I wanted to make a cheap, good quality 6 plate clutch from "normal" lambretta parts rather than cassette type so that I could modify easily and also just because I like farting about with stuff like that.
So, I've been keeping an eye out for cheap parts on ebay and Facebook and gathered together; stratos extended spider, stratos deep crown wheel, some unknown make deep pressure plate. No science went into this at all, I just figured getting bigger stuff would have more room and I'd be able to squeeze 6 thin 2.6mm plates in.
Well, I couldn't. Or I could if I'd used 1mm steels right through and a 2mm top plate, but it wouldn't have been very robust, nor do I really need 6 plates. I just wanted 6 so that I could use really light springs.
Anyway, I've ended up using 5 x 2.6mm corks, all steels are 1.5mm and the top plate is a nice thick 3mm one. BGM springs are my favourite because they have a longer free length but when compressed have an appropriate preload. This means that the force at the lever doesn't increase as much as the lever gets closer to the bar.
So, as a result, I've got loads of clearance, so no drag (specially for WT1).
Normally I just build it all in one go, but this time I decided to try building without springs which turned out to be a good way of getting it nicely set up and operating smoothly. Then springs right at the end when it's all good.
You can see about 2mm clearance here..
It's not a super powerful motor and the gearbox has a high ratio, so I reckon this will work.fine. if not, I'll swap one or two plates for 3.5mm ones.