LCGB Forums

Hi all. I’m building a standard GP 200 engine. I’ve got the internals from an early Series 1 or 2 Li 150 engine. I’m planning to use the gearbox and drive sprockets as despite their age, they’re in perfect condition. My question is : the clutch sprocket has springs in it which I think is a form of cush drive. Would this be o/k to use or should I upgrade it to a later type ?. If I use this, I will use it with the GP type bronze bush rather than the two needle roller bearings. Thanks for your advice.

I was told not to use the ones with the springs in them as they aren't strong enough

Those old clutch sprockets do make good door stops. But that's about all

Fast n Furious wrote:Those old clutch sprockets do make good door stops. But that's about all

Is this true even on a big standard li125? I'm building mine with as many original parts as possible but I'm not going to be stupid about it. The plan was to keep all motor and gearbox internals original The layshaft for example will be getting changed as I really don't fancy it snapping on me. But I can't think of anything else.

Whilst the cush drive versions of the rear sprocket have a reputation of breaking, you still find plenty of them in old engines that are in perfect working order. Their reputation for breaking seems founded more on failures when used in tuned engines, rather than standard machines.

Innocenti’s decision to move away from the cush drive rear sprocket was almost certainly driven more by cost-savings in production rather than a history of component failure.

I wouldn’t hesitate to fit a cush-drive rear sprocket on a scooter I was restoring or preserving if I was planning to use as many original parts as possible.

Let’s face it, there is loads more things to worry about than the failure of a cush drive.

Knowledge wrote:Whilst the cush drive versions of the rear sprocket have a reputation of breaking, you still find plenty of them in old engines that are in perfect working order. Their reputation for breaking seems founded more on failures when used in tuned engines, rather than standard machines.

Innocenti’s decision to move away from the cush drive rear sprocket was almost certainly driven more by cost-savings in production rather than a history of component failure.

I wouldn’t hesitate to fit a cush-drive rear sprocket on a scooter I was restoring or preserving if I was planning to use as many original parts as possible.

Let’s face it, there is loads more things to worry about than the failure of a cush drive.

+1

In a puny 125 engine it is likely to be ok I agree.
I wouldn't fit one in a 200 motor.

Yes, I guess it's too easy to get dragged along with all these things.

Lambrettas mustn't have worked at all in the 60s and 70s.

I had an original cush drive sprocket fitted to a 200 block putting out about 16hp i think.
Did quite a few thousand miles with no problem.
I must say it did give a most pleasing gear change/ride

Super

A mixed cross section of views. I might put a solid one in and sell the Cush drive sprocket as it’s immaculate. Thanks for all your opinions.