Shindaiwa 62cc build- Shift kit, Giant 760... HELP!

[Nashville Geoff]

I'm an old gear-head, built/restored many motorcycles, and have a fairly well-equipped shop. I ran a HT 80cc kit on an old cruiser frame 'til the frame snapped in two places- Shouldn't have drilled holes in the frame, I'm sure.
Anyway, going in a new direction. I picked up a very nice Giant ATX 760. It's a very light 20 inch frame with 26" wheels, 21 speeds, and no suspension. Bought a front suspension fork off of eBay. Looking for a suspension seatpost.
Got a Shindaiwa 62cc blower motor in great shape. I've found that the motor is supposed to make almost 4 hp, before I start modifying it.
What I want to do is install the engine mid-frame, and jackshaft over to the front derailleur. I love the idea of using the gears.
There is no clutch with this engine- a four bolt flywheel/hub assy. to bolt to the blower fan is there.
What sort of clutch would you suggest? How best to lay out a jackshaft? How to mate with the front derailleur? I want to do this RIGHT. I want to fab some great motor mounts that will be kind to the chromoly frame.
As the project unfolds, I'll post photos... I don't want to reinvent the wheel; I'd rather just roll what I've got, at MAXIMUM VELOCITY! Thanks, ~Geoff, from Mashville, TN

[Dave31]

Hello Geoff, Welcome to the forum

I really don't have an ideal on what clutch to use but if I come up with something I'll be sure to let you now. I'm sure others will have some advice for ya.

[comfortableshoes]

Another guy is using a go kart clutch and bell. The only issue is that he needs to fab a shaft for it.

It's a home lite build and user name is spiderspartan.

[Andyinchville1]

HI,

That is so neat that you are going to try to use the blower engine for motorizing a bike....I have several of those blowers (my other business is lawn care) and have often thought about the same thing.

As far as the clutch goes, I am thinking that a centrifugal one would be easiest to do (only problem would be to find one that mates to the engine)...I much prefer the idea of mechanical clutch like that of the HT engine but I believe that would be harder to find and rig up...Actually, in thinking about it....I think there was a post somewhere about a person using another engine for power and the lower portion of used HT engine to act as a gear reduction box AND clutch mechanism....I don't recall what ever happened to that BUT that would certainly kill 2 birds with one stone (gear reduction and clutch).....

Another method may be to rig up a belt and pulley primary drive and use an idler pulley to tighten and loosen the belt thus acting as a clutch of sorts...

The only other thing that I can think of concerning the Shindaiwa engine is the fact that the engine is fan cooled....I think that may have to be retained to prevent overheating?....I didn't really look into it really closely BUT I think the HT engine has significantly more / larger cooling fins....

Good Luck on your project....I an really interested in seeing how it turns out!

Andrew

[Pablo]

What size if the motor output shaft?

Indeed, simplest seems to be a centrifugal clutch.

[Nashville Geoff]

Andrew,
Thanks for the great input. That's the beauty of a forum like this... I hadn't even considered the cooling situation- I do have a lot of the components of the blower still, but don't have the large duct housing- ditched it. I'm going to look to see if the fanshaft is employed to distribute cooling air thought the engine shroud. The shindaiwa engine appears to be industrial strength, and I'm assuming that it has replaceable, serviceable parts- Is that so? I'm headed to the shop downstairs for a bit, to put on the new suspended front fork, and to get some dimensions for a possible clutch application. Thanks again, ~Geoff

[Nashville Geoff]

Pablo, the output shaft is all but nonexixtent. The flywheel takes all of the shaft, and the flywheel has four bolt holes tapped into it to attach the fan. Whatever I use to transfer power, it will have to be machined & balanced to attach to the flywheel.

~Geoff