Help Me Figure This Out *PICS*

[trike5]

I have a 3 wheeled bicycle (more than two wheels so figured it belonged here instead of the mini bike section ) and a 5hp briggs and stratton. The briggs and stratton is from an old generator and I haven't been able to get the coils off the output shaft. I got the three wheeled bicycle yesterday and so far I've only set the motor on the bike.

What I need help with is figuring out how to get power from the output shaft to the rear axle. I'm planning on getting a centrifugal clutch. The output shaft is so long I'm thinking I might be able to put a longer rear axle on the bike? so that enough is exposed on the ends to cut a notch into and put a go kart sprocket on? But I'm not sure. Take a look at my pics and tell me what you would do. Yes I know the bike has a flat and a taco'd rear rim. I'll be getting all new tires and wheels, and I have the carb for the motor and gas tank disassembled to clean. I am also quite aware of the speed and danger possible on this, so please no preaching.

Any ideas on how to construct the drive would be appreciated

EDIT: There is about 6 7/8" from center of the axle to center of the drive shaft, is that enough clearance for a gokart sprocket and a centrifugal clutch? I am going to be putting a steel plate and rubber pad on the back which will raise the motor up another 3/4" or so? but I might be able to raise it more? and I think I will cut notches so I can slide the motor forward to adjust chain tension?

 

[kibble]

Having taken two generators apart, I might be able to help you. The shaft on the engines I had both had tapered ends that go into the rotor. If there is/was a a long bolt on the other end of the rotor opposite the engine you can spray some wd40 into the hole to help loosen it up. Then you just have to try really hard to wiggle it out of there, maybe hitting it a bit from side to side might help. It took me forever to figure out how to get it out.

 

[trike5]

thanks for the input! Yes, there was a long bolt that came out of there. However,I think I want a long drive shaft so that I can put the centrifugal clutch/sprocket out at the end, so it is over the axle past where the frame ends, and put a 55tooth sprocket on some sort of longer axle so that area is exposed...? I will spray some WD in and try to get it off though to see what it's like

I've done some math and at 5000rpm with 11t drive sprocket and 55t driven sprocket I'll have 1000 rpm at the wheel x 24" wheel = 24,000/12" = 2000ft per minute, which is roughly 1/3 a mile a minute, 1 mile in 3min, 2 miles in 6min.... 20mph!

Edit: I jut found out 4000rpm is max on my motor, and when figuring in 5,280 ft per mile, it looks like 18.18mph maybe I'll have to go with a smaller driven sprocket... I'd like to go 20-25mph.


How much space between the frame and wheel, on the axle, would I need to fit a hub for a sprocket?

 

[Lousailor]

Your biggest problem will be connecting the engine output to the rear axle. You may have to weld a jack shaft under the frame so you can connect to the gear on the opposite side of the motor.

 

[ed1380]

Having taken two generators apart, I might be able to help you. The shaft on the engines I had both had tapered ends that go into the rotor. If there is/was a a long bolt on the other end of the rotor opposite the engine you can spray some wd40 into the hole to help loosen it up. Then you just have to try really hard to wiggle it out of there, maybe hitting it a bit from side to side might help. It took me forever to figure out how to get it out.

true dat, but we used big flat screwdrivers and wedged them between teh motor and generator case

 

[2or3wheels]

It it a live axle?

also if the pedals are directly on the axle you migh want to take the chain off.

 

[ryf]

leave it on there, the extra weight will give it momentum for burnouts(joke)


take the gen head off, run a chain forward to a jackshaft, over to the orginal sprocket, clean, simple, no extra axle work needed. no long motor shaf needed either.


i'd take it to a small engine mechanic and let him earn 2 hours pays for it..... but not until after I tap the shaft with a hammer LIGHTLY (repeatedly) while some people are pulling the parts apart while sitting(or else they'll fall). I've had good luck with it... but DON'T just whack the snot out of it...

 

[trike5]

It's not a live axle, there's only power to the left wheel, but I've thought about trying to make it a solid axle... probably won't though

The rear sprocket lets you coast so the pedals don't keep turning when you stop pedaling. I was hoping to leave the pedals on so I could pedal the bike if necessary, but it's hard enough without a motor on the back, so it might be next to impossible to ride it with it on there.

So... Now I am thinking about taking the pedals off, leaving the sprockets and chain that are on it, on, and putting another large sprocket on the left side...? so a chain will run from the motor to a sprocket n the left side, which will turn the sprocket on the right side which goes back and turns the sprocket on the axle.... cool. Now, I have to figure out how to get a sprocket on the left side... and what type of"axle" to run through the crank part of the frame for both sprockets to mount on. I think I might have to extend the left one a few inches away from the frame so it lines up with the motor sprocket(once I get the coil part off)

Realistically this seems a lot more feasible, and if the motor craps out or I run out of gas I can just get off and push.

Thanks for the advice

EDIT: ok I get it, I should put a jackshaft through the crank/pedals part of the frame is what you guys are saying? I think I might need to change the sprocket on the right to a smaller one too, or the left one would have to be huge...

EDIT #2: I just went and looked and I can't put a smaller sprocket on the right or the chain will hit the frame... and it's geared the opposite of how the motor needs to be so to compensate I would have to make the left sprocket gigantic. how do I get around that?

 

[mikeandike]

I dont think you want to use the bike chain because itll probably break under that amount of hp/torque. Bike chains are only made to withstand human "power". I think you should just take the whole pedal assembly thing out and figure out a way to mount a jackshaft through there and put a different sproket on. But then you have to change the sproket no the axle which could become a pain. You could always try the bike chain first and see how long its lasts but be careful if it snaps.

 

[trike5]

Update

OK I managed to get the coils thing off the drive shaft and I took apart the left pedal to try and figure out if I could mount a sprocket on it or put another right pedal on but it's a once piece crank so right there I am stuck. I know I need to put some kind of jackshaft through there with a sprocket on each end, but I have no idea what size shaft I need ot where to get it. Or how or if I could mount it up right? If I could figure that out all I'd need is to get the gas tank carb and exhaust back on and a centrifugal clutch and I'd be on the home stretch!

at northerntool.com I see these jackshafts http://www.northerntool.com/webapp/...t=Search&cm_pla=SO&cm_ite=ALL&cmnosearch=true but they are only 5/8" and 3/4"... I think I need a 1" to be able to put a hub and 72 tooth sprocket on the left side right? I haven't seen any 3/4" sprocket hubs???
If I were to put a piece of 1" axle through there, how would I tighten it up so it doesn't bounce around or slide back and forth?

 

[mikeandike]

well you could always go for a 12t on the engine -> 36t on the jackshaft, 12t on the other side of the jackshaft -> 24t on the axel and that would give you a 6:1 ratio.

EDIT: Changed one of the ratios it was wrong. You can swap the 36t and the 24t it dosnt make a difference

 

[trike5]

that sounds like it would work, but what I don't get is how I put the jack shaft through that part of the frame, and keep it stable? Like not wobbling or sliding side to side if you know what I mean. I can't visualize how that works...

also I need the small sprocket on the right to be right up against the frame but the larger one on the left will have to be about 4.5" out.