1951 Safti-Cycle

[Carbineone]

I guess this could be considered a Motorized Bicycle..I have a question on gearing drive train setup..

These Safti-Cycles were made in Wisconsin..In the first pic you will see what I purchased a couple weeks back for a somewhat rat build you could call it I guess. Secone pic is where I am at with it....It is more less a glorified Bicycle with a motor..They came with Clinton engines.. I am putting a Honda GC190 in it..All the plastic and such will be stripped from it.. I will be putting a kickstarter on it.

Anyway I have some questions regarding drivetrain.. The Honda Engine is a 6.2 HP.. The wheels are actual Mpotorcycle wheels and are 23 inches tall with tires mounted.... It will have functioning front and rear drum brakes..I am hoping to get maybe around 40MPH plus out of it..

My first thought to try is just a centrifugal 10T clutch and around a 60 tooth rear sprocket.. But I do not know the feasibility of that simple setup..May work, may not.. Next option I think would be a Belt clutch off the engine to a jackshaft then a chain to the rear sprocket..Want to stay as simple as possible, but will do what I need to to get there..This thing will probably approach 140 pounds when fully assembled..

Knowing the tire size, engine HP and weight..What kind of setup might you suggest I try? I am not good at figuring ratios and such on something like this at all.. Any help would sure be greatly appreciated..

Any a couple pics..My engine should be here tomorrow.

 

[Venice Motor Bikes]

Hi, welcome to the forum!

That's a cool looking little project you've got going!
There's lots of large 4-stroke bikes that have been posted on here over the years... I'm sure you can get some good ideas from them.

Right out of the gate I'm going to suggest building a gear reduction jackshaft & use two drive chains.


I've built several 212cc bikes with jackshafts, Jeff Wolf has built several, & Sportsman Flyer has built dozens.

 

[Carbineone]

So you are saying use a centrifugal chain clutch on the motor and a jackshaft. Or maybe even put the centrifugal clutch on the jackshaft?.I know a jackshaft of some kind would be an easy way to try some different gearing by changing the sprockets on the jack shaft.. I will look through some threads and see what I can find by those builders..Thanks.. It should be a fun little Bike if I can get it geared properly..

There was zero chance of ever finding the parts to put this back together as original..So I am making what I can..I like doing crazy projects like this.. Besides fishing, this is what I do for "fun" now..LOL

 

[Venice Motor Bikes]

Let us know if you have any questions

 

[Carbineone]

I am sure I will..I have decided I am going Jackshaft for sure to get the engine more centered.. But will sure pick your Brains as far as what gearing may work the first time out.. Only expecting and educated guess..Not your fault if it fails to work,LOL

Here a pic of the Honda GC190 stripped of all the plastic junk and sitting in the frame..Should look great and work very well..Thanks

 

[Carbineone]

The fenders I took a chance on came today..They are going to look and work out fantastic.They are off of a 1970 Puch I think...Also finishing up the front brake lever and cable..

I was digging through my buddys junk boxes and found this really cool little lever that will be my choke lever on the Handle Bars...Looks to use a simple Bicycle Brake cable..Coming along..

Sorry in a senior moment I had the choke and Brake Levers reversed,LOL

 

[wrench]

You got a Gem
That 190 6.2 hp Honda motor will give that bike the power it always needed and wanted
It had a 2.5 hp Lawson engine
Unique to the bike was the floorboards - Gas and brake was operated with your feet

Looking forward to following your build

 

[Carbineone]

Thanks

Has anyone here used a GC190 in their builds? If so did you leave the Governor intact? Not looking to turn crazy or dangerous RPMs..If it will be fine with leaving the Governor intact I will.. Just not sure it will have the RPMs to work my centrifugal clutch with the Governor working.. I know on my old Mini Bikes and Go Carts as a youngster we never removed the Governors on the Briggs..We just throttled right off the carb direct..

I read they used Lawsons, 3HP Clintons and even 1.5 HP Briggs maybe..

 

[wrench]

Yep Commando 3 hp Clinton or 2.3 hp Lawson

Sportsman 1.5 hp B&S
Mountaineer 2.3 hp Lawson
Cruiser 2.3 hp Lawson