Eliminating the driven sprocket

The method you are using has been used from the beginning, all the early motorcycles were using the sprocket in the cranks to transfer the power to the rear wheel. look at a 1903 Indian, its not new. A two speed gear box is all you would need, a bicycle should never be over 30mph for long, keep it safe. Have fun, Dave
This is a pic of a stock Honda 50 gearbox, only 2.5" wide. Three speeds.

Attached Thumbnails

 

__________________
Chuck - The monkey has the spark plug again!

On so I got the bike and the crank and the jackshaft...does anyone know where to find the right gears?? arrrggggg....

I would assume you are using the method Pablo is using. I would use the smaller chain-wheel to drive the rear wheel and the larger one to feed from the engine. I would think a 14 tooth would be a good start. There is a sprocket calculator on the net, I think you can Google it. Have fun, Dave
PS: I put a pic of an early Indian to get an idea of the sprocket sizes, remember you have a reduction off the crank first, then the output.

Attached Thumbnails

 

__________________
Chuck - The monkey has the spark plug again!

Yes I am going for that type of setup that Ghost and Pablo have so kindly shared with us. Im just having trouble finding the gears to match the chains.

Unfortunately the chain that comes with the kit is not a common chain. It has the same pitch as the 420 & 428 motorcycle but the width is larger for the Motorcycle. A bike chain is again the same pitch but they use a narrow sprocket, I think you can just use there sprocket if you can find a way to mount it. The only other thing I can think of is use sprockets for the 420 chain and then have them Ground down narrower to fit the chain you decide to use.
Have fun, Dave
PS: This might be just what you need, I think the #35 chain is the same pitch we are using. Do a search and see if you would just need to narrow a sprocket for use to the bike speocket. Jack Shaft Kit — 5/8in. x 10in. | Chains + Sprockets | Northern Tool + Equipment

__________________
Chuck - The monkey has the spark plug again!

Thanks Egor...for the help. Thought that this would be an easy buy for the sprockets. I was going to go with a typical bicycle jackshaft setup that they have ben using forever on recubents and now adays on wide rear tire bikes. I had already bought the 3/4 inch jackshaft and wanted to stay close to what the guys were doing so I could help give them anymore input on their project....so going to have to make a choice. The freewheel crank on my schwinn I bought is pretty cool and I have found many parts and pieces so with a little looking anyone should be able to get one of these cranks without spending 150 bucks for them. I bought the whole bike for 80 but most was shipping...also about the cranks it looks like they will go on any crank arms because the bearing screws on just like the cone does. I found the bearings and sprockets for less than 50 bucks on ebay.
Terry

Well we have not been idle. There are more things to overcome than you might imagine. It's one thing to jerry rig a set-up, it's another to engineer something to last, and it's a whole other planet to plan something of commercial viability for others to use.

__________________
http://oilslubesfilters.com/ AND NOW http://www.sickbikeparts.com/

cool! does that really make it that much quieter or just a little quieter

__________________
also visit our stock market forum if you like to trade
http://stockmarketcats.com/

Well hows the testing been going?? Is it doing what you thought it would? I see you have a new rear motor mount the downward pull on the motor still causing problems or just an easier way to tension the other chain?
I have checked the covers on my 48 cc motor and my 80 and they are about as dead on as they get so you might be good on your setup for multiple motors.
Cant wait to here more about how its going and how its holding up.
Keep up the great work.
Terry

Quieter? Are you talking about the pipe? Definitely not quieter, but more powerful. Tuned pipes are a must to obtain good performance out of a 2 stroke. Luckily it isn't that much louder than the stock pipe.

The new rear mount was critical in keeping the chain tension. With the stock mount it would just slide. It is solid as a rock now. No slipping and pretty easy to adjust. I put a few miles on it today and it performed nicely. I am out of gas now but plan on a long ride tomorrow.