GG EC 250 2011 s3 extreme head
 

Hello everyone
I just got a s3 extreme head (low compression) and after I removed the original from the engine I didn't notice any difference with naked eye. Is it possible the original is already low compression head or the difference is too small to find it out with naked eye?
Thanks a lot

I believe the low compression is same as the OEM.
Measure the squish using the OEM head and have it machined.

If it is the same the better is to sell the s3... There's no machinery shop round here to modify the s3 head

Here's how to measure the squish.
http://www.gasgasrider.org/html/measuring_squish.html
Use the OEM head and have it modified.
Any machine shop with a lathe can modify the head.

How can you market something as Extreme and low compression at the same time?

New, Ultimate Mediocrity Pants. Made with cotton.

So let's dig into what you're trying to achieve and where you ride?

I believe that they are trying to bill this as a hard enduro head, and that the lower compression will reduce wheel spin and increase traction.

I do not agree with their marketing tactic here, just pointing at their possible rationale.

What is more disconcerting to me is that they could be marketing an "Extreme" head which may be the same squish and dome volume as the stock head! Which makes absolutely no sense!

I had good luck with sending out my stock head to RK tech for machining.

Your best results are going to be taking a squish measurement and talking to a good machinist about tightening up the squish band and getting the dome cut for the fuel (or compression ratio) you prefer to run, as others have suggested.

Higher compression will give you more power low to mid and take away some over-rev. The caveat being you will need to run higher octane fuel. Worth doing IMO with the 250 in some cases, probably not needed with the low-end torque of the 300. Unless you ride at high altitude.

The biggest benefits are getting the squish band correct, which makes for a more complete burn of the fuel in the combustion chamber and makes the jetting more tolerant of altitude and temp changes.

My 2 cents. There are definitely guys on this site with more knowledge than I have....