"There is a madman lurking somewhere on this forum who would know"
Is that someone calling my name, perchance??
A TZ would kill that, better accelleration, lighter, more nimble, less thirsty.
130 BHP every day reliable from a properly built TZ750 (with not many Yamaha made parts in or on it!) - at least that is what mine makes. Possible to get 135, with more time and money that I could ever find.
IMHO The Irving is just an interesting engineering exercise, at over 1300cc (1440??) -don't know if its on methanol, it should produce lots of power, but that engine size excludes it from every (UK based) race class, however I don't know what the Aussie class limits are, so relegating the bike potentially to a 'special special' - so why do it.
The heads are the main problem, but in keeping it looking 'Vincent
' like they have just reproduced the heat problem that the originals have when worked hard - its fixable, but not that pretty!
I also fail to understand the 'Irving Vincent
' tag, I know they have a beef about PEI's recoqnition, but he was paid to design stuff, you don't see any castings dor Hopwood BSA, or Hele Triumph or Page Ariel, Irving Vellocette.........