Is it worth it?

[magrider]

I measured the jackshaft and it measures 7.5". I tried an experiment for the cranks, I shortened them. It doesn't give an advantage on the track, can't use them for starts or getting out of the corners, but I like them.

I mounted the engine horizontal, so I had to cut the down tube, spread the frame apart, weld angle iron to the down tube and seat tube, then welded a mini bike mounting plate to the angle iron. this lowered the center of gravity a lot and it helped with cornering, I also adjusted the rake.

 

[BlackIceBicycleWerks]

wow that is an awesome bike! did you modify that frame yourself? it looks stock! everything looks clean and well though out. that doesnt stick out as bad as i thought it would. that 120 looks perfect in there!

 

[magrider]

Hi, thank you for your reply, yes I built the bike in my garage with a grinder, propane torch, chop saw and mig welder. Brother and dad helped a bit but I mostly get to do what I want to my brothers bikes. He bought the micargi frame for $25

This bike started with a modified HF 212CC but my brother sold it to get the Honda 120CC to race in the mid-class, which is the funnest class. I bent the seat tube back last season to get the 212 in the frame. I also welded the gussets, exhaust and chopped the sinlencer.

The bike handled real well at the April race which my brother couldn't make it so I raced it and took 1st in the mid-class. It is a stock engine with the governor removed and has a CNC billet flywheel.

I used parts from Sick Bike parts shift kit to make the jackshaft assembly, that I won at a previous race. Like I said before AGK makes a jackshaft assembly that bolts directly to the engine, which looks like a cleaner and simpler jackshaft, I just used what I had.

Not pictured is the horizontal rear dropouts that I made with 2"x1/2" C-channel because I needed to get the rear wheel farther back due to the SBP jackshaft assembly. It also works great for keeping the axle where you want it with tensioners.

CCC (Jeff) made the fuel tank for my brother a few years ago.

 

[BlackIceBicycleWerks]

WOW 25 for that frame is a steal! And I think Ill have to start taking measurements and such to build one of my own for the summer before its over!

 

[magrider]

good luck, as you know we are all here to help, I look forward to seeing your build. magrider

 

[BlackIceBicycleWerks]

Thanks and dont worry if i get myself in over my head you guys wil be the first to know!

 

[BlackIceBicycleWerks]

So starting to plan the build and already have a question! what would be better? to leave the engine driving the side of the rear wheel that the engine crank is on and switching the bicycle drive train to the opposite side? OR Should i leave the bicycle stuff on the side it comes stock and build a jackshaft that transfers the drive for the engine to the other side opposite the bicycle drive train? I see you did it the first way i mentioned is there a reason you chose this way?

 

[magrider]

Most bicycles run the chain sprockets on the right side so I left it like that. He bought a single speed conversion for it. Mountain bike hubs use freewheel sprockets.

The hub is a downhill mountain bike hub with sealed bearings 135mm spacing, which is made for disc brakes, which is on the left side of the hub, so my brother had a sprocket made to fit the 6 hole brake disc hub pattern and mounted the sprocket where the disc brake would go. I think he bought the sprocket from kings

So the engine, clutch, jackshaft drive sprockets are on the left side and we mounted the disc brake on the right side of the jackshaft. Just be careful because the rear brake is real touchy, we had to groove the disc pads to take some of the bite out.

 

[BlackIceBicycleWerks]

Oh ya i have no idea what I was thinking its been a long week with little sleep because of finals now in my dark basement I am starting to become delusional i guess. hahahahaha well that should make things easier. Thanks again