clutch help

[Bilko]

Definately.

[mark]

update: i have had a long chat with jerome at readspeed and he helped me out with my clutch as he wants it to work as well as it can, he couldnt apoligise enough about my last call which i admit wasnt helped by me being snappy after a shite day at work .so all is good there and there is no hard feelings on either side

my clutch arm in side casing is very stiff to turn so i think it still has some grit from powdercoating its that stiff the spring will not return lever

turns out i was running st90 rockoil and not sae90 as recommended by readspeed this will all be remedieed tomorrow when i rebuild it and try it out on sunday.

once again thanks for the chat jerome

[Rich_T]

After reading your first post again, I'd be curious to see if the oil change would have such a dramatic effect.

The stiff clutch lever is a bit of a school boy error, but again if you were riding at 60-70 mph you would have thought that the slip would have been progressive and started when you accelerated hard.

Your engine will be or is certainly very capable of producing a lot of power. If the problem persists I think you will have to inspect the clutch components carefully. Perhaps the stiff lever has been applying enough pressure for the clutch to let go at 70mph but it sounds odd that you didn't notice it changing gears.

[mark]

jerome did say that when he designed this clutch 8 years ago it was only tested upto about 30bhp so it may not cope with 44bhp but seeing this was the best of clutch's at time of building this engine, it will have to do for now until a new clutch that fits inside a unspaced casing is available(i'm willing to test ) it will have to be alright.

the lever is not stiff its the arm thru side casing

[Rich_T]

Yes, I was reffereing to the casing lever too. Some get stiff if you get them plated or put them in upside down.

[mark]

def graunchy

[Rich_T]

Is it a genuine 44BHP from a dyno reading or "seat of the pants" reading?

The original Aprilia clutch handles a stock 34BHP with 6 plates. The RS125 Polini kit (150cc) boosts this to 44BHP (supposedly) again with 6 plates and race springs. A combination of 7 plates and race springs in the low cost clutch is probably the closest you'll get to coping with that power on a budget, but you'll need 10mm packer and extended kick start.

The 8 plate clutch uses RM125 plates and fits with no packers BUT,it costs a shag of a lot and I haven't made any yet. The last of the RM125 7 plates went on White lightening's scooter which has a 34BHP. As I understand, it's running fine.

I have this hunch about the pressed metal spiders and pressure plates, that under heavy load the pressure plate may "walk" if in contact with components that are not entirely concentric.

[mark]

i had another look today and im using a pressure plate with a locating rod, this was running out of true by 0.75mm we got it down to 0.15mm after some persuasion.
im still not happy with it so im getting a new pressure plate now.
i will beat it
the first one of the 250's running exactley the same setup put out 44bhp on diablos dyno so im using that as a benchmark figure