Lambretta Forum

engine number and cylinder cc don't match?

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Freoway Lloyd Hammond
Fremantle, WA, Australia   AUS
Hi. New to the forum. I hope you can help. According to frame numbers, I have an Li150 Series III (150LI3*693965 * ), but the engine casing number has 125LI *587422*. Furthermore, the cylinder is a 150cc (diameter around 58mm), not 125cc. Can anyone help me as to how a 150cc cylinder could be mounted on a casing stamped 125LI? I presume the motor must have been changed at some time. Cheers, Lloyd

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MK Monty Alistair Montgomery
Manchester, UK   GBR
Once you get to the LI range with a few odd exceptions Lambretta engine cases fall into 2 types. Up to 175 are classed as small block. 200's are classed as large block, the main difference is the spigot size and stud spacings for the barrel. If you had a 125 cylinder the outer spigot that fits inside the case is the same size as a 175, a 125 has a little hole with a hell of a lot of steel around it, Great for boring out bigger. That been said you can get nicosil lined kits that will fit a small block to slightly over 200cc The walls of the spigot are paper thin but they work well. Personally cast iron barrels are great other than the 1000 miles you have to do to run them in, you can nip them up and they will be OK when cool, Nicosil aluminium kits can be run in, in a few days dont nip up so much but are a bugger for holing pistons if the timing and carburation is not spot on
So quick answer is any barrel will fit your case, in the UK tax and maximum engine size often had people changing things to 125 as you can ride these with L plates as a learner.

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