I have never been a fan of huge carbs perhaps its because the rules kept the pre 49 to TT carbs and that meant 1-3/16 at best I have opened a road bike to 32 and would goto 34 on a standard head with a Mikuni after that I think you risk making a hole in the head to the spring housing (but I have never tried it)
What prompts my thread is that last weekend at a CRMC meeting with Bens flying bricks we were camped next to a guy with a NOR Vel, and his 500 Velo push rod engine had the most enormous Mikuni. On discussion he said its 44mm thats almost 1-3/4 in real money! it was mounted very close to the head and had no belmouth (in fact all the singles on the minivation racing team in the nex bay had no belmouths on their Mikunis either)
I was a bit taken aback at the size but then I was even more perplexed as he started it up on the rollers and warmed it up not sitting on and going Blip...blar in the time honoured fashion, oh no! once running he popped it in neutral on the stand and let it tick over unattended, sounding for all the world like one of those stationary engines at a steam fair where you can hear every stroke, then after 5 to 6 miniutes he jumped on and rode off to the start as smooth as silk.
I think modern carburettors like Mikuni may have changed the game while I was not paying attention.....
What prompts my thread is that last weekend at a CRMC meeting with Bens flying bricks we were camped next to a guy with a NOR Vel, and his 500 Velo push rod engine had the most enormous Mikuni. On discussion he said its 44mm thats almost 1-3/4 in real money! it was mounted very close to the head and had no belmouth (in fact all the singles on the minivation racing team in the nex bay had no belmouths on their Mikunis either)
I was a bit taken aback at the size but then I was even more perplexed as he started it up on the rollers and warmed it up not sitting on and going Blip...blar in the time honoured fashion, oh no! once running he popped it in neutral on the stand and let it tick over unattended, sounding for all the world like one of those stationary engines at a steam fair where you can hear every stroke, then after 5 to 6 miniutes he jumped on and rode off to the start as smooth as silk.
I think modern carburettors like Mikuni may have changed the game while I was not paying attention.....