Performance Crank for Hybred

Quote:
Originally Posted by FlyGuy
Mobike91

Here is a nice crankshaft.

puch moped race crankshaft stuffed

or

Puch E50 Teflon Stuffed Race Crank Everything Kit for $120.00 in Crankshaft from 1977 Mopeds

Made to be rocked.

The deal is these cranks use 6203 bearings.

The chineese engines use 6202 bearings.

That leaves 2 options.

A) Grubee Starfire Super Rat takes 6203

B) Other Starfire Engines may use 6203 bearings look at grubee site for that info.

C) If cant get any starfire cases then ummmm Machine Custom Cases YA.

We will get to the other good stuff soon.

Originally Posted by Mobike91

so are those cranks a little wide? or will they fit right in? im thinking you have to cutt them down or something. and add a keyway or something to make the crank sprocket fit on it. then on the other side you gotta mill it down and tap it to the right size for the magneto to fit. least thats what im thinking. the crank looks wide. but then again it was a big picture lol.

so the 6203 bearings. will they not fit right in? is it a different size at the crank or in the case? i might be looking into making one of these builds for fun. sounds like a good way to make a bad mobile. lol.

so you said you was gunna run a 70cc piston right? do you think the bottom of the jug will fit into the bottom end of the bike? and will the crank clear the bottom end as well as it swings around?

dont need to answer all the questions. just put some imput. just throwing out questions that might help you in your build
__________________
every run is a test run . . . and i just hope it dont blow up - wil

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#1 Lets take a look at the width of the crankshafts.
A) Stock Chineese Crank for 66/80cc engines.
1.9625 inches wide ( includes weights.... 3 piece crank )
This means 1.9625 / .039375 = 49.84 MM wide

B) Stock Chineese Crank for 66/80cc engines.
1.250 inches wide ( WITH WEIGHTS REMOVED )
This means 1.250 / .039375 = 31.75 MM wide

B) Puch E50 Performance Crank ( Single Speed.
173mm - 65mm - 75mm = 33mm wide
33 / 25.4 = 1.299 inches wide

However the grubee cranks are cut out to go around the bearing bosses inside the case. Thats why the crank is 1.25 inches wide without the weights (thats the space between the bearing bosses). So approximatly .025 inches will need removed from each bearing boss. And some sort of insert will need to be placed in the space left in the case where the weights normally are to bring the primary compression back up.

Next as far as the sprockett it bolts to the countershaft of the engine so we only need to worry about the clutch and the magneto. But to machine down the crank to fit 6202 bearings / the stock magneto / and the stock clutch would not be taking advantage of using the crank.

Puch carnk means a puch magneto will bolt on.....means 12v running lights......means ability to use aftermarket high performance magneto and cdi.....means a world of endless possibility. Plug and Play.....Bolt on and GO.

Puch crank means much upgraded clutches that bolt on are available.
Motobecane clutchless variators fit puch cranks......means we have the opportunity to BOLT on a very easily tunable Doppler ER3 Variator.
With that and a GY6 Rear Clutch Pully using the motobecane GY6 Rear Input Shaft for a Jackshaft and the Rear Gears to gear down. Or we can choose a Puegot or Motobecane clutch pully and use the Motobecane Pedal Crank as a Jackshaft. But note the first setup provides a Fully Variated CVT.


About the 6203 bearings no the 6202 bearings are way smaller sizes. And even the good 6202 bearings dont hold up to the engine built like this.
I cant say for sure what the diameter of the crank flywheels are until i get one but im pretty sure it will fit. The stroke will be 43mm and never exceeds the flywheel diameter. As far as how the cylinder fits the case...FourEasy put a puch top end on a chineese bottom end so i think it's possible.

Input is appreciated. The more ideas the better. It will be super cool to build this thing.

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