Building a mini bike

[5hpbriggs]

Hey guys,
I am new here and I thought I just wanted to ask some questions on how to build a mini bike.
First I thought i would use some 1 inch square tubing being that round tubing can be a P.I.T.A to work with. Then Here are some muesurments I came up with.
24 inches from bottom of frame to bottom of seat
8 1/2 inches wide
3 foot lond (frame)
Forks: 32 inches long

Picture below:



(clickable thumbnail)

Also I have a 1 inch axle and a set of bearing hangers and bearings.
I was going to use a hydro brake set up by foot pedal being I am might be using a race engine for this thing

What do you guys think?

Thanks

 

[2or3wheels]

Sounds fast, how many HP?

 

[5hpbriggs]

The motor turned 9,200 RPM @ 15 Hp

 

[mikeandike]

whoa. thats a lot of power for a minbike. Jackshaft is a must and you might want to add a wheeley bar.

 

[5hpbriggs]

I was thinking about it...... But..... I can control wheelies..... I know I want the sprocket combo to be a 12 on the clutch and a 12 on the axle.

 

[2or3wheels]

WHAT, what size tire? How fas are you looking to go, you may want to get stronger materials because thats alot of gusto.

 

[my_mini_bike]

holy crap, 15 hp @ 9200 rpm!!!! thats is freakin crazy. if u have a 1:1 reduction it will do like 100+ mp/h. and u will need a wheelie bar other wise it will just flip and/or bend the frame. i would recomend going with something like a 6.5hp, thats still more than most mini bikes

 

[5hpbriggs]

WHAT, what size tire? How fas are you looking to go, you may want to get stronger materials because thats alot of gusto.
Yesterday 06:45 PM

10.5 inch tire

holy crap, 15 hp @ 9200 rpm!!!! thats is freakin crazy. if u have a 1:1 reduction it will do like 100+ mp/h. and u will need a wheelie bar other wise it will just flip and/or bend the frame. i would recomend going with something like a 6.5hp, thats still more than most mini bikes
Yesterday 09:23 PM

To get a 1:1 ratio the clutch I have is a 12 tooth clutch so... you need a 12 tooth on the on the axle.

 

[2or3wheels]

I think it will give you to much speed, it also depends on the gearing on the jackshaft. But to have any power you would need a big sproket on the chain that goes to the engine and a small one on the chain that goes to the wheel.

 

[RobertD]

what kind of engine is that? is it horizontal shaft?

 

[robin]

you will eat clutches ive git a ported honda gx 240 and ime esaly geting 65 with a smaler back sprocket 1/4 ratio but my secon clutch just flew apart becuse it worn out

 

[2or3wheels]

I dunno, clutches just end up engaging and stop slipping at a certian point, thats what burning a clutch means you speed it to high and it never fully engages and is getting hotter and hotter.