High Compression Head

[gasIdaho]

I just picked up GG brand high compression head(part# ME25-30916000). Anybody out there have any experience with these?

[Bandit9]

Not with that particular head, but my stock head had a couple thousandths shaved off of it and it works pretty good. Has more bottom and hits a little harder.

[RBD]

Originally Posted by gasIdaho

I just picked up GG brand high compression head(part# ME25-30916000). Anybody out there have any experience with these?

The part number you just posted is the same number that is cast on all 250 and 300 gasgas heads (2001 and later) that I have seen to date.

Ron

[gasIdaho]

I'm pretty sure mine is ME25-30'8'16000 vs. ME25-30'9'16000. Hope I haven't been duped! They claimed it was from dealer edition motorcycles offered by Don Knight and that it differed from the stock heads.

[RBD]

Hi gasIdaho,

I am not really sure about the numbers my self. A long time ago I wrote the numbers that were on a gasgas 250 head that I was working on (thinking that there were different numbers between the 250 and 300's, but not so).

Every time I do head work on the gasgas, I will compare the numbers. Each time they read ME25-3091600 and it does not matter if it was a 250 or a 300. I have always assumed that the cast in number was just that, a casting mold number.

The 250 and 300 heads are the same casting as far as I can tell, they are naturally machined differently.

It will be nice to hear how the new head works.

Ron

[GMP]

Ron is correct. I have an '07 250 and an extra head from a '02 XC250. The '07 has slightly different machining on the top of the head for clearance using 13mm hex bolts rather than cap screws. Both heads are ME25-30916000, its the same casting. There are high compression heads, and likely yours is one. Measure the squish band width, I was told the the hi comp heads are cut narrower than the standard EC heads, on the 250s anyway.

[gasgasman]

My 2001 SE250 was supposed to have a high compression head on it.
Which it didn't.
After having Ron machine it, it ran 10 times better.

[iancp5]

Guys,

Surely they would not have the same part no. unless they were the same part! Even if they're machined differently they would have to be marked differently - how would you order a spare? It makes no sense - it would even be confusing at the factory. An order arrives from the sub-contractor or head making department and no one knows what bike they are for! I can see the delivery note: "Heads for some GasGas or other"!

I can understand how there might be one number the same but there must be something else to easily separate them.

[GMP]

I can understand how there might be one number the same but there must be something else to easily separate them.

The bag perhaps?

[Ryno]

If you have both GG heads in your hand you can measure down from the lip on the outside to the machined surface and see which head is which. I think its about .025 difference. My heads I had were the same part# on the top but one was machined more than the other. Don't know if this was stock or someone did the work. But fairly easy to tell which one will have more compression.