will chain tension to the wheel or jackshaft or wherever.

The kicker is, the 2015 4G's put a big HD freewheel inside the big pulley that drives the output sprocket on it's own shaft.

That means the output pulley lets any coasting chain spin free before it even gets to the belt let alone the clutch bell which again, is isolated from the output shaft anyway.

I am just try to help BB, its just understanding mechanical power transfer without a manual clutch.

 

[HeadSmess]

cool, no engine braking on centrifugal clutches.

somehow the springs can react to the different centrifugal forces created by spinning and or...hmm, spinning.

stick one on a concrete mixer, air compressor, sure...i agree... they dont engine brake. simply because the load stops. and stays stopped. there is no wheel rolling down the road to keep spinning the clutch bell. same applies if there is a freewheel somewhere after the clutch.

as long as those shoes are being flung OUT and are ENGAGED... it doesnt matter which part is driving which part. the force is still there, flinging them out. they are engaged. end of story. they will not retract until something stops spinning them. this requires BOTH shafts, input and output, to drop to the idle or disengagement speed. friction does play a part, stiff springs and slippery, glazed shoes will release a touch earlier. but they will NEVER release at full throttle if something keeps them rotating at near full speed.

if your clutch springs can retract the shoes WITHOUT a freewheel in there...you have mighty powerful springs and your engagement speed is going to be pretty close to operational speed. or your governor is set so low that youre barely cracking idle.

and its really noticeable if you have a ridiculous ratio like 30:1 or so. if i hadnt experienced it myself and had the shock of my life, as i had always believed centrifugal clutches dont engine brake... i would be vehemently denying that they CAN actually apply engine braking.

until the whole contraption slowed down to just above engaging speed...at which point, off it rolled. i was puzzled for a few hours after that ride.


simple way to prove me wrong KC...go set a bike up with mountain crawling redux gears. then try backing off from full throttle. DOWNHILL.



some people also say you cant clutch start honda ct110 or lifan type engines without the manual clutch. yep, they have a centrifugal clutch but they CAN be clutch started, as even the semiauto (centrifugal clutch) ones come equipped with a clutch lever.


not that it really matters, anyway.

 

[KCvale]

if your clutch springs can retract the shoes WITHOUT a freewheel in there...you have mighty powerful springs and your engagement speed is going to be pretty close to operational speed. or your governor is set so low that youre barely cracking idle.

If i hadnt experienced it myself and had the shock of my life, as i had always believed centrifugal clutches dont engine brake... i would be vehemently denying that they CAN actually apply engine braking.

That would scare the hell out of me too.

I think I follow...
You are saying the clutch shoes can kind of stick to the bell, and as long the bell keeps spinning, like chained to the back wheel, even killing the engine will keep them engaged.

I have never seen that, but it sure sounds like a broke clutch to me.
Or at least really weak springs as the engine has to spin them up to ~2200 RPM to overcome most typical 49cc clutches to even engage, and even then they want to slip until you get RPM's to 3K.

I know about other drag, like the 7G with no freewheel but the clutch bell so when you let off the engine and the pads disengage, you drag the whole belt system to the bell.

The bottom line however is, even of there are no springs, if the clutch pads are not spun out and engaged to the bell to begin with, spinning the bell won't engage them ;-}