A few questions before i build my motor bike

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Mr. Manta Ray

New Member
Oct 21, 2009
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ldjk
I figured i would get some good advice from people who know what they are doing before i start so here they are i am using a honda gcv 160 5.5 hp lawn mower engine with a vertical shaft on a schwinn manta ray bike it seems the only two ways to get a vertical shaft to work for this are to one use a belt that twists to a spool on the tire or two use a wheel of some sort to rub directly on the rim to drive so because of how the engine needs to be mounted it seems like #2 is my only choice unless somebody has some better ideas also my clutch system was to have a mechanism to shift the engine away from the tire so that the peice no longer rubs on the rim thus the tire stomps moving any comments would be much appreciated
 

Spunout

MB Builder Extraordinaire
Jul 21, 2008
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coventry, RI
blog.360.yahoo.com
welcome to the forum it sounds like you already have a pretty good idea of where youre going but maybe if you could throw up some pictures of your motor somebody could point you in the right direction there are lots of guys here who DIY but unfortunately i'm not one of them but good luck and again welcome hey is this it i found this but i dont know if this is the same as yours GCV160
 

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diceman2004

New Member
Aug 26, 2009
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Kitchener , Ontario
my advice ( seriously consider finding a horizontal shaft motor )
not only is it going to take a bit of inginuity to get your drive to transfer from vertical to horizontal at the wheel , you also need to consider how you can solidly mount a quite torquey 5-1/2 hp motor ( i assume your thinking of mounting it over top of the rear wheel ? )

dont forget once you attach iether a belt or a chain and apply torque , the motor is going to want to twist ( and instead of twisting in the same direction as the axis of your wheel , you will be twisting perpendicular to the axis of the wheel )

personally i think your more likely to scratch a hole thru your skull tryin to figure this one out , and you,ll likely spend more money getting it to work , than a horizontal shaft engine will cost you .

BUT , it would be cool if you do get it going , probably a first of its kind , you,ll be famous
 

Mr. Manta Ray

New Member
Oct 21, 2009
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yes that is the engine just a new version the one i have looks like this
it is going to be mounted above the rear wheel the shaft will come down and a type of rubber piece will rub on the rim wall thus moving it, it will be securely mounted and the clutch will just pivot the engine so that the rubber piece no longer comes in contact with the rims sidewall i have heard people have gotten this to work the only error i may see is that the rubber piece may be able to slip a little against the side wall of the rim but i figure i have so much more power than i need i can always just hit the throttle a little harder and someday it might carry two people since it has excess power. thanks i hope i answered your questions any other input will be appreciated. oh and the bike kinda looks like this except i made some adjustments.
 

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2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
Manta,
I have not seen this done but have you considered a drive shaft? There are some shaft drive bicycles out there that do not use a chain from the pedals to the rear wheel but rely on a shaft with a ring and pinion gear in a housing at the rear hub. You'd have to figure out a way to mount a centrifugal clutch between the engine and the drive shaft but it sounds as if you're intent on this project and you asked for ideas. There's one. Just be sure to consider your rotation.
Tom
 

bandito

New Member
May 22, 2009
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colorado
I have a friction drive setup and it takes alot of force to get the rubber wheel to clamp down on the tire to get the right traction. I dont know if a bike wheel will hold up to that kind of sideways force against the rim. You can bend a rim just by kicking it with your heel sideways......good luck.
 

a_dam

New Member
Feb 21, 2009
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Momence, IL
A motor on a bike catches the attention of people and starts conversations about different MB designs. An older guy (I'm 45) was telling me that when he was young, they would use vert-shaft lawn motors on bikes with friction drives on the side of the tire. I didn't ask him detailed technical questions. I did a google search and noticed you are researching other MB forums as well. No harm in that.

The rim might seem like the best place to apply the sideways friction, but I doubt it. You could try it and if it doesn't work, then try the tire's sidewall.
Like bandito says, it takes a bit of pressure to keep a friction drive from slipping.

On my bike, I know it is about 20 lbs because I use springs. I used to have one spring on each side, but they were being stretched close to the limit. When one would break, slippage would result, rendering the motor unusable. So I measured the spring tension and modified my setup to have the same tension with 2 springs on each side. I haven't had a problem with it in 2 years.

That 20 lbs of pressure is pressing a roller (my setup is all homemade) made from hockey puck material, downward onto my skinny 10-speed tire - 27 x 1 1/4". A friction drive roller against a steel rim will have to be made of rubber. You would be getting even much less contact area than my setup, and the rubber-to-steel friction would be less than rubber-to-rubber friction. Plus, friction drives probably depend on the "give" of the pneumatic tire.

SO... I don't think there is any way you can get proper sideways friction on the rim. It would be nice - no tire wear - but I'd bet 1000 bucks it ain't practical.

That leaves the friction-on-the-tire-sidewall option. It will work, I'm sure. Fat tires probably have as much rubber on the sidewall as my skinny tires have on the tread. I would definitely only use a rubber friction roller, but I'm sure some will disagree. The wheel ain't gonna like the sideways stress, but you could probably get a few miles out of it.

People here are recommending a horizontal-shaft engine for a reason.
 
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Blakenstein

Member
Sep 15, 2009
561
2
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Alta. Canada.
Where is it gona fit? that motor a little too heavy also. If u do get it working your front wheel gonna be in the air all the time. It just dosen't seem very practical .Maybe u could come up with some thing else,like maybe a chain saw motor-get a nice big one if u want -they have cent. clucthes and horiz.shafts.:):)
 

motor_head

New Member
Dec 18, 2008
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iowa
for a vert shaft you might be able to put an idler wheel on one side if the rim and the drive wheel from the motor on the other so the rim won't bend
 
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Clotho

Member
May 25, 2008
304
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for a vert shaft you might be able to put an idler wheel on one side if the rim and the drive wheel from the motor on the other so the rim won't bend
I have seen a video of something like this done before. (Found it here: Vertical Shaft Motorized Bike) It seemed to be functional but it looked like a great deal of work and I would prefer a brake lever type of clutch.

Judging by the number of times the question has been asked (many) and by how many bikes have been built (few) I would say that most people who start with a vertical shaft motor abandon the idea and find something with a horizontal shaft.
 
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Mr. Manta Ray

New Member
Oct 21, 2009
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ldjk
hey thanks for everything this is definetly the most helpful site so far just a couple things my engine only ways about ten pounds or so and my dad and i will be able to mount it umm it sounds like if i use this method i should put on the tire sidewall the only thing is i am worried the tube will blow and the tire will wear really fast so how often do your tubes blow and and how fast do your tires wear out also i have some trampoline springs i could use for what you are talking about so could you maybe post some pics also if this fails i will try and find somewhere to trade my engine for a horizontal shaft weed wacker engine since they have centrificul clutches how would i mount that though?
 

motor_head

New Member
Dec 18, 2008
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iowa
if your going to do a sideways friction it would be ALOT better to put it on the rim
you can still have a lever clutch just have to make it pull the motor sideways away from the rim
 

Mr. Manta Ray

New Member
Oct 21, 2009
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ldjk
yes that was my plan but for some reason people think it will bend my rim wall which i highly doubt it will and if that is the case i will use a brake disk for it to rub on then no wearing on the tire and no blowout
 

Mr. Manta Ray

New Member
Oct 21, 2009
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ldjk
i am thinking i will try it on the rim with an idler wheel on the other side the only thing is will the the rim bend or just one sidewall cause then the idler would have to be inside the tire and that wont work
 

Mr. Manta Ray

New Member
Oct 21, 2009
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ldjk
i think i will start soon with a friction drive and an idler wheel will try to keep u updated thanks all other input still appreciated
 

Clotho

Member
May 25, 2008
304
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has anyone ever heard of that break disk idea above mentioned
Friction drive on the disc for a disc brake? In the usual spot with a vertical shaft 4 stroke friction drive providing the motivating force?

If I understand this correctly then I think you might want to look into the rack mount kits. They are the simplest to install and have proven to be very reliable. It is likely that you will find the greatest success with one of these.