I loosely bolted the engine on today. I like the way it sits in the frame better now. the flywheel cover and drive sprocket stick out each side more equally. I welded the brackets on and bolted on the bearing blocks, installed the jackshaft and driven clutch. every thing seems to be working out. The driven clutch will later be painted BBQ Black like the drive clutch. I still have to drill and tap the ends of the jackshaft for 5/16-18 X 3/4" retainer bolts. So far, so good.:thumbsup: Next after this will be the forks, I'm thinking about a reverse leaf spring springer.:hack::grind::hammer::weld: :smile:
Minibike Build Off jimh's Bird
- Thread starter jimh
- Start date
Made a little more progress. But first I wanted to back up and show the bearing blocks and mounts in the first pic. I salvaged a couple of pieces of leaf spring from a pony cart. The short one will go on the bottom and the longer one on top. I'm going to add a medium length one between them which will be slotted for adjustment to get the ride I want.They will be bolted on with the bottom steering head nut. I will drill beside it on either side and add pins or bolts to keep it centered with the triple tree. I made some rockers from 5/16X1" mild steel bar. I plunge drilled pilot holes on the mill for accuracy, then drilled on the drill press to 5/8 and added flanged bronze bushings. Made some pivot axles from 1/2" precision ground steel rod,threaded the ends with fine threads. Made stuts from 5/16X1" steel bar. The struts will be drilled with a series of holes over the whole length of the struts, to lighten and make them a little more presentable.The upper and lower ends will also be rounded off. The cross bar on the top end of the struts will be drilled and tapped on either side of the spring for a flat bar clamp to clamp the spring to the strut. The forks actually function pretty smoothly, but I'm sure it will take some tuning to get it right. I would like to echo Yellowhands saying that if you plan to build a front end, do a lot of research on rake and trail, spring weight, load, rate, etc. If you'r over 40 years old, and have been chopping and modifying everything you've ever owned since you were 10 and/or have studied a little Geometry, Physics, engineering, hacking, hewing, beating and thumping,cutting and welding......go for it. Jeri's Springers site has a simplified explanation of rake and trail. It is very basic but a good place to start. Just remember he is most likely using a 21" wheel, and everything must be scaled down in proportion to a mini.:hack::grind::hammer::weld: :smile:
Got a little more done lately. Made some pike nuts from hex stock. Painted the bearing blocks and engine adapter/re-locaters. Drilled the struts, and clamped the top bar to the leaf spring. Also added the leaf spring which will act as the seat spring. The front end seems to function great. I've pryed,leaned, and bounced on it and it seems very stable. I see no reason why it won't ride nice. My wife says it looks weird. I say excellent, that's the exact look I was after. The design is so simple, it's hard for me to believe it works. Most of the minis were built in a era when weird was normal. I tried to build this with minimal machine work, as did mini manufacturers. So simple that someone can look at it and say "Oh I see how it works" Also cleaned up and primed the rear mounting area and the rear half of the frame. Broke out the Bondo and hit the rough spots. My goal is to have it ready to paint by next weekend. The paint will be some that I had left over from a Lexus. It's Solar Yellow or Sunshine Yellow or something like that. Everything that isn't white will be yellow. The white will be cleared with a little silver pearl powder. The yellow will be cleared with holographic mini flakes :grind::hammer::weld::hack::smile:
Nice! with that leaf "Springer" you've given me some ideas to spring my side car. I can see the colors on your mini after seeing the engine. Can't wait! Looking good! I think I have half a leaf laying around from an old (54) chevy pick-up. I was trying to use it for a pry bar but too springy! Guess it won't go to waste!
.........also like your springer seat,a first for the minibike build off:thumbsup: tall handle bars are cool too:thumbsup:
I think it's a first too...I've never seen a leaf springer on a mini, but I'm glad you thought of making it...very cool, as is the 'theme' repeated in the rear for the seat mount...
It is 'shocking' (sorry, had to...) how well a springer can work...they can really smooth out an otherwise bumpy ride...
It is 'shocking' (sorry, had to...) how well a springer can work...they can really smooth out an otherwise bumpy ride...
I was going to build a regular springer, but you were already doing that. I was going to put the springs on the rear lower instead of the top front though. This one required less machine work, and was something I'd never seen before. I just had to try it.The only time I run the lathes and milling machines at work is to make repair parts or mods to equipment, and no cameras are allowed in the facility where I work. (Due to someone in another plant taking pictures of the Harry Potter pages while publishing, and posting on the internet before the release) I have to make some billet aluminum guide wheels today for a machine today. I'm going to try to work in a couple of slip-on billet foot pegs.:thumbsup:
Made some more progress. Made a set of billet foot pegs and a brake pedal. The footpegs were bored to fit over the originals and will be secured with a pin and/or set screws. They will have O rings super stretched into the grooves like the ones in the pic. The brake pedal will slide on before the right peg cover and pivot on the original peg. Perches will be mounted to the front and rear of the frame for the cable. The brake will be a CT70 drum brake for now, and I'll add a band brake to the jackshaft later. Also painted the frame and forks......Freakin' Yellow.
It's some urethane enamel I had left over from a Lexus. 3 coats of yellow followed by a coat of clearcoat laced with holographic mini flakes,then 2 more coats of clear. After the paint lays down and cures for a few days, I can start the final assembly.:hack::grind::hammer::weld::smile:
It's some urethane enamel I had left over from a Lexus. 3 coats of yellow followed by a coat of clearcoat laced with holographic mini flakes,then 2 more coats of clear. After the paint lays down and cures for a few days, I can start the final assembly.:hack::grind::hammer::weld::smile:
More pics of progress. Today this one drew its' first blood. While working, I reached down for the engine and nailed my forehead on a shelf. Put about a 2" cut on my forehead. When my eyes refocused and the birds quit singing, I got back to work. I cut a Honda air cleaner boot to accept my air filter and painted the ends of the filter. Made a hubcap for a filler on the front brake drum, since I'm not using front brakes. It's a starter cup and flywheel screen from a Tecumseh engine turned inside out. I used The Amazing Goop to attach it. Goop is available at parts stores. The sreen pushed in tightly like it was made for the job, but the Goop should make it stay. Mounted the metal flake and yellow kbs8ball seat. Started putting the rest of the parts together. Stuck a front Boonie fender on the rear to try it on for size. It fit pretty well. It will be painted white and I will fab some mounting brackets. I'm stuck with a 3/4 pipe nipple to build the exhaust off of, because it is stuck in the port. I'll make a stainless cover for the first section and a short exhaust running back, then down at an angle. :hammer::weld::hack::grind::smile:
It's a leaf springer. The rockers at the bottom pivot on the original axle holes.
The wheel axle is mounted in the front hole. As the wheel rises for bumps,the rear is pulled down, pulling the struts (white part) which is attached to leaf springs at the top. Bet you never saw one of those before, huh.:thumbsup:
The wheel axle is mounted in the front hole. As the wheel rises for bumps,the rear is pulled down, pulling the struts (white part) which is attached to leaf springs at the top. Bet you never saw one of those before, huh.:thumbsup: