Super Bronc 10 Build, from the bone yard.

[KenZ]

The jack shaft rear brake on my 1040 is more than enough for dirt riding. Mine will easily lock up the rear wheel, even as big as it is. Any more braking than lock up is just wasted.

Well, I have nothing on the rear of the bike, I don't even have a wheel yet, working on that when I get back from a weeks vacation starting tomorrow.
The original jackshaft plate, if it ever had one was gone when I got the frame. A piece or 2.5" channel iron was welded there to hold a kick starter for some unknown 2 stroke motor apparently.
I could do a jackshaft, with a little disc brake, I've been thinking of that also.
I also watched a video today of doing a 2 speed jackshaft drive, 2 chain centrifugal clutches, one for low speed, one for high speed, it's also been a topic here on OldMiniBikes in the past. I just don't know how it will perform, I want this bike to be able to climb very steep terrain here in Montana if called to do it.
The biggest issue I have is getting the rear wheel and drive system fabricated or cobbled together as in the photo's in my previous posts.
I've gleaned through hundreds of photos here and elsewhere on the web to try to figure out what will work, especially for the rear wheel.
There's a good photo essay on OldMiniBikes of the Low and Wide bike, the builder made his own rear hub for the wheel.
We shall see.
I'll be back a week from this Thursday.
Give me a ton of comments on everything I've said so far.
Thanks for the help guys, as soon as I have a wheel it will start falling in place.
Below is the goofy channel that I had to cut off the frame to start with.

 

[delray]

The jack shaft rear brake on my 1040 is more than enough for dirt riding. Mine will easily lock up the rear wheel, even as big as it is. Any more braking than lock up is just wasted.

I have only road one 1040 and that one seem to have more control over stopping it then the older model's with the band brake on the jackshaft backing plate. i am going to be riding with some local super bronc guys this weekend and couple of them had modified there band brake setups so the brake doesn't lock up so easy. i like to look into how they modified there band brake. i still want to keep my band brake on my vt-8 bike. that bike is still all complete. right now i have a vt-10 bike that i am making a disc brake on the back side of a comet steel plate jack shaft unit. that will be alot like the 1040 disc unit and brake in size. also making my brake caliper into a floater. this way both sides of the brake pads are working and have control of my braking power when stopping.

 

[stupid bronc]

Okay, for Today's exploration... Bare with my guys, I'm getting up to speed here on what I need and the correct terminology for each, I know I'm the FNG, but someone has to be!

Drive Hubs : So, the Biggest issue will be the correct size for *Peerless* style drive flanges for the rear chain wheel and brake disc hubs. I've taken pictures of how much room I have with the front wheel positioned as a rear wheel below. I am guessing I'll have to speak to one of the suppliers. See pictures below please.
Seat Dimensons: Next, How long is the seat?, how wide is the seat at the front and back, and what is the distance from the front to the shock mount? I have some good high layer count 3/4" cabinet making plywood I can make a sturdy seat base with. Is there any band iron reinforcement under the seat base tying the front to the shock mount strap? See Nasty Broncs picture below that I scribbled on.
Seat Shocks: How long should they be? I found some on the web that look about right, but I have no idea if they are correct, you all do!
Carburation: I found an adjustable Tecumseh carb # from a YouTube video by a guy that does small engine work. I Googled the # and found a factory Tecumseh carb for about $80 and many knock offs for $15 or less, I think we'll try the less first!
Torque Converters: Looking at what's available and quality I'm going to go with a Comet, the only thing is, with left side drive do you drive directly from the torque converter as supplied from the rear sprocket on the TC to the rear chainwheel? Does there need to be any support at the rear of the TC? or is the TC plate enough for the loads? See pic below of the Red Bronc from OldMiniBikes archives. I believe that the drive goes from the TC to the rear chainwheel without any other support to the motor plate. Correct me please if I am wrong.

First off, my rear shocks are 13 inches long center to center. Dimensions of the wooden base are overall length, front pivot bolt to rear of seat 24 inches, rear width 15 and 1/2, front 6 and 1/2. Distance front pivot bolt to rear shock bolts, center to center, is 18 inches. There is no steel reinforcing under the seat, just the front and rear u-shaped mounts going across under the wood base. If you check closely on the front seat hinge you’ll see some numbers stamped in it, those are the serial numbers of your bike. I don’t know what they mean or what the sequence is, maybe someone with a lot more knowledge than I can help you on that one. Hope this helps. And my handle is “Stupid Bronc”, a name given to my bike by my son as an adolescent and he still calls it that today as a grown man. But it doesn’t stop him from riding it whenever he can!

 

[delray]

something to think about in the future if you build another super bronc bike. look at the 1040 bike and see how that one is built from factory. they kind of took the bugs out of it. for example they use a 40 series clutch with a larger 7+ rear driven pully. helping pull much better when riding off road conditions. use a disc brake that makes it little easier to control the brake stopping. i have seen the older band brake lock right up because of how the brake wants to grab the drum and wrap right around it.

 

[KenZ]

I'm back!
Had to work on some projects around the house and do taxes.
I solved my rear wheel/axle issue. There was a guy on the Heald Facebook group selling excess Bronc stuff.
Now that I have the factory wheel/axle and hub with sprocket in hand I can get on with things. I'm going to have a round flange welded to the axle hub shaft that will be able to pass through the wheel center hole so the tire can be serviced. To that I'll bolt on a brake disc.
Now to order the rest of the things I don't have yet to kick this project into gear again.

 

[jeep2003]

heres some drawings of the seat pan and bracket. the stock shocks are 13" but you can make the bracket 1" taller to make up for it. The problem with running the chain on the drive side is you have to offset the engine so much. Its much nicer to center it up and run over to the other side with the jackshaft extended. You can still run your disk on the left side. #40 or 41 chain is much better then #35 because it stays on better and is stronger. But you can only go so low with the ratio. the factory size it too small in my opinion. atleast for trail riding. Kinda hard on the belt with a 6" driver. The back of the torque converter is unsupported. I recommend you reinforce the engine plate with some bars across where it bolts on. The plate is too big it lets the engine vibrate and move around under load.

 

[KenZ]

heres some drawings of the seat pan and bracket. the stock shocks are 13" but you can make the bracket 1" taller to make up for it. The problem with running the chain on the drive side is you have to offset the engine so much. Its much nicer to center it up and run over to the other side with the jackshaft extended. You can still run your disk on the left side. #40 or 41 chain is much better then #35 because it stays on better and is stronger. But you can only go so low with the ratio. the factory size it too small in my opinion. atleast for trail riding. Kinda hard on the belt with a 6" driver. The back of the torque converter is unsupported. I recommend you reinforce the engine plate with some bars across where it bolts on. The plate is too big it lets the engine vibrate and move around under load.

Thank you so much. I am ordering parts this week to get underway.

 

[Docdng]

Thank you so much. I am ordering parts this week to get underway.

I'm a new guy to this mini bike business (unless you count the 400,000 miles I put on my Cushman Eagle as a kid!) but I started following your project recently. I'm trying to do some CPR on a Super Bronc too--like you, for my 13 yr old grandson. Mine is complete for the most part (because I got it that way when a friend gave it too me several yrs ago). Been parked too long and now needs some work. I will watch your project with interest b/c I need to learn the ins and outs of carbs, vacuum fuel pumps, tires, wheels, braking systems, etc... (mine has the baby rotor and brake pads/caliper on the jackshaft and I'm tuning in to the discussions regarding the short-comings of that system). You clearly have more to do on yours than I do on mine and that is a wonderful state of affairs! Not for you, of course---but for me, as I shall benefit from the "sweat factor" you put into your project. Thank you for letting me watch!