Yet another newbie (confused about transmission)

[ottoseeker]

Greetings!
I have just purchased a Simplex that is fairly complete, except for the motor and ALL of the drive components. The wheels are there, but missing spokes,and the large pully is the only rotten part on the bike.
I am thinking about modernizing, but without causing irreversible modifications:
option 1: buy a honda pc50 moped, and use the entire drivetrain, with 19" wheels.
option 2: I already have a c70 passport, but the wheels are too wide
option 3: use a briggs with worksman wheels
option 4: electric (advantage: I can legally ride as a mobility scooter when I lose my licence to parkinson's)
ANY THOUGHTS?

The thing I am most uncertain about, is the drive line from the engine shaft, to the wheel. Any suggestions would be greatly appreciated!

[Mike Sal]

Welcome to the group.  Does your bike have a serial number (located under the neck, just in front of the crash bars)?  There are several guys who opt for the honda (or honda clone) motors & they seem to work out well.  I would thing the 19" wheels would look out of place on the Simplex chassis, but I wonder if a guy could re-spoke the honda hubs into the Simplex rims (the width might be too much?).  Don't give up on the simplex wheels if they are useable.  The 2" wide rims (depending on what year you have.....if it's an early bike, it might have narrow rims) are hard to come by & somebody here will want them if you want to get rid of them.  New spokes are available to fit the original rims to the original hubs. 

Is your large pulley the bolt on kind, or is it made to clip over the edge of the rim?

An electric bike is an interesting idea.....I've seen a few electric motorcycles sell on ebay, but have never seen one in real life to know how well they get along.

As you've probably seen from the photos on the site, the original path of power is from the right side of the engine, thru the jackshaft transmission, to the output pulley on the left side of the bike (early Simplexes, that were direct drive, were all on the right side).  Since the bikes are fairly semetrical, you can go with what ever power train you come up with.  The notch for the rear fender is the only thing that would need attention if you switch to right side drive.
Good luck,
Mike S

[ottoseeker]

Thanks for the reply,
I might be best to keep and repair the stock rims, assuming the clip-on rim can be repaired. There are no jack shafts, pullies etc of any kind. Can they be made from over-the-counter parts? I'll dig through the site to find a close-up picture. Is there another way to attach a pully or gear? Maybe a hub from a

[Mike Sal]

Otto, Ya, check out some of the pictures in the different sections & you'll be able to see what the automatic transmissions looked like.  I don't think there are many close up pics of the manual transmissions.  The basic idea is there is a U-shaped pivot that attaches to the 2 vertical bars which are under the seat area, between the upper & lower frame rails.  A jackshaft is mounted to this pivot loop onto which is mounted 2 variable pulleys....one for the motor & one for the drive pulley.  A centrifical clutch on the motor side engages as the motor speeds up, which drives some weights out to make the output pulley change diameters, thereby changing the drive ratio.  On the manual transmission models, there is a foot operated lever attached to a actuator rod which forces the pulleys to slide to one side or the other, making one small as the other gets bigger.

If you look in the Manuals & Such section, look thru some of the operator manuals posted there.  Some of them have some good illustrations on how the tranny's work (probably better than my feeble attempt here).

If you go with an alternate motor & it has enough torque, you won't need quite as much variation in the tranny as the original.
Mike Sal