Head Gasket Material

The mechanic that is working on my ped discovered that the decompression valve in the cylinder head was badly mangled and that's what was in fact hitting the piston and causing that awful noise. He showed me and I can't believe I thought that's how it was supposed to be, it honestly never occured to me that it was the problem. It somehow came loose i guess and it jammed right into the side of the combustion chamber. I didn't notice because I think it was the first time I removed the head so I figured that's how it was supposed to be. I've ordered the valve but until then he explained over the phone that he could somehow fix this by making a new head gasket with a few changes. The problem is he was all out of gasket material, so I need to find some. I think I remember a while ago this being discussed and somebody mentioning going to a hobby store. I'd like to know what thickness I need, what material's best to use etc. I've attached a picture if it helps, the piece that caused the trouble is that one that looks like a big nail or a valve on a trumpet. It's a 1975 Motobecane Mobylette. Thanks a lot everyone, and keep an eye on those valves, they can cause a lot of trouble !!!!!

Re: Head Gasket Material

sorry here's the attachment


Re: Head Gasket Material

Reeperette /

Moby, seek out your local Hobby or Craft store and ask them for some "Aluminum Shim Material" and get it in a couple of various thicknesses.

Once your mechanic, or yourself, has it in hand, take the thickest piece and cut it to size and shape - if that works, later you can use the thinner stuff for a little more compression if you wish to try that.

I forget who originally made the suggestion, but I've also seen someone cut a new gasket out of a soda can before, hell...I did that for someone at BBQ4, and it worked fine.

Most moped head gaskets are made from a thin sheet of aluminum.


Re: Head Gasket Material

T.J. Smatters /

A friend of mine bought a new head, compression release valve, and head gasket for heis 78 motobecane 50L from the moped warehouse in New Jersey last month so they should have a gasket for yours too.


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