I am a Classic Scooter mechanic in Melbourne, Australia. I have put this problem to the other Vespa dudes in Australia. Now it goes out to you.
I have been battling with a tuned PX destroying clutches for far too long.
I am absolutely stumped. In desperation I am putting this problem out to the great minds of scootering. Here is the timeline. If I have missed something Stupid then good. Tell me. I have ridden this scooter for 100 metres and it has hammered its clutch to bits so I cannot blame the rider, the Horsepower or the fact that cosa clutches are weak.
I have another 24HPO at the wheel px here that has has an off the shelf banded cosa on for 8000kms.
My next step is to get new cases and start again.
It’s a shame as it pulls 20horses between clutches. (I have a dyno)
2nd hand px200 (2004) done 18000 kms
Pinasco kit goes on with mild pinasco pipe
Rides for another 4000kms
Vespatronic (1.5kg) installed
Rides for approx another 1000 km
Rivets shear on cosa clutch, two go into motor
Split cases and remove rivets (crux/seals)
New banded and welded clutch (newfren)
200 kms later Clutch blows its retaining ring
On inspection the clutch cork tabs had hammered into basket completely destroying it .
Pulled motor down and rebuilt cush gear plus installed JL right hander.
200ks later another clutch destroyed - Pulled motor down and installed LS crank, new bearings seals crux etc. Matched ports.
installed billet clutch gave up getting it to work without grabbing and used 7 spring px clutch.
Chewed up in 500metres - Pulled motor down and replaced drive shaft (axle), several gears, ALL bearings etc. NEW genuine stock cosa clutch.
50-60km corks show signs of wear (;ike 10-15000 kms) and basket is beginning to show damage.
Replace and continue carb tuning.
Clutch retaining ring blows out in neutral while revving. Dismantling shown demolition of corks, plates and basket. Corks appear a little dry but not burnt in any way.
THINGS DONE IN HOPE WITHOUT A RESULT – changed crank, bearings, drive shaft, 5 clutches, rebuilt cush gear, pressure plates, levering plunger arm, plunger, gears
THINGS NOT DONE – return to standard flywheel, spacer cog behind clutch, engine cases.
Thanks for reading
let me know if you have come across this before.