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Piston clearance @ BDC on long stroke
Posted: Thu Sep 13, 2012 7:24 am
by bogs
I have bought a Malossi 210 and matched the transfers and now thinking about putting a 60 mm crank in.
Is there enough clearance from the casing at BDC for the piston skirts lower edge to clear or is some modification required.
Which brand crank will be best suited or do they all clear or not ?

Re: Piston clearance @ BDC on long stroke
Posted: Thu Sep 13, 2012 1:01 pm
by buttontobutton
First time I used a 60mm with a 210 it was fine and had no clearance issues at all.
Did it again with another engine and I had to take a mm off the piston skirt. Both times was with a Mazz 60mm crank, so with different tolerances from manufacture it's a case of suck it and see.
Obviously when you assemble the engine make sure it turns over and it all clears as you build it up.
I would not use the Mazz crank again. They break...
Re: Piston clearance @ BDC on long stroke
Posted: Sat Sep 15, 2012 1:23 am
by bogs
thanks for the info on the Mazz crank Button.
So can i take it as read that some 60 mm cranks are in fact longer ? or could it be a difference in the case machining?
Does anyone else have any experiences of pistons touching casing and if so which crank was it
Re: Piston clearance @ BDC on long stroke
Posted: Sat Sep 15, 2012 12:52 pm
by cezeta
60mm crank and 110 rod is the way to go on lambretta so the same should apply on a vespa, with the appropriate packer
http://www.sip-scootershop.com/en/produ ... +_46041000