MX125 and YZ125A

[TM BILL]

I really like this project Firko with the reed valve engine I go for 34 Bing and I will set it up for you.

Which project Mick? The Trackmaster 125 thing? It's to be a Klub Kevlar community project, everyone's pooling their resources and parts to get it together for next season.
Thanks for all of the info boys.....I'll look further into just what I've got and hopefully can get a YZ bottom end matched up to a good MX iron bore top end, the X model CDI, a decent 32mm carby, the NOS Vintage Iron YZ125A pipe I've got and pass it all along to Jonesy to finish off. If the bike looks as if it's going to be competitive we'll look into either whacking in some ports or fitting the 'FP' barrel.
Besides Webco, were there any other aftermarket heads made for the MX/YZ?
             
Below: the Trackmaster frame that'll be used for the MX/YZ125 engine
                                                         

Firko you can get DG radial heads and FMF porkepine heads for them , Most significant performance gain i got from my 125A was a GMC pipe 

[firko]

Firko you can get DG radial heads and FMF porkepine heads for them

As you can guess 125's are fairly alien to me, I haven't taken much notice of them since I briefly raced an MX125-B in the very early VMX days. Because of that I haven't taken enough notice of what you can or can't get for them. I knew about the Webco head because I had one on mine but I don't ever recall seeing an MX or YZA fitted with DG or FMF porcupine head. I'd love one of those cool porcupine heads if anyone's got one up for grabs but I suspect that they're pretty rare. A mate had one on his Elsinore 125 and I recall him gloating about finding the 'holy grail' of heads .

[Slakewell]

Yeah Firko the pre 77 125 project