TWIN ENGINE 30cc+ friction drive bmx build

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sscustoms

New Member
Mar 13, 2011
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australia
hi everybody so today i decided to attempt a dual.twin engine .bmx build
both are goin to be friction driven from the back one two 30ccs or one with something else eg 25cc im goin to have to fuel tanks on the front top mount of the bike i still have to goin and see about the engines used go for bout anywere from 15$ to 25$ so i havr to see plus the bikes go for $30 complete the bmx i was looking at was missing some cables so i should be able to get it cheaper look ford to the next part coming this thursday

heres part 1
YouTube - S&SCUSTOMS, ,TWIN 30CCS ENGINES MOTORISED BIKE BUILD .PART1
 

sscustoms

New Member
Mar 13, 2011
29
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0
australia
so today arfter finishing off some stuff i decied to clean my walbro tye carby i tyred it on the engine couple days ago but had no luck starting so it sat for couple days , but i got back into it its one of the engines i will be using on the twin engine bmx build i think the gmc is somthing like 25cc but im not goin to be using this engine to many probelms insted im goin to get another one
 
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deacon

minor bike philosopher
Jan 15, 2008
8,114
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north carolina
I tested a 25cc ww on the front wheel of a bike recently and it did decent. a second one would have made a lot of difference I think. The twenty five would make a decent front wheel drive on a bike with about ten speeds. If a guy wanted to mostly pedal it would be ideal. The problem for me is juggling so many controls. Im about to finish a 3.5 hp friction drive and I have a coaster wheel on the back to eliminate the controls, and a front brake for safety. There will be a throttle on the handle bars, and a lift clutch on the bike frame. I would love to elimate even more controls but I really think this is about minimum for the simplest build possible.
 

sscustoms

New Member
Mar 13, 2011
29
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0
australia
I tested a 25cc ww on the front wheel of a bike recently and it did decent. a second one would have made a lot of difference I think. The twenty five would make a decent front wheel drive on a bike with about ten speeds. If a guy wanted to mostly pedal it would be ideal. The problem for me is juggling so many controls. Im about to finish a 3.5 hp friction drive and I have a coaster wheel on the back to eliminate the controls, and a front brake for safety. There will be a throttle on the handle bars, and a lift clutch on the bike frame. I would love to elimate even more controls but I really think this is about minimum for the simplest build possible.
yeah . i think the 2nd engine will make all the differance , say with your build you could go with a hinge to tilt it back and ford to you can just coast
 

deacon

minor bike philosopher
Jan 15, 2008
8,114
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0
north carolina
yes I always use a henge to attach to the bike. These days it's my clutch. when I get to a corner I just cut the throttle and left the engine. I sit and wait for the light or traffic with the engine idling. Then I pedal a few strokes and drop the engine and crank up the throttle.

In an emergency I kill the throttle and go to the brakes hard the engine dies and helps with th braking. Then when I want to go I drag start it. Once the motor is warmed up it is very easy to drag start almost any of them. Those small engines need to warmed up good, because the choke is an issue. The bike runs like crap, if you forget to open it completely.
 

5-7HEAVEN

Well-Known Member
Aug 2, 2008
2,661
240
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hi everybody so today i decided to attempt a dual.twin engine .bmx build
both are goin to be friction driven from the back one two 30ccs or one with something else eg 25cc im goin to have to fuel tanks on the front top mount of the bike i still have to goin and see about the engines used go for bout anywere from 15$ to 25$ so i havr to see plus the bikes go for $30 complete the bmx i was looking at was missing some cables so i should be able to get it cheaper look ford to the next part coming this thursday

heres part 1
YouTube - S&SCUSTOMS, ,TWIN 30CCS ENGINES MOTORISED BIKE BUILD .PART1
Ever thought about using one engine per tire?
I did that with two 2.2hp Mitsubishi TLE43 engines on friction drive.
It worked pretty good.xct2
 

deacon

minor bike philosopher
Jan 15, 2008
8,114
9
0
north carolina
I used them on the front often with very little change in the balance. The weight of them is so little that I don't think they pull the wheel much. My electric friction drive bike was much worse.
 

deacon

minor bike philosopher
Jan 15, 2008
8,114
9
0
north carolina
Now you did know that most of these whacker motors will run backwards. Which is a good thing to know if you want to mount one on each side.
 

5-7HEAVEN

Well-Known Member
Aug 2, 2008
2,661
240
63
[UOQTE=sscustoms;264207]im prob goin to go withe the twin at the rear , how the steering go with the engine mounted on th front[/QUOTE]

I used a double-legged center stand. With the front engine mounted, the handlebar would cock towards the engine side. Then the bike would fall over. To prevent falling, I tied both handlebar ends and secured the rope to the seatpost.

The bike leaned heavily at a stop or while rolling at a walking pace. Any speed higher than that and it was pretty stable.

The bike was heavy, though, about 55 lbs. over a stock bike.
 

deacon

minor bike philosopher
Jan 15, 2008
8,114
9
0
north carolina
I think this new 3.5 hp adds about twenty pounds of hardware to my bike with the mount and all. It's all in the rear but it is still off balance enough to be noticeable. I'm thinking pocket bike motor with a scooter wheel to drive it chain and all of it sitting centered on the rear tire as my next project. balance is the real issue with friction drive in my opinion.
 

deacon

minor bike philosopher
Jan 15, 2008
8,114
9
0
north carolina
I must not, since I have no idea what a YT channel is . You mean Utube. No im just an old country boy. I don't put no stock in the Internet, it is just a flash in the pan. I will be gone in a month. lol.

No i really don't. I don't do video so it would be a wasted on me.
 

sscustoms

New Member
Mar 13, 2011
29
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0
australia
hey deacon and sscustoms, i know you guys from somewhere. deacon do u have a YT channel maybe? i know SS has one[/QUOT

hey blair yeah you no i have a yt channle sscustoms100 i was goin to go ahead with this build but decided to no just goin with a sigle engine and i see how she goes if everything turns out good ill wack another one on there

cheers sam