A Crazy Idea

J

jerb

New Member
#1
#1
I'd like a minibike that gets 140MPG+ on the highway (to beat these gas prices!).

I might be :eek:ut: but what if...

1. Keep bike+rider around 300lbs or less (I'm 145 now, don't think I'll ever be over 160)

2. Stock 6.5hp 200cc (with maybe just a K&N air filter, tuned carb. & nice exhaust pipe)

3. Torque Converter (or racing centrifugal disk clutch, but probably TC)

4. Rear sprocket cassette & derailleur.

With a TC it'd have two gears (40mph and 70mph at 3600rpm) and with a centrifugal I think it'd need a 3-sprocket cassette (25mph, 45mph and 70mph at 3600rpm).

I'd want to keep the chain as straight as possible so I think the TC with the 2-sprocket cassette would be best. If bicycles can pull this off, why not a mini bike? I've had this idea in the back of my head since I started building bikes.

What are your guys' thoughts on this?
 
MikeBear

MikeBear

Active Member
#2
#2
jerb said:
I'd like a minibike that gets 140MPG+ on the highway (to beat these gas prices!).

I might be :eek:ut: but what if...

1. Keep bike+rider around 300lbs or less (I'm 145 now, don't think I'll ever be over 160)

2. Stock 6.5hp 200cc (with maybe just a K&N air filter, tuned carb. & nice exhaust pipe)

3. Torque Converter (or racing centrifugal disk clutch, but probably TC)

4. Rear sprocket cassette & derailleur.

With a TC it'd have two gears (40mph and 70mph at 3600rpm) and with a centrifugal I think it'd need a 3-sprocket cassette (25mph, 45mph and 70mph at 3600rpm).

I'd want to keep the chain as straight as possible so I think the TC with the 2-sprocket cassette would be best. If bicycles can pull this off, why not a mini bike? I've had this idea in the back of my head since I started building bikes.

What are your guys' thoughts on this?
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Yeah, how do you think you'd get 70mph with 6.5 hp, 3600rpms and a torque converter? If you gear it up, I doubt you'll get it up to that speed sooner than running a couple miles down the road. It won't have any guts, and It for sure won't get 140MPG. It will also not be legal on the highway due to size.
 
J

jerb

New Member
#3
#3
That's where the sprocket cassette would do its job. At 40mph in 1st a light bike would jump off-the-line, and easily make its way to 70 from there in 2nd. I have a bike ATM that's about 180lbs and geared for 46mph with a TC and it's pretty torque-y.

It'd meet the minimum requirements for highway use. Kind of a medium-mini. :thumbsup:
 
S

Supafly

New Member
#4
#4
SupaFly think yo need to recalculate yo speeds...:eek:ut: 3600 rpms 45 or 70 mph and a two speed torque converter...research your topic befo you post and look silly bro! If you could ride around on the highway at 70 with a stock 6.5 on a minibike and get 140 mpg don't yo think somebody would have already done it? SupaFly do!
 
thtsjon4u

thtsjon4u

New Member
#5
#5
i'd worry about the mpg instead of the mph. Ive done a lot of calculating before about speeds given rpm and drive/driven gear ratio and tire size. I'm not going to do it all again here.. but with 12t front and 52 rear and 12in tire i was doing about 8k rpm to do around 50mph. rrg i had it all written down and lost the cheat sheet. But the derailer would be a neat idea.. hope you dont break chains?:shrug:
 
toomanytoys

toomanytoys

Well-Known Member
#6
#6
It's not going to happen

I know there was a 60 tooth on the rear and I think I had the 15 on the front on my super bronc. Tiny tach and gps shoes 3950 rpm and 58mph

It ran good got up to speed plenty quick and would run down the road nicely.

But even if you did manage a 2 speed gear box it wouldn't work as well as you think. I've owned two cushmans with the shifter and they were a pita

140mpg I might get a 40 if I am lucky.
 
Last edited:
mmisterbungl

mmisterbungl

New Member
#7
#7
Supafly said:
SupaFly think yo need to recalculate yo speeds...:eek:ut: 3600 rpms 45 or 70 mph and a two speed torque converter...research your topic befo you post and look silly bro! If you could ride around on the highway at 70 with a stock 6.5 on a minibike and get 140 mpg don't yo think somebody would have already done it? SupaFly do!
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why do you insist on referring to yourself as some Yoda Grand Jedi? We know your name dude.
 
DZLBIKE

DZLBIKE

New Member
#8
#8
You could always go Diesel!
This is a Royal Enfield diesel, 5 speed. It is suppose to get 200 mpg, but won't get anywhere near that with me on it. I'd say I get about 120mpg or so...
 
Strigoi

Strigoi

#10
#10
Supafly said:
SupaFly think yo need to recalculate yo speeds...:eek:ut: 3600 rpms 45 or 70 mph and a two speed torque converter...research your topic befo you post and look silly bro! If you could ride around on the highway at 70 with a stock 6.5 on a minibike and get 140 mpg don't yo think somebody would have already done it? SupaFly do!
Click to expand...
you sound like a dumbass speaking in 3rd person, but i kind of agree with you.
 
MikeBear

MikeBear

Active Member
#12
#12
jerb said:
That's where the sprocket cassette would do its job. At 40mph in 1st a light bike would jump off-the-line, and easily make its way to 70 from there in 2nd. I have a bike ATM that's about 180lbs and geared for 46mph with a TC and it's pretty torque-y.

It'd meet the minimum requirements for highway use. Kind of a medium-mini. :thumbsup:
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It might meet the minimum requirements for highway use, but you'd be a fool to drive it there if you build it. Car drivers do NOT see full-sized motorcycles now, how do you think you'll be seen? My son's bike was totaled a few years back, 75mph hit and run, but he lived to tell the tale. Full sized bike, and the guy still nailed him like a croquet ball.

Too many idiots out there, I would never ride something like this even on a country road for long, much less a highway.
 
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