i wondered why they go on about the jets as a starting point being so many turns out etc
I think your in the wrong thread
As Al says
balancing is adjusting the throttle plates not the air fuel ratio as such. Now the throttle plates will always leave a small gap and never close fully. The throttle plate basically allows a small mix of fuel and air into the cylinder as to allow the bike to run with no throttle. A carb balance is syncing the two
carbs together so the same amount of fuel and air is getting through the throttle plates so things are consistent between the two cylinders which in turn keeps things smooth with no out of sync vibrations from idle speed with no throttle to full speed wide open throttle.
Your right about the
carbs spitting back (fart) being an indication of too weak a mixture and depending at what revs and throttle opening one is at when the bike farts determines which carb circuit is the problem. 9 times out of 10 it will be the pilot circuit, especially if cutting out when coming to a full stop, or right on that crossover point onto the needles at around 3500 - 4000rpm. It's more critical to have a good balance at lower revs/speeds as this is where things are most sensitive to changes, especially with these huge twin cylinder
carbs/pistons.
A carb balance is last in the chain of command and as long as valve clearances are all good and the
carbs are jetted with the correct mixture and there are no intake or exhaust leaks, then a common solution to a carb fart and the simplest to adjust is to balance/sync the
carbs so is always the first port of call as this often solves/alleviates it.
As for being to lean blowing holes in pistons. With standard compression ratio, one would have to be running super lean for a very long period of time, and to be honest with the quality of modern day fuels with all their additives this is not so much of a problem as it used to be so there is very little chance of damaging things to that point from running lean alone.
(:-})
