Squish too large?

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PSC
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Sat Mar 09, 2019 3:43 pm

Hi,

I’ve just fitted a LML 5 port 150 kit to my 125 LML with an FA Italia head to suit.
The piston is level with the bottom of the transfer ports at BDC and almost at the top of the bore at TDC, which seems normal. With a 0.3mm (supplied) head gasket fitted the squish is about 3.5mm, which I think is far too much. The roof of the combustion chamber to the gasket face is about 2.8mm, which also seems a lot. Any thoughts/solutions? Ta

holty
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Sun Mar 10, 2019 9:42 am

I would machine the head to get down to 1.2 mm, you could machine the top of the barrel instead, but head is easier to do.

PSC
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Sun Mar 10, 2019 9:50 pm

Thanks. Is it normal for Vespa heads to be so deep?

holty
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Posts: 848
Joined: Wed Jul 15, 2015 11:52 pm
ebay user ID: amholt123
Main scooter: lambretta gp
Location: east yorkshire
Contact:

Mon Mar 11, 2019 10:51 am

I don't think its too much of an issue for vespas, but lml parts are made in india and are not made to the same high standard, that said ive got a mate with a 5 port 150 and it goes well, a little bit of lathe work will soon get your squish to a better size, a good machine shop should be able to sort it for you if you don't have access to a lathe.

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