Homebuilt "Primary" Belt-Drive

[gone_fishin]

yep, mike...the black zip-tie is my centerline as determined by balancing it on a broom handle...that must be another one of those "great minds..." moments 8)

i know the center of balance will change as i add components, but this is close enuff for now.

i did it by myself because i just knew srdavo'd be too wasted to help with a balancing act

 

[MotorbikeMike]

Step 2 Already done?

Hi well, ok, now what you got to do is figure out how low you can mount your engine, and yes I said low. Now what you are instantly gonna find out is a large engine is going to be much happier in a cruiser bike, than in a v-frame (easy to figure out how the drop-loop came about, ain't it?). You may wish to consider to modify a frame or do some building but lets get on with it.
Now, with engine mounted, to use the Whizzer style of drive, you want to look into your ratios if you are doing a dual belt, the cool thing is the center pully is above center, spring loaded into drive, pulled down by the clutch lever to make a "Nuetral"(non-moving) position. The only thing I think you'd need for this real special would be a Whizzer drive sheave and clips. The center pulley section could be made from 2 pulleys fastened together, on an axle (even an old bicycle front hub could work) swinging down from a piviot, a large extension spring hanging down from a point on the frame. I suppose I could make a crude drawing if I've not spoken clearly. If there are no real questions:

Next, the concept of Single belt, cam-over pulley

Mike

 

[gone_fishin]

mike, is it ok if we assume, for now, that the engine's mounted? in sabrina, it WILL sit very high (but it's a surprisingly nice fit)...the only reason i can get away with this is because i also sit quite high, plus i want my project to be truly "engine" on "bicycle". this is a project that must be done in a fell swoop, with everything rocked out ahead of time.

so, do tell more, please, about the whizzer method of clutching (and shifting?) and how it can be homebuilt. as the king of crude drawings ( ) i would love to see some sort of diagram, if you have time...thanks very much for helping with this

 

[MotorbikeMike]

High mount

Hi Augidog, yes It's ok, you just have to know that the bike will need a VERY good stand to help overcome the High Center of Gravity (we will now out call COG).
The other thing to know, is that for the "Falling Pulley" clutch to work properly, the "clutch" or center pulley MUST be signifacantly above the centerline of BOTH the front and rear pulleys or you will not get adequate slacking in the belts, and you'll never be in "nuetral".
What we are seeing here can work very well. I will sharpen a pencil, and give some thought to stick-figure quality drawings, if indeed we get to the point where I'm not able to paint adequate "Word Pictures"
This whole concept is a wonderful drive system, cheap, effective, andique, and do-able.
I need to go to the store, and get a card-reader for a treat for all who will see, Mike

 

[MotorbikeMike]

Today's Treat- Single Belt 1910 Excelsior

Hi well we had quite a day, and there was so much to see. Here is a perfect example of a single flat belt drive, with a spring loaded cam over style engagement.
Notice that the lever actuates a curved bar, which loads a pulley into the bottom of the belt, loading it into the small primary pulley, which of course is much more likely to slip, than the larger pulley with the larger contact area. The lever runs in a series of notches (Ratchet type) to hold it in the position you want (locked).

I think this is a 31cu in making a small HP that I will look up, as the owner did not know.

 

[gone_fishin]

8) standing by...and getting psyched!

 

[MotorbikeMike]

Indian Belt drive

Indian built a lot of chain drive bikes, even some of the earliest ones, this is a pic of a rare belt-drive indian, see the same concept for the belt clutch. Mike

 

[gone_fishin]

i'm getting this in my head and this is my best effort to express it...2-speed?

i'm not sure how loose and tight the belts need to be so this is very rough...it's based on off-the-shelf hardware-store stuff...how'd i do so far?

someone have close-ups of similar systems?
do i have to use mini-bike grade belts and pulleys or can i go a tad lighter?

 

[SlicerDicer]

Augi would you mind telling me what hardware you were planning on using for this? I am getting my tecumseh this month it looks like. I am debating about using a chain drive and modifiy the clutch to where it can engage at lower rpm to give me better control but I would love to hear what you are planning and aprox cost

 

[gone_fishin]

sorry for the delay...just saw this.

i didn't really get into specific parts or costs. basic shafts, pulleys, bearings, collars, strapping, etc...

it's really as simple as building one drive twice with different ratios, all you have to do is figure out the geometry needed for your desired range & performance 8)