850 experts...

[tkent02]

Making my '78 750 into an 850, have cylinders and pistons from a '79 850, have a head and set of carbs from both a '79 850 with VM carbs and a '81 or so 850 with CV carbs. I would rather go with the CV carbs, I know CVs work better at altitude. I live in Colorado and almost all my riding is between 5,000 and 14,000 feet elevation, with an occasional run down near sea level.


My question is, is there much difference power-wise between the two styles?

Much difference in throttle response?

Anything else that would sway me towards the VMs?

The engine, intake and exhaust will be stock except for the displacement.


Thanks.

[psyguy]

vm carbs offer more adjustability than cv carbs
if you're running stock airbox and exhaust i'd go with cv carbs as they are simpler to adjust

[bwringer]

I'm pretty sure you'd also need the airbox from a later model if you want to use CV carbs.

The later models with CV carbs do have a bit more power, something like 5 hp, but there's certainly nothing wrong with the VM carbs. As noted, they're a bit easier to dial in if something is non stock.

I've ridden to Mount Mitchell (6,684 feet) on my GS850 (83 model, CV carbs) several times, and it's always performed flawlessly at higher elevations. However, the guys with VM carbs didn't seem to have any trouble either. I don't know how much of a problem this is.

[tkent02]

Big problem over 10,000 ft.
Thanks, think I will go with the CV setup.