Jackshafted 66cc on Carbon Fiber frame?

KCvale

KCvale

Well-Known Member
Does anyone have some experienced opinions on the best way to mount a motor to a one piece carbon frame?

The bike is a nearly new Extra Large 29" Specialized Stumpjumper the customer dropped off in his Hummer for me to 'kick ass' motorize with a wad of cash and I am getting concerned I can't.

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The bike is for a pro ball player and way bigger than the pic shows, the seat for the guy was chest high on me and I'm over 6' tall so we lowered it but anyway back to the bike.

Carbon fiber one piece frame, the whole thing, a frigg'n 10 gear carousel rear sprocket which is problematic to start with but nothing I can't deal with.

Carbon Fiber is tough stuff yet the whole bike only weighs 26 pounds but I can't just use the muffler clamps that come with the JS kit against it nor have I solved how to get a front mount on it's 2 5/16" wide semi square front down tube.

It's a $4,000 bike so I can't afford to screw it up.
It is also a handsome pay day if I can.

Keep in mind no BS fix things will fly on this build, I have an open ended budget, but it has to work AND look good.

Luckily that build is just on deck, got another 29'er in a few hours earlier (the same day!) that is getting the same treatment but a metal bike. A Genesis GX7 7-speed, all chrome with big ass'n wheels and tires.

The GX7 will be a pleasure to build though, I have a lot of room to work with it and though aluminum it's sturdy for a $400 bike.

Hehehe, I know, don't you wish we all had these kinds of problems all the time?

Really though, any informed opinions on how to mount a motor to a carbon frame?
 
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I told him I wouldn't risk a gas motor on it this morning but it turns out he also has some nice ($1000+) Giant bike he is going to bring over to motorize and keep the carbon bike intact.

Not seen that bike yet but I like Giant bikes, Bad Mojo was one and I loved it.
 
I totally agree, my second build was a Giant and that was a great bike. Mine was a 90's steel Boulder. I transferred the Dax 66cc and 7-speed rear wheel with 34T sprocket from my first build (Schwinn Alloy Seven) after the Schwinn suffered a busted frame. The Giant was my ugliest build, but it was definitely the fastest (42-44MPH) and possibly best-handling motorized bicycle I have ever ridden.

Every Giant I have pedaled has been a joy, too :D
 
I have rode a LOT of bikes but noting beat Bad Mojo, the Giant Suede.

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I beat the living piss out of it and it never even coughed let alone break.
Damn hard JS build with that tiny cavity and forward cranks but I made it go, go real friggn well actually, I hit 48 MPH on it's speedo easy but ride in that 35-40MPH comfort range which was comfortable on that $400 bike.

I guess my point here here now that the carbon fiber bike is a moot point is I no longer have just an acceptable low end bike I;ll build on, there is a high end type I just won't do either like this $4K carbon bike.
Man I would LOVE to motorize it, I really would it's so darn nice, but a properly mounted JS and front mount would compromise the frame to point of being just as bad as an $80 Wally Huffy with a frame drilled front mount.

Anyway he's coming by tomorrow with a Giant and we'll go from there ;-}
 
You could make fiberglass mounts, they would conform very well to the odd shaped tube and spread out the stress. If money is no object to this guy, why don't you put a morini in there?
 
young grease monkey said:
You could make fiberglass mounts, they would conform very well to the odd shaped tube and spread out the stress. If money is no object to this guy, why don't you put a morini in there?
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Fiberglass mounts won't work, either. Putting any engine, not to mention a Morini, in a carbon fiber frame will very quickly shorten the life of the frame. Carbon fiber frames aren't as durable as metal frames over the long run. Any engine will compromise the frame's integrity. It's also very very difficult, if not impossible, to gauge the integrity of such a frame - they tend to not show damage, but will fail quickly and usually without warning.

Carbon fiber frames are awesome for high-end pedalheads, they make lousy platforms for motorvation.
 
The_Aleman said:
Fiberglass mounts won't work, either. Putting any engine, not to mention a Morini, in a carbon fiber frame will very quickly shorten the life of the frame.
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As mentioned in my last post this bike is not getting a motor, it will remain pedal power only but man is it nice for that!

Even though it's been like a hundred and ten thousand degrees outside here I couldn't resist riding a 26 pound 29" bike up the street and back, it is almost rides like you are floating on air.

It would have been sweet but I'll see what he brings me to replace it today and go from there which is fine with me, I had a 29" GX7 to jackshaft with a 66cc Skyhawk in the mean time ;-}
 
I am so glad to see you're not putting a motor on that carbon fiber frame. I used to have a TREK Y-22. It was a pure joy to ride. I really miss my carbon fiber bike.
 
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