Engine Transmission Question

Hey Everybody,

I am in the process of building a Roadmaster frame with a Briggs and Stratton 5hp engine.

I have really been studying and doing a lot of thinking/figuring about the type of transmission to use on this build and I thought you all might be able to offer some advice. I was originally going to copy msrfan's style of using two belts and a Whizzer automatic clutch with a rear sheave on the back wheel.

Muchos Gracias to msrfan for your help and a copy of your book. It is very helpful.

But then I found out about the current price for the automatic clutch (around $300?, the lowest I saw on ebay was 170 something and it was incomplete), and I started trying to figure out less expensive ways. Also the auto clutch seems to be a little "rare", so it seemed like it might take a long time to procure one.

Anyway, I have been thinking about a centrifugal clutch with two chains and a jackshaft, but I am not sure how I will fit my regular bike pedals into the equation.

I have also considered the EZmotors Q-matic transmission. I used to think it was expensive, but now that I find out how much different clutches and transmission systems actually cost, it doesn't seem so expensive.

Does anyone know if the Q-matic will bolt onto a 3/4" shaft like my Briggs engine?

Then I have even considered a manual clutch with a suicide shifter to engage/tighten the one belt. I don't think this is legal in California, but it would be so vintage and cool.

I guess I am leaning most towards the centrifugal clutch, just for cost reasons. But I wouldn't be able to pedal start, I was thinking of using a kickstart like briggsbiker.

But if you all have any insights, suggestions, I would really like to hear them.

Thanks,

Gilbert

Thank you all so much for the responses. Msrfan, I definately hear you on the ease of set-up, less noise, and easy maintenance of the belt system, and to me it makes the bike look more like an old motorcycle, its just that automatic whizzer clutch that is holding me back. They seem hard to come by and pricey. I am sure they are worth it, I'm just a little cheap I guess.

That's when I started looking into the manual/suicide belt clutch solution. This looks really cool, but maybe difficult to operate at multiple stop lights and probably illegal in California.

Anyway, still puzzling it over. I will have to make a decision soon though, as I am preparing to cut and stretch my frame soon, the most challenging part of the build so far.

Thanks again everyone,

Gilbert

Thanks for all of your help msrfan.

I have looked many times at briggsbiker's build pics and I am wondering. Is the Max Torque clutch mated with an extra pulley for the primary belt (the one from the engine to the jackshaft?) Do you have any insight as to how this is done? Or does the clutch have two separate belt pulleys?

I am sorry to always be asking questions, but I just don't have a lot of experience with self-building motorbike transmissions.

Again, thanks for the help. I have a dream that someday when I finally get this bike running, I will drive it out to Costa Mesa or Corona (I am not sure where you live) and come meet you and shake your hand for the help that you have given. I'll just have to figure out a way to take streets all the way.

Gilbert