Why not mount engines in rear instead of squeezing them into the frame?

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boyntonstu

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After speaking to several motorized bike builders, I notice that there seems to always cutting away of the engine to make room for the air intake etc.

Wouldn't it be nice to have all of that room?

I suggested a rear mounted kit to fit all bikes from 20" all the way to 29".

Take a look at these videos and see how you would do it on your 26" bike.




 
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GEBE, friction drives, axle-mounts are all rear-mount, and all old hat.I prefer rear/rack mounted to frame mounted, frame mounts look like motorcycles, not bikes, and with rear mount I can put a 1 gal. gas tank in the frame and ride without fill ups. I don't watch vids, is it drastically different?
 
GEBE, friction drives, axle-mounts are all rear-mount, and all old hat.I prefer rear/rack mounted to frame mounted, frame mounts look like motorcycles, not bikes, and with rear mount I can put a 1 gal. gas tank in the frame and ride without fill ups. I don't watch vids, is it drastically different?

Great!

I prefer rear/rack mounted to frame mounted, frame mounts look like motorcycles, not bikes, and with rear mount I can put a 1 gal. gas tank in the frame and ride without fill ups.

Exactly my opinion.

Does the center of gravity shift result in any negative ride characteristics?

(I suggest that you watch the 3 short vids and give us your opinion.)

Photos of you mount?
 
Does the center of gravity shift result in any negative ride characteristics?
Of course a high center of gravity results in negative ride characteristics.
Ever pedal your bicycle with someone on the handlebars or a 50 pound package on a back rack?
That's why they have painner bags and baskets to lower to fixed loads center of gravity.

Most of bicycle steering is done by leaning, when your center of your gravity has weight that does not lean with you will feel it.
 
It's all personal opinion when it comes to "looks".No negative gravity shift, except when it's on the kickstand, even then minimal.Think of the avarage human rump (these days) how far does each side hang off the saddle, a friction or GEBE is only inches more than that, you can't really tell.If you're into jumping, frame mount is really the only safe option, but I just commute.No pics, I just take an old RV antifreeze bottle, hit it with a hotgun, shape it to the diamond bottom and you have long distance riding, if it leaks it's at calf level.I don't watch vids, the pics explain it, it's a rack mount china girl.Pretty neat, I personally don't use (never bought never would) chinese engines, tanaka, RS, or Mitsu are the only things I trust.
PS:KC what rack drive system weighs 50lbs?? A gearbox and 49cc would only come to 35lbs, a FD with engine is around 20lbs, a GEBE about 15lbs, you know like a few books on the back rack, no where near 50lbs.
 
I think most builders that mount the engine in the frame do it because they like the way it looks.
Every mounting position has advantages if you select the right engine for that mounting location.
There are many paths to enlightenment.
 
I think most builders that mount the engine in the frame do it because they like the way it looks.
I mid mount because that's the best place for an engine other than maybe an electric hub, that's about as low a center of gravity and sturdy mount as you get and they stand up with your kick-stand just like a mid mount gas.

Bottom line is if it can pass the Good Mount test.
Form a side..
Hold the top bar of your bike with one hand...
Hold the top of your engine with other hand...
And try to push and pull your motor AS HARD AS YOU CAN...
If it moves AT ALL it will fail eventually, usually sooner than later unless you tighten it every trip.

Don't get me wrong here, small 4-strokes on a back rack can work very well if it's a good rack, it's is just the last option I would choose for motorizing a bike is all.
 
I mid mount because that's the best place for an engine other than maybe an electric hub, that's about as low a center of gravity and sturdy mount as you get and they stand up with your kick-stand just like a mid mount gas.

Bottom line is if it can pass the Good Mount test.
Form a side..
Hold the top bar of your bike with one hand...
Hold the top of your engine with other hand...
And try to push and pull your motor AS HARD AS YOU CAN...
If it moves AT ALL it will fail eventually, usually sooner than later unless you tighten it every trip.

Don't get me wrong here, small 4-strokes on a back rack can work very well if it's a good rack, it's is just the last option I would choose for motorizing a bike is all.
Not to be contrary, but that's bad advise.That would surely bend something out of alignment.A "Friction" holds fine, the only forces on it are up and down, not side to side, locktight on the mounting nuts (fingernail polish works great) an I've never had a problem.A GEBE, they are $600 plus for a reason, they are delicate, highly refined motor assist at it's finest.I personally have just had to change a belt at 3000 miles, nothing has ever come loose, or broken, simplest maintenance of any vehicle I've ever driven. Just saying.
 

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That looks heavy, but it seems to work fine.

Tandem, HMMM!

Take a tandem, remove the back seat components, mount your engine low down in the new space.
 
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