sunofjustice's gearbox idea...continued

[sunofjustice]

5-7.....I was considering th' same thing th' whole time I while conceptualizing! But...my experiences with a 47cc pocketbike engine is that with a stock CENTRIFIGAL ,3-shoe, clutch.......... hookup is instantanious! Barely off idle.....you would be able to rev as you like......until you let out th' happy time clutch. About using th' happy time block.....at first I thought of just butchering what you need....(transmission)....but, under further observation....leaving th' block Whole (sans cyl./head) allows a perfect platform for th' pocketbike sprocket to rotate in........plus, leaving th' block whole adds rigidity to th' gearbox. I have to get another 47cc for mock up, to see if this is really doable......but it looks like theres room to mount th' engine under th' very TOP of a mtb frame....AND still fit th' happy time donor UNDER that in th' stock position. I'm definently concerned about pedal clearance (pedal extensions?).......as well as WHAT SIZE pocketbike sprocket to use (55t-98t?) Using a strecth beach cruiser bike for more room DID come to mind though.......but I wanted to use th' mtb frames I have now. Got to do some measuring!

 

[5-7HEAVEN]

Brian, you mean to mount the gearbox UNDER the engine?

I'm beginning to see your concept.

Let me do some "Spatial Visualization" and get back to you.(The upside-down puzzle parts need to be connected, just like in an aptitude test.)

Myron

 

[Zomby Builder]

Don't own no carps!

You guys know that Zack has had the same problematic symptoms as all others before. Really!! Go to MotoredBikes.com SEE fo Yo SELF,,,
We have limitataions that prevent us from from becoming genuine idealists I AM (Pardon) Anothers quote LOOKING FORWARD YO THE RIDE!!!!!!!!!!!!!!!!!!!

 

[5-7HEAVEN]

Brian, time to start another thread on your pocket bike engine and happy time "gearbox".

Myron

 

[5-7HEAVEN]

In my thread in PARTS&ACCESSORIES, I have a quest seeking a reverse-direction gear-reduction gearbox. Basically, this is what I say there:

Firstly, this "gearbox" REVERSES engine direction, so cannot be used directly to link the left-side rear sprocket.

Secondly, it is the perfect reverse-direction gear-reduction box I have been seeking. Gear selection is easy and readily affordable and available. The box actually reduces gear ratio to 14.35:1.

HOWEVER, the box must be mounted on the right-side in an UPSIDE-DOWN position. This is so that the 10t output sprocket faces the 7-speed cassette.

The box's mounting brackets no longer line up with the frame. Mounts must be fabbed, maybe using the box's 4 cylinder head stud bosses.

Since a pocket bike engine is the only engine that'll fit above the gearbox in the frame, the gear ratios must be able to facilitate an 11,000 rpm range throughout the mulit-speed sprocket range.

Here's my suggestion:

6t engine sprocket-21t gearbox input sprocket-10t gearbox output sprocket. This links to 7-speed cassette's 34t-28t-24t-22t-20t-18t-16t sprockets.

Mph figures at 4,000/8,000/11,000rpm use ALL the gears. They range from 4,000rpm@6.5mph with 34t sprocket, all the way to 11,000rpm@38.1mph with 16t sprocket.

I will post a more comprehensive gear/rpm spread when I get home tonight.

Myron