Tri Rider In Need of Low End Power

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suiciderandy

New Member
I posted this in gears and hubs, but it is a trike so I finished my 49cc Tri Rider yesterday and not surprisingly there is no low end power. I'm running a 11T drive sprocket and a 24T on the axle. (4" diameter) I know it's small, but there are three support bars in the way and the max diameter sprocket I can squeeze in there is a 5.5 inch which I don't even want to try because the improvement wouldn't even be worth the trouble. The only thing I can think of is to build a 10" mini axle off of the back with two sprockets (44T & 20t) and then back to the original axle. Anyone have any suggestions? I only need about 15-20 mph top end. Get up and go is my main priority just to tool around the neighborhood with my dog. Thanks.


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perhaps try switching out that tranny for a cvt, if you can find one that will fit? I dont know if the huasheng engine will accept a cvt or not. its worth a try though.
 
Is that a 3.25:1 gearbox? If so, you have a 7.8:1 overall ratio right now! Assuming those are 24" wheels, the trike would go ~18MPH at idle!

You definitely need some more reduction in there. If you switched to #35 chain and sprockets, you can run up to 10>44T, tho you'd lose the freewheeling.
That will give you 14.3:1, or 10MPH @ idle. Like you said, not much of an improvement, since you'd be going 30MPH @ 6000.
That's the same as top gear on my own build, and I can't really take off in that gear!
Using your existing gearing, you can also do this by switching to 16" rear wheels :p

If you were using a 4:1 or 5:1 gearbox, you'd get closer to the optimum reduction for your setup, which I estimate about 18:1 overall.
With a 4:1 gearbox, you'd need 45T on that axle; with a 5:1 36T. Closest to your existing gears is 7:1 and 26T.

There are no suitable CVTs for these motors being sold, unfortunately.
 
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I have a worksman trike that I want to motorize. I live in calif. so I can only use the 4 stroke engine that has no low end torque so I was thinking of using an electric hub motor for the front wheel. With a little pedaling I could probably get it going fast enough for the piston power to take over and relieve the electric. The front electric would help it get up hills too. If the electric was only used to help start it and get it up hills it would probably last a good while between recharges. If you take this approach I would be very interested in the results.
 
woodwalla said:
I have a worksman trike that I want to motorize. I live in calif. so I can only use the 4 stroke engine that has no low end torque so I was thinking of using an electric hub motor for the front wheel. With a little pedaling I could probably get it going fast enough for the piston power to take over and relieve the electric. The front electric would help it get up hills too. If the electric was only used to help start it and get it up hills it would probably last a good while between recharges. If you take this approach I would be very interested in the results.
Click to expand...

I swapped out the 4 stroke kit for a 7 hp crate motor. My bike set up was just not gonna work without major frame changes. If you are interested I would be willing to sell you the kit for a descent price. It doesn't even have a half hour on the motor. I bought the kit from this seller on ebay three weeks ago. If interested pm me I have a video of the engine mounted and running.

http://www.ebay.com/itm/4-stroke-MOTOR-bicycle-Motorized-GAS-ENGINE-KIT-49cc-/190626108989?pt=Cycling_Parts_Accessories&hash=item2c6233963d#ht_8013wt_1356
 
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