Detonation.

[RedFoxCR]

Is this not what you said?

Yep, i'm about to say that again and again. Thin gasket never leads to detonation.

[ford832]

It depends how closely jetted/timed you are as well as what fuel you use.If you picture your piston at tdc,a thinner base gasket lowers your cylinder in relation to that which puts your piston closer to the top of your head which then means you have less comb chamber area therefore........

[Chokey]

Is this not what you said?

Yep, i'm about to say that again and again. Thin gasket never leads to detonation.

Seriously? You really believe that? Because I have personal experience with a thinner head gasket on my KX putting the engine over the edge and causing it to ping on 93 octane. I had to run 100 octane with the thin head gasket to not have detonation. Replace the head gasket with the standard thickness gasket and the pinging goes away. Imagine that...

Many modern two-strokes are right on the verge of detonating right off the showrrom floor, and it takes very littel to push them over the edge. Anything that raises compression increases the possibility of detonation.

[RedFoxCR]

I'm sayin about base gasket only! The head gasket is way much thicker.

[evo550]

For your viewing pleasure,

[125mx.com]

Eh, forget that! Base gaskets don't really affect compression - i counted! The only affecting thing is  the head gasket.   And the head itself.

Are you serious ? 

[TMKIWI]

I think you should listen to the above people RedFoxCR.
Base gaskets change both port timing AND compression.

It's a bit hard to put different size head gaskets on when there is not one.

[evo550]

Considerable diffeence in gasket thickness, the thicker one it originally.
Although KTM offer one at .25mm thickness which is thinner again.
It would seem higher compression can be run, but jetting chnbes are required.

[125mx.com]

Considerable diffeence in gasket thickness, the thicker one it originally.
Although KTM offer one at .25mm thickness which is thinner again.
It would seem higher compression can be run, but jetting chnbes are required.

KTM offer a wide choice of gaskets right down to 0.06mm allowing us to jack the cylinder around to suit applications, TM Racing also offer a good choice of sizes, must be a Euro thing !

[evo550]

KTM offer a wide choice of gaskets right down to 0.06mm allowing us to jack the cylinder around to suit applications, TM Racing also offer a good choice of sizes, must be a Euro thing !
[/quote]

0.06mm are you sure ?
My KTM parts diagram only goes down to 0.2mm.
It seems the reason they offer a few different gasket thickness is to match that particular cylinder the bike has been fitted with. When the cylinders are finished and ready to be fitted they vary slightly in size due to the casting and finishing process. The different gasket ensures that each bike comes out the same performance and tuning criteria.
The same thing goes on with their pistons.

[ford832]

It seems the reason they offer a few different gasket thickness is to match that particular cylinder the bike has been fitted with. When the cylinders are finished and ready to be fitted they vary slightly in size due to the casting and finishing process. The different gasket ensures that each bike comes out the same performance and tuning criteria.

Exactly so.While you can play around with different thicknesses depending on what you're after,that is the reason for the discrepancy.