Cush drive , necessary or not

[john11668]

slipping gear would, I think, refer to the slipping clutch in the magdyno.? those fibre gears won't take a lot of stress.

Lots of other solutions to your 12v considering your engineering abilities, an alternator off a Citroen 2CV used to be favourite.

I had the same problem as you are solving here, but I solved it by buying a Piaggio Scooter

More info might be usefull Mini me
Do you mean you used piaggio  as a donor,  or as a replacement for B31.  Latter would not be considered a suitable solution by my mate .

[john11668]

Looks like an interesting project. Do you have any more technical details of the starter motor, gearing, sprag etc? You never know, my right knee may give out one of these days.....

Will probably post all the details  when we have had a couple of trips out  and can be confident  of no problems .
All the proprietry parts are available on the net .  Some  material from local merchants and a bit of work on the lathe and miller.

Second hand starter from Ebay (Kawasaki xzr 750  , 99p) which turned out to be wrong rotation so had to add the idler to reverse it . Found this easier than altering brushes .  Gearing is initially 80/9 then further 2/1 at the belt giving a total of just under 18/1 
With the long stroke it can baulk occasionally at tdc but a slight touch of the valve lifter gets over that.

Working on a Mk 2  with correct rotation ( Suzuki 750) and  different adjustment so no idler is needed .   Happy to guide anyone interested once we are happy that there are no unexpected problems.   

[john11668]

You never know, my right knee may give out one of these days

I solved it by buying a Piaggio Scooter

Not a knee problem here . Rider is just not heavy enough!

[john.k]

A place where i worked used a Piaggio scooter to start a huge big Ruston and Hornsby 6cy diesel engine......the scooter was pivoted on the front,and the back wheel was lowered onto the big flywheel....it used to start up on a freezing cold night far quicker than the compressed air start supplied with the engine.....Scooters are powerful little things.

[mini-me]

I'm quite pleased with my Piaggio 125 , its an old mans bike that keeps an old man on two wheels. 80+mpg, 60mph screaming flat out, handles well, and reliable.

I can still kickstart a big single and have kept back  2 after getting rid of the surplus, but its impractical these days to leave an old vehicle unattended anywhere.

I have no info re the 2CV alternator, but the magdyno slipping clutch/fibre gear should be obvious if you remove the cover, if that is what you refer to?

[chaterlea25]

Hi All,
A major consideration when adding an electric leg to old brit iron is the quality (cranking amps) of the battery
Look at, http://www.startyourbsa.com/ and note the battery used
A proper battery will give a couple of hundred starts without recharging 
The Alton starter fitted to Vincents needs this battery to work even using the valve lifter
https://www.batteriesdirect.ie/magento/index.php/odyssey-pc680.html

A friend who has had two new hips has fitted a Honda car starter to his vintage black Ariel 
He fitted a ring gear to the back of the clutch and fitted the starter behind the gearbox
Total loss battery (PC680) but it lasts for months between charges

John

[mini-me]

Makes the bike even heavier though? and compound the problem?

[john11668]

Just following up on this . A couple of morning runs , maybe a hundred miles or so , and all seems to run well  without excessive heating of the sprag. There was a smear of excess grease on the first short run and a tiny amount of drag on the timing sprocket,  but just wiped off the excess grease which did nor reappear. The drag seems to have settled with running  too.
The hub ( crankshaft extension) which now houses the cush drive causes maybe 1/8" more compression of the cush spring but this does not seem to affect the rideability.
The fact that it starts at the touch of a button does vastly enhance the riders enjoyment since the fear of stalling at a cross roads disappears.

All the original parts are still on the shelf for the day when it may need to be reverted to original.

[john11668]

Just curious if I can upload a link to a video

https://www.youtube.com/watch?v=RsMitvkvEZA

[iansoady]

Good to hear the positive progress. The video doesn't work for me (gets a blank screen with an exclamation mark).

[john11668]

Seems to be only available if you are logged in .
Will try a  different site

[john11668]

Try this ! You may need to turn volume up
https://www.youtube.com/watch?v=RsMitvkvEZA

[iansoady]

That worked - the starter's looking excellent. Maybe the slow running mixture's a bit off though......

[john11668]

I suspect you are right Ian but the sound on the video is not good either. We are told that the carburettor is not correct for the model but it works and runs well on the road. We are on the lookout for the correct one but hens teeth spring to, mind