Which clutch top plate

[Snails]

Ok, my clutch plates wont separate, its a gp std clutch with surflex plates. I've measured my corks at 14.35 mm so in order to fix the issue I was thinking of fitting a thinner top plate, just not sure whether to go for the LI type or an even thinner one. There didn't seem to be much movement at all in my clutch when assembled. Obviously the gamble is that I go for 2mm plate I could end up with too much movement.

[hendy]

I had similar problems with mine, so I replaced all my steels with 1mm ones and it slipped badly (unsurprisingly), so I replaced half of them with original 1.5mm ones (or something along those lines) until I got a clutch that doesn't slip and is nice and light. The point I'm making is that it's easy enough to open the case and mess around. Furthermore, steels are cheap so why not buy a selection and get it perfect?

[rosscla]

There's a batch of oversize surflex branded plates I had a set sent to me and sent them back.all the corks should fit in a 14 mm spanner, if they don't then you're going to have this sort of problem.

The root cause is the bad corks, the correct way to fix it is to replace them.

[gaz_powell]

I had the same problem on a recent cluch build. I took surflex corks out which was originally built by me with taffspeed springs. It would not go back together with MB springs. I ended up using shorter AF GT springs and a 2mm top plate as I had them to hand - its spot on with this set up.
Did one the week after for a mate using MB springs and surflex plates and it went great no problems.
Chatting to a friend last week and he rebuilt his vespa clutch with a set of surflex and the same problem. Definately the problem was thick plates.

Scooter parts..........

[Snails]

There's a batch of oversize surflex branded plates I had a set sent to me and sent them back.all the corks should fit in a 14 mm spanner, if they don't then you're going to have this sort of problem.

The root cause is the bad corks, the correct way to fix it is to replace them.

Is 14.3 mm what would be considered faulty. I guess I could ask SR which is where they came from

[Snails]

I had the same problem on a recent cluch build. I took surflex corks out which was originally built by me with taffspeed springs. It would not go back together with MB springs. I ended up using shorter AF GT springs and a 2mm top plate as I had them to hand - its spot on with this set up.
Did one the week after for a mate using MB springs and surflex plates and it went great no problems.
Chatting to a friend last week and he rebuilt his vespa clutch with a set of surflex and the same problem. Definately the problem was thick plates.

Scooter parts..........

ah yes I forgot to mention I am using MB springs. does that add to the problem?

[rosscla]

There's a batch of oversize surflex branded plates I had a set sent to me and sent them back.all the corks should fit in a 14 mm spanner, if they don't then you're going to have this sort of problem.

The root cause is the bad corks, the correct way to fix it is to replace them.

Is 14.3 mm what would be considered faulty. I guess I could ask SR which is where they came from

It's outside the spec. Also check the steels to be sure they are what you think they are.

[shocky]

Scootopia do 1.2 mm plates for 2 quid each , im not sure that to much separation is a problem I have over 3.5mm on mine as I use a deep 5 plate crown wheel a 5 plate indian outer spider with a 45 deg radius machined on the bottom outside edge and some generic strong spings that I pre compressed to check they wernt to long I have nos Adige plates standard steels and a thin top plate I used this set up on my last 2 ts1, s and yes they were 4 plate
I machine the outer spider(could grind or file ) so that it does actually touch the bottom of the crown wheel if needed , ive found some springs go coil bound before the outer spider has fully bottomed out although this probably isnt a problem as long as you have enough separation I just like to know ive got maximum seperation available my last crownwheel clutch combo cost me about 100 quid and has been very reliable

[Snails]

That's interesting to know, i read that too much separation would lead to slip or drag (can never remember which way round they are! ). It would have been Stickys book or MB's website...........still need to make that call to SR........

[hendy]

The clearance that can or must be achieved varies wildly.

What is the spring constant?

What is the spring free length?

What is the coefficient of friction of the steels and friction plates?

Number of plates?

Engine torque?

Gear ratios?

Inner and outer radii of the clutch?

Unless you have all this info and are good at engineering maths the clearance is very much 'finger in the air'.

My clearance is way over 1.5mm, but i can't remember how much.

Have you got a tuned motor?