Stronger clutch springs

[Scooterdude]

Gosh! Just finished building my Mugello/Suzuki conversion I had off Harry, can hardly pull the clutch in its that strong! Can't see the cable lasting long at all haha, will get one of them there aircraft grade ones ordered sharpish! If that snaps going to go for the six plate I think.

[Adam_Winstone]

I saw the other side of Innocenti's design work recently and helped a pal sort out his standard UK 1 owner (him) from new SIL GP200 that both the top and bottom standard chain guides had failed on. Whilst stripping and rebuilding it, I couldn't get my head around just how soft and easily compressed (by hand) the original springs were. He assured me that the clutch was a joy to use and that the motor suffered no clutch slip regardless of how hard he revved it through the gears. Based on that we rebuilt it with the same springs. The clutch action is as light as a feather and, indeed, no clutch slip under load.

OK, I have known about the rationale behind Innocenti changing from the 5.2:1 LI150 final ratio with 15/46 to the GP200's 5.2 with 18/47 sprockets in order to give the clutch an easier life and to make it a nicer action for the rider, however, I hadn't grasped just how soft the factory originals are (SIL factory in this case)! Yep, I've long since understood the theory and have applied this to helping mates spec' 'tasty' engines, whilst avoiding the need for expensive multi-plate clutches but just how much difference it makes was a shock.

For anyone struggling to cope with a heavy clutch, the section about transmission in the original Home Workshop Manual does detail how the sprocket change allows the GP200 to cope, even with the softest of Innocenti's spring options. For some people that are finding that they need excessively strong springs to avoid slip, this concept of fitting a short gearbox and bigger sprockets might be worth considering.

Adam

[Darrell Taylor]

at what approximate power output was the engine in question suffering no clutch slip on the sil engine Adam ? was it std and if so why would it be a surprise to find it coped , i covered the std sil clutch relative power limitations recently in the bang for buck scootering articles and found it to cope as a completely std unit to around 14bhp was only the addition of an expansion power delivery and a bump up to near 16 that it let go occasionally

the linear power delivery of the std motor/pipe curve assists with the clutches coping ability

[Adam_Winstone]

Hi Darrell,

The surprise was simply because I don't think that I've necessarily felt genuine 'standard' SIL GP200 springs before... OMG are they soft and springy!

The motor in question is totally standard SIL and the springs may well be the same ones that were in there when he bought the bike new. The only difference is an AF VW clubman.

Adam