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1977 GS750--cv or vm?

  • Thread starter Thread starter wkmpt
  • Start date Start date
W

wkmpt

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I've been searching for a few hours now, I haven't found the answers I am looking for, so I'm starting this thread.

I just purchased a '77 750, has the stock carbs installed, running MEGA rich, and the seller threw in a set of carbs from an '81. Assuming that I will have to rebuild either set of carbs to use them, my question is which carburetor would be a better candidate to put on the bike? Is there an advantage to one style versus the other?

If it matters, the exhaust is stock, but the bike has individual filter pods and the stock airbox is non-existant. Ignition is currently points-based, but I plan on replacing it with a solid-state one on very soon.

Input? Thanks in advance.
 
VM, way better unless you ride where there are huge changes in elevation.
Much easier to tune for those pods with the VMs, quicker throttle response.
 
I don't have as much experience wth VM carbs, but I can say that you will have to do some other mods to use the '81 carbs on your '78 bike. The CV carbs are bigger, so the boots would be bigger, as well. Not sure about the ports on the head, though, so I don't know if it would be as simple as getting a new set of boots.

Either way, it would be cheaper and probably easier to just rebuild the VM carbs.

.
 
I think of CV carbs as vacuum computer controlled throttle carbs that will not open the throttle until the right conditions are met. I like to control the throttle by my right hand. I know when I should not open it all the way. Dan
 
The VMs are the only that will fit that set up as it stands. Its POSSIBLE to fit the BS32 (CV) carbs, but you will then be left with a decent amount of tinkering to figure out exactly where the propper jetting set up would be etc (the 8v head doesnt flow as much as the later 16v head, etc etc) at any rate, I would suggest you DIP and CLEAN, and use NEW ORINGs on your VMs, and go with that. If affixing a pipe and pods, we can help with ballpark jetting suggestions, but you will be forced to fine tune on your own...
 
VM carbs are stock for 77-79. CV's apeared in 1980 for the 4cyl bikes, more due to new emission rules along with bigger intake ports. I don't know of any intake boots to fit CV to the older head, so anything would be custom. Besides the VMs are less trouble
 
rustybronco said:
What main jets are installed in the VM's now?
Click to expand...

The guy I bought it from thought there were #115 jets in there, but he couldn't say with 100% certainty. I'm picking up the bike this weekend, so I'll know more then.
 
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