Hello,
My '89 750 K model is down on compression, carbs are pretty well worn out, cams are pitted, etc.
IF I re-build this engine, I'm wondering if the following is possible:
Next size up in re-bore (if it's more than rings) & potentially smaller carbs, to change the torque curve? I'm after a bit more low & mid-range in preference to top end.
Depending on size, getting a newer set of same size (36mm) carbs would be ok with some jetting to suit.
Is it practical to run smaller carbs on the bike if the standard bore is retained?
I realise a 750 is only capable of so much, but I'd really like to move the torque curve down a bit at the sake of outright power.
What size bores are safely being used on the short stroke motor?
Running out of breath at licence losing speeds anyway would be fine with me.
I don't want to do that with gearing changes, I'm not interested in revving the bike excessively hard for no reason.
I am considering a Bandit 1200 engine, but need to cover all options.
I realise the larger donk, although interchange-able, has it's own particulars, but I want to explore my options.

welcome to the forums 89, by the sound of your motor it will cost more to rebuild than
move to a bandit -will give you all the bottom end you want, better low/mid range cams, bigger capacity , you can use 34-36 -38mm with the bandit whatever's cheapest .

89, have you found where the compression is being lost?
Valves or rings? Or both? How many miles?

The choice of bandit or rebuilding the original depends on what torque/ hp figures you will be happy with.

If your happy to tootle along at the speed limit a rebuild just may do.
I say this cause,depending on condition of the donor engine, a lot of guys would rebuild the bandit 1200 anyway before fitting.
You really need to know what is shagged with yours first.

Different styles of exhaust system, cam timing and carby settings all effect where in the rpm the max torque curve lies as well.

Eg: 4-2 exhaust, standard air box, cams timed in the lower ranges 104, 106, jetted to suit, your engine will make torque a lot lower in the rpm compared to say, 4-1 exhaust, air filter pods, cams at 110,110.

How is yours set up currently?

iff the carbs are pretty well worn out it's prob been around the block quite a few times