Cylinders gaskets

[javito86]

hello my friends, I come to you today to consult on an issue that brings me to the end of the restoration of my mk3 49, I have to make cylinder gaskets, i dont know which material have to be, especially the thickness, im in the fina step to assemble the bike, if anyone can help me, since I'm near to the end, thank you!

[tck]

http://www.ebay.co.uk/itm/680-DOUGLAS-350cc-MKIII-IV-V-SPORTS-46-53-ENGINE-GASKET-SET-/231047907505?pt=UK_Motorcycle_Parts_13&hash=item35cb8748b1#ht_1260wt_758

there is a good picture of a real gasket

[javito86]

nice!
but still dont know which material is it, and the thickness, is it important to have a precise thickness?

[eddie]

Javito,
          You don't say whether it is the cylinder head gaskets or the cylinder base gaskets that you want details of. Anyway, the original cylinder head gaskets were made of an asbestos based material that was 1.2mm thick. We now have to make do with non-asbestos material which seems more prone to blowing. Back in the 50's and 60's, copper head gaskets were also available from some suppliers - these were usually only .8mm thick.
     Mr Douglas did not fit base gaskets to the Mark series engines, but instead used a .2mm thick brass shim. Evidently this was fitted to prevent any corrosive action occurring between the alloy crankcase and cast iron barrels. Whether this was effective is doubtful as this practice was not carried forward to the Dragonfly engines.

  Regards,
               Eddie.

[javito86]

thanks eddie, u saved me! now i can build them, thanks to you im one step closer to finish the reassembly, soon new pictures of a fully restored douglas mk3