Stand alone Clutch


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7:22 AM
Feb 18, 2008
Is there any such thing as a stand alone, non centrifugal clutch?

I was told the clutch in my "HT" motor can't take being used for starting off from a dead stop, but it wouldn't take a very big manual clutch to handle it, so since I plan to add a jack shaft for some gear reduction anyway, i figured a real clutch would be perfect.
I may be misunderstanding you here, so forgive me if I am...

You are talking about a "non centrifugal clutch"? The HT already has one of these.

I think what you are looking for here is a "centrifugal clutch". You are wanting to keep the engine running all the time, and be able to throttle from a dead stop and take off without using a clutch handle? This would be how a centrifugal clutch works.

A centrifugal clutch, to my knowledge, works off of the engine rpm and is spring loaded to "engage" as the engine rpm is raised and "disengages" automaticly as you return to idle.

Is this what you are looking for?
Nah, a non-centrifugal clutch. From what i was told, the "HT" clutch can't hold up to dead stop starts very long, and a normal motorbike clutch can. essentualy, they work the same, its just a longevity issue, as I understand it.

A centrifugal clutch would work for starting from a dead stop, but you wouldn't be able to pedal start the motor. So what I need, I think, is a manualy activated clutch.

50cc motorbikes use them, integrated into the transmission, and many of them can beat a car through an intersection from a dead stop. So i know the "80" HT I have should be able to pull away from a dead stop, if only the clutch can take the strain.
But if you pedal to get moving first the clutch durability isn't a problem. A motorised bicycle isn't really meant for standing drag starts.
I'm not aware of any HT clutch's that will handle the standing starts u require.....pretty soon ANY Chinese clutch will fail(the better the kit the later it'll fail,but it will fail)
Their not built for continuous standing starts,but if u want to beef-up a standard clutch you'll maybe have success,dunno how much though.
I guess its a matter of perspective. I've had a couple of electric bikes, the latest you can see here:
It runs a 74 volt battery and is capable of 40 amps max. Thats 4 horsepower peak. roughly what a gas motor does. With the electrics, I have no problem riding it like a motorcycle. It will pull away from a dead stop, up an incline, without pedaling, without a problem.
I've come to expect that level of preformance as a minimum. And I know the HT should be capable, if only it had a clutch capable. Adding an external clutch should be easy enough, but from where? Or would I just have to build it my self?
FYI the add on centrifugal clutch for the HT has a freewheel or one-way bearing in it so you can start by pedaling. It locks up in one direction - to start the moter, and operates like a normal centrifugal clutch in the other rotation direction - to start riding from a standstill.
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Check with Blue Collar (a vendor here) first... I've seen them on BoyGoFast's eBay store and sells them with motors, don't know about alone.

Bought mine in a pkg from BoyGoFast as a full kit with pull start and centrifugal clutch...

Beware, it adds enough width that you have to extend your cranks. (~6 7/8" motor width with both the pull start and the cent clutch)
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Drunkskunk what I believe you are looking for is a transmission.

Without a transmission, there is not a clutch out there that can withstand the constant abuse that high gear only starts would subject a clutch to. We have to remember that we only have that one gear, it could be a little taller for better top speed, and it should be a lot lower in order to take off reliably on a daily basis. I'm sure you will agree that if you took off on a motorcycle, car, or truck in high gear constantly, it would not be long till you started shopping for a new clutch.

Both the motor and clutch will be much happier if you can give it a helping hand by giving it a few pumps on the peddles when you take off. Don't forget, the motor also takes a beating when it is repeatedly lugged upon takeoff without a little help.