Thanks KC. Your bike looks very nice, with clean lines and well put together.
Thanks Pete.
Though I build many direct drive single speed bikes my forte is building shifters with 2-stroke, 4-stroke, and electric power plants and why I am so taken with the little shifting engine you found.
(your trike) will get going in first or second on flat ground. That is because I have it geared low. In first, it is a real hill climber. In third, it goes as fast as I would want to go on a light bicycle frame. In fourth, well that would be for the thrill seekers. I'm planning to get a steering dampner before I try 4th at WOT.
I have build 3 electric shifting adult trikes like this 7-speed and found that anything over 20 MPH was just too crazy fast so they were geared very low as well, so low that hitting the 'gas' in 1st or 2nd they would promptly pop a wheelie and spin like a top around the left static back wheel.
Another thing I found very disturbing riding them was how much stress a single wheel drive off center of the front put on that front wheel, you mentioned putting a 'posi-trac' type of rear drive on, that would be really handy I think.
I like the peace of mind of having a tranny that was designed for a motor. I'm still a little gun-shy around internally geared bicycle hubs since I blew out 3 on my chopper. In every case it was my fault. The fourth hub is holding up well, but I don't completely trust it to go far from home.
Not counting the 8 Nuvinci CVT hubs I built shifters on that had a 50% failure rate, I have 20 or so Shimano Nexus 3-speed hub shifters out there and never seen a failure yet.
I will guess your failures were caused by the same thing I have seen eat a couple of 7-speed derailleur shifters, downshifting too low when you think you'll have to stop but don't and hit WOT causing a high power hi torque hit on the back wheel.
One thing is for sure, there is an art to riding an MB with hub gears ;-}
The dimensions are 16 L x 10 H x 11 W. The width is 6" to the right of the centerline, and 5" to the left.
I was afraid of that as I looked over the pictures. It's not a deal breaker as I will be able to fit the 88cc 4-speed in that big Macargi frame nice and low and I do have a pedal system that will fit it to clear the engine.
This is a comparison of the SBP 4-stroke cartridge BB and the gasbike 4-stroke kit bearing BB with funky crank arms.
Since the power is not carried by the BB the gasbike pedal BB is fine.
For a traditional JS I will only use the sealed bearing cartridge type.
Hope this helps. If you have any other questions, I will be happy to help.
Thank you so much and I really appreciate you sharing what you know so far about the engine because at $300 that is $50 less than a gasbike 49cc 4-stroke kit and no need for the $200 sickbikes kits which would be a real boon to what I can add my shifting bike offerings ;-}
Ohhh, one last question...
The specs say the sprocket takes a 420 chain.
Will it take a 415 or maybe a 41?
Thanks again and I look forward to seeing how your trike comes out.