Anyone Running Power THRU the Bottom Bracket?

[5-7HEAVEN]

I'm still working on running power thru the bottom bracket.

It has so many nitpicking details.
Sometimes it intimidates me.

The inner shaft needs to be machined along its length, from 3/4" to 5/8".

The 1" outer shaft needs to be trimmed to 8" long.
Brass bushings need to be sized/fitted/honed to accept the inner shaft.

The 150t pulley has to be drilled to match the hub.
This hub needs to be welded to a 1” lock collar, then slid onto the left side of the 8” outer shaft.

The 150t pulley directly belts to a 23t clutch.

On the right side of the bike, the 24t chainring
sprocket’s freewheel adapter will also be welded to a 1” lock collar.

All these lock collars weld onto the hubs, because the 1” hollow shaft doesn’t have a keyway.

Once the pulleys line up, the hub for the pulleys can be welded directly onto the main shaft.

 

[CrazyDan]

I think all this custom stuff is why everyone before you gave up. The cost beyond outweighs the results unless you own all the machining tools needed already. If you can pump out a bunch at low cost and they prove reliable, I will be buying one. Gotta be cheaper than me just welding in a second bottom bracket for the jackshaft, the second sealed bearing bb assembly and grinding out the left side keyway.
I showed you the Y setup that would give you the same chain count to the wheel from the motor, but required welding instead of a very expensive double shaft bb with a ratcheting assembly that can drop in, universally almost, to prevent the motor from spinning your feet but you still being able to put in useful foot power.

 

[5-7HEAVEN]

At the bottom bracket(BB), external 30mm bearings and their cups screwed right in.

25mm Delrin adaptors press right into the 30mm
bearings. These adaptors have to be machined to accept the 25.4mm(1”) BB main hollow shaft.

Said adaptors also have 25mm bearing cups.
I might need the extra bearing support for the heavy BB shaft.

However, there is very little wiggle room on the right side of the bottom bracket.
So, I’ll shave off the right side cup for the 25mm bearing, but install the 25mm bearing on the left side of the BB.

The 25mm bearing needs to be clearanced to fit the 25.4mm(1”) shaft.

And of course, the right side SBP crank arm and freewheel need to be bolted to the driving chainring sprocket.

 

[5-7HEAVEN]

I think all this custom stuff is why everyone before you gave up. The cost beyond outweighs the results unless you own all the machining tools needed already. If you can pump out a bunch at low cost and they prove reliable, I will be buying one. Gotta be cheaper than me just welding in a second bottom bracket for the jackshaft, the second sealed bearing bb assembly and grinding out the left side keyway.
I showed you the Y setup that would give you the same chain count to the wheel from the motor, but required welding instead of a very expensive double shaft bb with a ratcheting assembly that can drop in, universally almost, to prevent the motor from spinning your feet but you still being able to put in useful foot power.

Lol, you're absolutely right.

If someone else had done the R&D, it would've been MUCH cheaper for me.

 

[5-7HEAVEN]

My parts returned from the shop.

I asked for a tight fit, not a press fit, where the hollow shaft slips into the machined Delrin plastic adaptors.

The Delrin then presses into 30mm bottom bracket (BB)bearings.

The shaft was so tight. When I pressed it into the BB,it popped the 30mm bearing right out of its BB bearing cup.

Back to the shop to machine the Deleon adaptors for a looser fit.

 

[Will'smotobikes19]

 

[5-7HEAVEN]

That’s how Sportsman Flyer sets up his bottom bracket “jack shaft “.

Their engine power runs to the left side rear sprocket.

Mine sends engine power through the bottom bracket, to the right side sprockets.

Theirs have 3 chains; mine has 2 chains.

Well, one chain and one timing pulley belt.

 

[5-7HEAVEN]

Back from the shop.

The entire assembly bolts onto the bicycle.

Both shafts spin perfectly on the bottom bracket’s (BB)30mm bearings.

The 2 sprockets’ hubs each connect to welded lock collars.

Both are adjustable, along each side of the hollow shaft/BB.

When they’re positioned correctly, I’ll make divots in the hollow shaft for the hubs’ setscrews....

and lock the welded collars.

 

[5-7HEAVEN]

I drilled the 150-tooth timing pulley and mounted it onto its go-kart hub,
Then it slipped onto the left-side of the bottom bracket spindle.

I had a 900mm timing belt on hand.
With the 212 engine on the bike’s temporary mount, I installed the belt onto the timing belt clutch and the 150t pulley.

Then I locked the motor mount into place.

Unlike chains, belts cannot be shortened or lengthened.

So I’ll use shims under the engine motor mounts to tighten/loosen the timing belt.

Or maybe fabricate a tensioner.

The clutch and 150t sprockets will accept belts that are 25mm wide.

However, I'm using a 15mm wide belt.
The narrow belt MIGHT be more flexible and better absorb the 212 engine's torque.

In turn, this MIGHT place less stress on the 7-speed bicycle chain.

AND it gives the belt 10mm(.39”) to walk before the belt falls off the 150t sprocket.

The belt won’t slip off the clutch.
Its pulley is sandwiched between the engine and the clutch assembly.

 

[5-7HEAVEN]

The frame now needs to have the gussets and motor mount welded on, as well as the rear disc brake mount.

I’m using angle iron and flat plate to mount the 212 engine.

With gussets at the steerer tube, dropouts and both chain and seat stays, the frame should be solid.

That’s next.