CV vs VM vs Ktana carbs?

[Crazy_Russian]

Advantages and disadvantages? Power? Fuel Consumption? Reliability?
My base is a 78 GS750. What dose it take to convert to CV's or to Katana carbs?
Thanks in advanced guys

 

[Spyderman]

you'll need to change the head to a 80 or 81 850g head that will take the CV carbs honestly your better off just doing a full rebuild on your VM's that came on the 78 and tuning them right and tuning them right can be easier if its stock and a bit harder if you have pods and a pipe on it

 

[tkent02]

Living in Albuquerque you would do very well to switch to the CV carbs, as they compensate for changes in elevation. I live in Colorado, CV equipped bikes are MUCH better to ride up in the mountains. You need the head from a 1980 GS 850, as spyderman said. While you are at it go with the 850 cylinders and pistons too, for an extra 15% displacement, also a good idea to help with the elevation. It's a bolt on swap if you have the correct parts.

Power is better as the carbs are bigger, especially at different elevations where the VMs don't meter fuel correctly. Since the fuel is compensated for elevation changes the fuel mileage is better, reliability is better.
There may be a very slight delay in throttle response but it can be tuned out. Also you can just open the throttle, even up at 12,000 ft. or so without the engine bogging out. No more need for feathering the throttle to keep the engine working as you climb.

 

[Crazy_Russian]

cool, thank you guys!
So im looking at:
80-81 GS850 Head
80-81 GS850 Cylinder block and pistons (any other years that may work? also cams?)
Rods and crank are the same i assume
Head to carbs adapters(x4)
what else am i missing?
Spyderman, i will be rebuilding these carbs, but, I'm at 5500 feet above see level and i take trips where i will +/- 2000 to 3000 feet in a day, and standing on a side of a road playing with carbs is not something i like to do. aslo i would like to get more power out of this bike, and my MPGs suck, and it takes me 10 to 15 minutes to warm the carbs up before they stop boging down... all this combined causes me too look in to a different direction for a batter solution then what i currently have

 

[SqDancerLynn1]

A bump in compression would help with the thin air at 5K ft. Yes you are running rich with the thin air. I was going to Yosemite many years ago on a 73? Honda 750 AT one point (Tioga Pass, elev almost 10K ft I thought I would have to get off and push it the rest of the way it had lost so much power

 

[Crazy_Russian]

what are some of the ways to raise compression on these motors?

 

[GS750]

what are some of the ways to raise compression on these motors?

Either hone + re-ring and lap valves,
or
bore and hone + oversize pistons, multi angle valves + seats