Double Jug Gasket???


New Member
Sep 24, 2011
My Chinagirl came with 2 gaskets between the jug & case. I've read sometimes that happens at the factory, as mine did. If I remove 1 of 'em, what's that gonna do to the performance? Will it move the powerband? I KNOW this will affect timing, lowering the ports & increasing compression.
Will it hurt?
Will it help?

Has anyone done this & what happened?


Well-Known Member
Sep 8, 2009
It's not even an issue. I run a double base gasket on my engine to lift the cylinder slightly, which gives more open time for the transfer ports , as their open time window is restricted from the factory. The double base gasket also opens the exhaust port slightly earlier which in theory should raise the power band, but in reality it doesn't because the greater restriction is in the standard muffler.

The next time the cylinder is replaced, i'm going to try 4 base gaskets, combined with an ultra thin copper cylinder head gasket to restore the compression ratio.
When i rebuilt my engine and dummied up the cylinder with 4 base gaskets, the transfer port open window looked much more healthy, and so did the exhaust port which was never fully open at bottom dead centre with a single base gasket installed.


Did anyone figure out what works best? Single gasket or stacking the crap out of them?


Well-Known Member
Nov 27, 2012
My guess is you have either a Zeda or CDH engine. These both come with a double base on purpose. With the stock head and stock head gasket using 1 base may be dangerously close to bouncing the piston. With a after market head that has the crush ring at 47mms a single base with a .7mm copper head casket is usually real close to the sweet spot. Still as Spare Parts said you need to check the squish gap to know it's good.