convert back from mikuni to 2 amals

Tri-man said:

Fitting a dual carb set-up to a 1971 Triumph TR6 (small ports) for a customer nailed it for me. I've had many Bonnies including 71/72 model 650s, and they were no match for the twin carb TR6 at any speed.

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Another vote here for twin carbs on parallel port Triumphs, in my case 928s on an iron T110 head.

Probably when the inlet ports are bigger, you are more likely to suffer from loss of vacuum as you open the throttle. For a road bike, a single constant velocity carburettor might be better than two normal carburettors.

Deckard said:

Well, keep in mind that 750's have slightly higher compression, lower gearing and a lighter flywheel, so they'll always outrun a 850 from a roll on. Of course, mileage on each vehicle affects performance. My '71 750 was always quick, even quicker when I went to 10:1 CR after head mill to Combat spec. Kept the same cam and just added Dunstall silencers. Although silencers was an oxymoron.

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Out on the road and especially on the mountain passes, the 850 leaves the 750 behind fairly easily, in my experience, although it's just with one pairing.
That is with equal gearing, both machines with 21 tooth cs, both twin carb and near stock . The 850 is an Estart, so about 25-30 lbs heavier than the 71 750.
The 750 is fresh, the 850 has 26,000 miles.
On a 6 mile 8% uphill grind the 850 pulled ahead by about a half mile, both wot top Gear.

Glen

Equal gearing must put one bike at a disadvantage, regardless of the weight. I would not expect a 750 Combat to pull as hard as an 850. And I would not expect an 850 to have as much top end as a 750 Combat. What you are experiencing might depend on the length of the road. The 750 Combat is probably better on a long road where it has time to wind out.. If you road-race, it is often important to notice where you get passed - at the beginning of the straights or near the ends.