Heathkit Boonie Bike 2 speed - how it work?

[cfh]

if you were breaking that spring once a month, that's enough that i don't think i even want to go there with the whole idea. i'll change to a torque converter or heck even a clutch with no gear changing. taking apart that jackshaft, if i could find the springs, isn't something i would want to do every month anyway! If i can use the original clutch guard with the torque converter, that would be ideal in my eye.

on the kickstand i'm just going to weld a bracket for the $10 style kickstand that is readily available. i suspect the original is a bolt on type, and those are like $50 + on ebay. it's not worth it...

 

[capguncowboy]

if you were breaking that spring once a month, that's enough that i don't think i even want to go there with the whole idea. i'll change to a torque converter or heck even a clutch with no gear changing. taking apart that jackshaft, if i could find the springs, isn't something i would want to do every month anyway! If i can use the original clutch guard with the torque converter, that would be ideal in my eye.

on the kickstand i'm just going to weld a bracket for the $10 style kickstand that is readily available. i suspect the original is a bolt on type, and those are like $50 + on ebay. it's not worth it...

What's the length of the original kickstand. I might have something in my stash

 

[cfh]

I have no idea on the kickstand since my bike never had one since I owned it. So I don’t even know what it looks like

 

[SCooke123]

I just looked at the one from my Boonie. The top part that pivots at the frame is 3 " long then has an approx. 45degree bend. The straight part is approx. 5" then bend again at an angle where it touches ground (that's approx. 1 1/2" long).

 

[cfh]

Thank you!

 

[SCooke123]

I'm hoping to find time to work on it this summer - I hope to have it running someday soon!

 

[markus]

This thread link below gives some info on the Boonie specific stands, The arm itself was pretty standard and could be found on other bikes, I had bought a batch of them last year NOS but with flat and raised style hinges out of old dealer stock that I built other style stands with. same goes for the W hinge, but usually never together except for the Boonie from what I have seen.

https://www.oldminibikes.com/forum/...boonie-bike-kickstand-style-verification.html

 

[cfh]

So i got my comet clone torque converter and jackshaft assembly in the mail yesterday. has anyone does that mod? using the existing stock jackshaft hanger, the driven side of the torque converter is too big to fit. and mounting the comet on it's aluminum plate housing onto the motor (which holds both the drive and driven TC parts doesn't really work either (motor sits too low and the briggs gas tank is in the way too.) so how do i approach this?? I guess i could use a Tecumseh with a front mount gas tank, but that seems extreme.... thanks!

 

[cfh]

I have given up using the original Bonnibike 2 speed manual transmission, and gone with the torque converter idea. Since this is a loosing (money wise) idea (that is the value of the bike isn't there with this modification), i'm trying to do this 'on the cheap'. Hence i bought a china comet 30 clone. I am using a tecumseh 4hp snow blower motor too. The original 5hp Briggs (which i have!) won't work with a TAV, since the gas tank interferes with the TAV system. hence the tecumseh. So here it goes... here's the starting bike...

 

[cfh]

I pulled the briggs motor off. First thing I had to do was increase the length of the motor mount slots. I used a dremel to do this, with some work with a hand file. Made the motor slots about 1/2" longer (towards the front wheel).

 

[cfh]

Here's the converted snowblower 4hp tecumeseh. it was originally orange. To keep a vintage look to the Boonie bike, i painted the motor white.

 

[cfh]

With the longated motor slots, the motor/tav30 can go in place. With the motor all the way forward, i'll modify the original boonie jackshaft assembly. i would have preferred to just mount the driven portion of the tav30 on the jackshaft, but the jackshaft isn't tall enough to allow that. so i have to use the aluminum plate to hold both the drive and driven tav30 assembly to the tecumseh motor.

 

[cfh]

Here's the modified original jackshaft holder. you can see i cut the front edge on the TAV side. i guess i didn't need to do that, but seemed to make some sense (to me.) The jackshaft is new from OldMiniBikes whorehouse (12" version) and came with the shaft (obviously), two new bearings, and two new #35 gears. i hope this gearing works!

 

[cfh]

The jackshaft is in a different position now.

 

[cfh]

I will have to drill new holes in the motor plate. I don't think i will have them enlongated. since the tire axle mount allows movement, and the motor can move, i don't think i need to have the jackshaft mount to be movable.

 

[cfh]

Got the jackshaft all mounted, and the chains installed.

 

[cfh]

 

[cfh]

 

[cfh]

Overall i'm pretty happy with the results. The overall speed with the Torque Converter is in low gear mimics the original low stock bonnie bike gear. I can't speak to when the TAV30 switches to high gear though, as i never had the stock boonie bike in high gear. But overall the bike goes about as fast as i would like (it's not a great handling bike.)

 

[cfh]

There are some modifications left to do.

1. weld on a kickstand.
2. extend the left side footpeg about 3 inches (the torque converter cover makes the left foot peg seem too short.
3. weld on a bracket to secure the torque converter's aluminum mount plate (this should help prevent breakage.)
4. weld on extensions to the rear wheel adjustments, to give the rear wheel more travel (for better chain adjustment.)
5. make a "boonie bike" custom sticker, based on the original design, for the TC cover.

After i do those things i'll probably have the bike powder coated and pretty it up. I'm not sure why though, because as i said before, it doesn't handle all that great. I might play with changing the front tire/wheel so it's bigger. that may help the handling.