Swopping 1997 Cylinder head with 2005 head
 

Hi I did post this under chassis/body not thinking !

Just wanted to know if I could swop my 1997 ec 250 Cylinder head for a 2005 Cylinder head without having to modify anything else and also wanted to know if it would affect the compression etc, I'm fitting the 2011 transformation kit so need a lower profile head in order to fit the 2011 tank.

Cheers for any help !

I might be wrong but wasn't the '97 engine made by TM? If so I wouldn't think a 2005 head would interchange.

To be honest I haven't got a clue, I was just told in order to fit the Transformation kit I wanted I either had to trim down the cooling mount on the head on my 1997 or get a later year cylinder head, I did call GasGas UK but the Tech guys were unsure if it was possible as they had not worked on such an early bike, I think if theirs no one here that has done this I would probably be betting getting someone to trim the cooling mount for me.

pics
 

Any pics I have an early head and I could probably tell you if its a gasser any way

I will get some pics on later today, cheers

I'm pretty certain the 97 motor is a GasGas motor. The earlier models were TM motors which had TM casting markings.
http://www.gasgasmuseum.com/
96 was the start of the GG motor. The GG 125 was TM motors .

GG head to GG head should be a straight bolt on. Don't know about the squish clearance, width, or angles, and trapped volume would also have to be checked. I'd say its probably easiest to just have a machine shop skim the cooling mount.

I have spent the morning phoneing round GasGas dealers, I have been told that in 2000 the head changed, but no one can give my any info on how it would affect the engine on my bike if added a later head to my bike, I was offered a S3 head ? I think I'm going with Jakobi advice on this and just get cooling mount skimmed, cheers for everyone's help.

In my prior post to you I stated that you can use a cylinder and head from a different year without any problems. But, you need the cylinder, head and coolant intake. The PV pieces are the same. GG used TM motors prior to 97'. Then continued to make subtle changes to there own design until present. What has always remained the same is the bore and stroke. With maybe some changes in porting. The guru's will chime in at this point and make any corrections?

Apologies, desertgasser300 I miss read your post.