Black Beauty Electric Mini-Bike Project

#2
Hi everyone! Newbie here. I picked up an old mini-bike frame at a rummage sale.

I'm one of those guys who would always have loved one as a kid, but my mother would forbid me even if we could have afforded one.

Now, I am an adult, saw this and thought it looked like fun. I really don't know anything about mini-bikes, but like working on projects and learning new things.

It appears that this frame is a Stellar Black Beauty. (Anyone know approximately what year it's likely to be from?)
I have worked on some electric projects before, including converting a Kawasaki KZ440 to electric, so I have at least some experience. I have a few motors and batteries around, and though it would be fun to put this mini-bike together as an electric.

I'm also a bit of an old time radio fan, and Black Beauty was also the name of the car of the Green Hornet. (Kinda like the Batmobile, only way more awesome...) So, when I'm done, it might be fun to paint it black with green accents and give it a Green Hornet vibe.

The bike came with the frame, handlebars, kickstand, one fender, wheels & tires, and hub. There were no brakes, brake handle, engine, gas tank or seat.

Unfortunately, no stores near me carry any mini-bike or go-kart parts. (Northern Tool, Tractor Supply, Harbor Freight, Farm & Fleet, etc.) Which makes me severely disappointed. About the only thing I could find locally was #35 chain.

I mail-ordered a 60-tooth sprocket with a 2" hole and four bolt pattern and was able to get it to fit the hub.

I was also not familiar with it, but it appears that some of the old mini-bikes had brakes where the drive sprocket was used as the brake disc. I mail-ordered a generic brake caliper. The bike does have a tab welded on the frame that appears to be the original brake mounting point. Unfortunately, it's not the right size/shape/position for the brake that I have. I believe that I will need to cut this tab off and make a new one appropriate for my brake and weld that on in the correct position.

I removed the front and rear suspension so that I can clean it up and paint it. The front shocks came right apart. It's interesting to see how they work - nice and low tech - a tube within a tube (were these things just made from conduit?) with some grease and a spin.
However, the rear shocks were all rusted up solid. I've sprayed them down with PB Blaster, let them soak, spray them again the next day, etc, etc. Still no luck with the shocks. I put one in a vise and tried twisting it an adjustable wrench. No luck, I could start bending the entire tube, but not have the two halves break loose from each other. I also tried heating it with a torch, and that didn't seem to help any either. Any secret techniques or special fluids to soak in to be able to still re-use the original shocks? I'd like to use the originals for several reasons, including that I don't actually have any money to sink into this project. I'd love to fix it up mostly with parts I already have.

So, my two big questions right now are:
1) Brakes - any and all advice on mounting the brake caliper appropriately to go to the drive sprocket?
2) How to break loose the rust on the rear shocks so I can re-use them? Any affordable sources for the same shocks if I just want to replace them?

I still will also need a brake handle and cable to go to the caliper, will need to make a seat, and need to paint the whole thing. Anyone have a favorite online parts vendor?

As for what electric motor and batteries will actually go in there.... I'm not sure yet, but it would be fun to have something that could do a burn-out AND run around a camp-ground late at night, without all the gas engine noise.

Here's the rear wheel with the 60 tooth sprocket temp. mounted up. I set the brake caliper on the drive sprocket. It's not in quite the right place, but I can't put is exactly where it should go right now because the original tab is in the way. I think I'll need to cut off the original tab, fabricate a new one, and weld it in an appropriate location, but I'll take some advice from you folks before I do that.
 
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#3
If you are looking for parts here is who you can contact. I myself own a Black Beauty. 1970ish.
Manchester1 for the seat. She has made me 2 for Stellar and a re-foam for a Stellar Red baron and is the best.
Gas tank was mounted to motors. 4hp Tecumseh.
Trinik for possible brake drum set up.
Oldminibikewarehouse for all levers, cables and misc parts you may need.
Rear fender hard to find as is the front but rear more difficult to find.
Hope the info helps!
 
#4
OldMiniBikes Warehouse should have most of the stuff that you need. You can ask here if a certain part will fit or work, many here are familiar with Stellar bikes. I am not I have never owned a Stellar but many here have.

BTW your pics are not working for me. Not sure if that is a me issue or a you issue but it just says attachment and then when I click on it there is nothing there.

I love the idea of an electric bike, would build one for myself if I had the parts.
 
#6
Hmmmm. I haven't been having good luck with the forum so far. It took me FOREVER just to make my first post. I kept getting a "You can't have links, no forbidden words" and weird errors like that.
Here's a link to photos on my blog. Lets see if the forum lets me link or not.
Stellar Black Beauty Mini Bike

Yea! It did. Please click that link to see some photos.
 
#9
I did some work taking off the rims and cleaning them up. Here's half a rim after hitting it with a wire wheel for a bit.
IMG_9232-360x480.jpg

I'm also starting to prime some of the parts. I've decided that I'm not really doing a restoration on this, it doesn't have to be perfect, but I don't want it to be a rat-rod either. So, I'm just doing some rough brushing, hitting it with primer, and I'll see where it goes from there.

IMG_9233-360x480.jpg
IMG_9234-360x480.jpg

There were multiple layers of paint on this bike, but it looks like the original factory paint was bright red!
IMG_9235-640x480.jpg
 
#10
Black Beauty's were only black. The Red Baron came in red but did not have suspension. We have one of each and am pretty sure about that. There are many guys on here with Alot more knowledge of Stellar then I do. The BB's wheels are different then what you have shown. Original did not have the center hub attachment and came in aluminum w/ pressed bearings. The Red Baron had those wheels you have shown but did not have suspension.
I am sure it will be pretty cool when done!
Keep posting the progress.

Thanks,
Greg
 
#13
I was FINALLY able to break loose the rust on one of the rear shocks!
It only took about a week.
I had sprayed down the shocks with PB plaster every day for like 5 days in a row. Tried shaking, smacking, and twisting them with NO results.

I ended up drilling an 1/8" hole in the shocks so that I could spray PB Blaster INSIDE them. I filled the shocks with PB Blaster and let them stand vertical, filled with the penetrating oil. After two days like that, I finally was able to get the one to rotate with one end in the vise and twist the other with a pipe wrench. Yes, it left a few marks on the shaft, but if I just put an adjustable wrench all the way up on the flat end, I would just bend that.

It only moved a tiny bit at first, I wasn't even sure if it happened or not. I worked it back and forth a few times, and then it loosened up to the point that I could unscrew the spring.

The other shock won't come loose yet. I'll have to keep soaking that and see what I can make happen.

IMG_9262.jpg IMG_9263.jpg
 
#15
Can anyone tell me if the brake caliper sold at Old Minibike Warehouse would fit the bracket on this frame?
I'm looking at the "Disc Brake Assembly 2" - https://www.OldMiniBikes.com/Disc-Brake-Assembly-2.html?category_id=164
The holes on this brake bracket do appear to be centered 1 & 5/8" apart. I got a "universal" brake caliper which, after lots of tinkering, I realized will never fit. A big part of it is that the mounting holes are on the side near the disc instead of away from it.

In the photo, you can see the mounting bracket and me messing around with the caliper that I have.

IMG_9191.jpg
 
#16
Well after looking at a couple pics of black beauty bikes, it looks like some do have the disc brake setup and bracket like you have. The OldMiniBikes mechanical caliper that you linked to looks to be the correct TYPE of caliper for what you are trying to do, as far as will it bolt right on, well I can't say for sure. Careful measuring along with an email or phone call may determine that. Don't forget you could always make an adaptor bracket that will bolt to your brake bracket but also have different pattern to bolt on a different caliper. if you get in a pinch. Or you might have to shim the caliper with washers to get it to ride where you want it.
 
#17
Try looking on Thunderstruck electric vehicles website for your parts, I met a young man who built a minibike using some stuff from them but it is not cheap so prepare to spend to get quality components. $900 for a go kart kit so I would imagine that would be the kit you need, you can source parts from mobility scooters but I'm not sure they spin fast enough so maybe gearing could change that. I'd be interested to see a good electric minibike made from a vintage piece.
 
#18
Got some more work done on the mini-bike.

This is sort of a low-budget "use what works" project as much as I can make it.

I had already taken the rear wheel apart, wire-brushed the rim, and primed it. I took a look at the tube. Although it had been patched before, the patch looked good. I scrubbed off all the rust and inflated the tube. Holds air just fine. The tire itself is pretty cracked, but that shouldn't be an issue since it has the inner tube. I hit the rim with a quick coat of matte black, which matches what the front wheels already was.
IMG_9283.jpg IMG_9284.jpg

I also kept working on the other shock. The good news is that I got it apart. The BAD news is that I mangled the spring! I was twisting so hard that the spring sprang open a bit. I don't know if there is any way to bend a spring anywhere near back to original or not! The shock components themselves look pretty good brushed off with the wire-wheel, but that spring.... Yipes.
IMG_9290.jpg IMG_9292.jpg

I put the bike back roughly back together now that I got the frame more or less cleaned up. Both wheels hold air. One bearing on the back should maybe be replaced. The front wheel also doesn't seem to spin quite as freely as it ought to, so I'll need to look into that. There' probably won't be much more work on this project until I get the brake or figure out what I am going to put in here for a motor. I'll start pestering some of my friends and see who has something decent kicking around that I can stick in there.

IMG_9294.jpg IMG_9296.jpg IMG_9297.jpg
 
#20
Those electric scooters have motors that are somewhat strong and with proper gearing could work plus all the control boxes and potentiometer are in place if you can find a complete donor. Or maybe mobility scooters and controllers, they have much more power and can be bought cheap if you look in the right places. So if you don't want to pop for the near one thousand dollar go kart kit Thunderstruck sells there are certainly less expensive options. I look forward to seeing what you end up with, electric stuff can be quite fast and they are quiet. Good luck.
 
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