I would agree with Steff750, back in the 70's big bore kits were all the rage and there were many questions about upsizing the jets.
The thing is, if you alter the exhaust, you generally need to alter the jets to compensate for the loss of back pressure. When my 750K1 exhausts rotted and fell off I fitted Dunstall four into twos, and the correct jets came with the kit. The bugger then gobbled fuel, ran ok but really did not go any quicker as Dunstall would have you believe.
If you are increasing capacity, but are not increasing the choke diameter, then there is little to gain by changing the jets. The bigger pistons will suck more air per stroke, but the carbs will simply supply the correct fuel/air mixture according to demand, that's what carbs do. It does not matter whether x amount of air is being demanded by a 736 or 836 motor providing that the choke size can cope with demand, which it can. If you were to go track racing, and wanted peak power then you would mod the intake and put larger carbs on.
If it worries you, check the plug colour after some use, if you feel that the motor is running a tad weak you can always lift the needle jet one notch but I think you won't need to alter the carbs at all for normal use.
