I've got a 95 750. It runs great, once it warms up. Seems to take a long time to warm up. Choke works fine. Starts immediately. Just cold natured.
I'm guessing that you are running a stock set up on the carbs..
Not unusual.. It's better if you put in some larger jets, but still a little cold natured..
The Magna can be a little cold-natured. If it didn't start up fast, I'd say check your valve adjustment.
Hoot's right about the larger yets. But if you have stock pipes, filter, etc. I don't know that I'd mess with the carbs until I had a dyno run or an exhaust gas analyzer report on it so you could see the lean and rich ranges.
Is your idle set between 1,000 and 1,300 rpms? (I think that's what the owners manual specifies but I hope I'm not getting that crossed with another bike.) The idle will increase as it gets warmer so you might want to make sure it's set at about 1300 rpms when it's warm. That way it will be about 1,000 rpms when its cold (and not choked). You might want to try that for awhile.
And a basic carb sync may not hurt. There's also the idle drop procedure but I honestly don't think I can do it by ear and I don't have a tachometer like the shop manual specifies. So I've never tried it.
They are a bit balky independent of ambient temp. It's not about how hot it is outside, it's about how hot the engine is. 90 degree morning in TX during August I'm still giving it a bit of choke first thing but not as long as when its below 40 in the winter.
The owners manual specifically states to lightly feather the throttle upon start up with the choke on until the engine is warmed up. For my bike this is an art. If I feather it correctly when I hit the start button it will start immediately and I can take off as soon as I back down my drive during the winter and push the choke in in less than a mile at highway speeds. If I screw it up, even during the summer that little cantankerous thing will sputter and stall without mercy until I get it right.
It's just the nature of the beast. Just remember a carbed gravity fed engine will always need a little choke to start after an extended period of not running. my v65s only need choke during the winter but they have a fuel pump. These are not fuel injected engines with OBC to automatically control fuel flow based on feedback from the engine sensors. Its 30+ year old technology that demands a soft touch sometimes and at other times a small sledge to persuade it.
1. I would leave my idle at 1000-1100 RPMs warm
2. IF the carb is clean, namely pilot jets/circuit
3. Turn Pilot screws out to 2.5 - 2.75 turns out.
4. If you have pipes and a freer flowing air filter, larger main jets will help overall
I have two '96 Magnas, modified substantially with aftermarket (read -- free flowing) pipes, K&N filters, reworked carbs as per Greg's post on the MOOT home page. In summer, I don't choke at all. Don't touch the throttle, either. Just turn turn the switch on and hit the starter. I let them warm up for a minute or more at the "cold idle" -- about 900 rpm. When warm, this moves up to 1100 rpm. I find that the machines are ready to ride when they get to 1000 rpm. In winter, I use choke, but leave it on only until they will idle without it. I also use a little fuel detergent (I go with the forum's preferred SeaFoam) occasionally, and make sure they get started and allowed to warm up every 10 days to two weeks. They start and run flawlessly.