Base gasket

[eff]

Thanks. I'm not sure I want or need the compression to increase either. I run 93 octane pump fuel and my bike runs really well form me.

[eff]

OK, just clarify things.

The green gasket is the 0.3mm and the thinner brown gasket is the 0.15mm. The black one that was on my bike originally was a 0.5mm.

According to the manual, you should run the 0.15mm and either the 0.3mm or 0.5mm.

I am running the 0.15mm and 0.3mm combo right now and I'm very pleased with the it.

[skid jackson]

so I go out and paw through the parts that came for my top end. I have one base gasket that appears to be the .5. it's black, the bike has two base gaskets on it right now, one green one. I'm guessing its the .15 and the .3. I really wanted to get into this top end this weekend. I'm assuming it is ok to to run the .5 by itself and this should make for a bit less compression than the two that are on there now. which would tame the motor a bit. is htis correct?? what effects will the .5 have on performance

[eff]

The .5mm alone is fine.

[Jim Cook]

When we had the shop going, we tried to run a single .15 mm gasket, but had a lot of trouble getting it to seal. We/I don't like to put gasket sealer on the base gasket, but prefer to let the cylinder nut torque compress the gasket to achieve a good seal.

The .15 mm gasket is provided to work with one of the thicker gaskets to achieve desired compression and port height. The original 300 ('99) came from the factory with a .5 and a .15 stacked together.

On my '99, I ran a single .3 mm base gasket, but on my '06 I use a single .5 mm base gasket.

[PEB]

Jim, Why don't you like the sealer? I ran the .3 by itself for years with no problem, I now am running the .15 with some sealer and it runs great! I have about 400 miles on the .15 with no leaks yet. The performance gained by using the thin gasket has me wanting to sent the head to R&B for his treatment.

Paul B

[Kent A]

Raising the compression ratio on the GG 250/300 by removing base gaskets is kind of counterproductive since lowering the cylinder shrouds/blocks the transfer ports. The cylinder actually has to be raised 0,5 mm from standard to unblock the transfer ports completely.

On my previous GG bikes I ran just one 0,3 mm gasket and it didn't make any difference whatsoever in the way the bikes ran. Instead, when I raised the cylinder (0,5mm) and modifyed the cylinder head to suit it completely transformed the bike. There is really no comparison to a std GG 300, maybe a bit too powerful for tight woods riding but absolutely wonderful in all other conditions.

Kent

[PEB]

Kent, Thanks for pointing out what a hack I am. It sounds like if I were to send the head out for modification I should first install about .8mm of gasket to get the ports aligned and then have the squish adjudsted from that point, good info for sure.

Paul

[socalscott]

Originally Posted by Kent A

The cylinder actually has to be raised 0,5 mm from standard to unblock the transfer ports completely.

Kent

So, 1.45mm is the total?

[skid jackson]

ok so I know nothing of this stuff ..... by using the one .5mm gasket that I got will these ports line up correctly??