first post, would appreciate help understanding transmissions

J

JDP

New Member
#1
#1
hello all, this is my first post here, and im very impressed so far. I've been looking at minibikes for a while now, and have decided to build one from scratch. My problem is i don't quite understand how a transmission and clutch for something like this would work. I've been looking at this Comet Industries Torque Converter Kit — 10 Tooth, 3/4in. Bore | Power + Steering Components | Northern Tool + Equipment

and this Heavy-Duty Clutch With Bushings | Brakes, Clutches, + Hubs | Northern Tool + Equipment

for a bit, but i don't quite understand how they both work. I think the first one is an actual transmission with a clutch, but i don't understand the second one- its a clutch, but what would i do for a transmission sort of thing?

So basically i'm looking for some help understanding "shifting" for small vehicles such as minibikes.

Thanks all,

JDP

PS. if this is in the wrong section, please feel free to move it
 
frankydodo

frankydodo

New Member
#3
#3
the second one is a centrifugal clutch, when you start your engine it run at like 1500 rpm +/- 250 rpm and the clutch engagement is at 2400 rpm, when you give some gas the rpm of your engine increase and the cluth engage and it makes your minibike moving. the torq-a-verter will makes you go faster because it has a variable ratio and the clutch is always 1:1 ratio
 
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dave dickson

dave dickson

New Member
#4
#4
Good answer both you guys, I see you've learned something from hanging around, lol, now the second clutch, in 41 chain, with a 5hp briggs, and a 40 something tooth rear sproket will give you all the power and speed you could want for awhile, I'll be trying out my 6.5 clone here soon and I'll update everyone on the performance between the 2 different styles as I'm building 2 bikes with 2 identicle motors, one with the 35 chain set up and the other with the 41, I'm going to have 2 brothers, one is heavier than the other so I'm going to have the heavier one ride the 41 chain set up, you will see the difference, I'm sure. to tell the truth I'm looking forward to experimenting with the tav type torque converter, there are a couple of different styles of those that have my interest, and that I have them on my wish list, as they are parts that will complete 3 of my bikes.
dave
 
jesse8931

jesse8931

New Member
#5
#5
dave i had a mini with 41 chain and i had it for 10 years only replaced the chain once and i had a mini with 35 chain and i cant tell you how many times ive had to replace it
 
Stang

Stang

Member
#6
#6
The first one is like a CVT transmission. Here's a few links to help.

Howstuffworks "Pulley-based CVTs"
Comet Torque Converter Terms @ gokartsupply.com

And here is a basic description of a centrifugal clutch

Howstuffworks "How Chain Saws Work"

Both use the centrifugal force from the crank rotating to engage, the torque converter just varies the diameter of the driver ( on engine ) and driven ( placed on jackshaft ) to achieve different ratios like an 18 speed mountain bike would, except the bike is manual :)
 
nostrixoxide

nostrixoxide

New Member
#7
#7
Very informitive information. Thanks for the links!!!

One question I have is "How do you dertermine when to use a centifugal clutch vs. a TAV". For example if you have a 3/4" shaft built clone motor that makes 20hp or so would a standard TAV be able to handle that kind of output? I guess what I'm getting at is what are the limitations of the TAV & at what point do you need to upgrade to a high dollar centrifugal clutch???

Sorry to high-jack. but I feel the question is closely related to the topic & deserves to be here along with the other great information....
 
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J

JDP

New Member
#8
#8
wow cool thanks guys, that was what was really confusing me in building my mini. Now i think i can get started- one more quick question- does the clutch just mount on the engine output shaft, or where/how does it meet??

Now i think i'll start designing my mini, i'll keep you guys updated!
 
pro69nova

pro69nova

New Member
#9
#9
nostrixoxide said:
Very informitive information. Thanks for the links!!!

One question I have is "How do you dertermine when to use a centifugal clutch vs. a TAV". For example if you have a 3/4" shaft built clone motor that makes 20hp or so would a standard TAV be able to handle that kind of output? I guess what I'm getting at is what are the limitations of the TAV & at what point do you need to upgrade to a high dollar centrifugal clutch???


No TAV is gonna come close to a nice 2 or 3 disk clutch. if you think you are making 20hp go right for the multidisk.

JD
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