barrel twisted??

graeme · Renault 5 Driver Joined: 02 Jan 2005 Karma :

following all my problems, bought a new piston from malossi, got it fitted, ticking over for 5 mins then cut out. The guy fixing my scooter says the barrel is twisted.....
does anybody know what could hav caused it and how much it would cost to fix it??

thanx
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g.macdonald

Git · Brolly Dolly Joined: 17 Dec 2003 Karma :

Would be good to know how a barrel twists. Maybe the liner?
Can't help much i'm afraid but would love to know the experts thoughts.

tatters · Exxon Valdez Joined: 04 Jan 2004 Karma :

l,ve hear of cylinder heads warping due to a head gasket leak but not a solid alumuim cyclinder Confused

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Kye · Scooby Slapper Joined: 13 Sep 2004 Karma :

Some guy must be taking you for a serious ride, how the fuck can a barrel twist? Confused

He must be having you on
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Ducati 600SS
Vespa PX125

mr.z · World Chat Champion Joined: 04 Feb 2004 Karma :

The only way i know of is if the engine has overheated massively for some period of time, possibly being starved of oil or coolant, never heared of anything else causeing it... one part gets hotter than another and expands and then doesn't return to its original size = warping/twisting, afaik it will happen more to the internal sleves than anything... if youve ever seen whats left of a bike after its been in a fire theres not allot left, it melts at a realatively low tempreture (one of its advantages) older cast iron engines you can set on fire and most of it will be ok Very Happy

I'd have thought it would be utterly buggered and not go at all if it was all that bad, to be honest you would probably be far better off hunting down a new engine from a breakers...

Allthough i may be very very wrong...
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Kye · Scooby Slapper Joined: 13 Sep 2004 Karma :

Moped engines arn't sleeved as far as I am aware, standard barrels are just cast iron and alloy aftermarket barrels are Nicasil lined
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Ducati 600SS
Vespa PX125

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

Smells a little like bullshit to me.

Never heard of a barrel twisting before, and I'd expect it to take a while - not 5 minutes.

May have warped the head, particularly if its a water cooled model and it was started after the rebuild with no water in the engine.

graeme · Renault 5 Driver Joined: 02 Jan 2005 Karma :

i duno, but thanx

he said he has sent it off to get re-bored. it could be due to no oil gettin to it, he said it might have twisted because i was kicking it when no oil was gettin it, due to the reason i had to get a new 1

oh yer and its a malossi 70cc bore kit if that helps??

thanx all
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g.macdonald

BFG · Brolly Dolly Joined: 14 Feb 2005 Karma :

Guy might be saying "twisted" as in "fucked".

A rebore would not remove a "twist". A twist sounds more like warping - where the mating surfaces are no longer flat, and yes it can happen to an alloy barrel.

In this case I think he means it is badly worn. IUsually happens if you try and ride the bike without two-stroke oil.

graeme · Renault 5 Driver Joined: 02 Jan 2005 Karma :

he says it warped or sumfin an when it heats up, the skrt (or the bottom) expands an one side catched on the piston, i think.

just spoke to him an he said he is gettin it bored so it will be about 74cc an will b perfect after that. where it will b perfect i duno.

thanx
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g.macdonald