Jetting suggestions for VM22s on 740 kit?

[prichmon]

Would anyone have jetting suggestions for the 550 VM22s on a 740cc kit in a 650?

I was planning to run stock airbox or uni pods on vm22s with the stock 650e header if it will fit. No other mods.

Thanks

Rich

[Steve]

Looking at my chart, the 750s had VM26 carbs with 100 main jets. Not sure how that would translate with the VM22s, but it might be a starting point.

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[GregT]

It'll be high vacuum and high airspeed with the small carbs. I'd start with the stock 550 jetting and see how it runs.

[prichmon]

sShould I try to get ahold of a set of 77-79 750 vm26s?

[Steve]

Then you would have to find boots to fit.

Not sure if the bolt spacing would be the same as the 750 boots. If you ordered 750 boots, they might be the wrong length and/or angle, so I would not suggest them.

Look on the bright side. Having smaller carbs will give you GREAT throttle response.

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[prichmon]

thanks again steve

[93Bandit]

Looking at my chart, the 750s had VM26 carbs with 100 main jets. Not sure how that would translate with the VM22s, but it might be a starting point.

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I don't mean to highjack the thread but what chart do you have, Steve? I'm tearing down two sets of 750 VM26 carbs and both have 102 main jets. I have no way of knowing if the jets have ever been replaced, but I suspect they haven't since both sets of carbs have 102's.

[Steve]

The list I have started with a posting someone made here several years ago. As necessary, I look up service manuals to get jetting information and add that to the list.

At the moment, the only VM jetting info that I have for 750s is for a '78, and it shows 100 mains and a 15 pilot jet.

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[93Bandit]

Ah ok. Interesting; I wonder if they changed the jetting from 77 to 78? Mine is a 77. I'm not sure why they would change the jetting because as far as I'm aware the engines are the same, right?

[Steve]

I do remember hearing from a former member that there were jetting changes every year for the first few years, but the manual I have only has that one combination.

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[93Bandit]

Interesting. I wonder why?

[Chuck78]

Hey Richard, I'm just seeing this. Grant and I will try to come out to Newark and pay you a visit this week, FYI.

I see what you are trying to do, but you are best off running the 650E carbs. Was there something wrong with them? I take it you must not have held the vm22 carbs up to the 650 head yet, have you?
if I recall correctly, which I'm pretty certain I am, you would need some custom machined aluminum spacers to bolt on to the head to space the intake boots back 1/2 inch further, as the VM carb rack will interfere with the cam chain tunnel area bump out in the center of the head. No go. Run CV carbs from a 1980+ 550 or 650, maybe even a 750.
or perhaps if you really insist on the direct linkage carbs, run some GS750 VM26 carbs or KZ1000R VM28, but you will need a gasketed custom machined aluminum spacer to pull the intake boots back further away from the head approximately 13 mm. And the CV carb heads have a wider bolt spacing than the VM intake boots, except for one Kawasaki intake boot whose application I don't recall, so that adds to the complexity of machining a spacer.

[Chuck78]

A 22 mm carb on a high flowing engine will give you great low and response, but your top end power will be severely limited... It may even run severely a rich due to the extremely high air velocity through the small carb. A bit of a restriction...

[prichmon]

A 22 mm carb on a high flowing engine will give you great low and response, but your top end power will be severely limited... It may even run severely a rich due to the extremely high air velocity through the small carb. A bit of a restriction...

The 650E carbs came disassembled. I'll have to figure out if all the parts are there and reassemble.

Sent you an email. I'm off this weekend if you guys want to visit. Just give me a day and time to expect so I can make sure I'm home.

Thanks