Utilizing the derailleur gear system?

[86BG]

I've searched the forum -

I finally got a 49cc engine free from a friend and was wondering if anyone here has ran a drive chain down onto the opposite side of the crank with a sprocket and removed the pedals? with a centrifugal clutch you could simply let off the throttle for a second or two, then shift gear, then apply throttle slowly to let the chain fall into place.

I don't see why it wouldn't work as the problem would be too much torque to the chain when the chain is falling into the next gear, but that's eliminated with a clutch.

You can keep your bike in the power band and get much more torque out of these small engines.. I don't see why EVERYONE isn't doing this. It's a free gearbox!


What is your experiences?

 

[Mountainman]

yes -- it should work

easing up on drive pressure at times of changing gears

I think that it will be tricky -- not tearing gears ect up

let us know -- if you take on the project -- and how it works

Ride That Thing - Mountainman

 

[86BG]

Yes I am taking on the project. I just tore the 49cc off the kid's sit down scooter that was messed up at the frame, so I know the engine outlasted the scooter. It's in pretty good condition and has good compresssion.

The problem I am having now is that this engine was on a scooter with a 12v battery for the turn signals, horn, and headlight, and taillight and there's a terminal on the coil next to the pull start and a 2 terminal connector coming off the spark plug area. I think the connector coming from the spark plug area is for the kill switch and the other terminal on the coil is for charging the little 7AH battery.

Also, this engine seems to have a sort of wet bath clutch looking housing coming off the shaft. Can anyone confirm this? I know it is a sort of clutch because sprocket doesn't spin when cranking

 

[ZnsaneRyder]

My brother is making a bike-trailer out of a bike frame, but wants to do similar to what you are. One thing were trying to figure out is if there's enough torque, and if the gear ratio will be low enough on the low gears, so you can take advantage of the higher gears while shifting.

 

[86BG]

I fired up the 49cc today and it idles PERFECT and spins up to full RPM very smoothly. Best part - I pulled it from the scooter frame and the twist grip works flawless. I was planning on it not working and cleaning the carb but I guess the leftover gas kept the carb clean the year or more that it was sitting. I can also salvage the blinker relay and switches from the scooter and use them on the bike.

I have a mountain bike with shocks in my shed that's in flawless condition and I plan on using it. I will work as hard as I can to get this done while I wait for my next check on the 1st to come in and go buy the 250cc twin cylinder 5-speed honda motorcycle engine for my homemade 2 seater full suspensioned buggy.

ZnsaneRyder -

For every time you half the gear ratio you get twice the torque from the engine, so lower gears are a good thing. Gear the last gear at the max RPM so that it reaches maybe 50. The lower you gear it the more torque you get. It will easily outdo the kits with a single gear in acceleration and speed. Use a gear ratio calculator at a go kart website to get it all right.

If you want to alter the gear ratio a great deal you can make a small jackshaft with a go kart jackshaft kit or 2 small pillow blocks and a piece of axle or pipe.

If anyone has some real experience with this method be sure to let me know how well it works. Also, is it still legal to drive the bike on the roads if I remove the pedals?

 

[williamsk1936@yahoo.com]

Deraleur transmission

With a recoil starter, it might work but if you eliminate the peddles, all you have is a MO. Would it still fall into the "with peddles, not over 30 mph" law? Maybe it is different than Oklahoma. Keith (trackfodder)Williams:???: Nutz-misspelled derailleur and can't edit title

 

[86BG]

I live in alabama and a friend said as long as it's under 50cc it doesn't matter, but I think he's wrong.

It looks like I'm going to have to remove the front casette and replace it with a small sprocket for this to work.

 

[s_beaudry]

How are you going to mount it to the frame?

Any pictures of the project yet?

 

[Ghost0]

Try this for some inspiration.
www.sickbikeparts.com

 

[sideshowsideswipe]

Try this for some inspiration.
www.sickbikeparts.com

Actually try this for exactly what you're talking about.