OP
@ricky_cantley avatar
UTC

Hooked
Vespa 125GTR p125x p200
Joined: UTC
Posts: 368
Location: Kent
 
Hooked
@ricky_cantley avatar
Vespa 125GTR p125x p200
Joined: UTC
Posts: 368
Location: Kent
UTC quote
Cases destroyed 10 miles into a rebuild any ideas why, I was putting it down to old age until I noticed the clutch cover tonight. Original build was only run in 1500 on the first spec Mazz crank, ported cases, reed valve, mallossi 166, vespatronic, Prior to the second rebuild it had destroyed 3 Cosa clutches. So new sip clutch with new main shaft as I was told the main shaft was bent and the selector shaft was trashed so new selector shaft and cruciform

1 flywheel came off on first ride out bolloxing the woodruff key way
2 gears were a bag of neutrals the cruciform was brand new but now done in

Went back to the second builder who showed me the cases the next time I visited
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Forum member supplied image with no explanatory text
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@niz76 avatar
UTC

Hooked
1980 Vespa P200E
Joined: UTC
Posts: 199
Location: Tampa, FL
 
Hooked
@niz76 avatar
1980 Vespa P200E
Joined: UTC
Posts: 199
Location: Tampa, FL
UTC quote
Ouchy.
@willie_b avatar
UTC

Ossessionato
'20 300GTS Super Tec '09 250 GTSie '75 Rally 200 '79 P200 '09 Stella 221
Joined: UTC
Posts: 2610
Location: Midway, Kentucky
 
Ossessionato
@willie_b avatar
'20 300GTS Super Tec '09 250 GTSie '75 Rally 200 '79 P200 '09 Stella 221
Joined: UTC
Posts: 2610
Location: Midway, Kentucky
UTC quote
A guy I know who had a hot motor (expensive 221 Polini) trashed the cases in the same manner with a brash downshift at speed. Just had gotten the motor broken in.
@subetherbass avatar
UTC

Ossessionato
1997 Italjet Formula 125, 2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: UTC
Posts: 4859
Location: Australa, Mate
 
Ossessionato
@subetherbass avatar
1997 Italjet Formula 125, 2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: UTC
Posts: 4859
Location: Australa, Mate
UTC quote
No Idea
Well, this is something I have NEVER broken!
Well done.

but my guess is mis-matched cases causing the crank to spin unusually.
@ginch avatar
UTC

Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and '66 Blue Badge Smallframe
Joined: UTC
Posts: 8784
Location: Victoria, Australia
 
Veni, Vidi, Posti
@ginch avatar
74 Super, 75 Super, PX project, LML off-roader and '66 Blue Badge Smallframe
Joined: UTC
Posts: 8784
Location: Victoria, Australia
UTC quote
If there was a mis-match between the clutch gear and the primary gear - as in not enough clearance between them, or not the right gears - it might cause this to happen.
I have a ruined clutch gear... when I pulled it out I noticed that the primary didn't run true but looked like it was slightly oval(!), which must have caused the problem.

I'm just guessing, but might be worth looking at anyway.
@joshzingzing avatar
UTC

Veni, Vidi, Posti
px200 cutdown,px180,px150. Puch SR. Puch scooterette
Joined: UTC
Posts: 5109
Location: west aus
 
Veni, Vidi, Posti
@joshzingzing avatar
px200 cutdown,px180,px150. Puch SR. Puch scooterette
Joined: UTC
Posts: 5109
Location: west aus
UTC quote
clutch holder hook was used incorrectly
OP
@ricky_cantley avatar
UTC

Hooked
Vespa 125GTR p125x p200
Joined: UTC
Posts: 368
Location: Kent
 
Hooked
@ricky_cantley avatar
Vespa 125GTR p125x p200
Joined: UTC
Posts: 368
Location: Kent
UTC quote
Food for thought. If it was mis matched cases or mis use of the clutch tool the problem is solved. Crank is off for work so that will be checked. I will very carefully look over the remaining parts to see if they run true, but I am thinking the fact that it was repeatedly jumping out of gear / downshifting may be the cause.
@greasy125 avatar
UTC

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: UTC
Posts: 14995
Location: The state of insanity, SoCal
 
Sergeant at Arms
@greasy125 avatar
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: UTC
Posts: 14995
Location: The state of insanity, SoCal
UTC quote
are you saying that the cross in the picture only has 10mi on it?
OP
@ricky_cantley avatar
UTC

Hooked
Vespa 125GTR p125x p200
Joined: UTC
Posts: 368
Location: Kent
 
Hooked
@ricky_cantley avatar
Vespa 125GTR p125x p200
Joined: UTC
Posts: 368
Location: Kent
UTC quote
Yes that was a new cross on the last build its not done any more than 10 miles as it would not stay in gear, I thought I had a mis mach between the selector box, selector shaft and main shaft that's why the scoot went back to the engine builder and the failure of the casings was pointed out to me.
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