Possible to modify gsx250 cylinder head to gsx400 specs??

[Guest]

Apologies if I'm doubling up on some questions but now that a fire has been lit under myself and this thing I'm wanting to get as much info as quickly as possible (I also enjoy sugar laden soda pop for the similar effect...) Anyways, I'm wondering if it's possible to modify a gsx250 cylinder head to take the same sized valves as it's larger 400 cube relative?? From what I can see the stems etc are the same size but I'm not entirely sure if theres enough room between the seat for it to work.

I want to try and upgrade a 2 valve per jug 450 to use a 4 valve head, but all I have to hand is a gsx250 unit. Added to this I'm kinda hoping I can also take the 450 out to a 500 and who knows mebbe even use the longer stroke crank used in some of these low/mid capacity GS's...

Answers on the back of a postage stamp folks

[GregT]

Just take the 450 out to 500. Well worth doing and quite easy.

[Raffspeed]

Hmmm, but aren't the 500s 2 valve per cylinder setups as well?? I was hoping to get the use of a 4 valve head, or is there not much benefit to doing this?? I have read that thanks to the relative youth of 500s the parts are readily available and cheap. Would I also be able to use 500 pipes?? I actually originally bought this engine and frame thinking it was gsx400 stuff but it seems not...

[Raffspeed]

And I just realised I put this in the 4 cylinder section (I'm guessing I thought it was the 4 valve section...)