Speedway style clutch?


Local time
7:43 AM
Sep 24, 2023
Has anyone ever tried to build a bike using a small stationary motor and a clutch jackshaft, similar to what is found on old speedway bikes?

Some boardtrack racers also use a similar system in the current "son's of speed" competition that Billy Lane is involved in.

I have in mind building a custom shaft to hold a small clutch on the drive side (LHS with honda gx160 clone sitting upright) and driving a reduction gearing transfer (using a starter gear) to the driven basket of the clutch.

Through the centre of the of the clutch I figured the pushrod for the clutch will have to go.

Has anyone tried using a complete motocycle clutch and built a jackshaft clutch/reduction drive setup like on a speedway bike before?

I am doing it the hard way i guess, because i could just use a bully clutch, the go cart reduction drive kit from china, or the 3d clutch.

I have decided to do it this way because of reasons too expensive for postage and freight.

The clutch basket, et al is a super easy thing to come across, new, or old. If i can have a bike that has a setup thar allows me to use different engines and bolt in, bolt out time is reduced i can have a redundant powerplant on standby.

Enough of the justification, i want to be able to operate this machine like a motorbicycle pedal to roll, drop the clutch and head off under power, cut the engine to sneak past things that dont like sound, drop clutch and power away...

Also, given i have the tendency to want redundancy in any setup, being able to pedal somewhat of any distance with a busted veloceopede instead of pushing, makes life all that much less of a hassle.


  • Screenshot_20231016_150831_eBay.jpg
    46.6 KB · Views: 71
  • Screenshot_20231016_150642_Chrome.jpg
    91.2 KB · Views: 50
  • Screenshot_20231016_150536_Google.jpg
    72.3 KB · Views: 55
  • Screenshot_20231016_150728_Google.jpg
    91.1 KB · Views: 53
  • Screenshot_20231016_150812_Chrome.jpg
    111.5 KB · Views: 61
I purchased 2 clutches, one is apparently from a norton/ajs/bsa (but i think is from Royal enfield) and the other is Royal Enfield 🤔


  • Screenshot_20231029_134339_eBay.jpg
    108 KB · Views: 37
  • Screenshot_20231029_134325_eBay.jpg
    105.4 KB · Views: 40
Yep. Reckon both of these came of the same type of box. Sweet! Now i have to get the main shaft, shaft sleeve and fulcrum lever (will be making that one from scratch).

I have ordered the new plates and friction plates and a clutch rod kit.

I will also have to build a bearing arbour to hold the shafts, with an oil feed in the top. Both the shafts have to slip over each other and the clutch rod also needs to be oiled also.

Then the fun part, finding the right double chain sprockets to fit onto the engine mainshafts that i am using.

It's going somewhere at least, to the ebay app...


  • 20231110_185918.jpg
    223.4 KB · Views: 28
  • 20231110_185803.jpg
    129.9 KB · Views: 26
  • 20231110_185815.jpg
    287.7 KB · Views: 28
  • Screenshot_20231110_223032_eBay.jpg
    80 KB · Views: 31
  • Screenshot_20231110_223012_eBay.jpg
    76.7 KB · Views: 34
It looks like a chain drive clutch
It sort of is, but for primary drive chain.
The actual drive sprocket does on the imside of the clutch basket, and would likely appaear on the build similar to how a bully gocart C.V. clutch does.


  • Screenshot_20231111_090235_Chrome.jpg
    108.5 KB · Views: 28