So who built the frame for JP's Spanish Gp bike? We've established a definite connection between Schwerma & Bul in MX (not just short track) circa 71. We have what appears to be a factory built cro-mo frame from early 73 w boxed-in pivot area long before CMS's evidence for it. We DON'T see CMS splashing the claim they made JPs frame thro all their ads when it would have foolish business sense NOT to milk it for all its worth (like Bultaco did) if it were true. But we do have JP claiming his frame was US made.
The US journo (& amateur MXer), John Huetter who travelled the whole 73 season w JP reported:
"Pomeroy's pursang was painfully stock. The only change had been a cro-mo frame w stock geometry & some one-off betor shocks that had been built for this race". (He should have noticed that the rear hub was very trick for the time too.) He doesn't mention the frame being US made. Nor does Vic Allen when he said (VMX #7 p67, 2000) : "I ended up doing the 250s (ie GP circuit in 73) on a standard production pursang w the barrel tuned by Tony Dowe, now director of racing at Arrows F1 team. When JP broke one of the lightweight cro-mo frames I was given it & had it welde up". (He is in the pic of Spanish GP start in VMX3 p26)
Since Huetter also reports that JP got some special factory parts (cyl & crank) later in the season, obviously the factory was producing special parts. And much of it seeking lighter weight. eg the lightweight rear hub (pre-prod'n Mk7) & special lightweight shocks (JP said they were each over 1lb lighter per shock). There seems no attempt to portray JP's bike as a std pursang.
But lets backtrack to circa 1970 & the Joe Bolger connection. This is his 205lb M48 from 1970. He got it down from 232lb by ditching the bulky f'glass, using much smaller l'wt hubs & cr0-mo s'arm.
Here is Snr Bulto visiting Bolger in his shop:
Cycle World reported (Feb 70) "Judging by Bulto's interest, it seems likely that the company could incorporate some of Joe's ideas in future pursangs". Guess what got progressively got ditched in following Mk5&6 pursangs? - the boxy f'glass, the heavy hubs &... its likely the cro-mo frame was next to be persued by the factory itself, not via aftermarket frames. They had to be working on their own by then, cos it reached prod'n in the Mk7 which appeared in ?? late 73??
I don't think there's any doubt JP used a cr-mo frame in Spain 73, but where was it made? Were JPs claims (that it was US made) a case of trumped-up patriotic hubris about US expertise/involvement thats typical of the yanks?
I'm inclined to think that neither Schwerma nor CMS made his 73GP frame(s), but rather, the Barcelona factory did.
I hope it all makes sense. There's a bit more to come later.