Mag flange gap

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Joined: Sat Jun 09, 2018 12:06 pm

Wed Jun 13, 2018 3:09 pm

Hi all im new to the forum and new to lambrettas so first post in need of advice.

Just bought a s2 lambretta resto project and trying to go through the bits that came with it to see whats good to use.

Ive got a new SIL 19010052 mag flange that doesn't look quite right when i drop it into the engine case.
It doesn't look like it drops in far enough, the transfer port cutout doesn't match it undercuts by about 5mm and the seal/ bearing face of the mag flange looks like it wants to drop in another 3mm also.

Does anyone know what the gap between drive side and flywheel side seal faces should be when assembled? Or width of crankwebs?

Not yet found a copy of Sticky's book but its at the top of my to buy list, so in the meantime could someone enlighten me as to what the differences are between the 19010051 and 19010052 mag flanges?

If it measures up ok ill epoxy and reshape the transfer port.


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Wed Jun 13, 2018 3:52 pm

The SIL 19010052 (which is the one that you've got)is for a 200 motor and the 19010051 is the one for 125, 150 and 175 models. According to "sticky's" manuel 125,150 and 175 models built after 1968 were fitted with the 200 mag housing.Your mag housing looks seated enough on the photo's.

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Wed Jun 13, 2018 6:21 pm

Luke you'll see once your crank is in place that there will/should be equal distance either side of the crank webs between drive side and mag side.
But as you said you must get your hands on stickys book,pictures speak a thousand words.

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Wed Jun 13, 2018 7:52 pm

You do need to be careful if you mix these the other way round. A 150 mag in a 200 casing can lead to the barrel not seating correctly but it's Ok this way round.

Agree that Sticky's manual is probably the best thing you'll buy for your Lambretta it will save you time and money in the long run and help avoid some of the bear traps in selecting parts.
"Our dilemma is that we hate change and love it at the same time; what we really want is for things to remain the same but get better."

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