Newbie question - Vm or CV carbs? preference please

[Guest]

Hello guys,

I'm new here and have done alot of reading through and searching and don’t think this has come up in exacly this form. (sorry if it has)

Essentially I have most of the parts for an 8v VM or CV carb system and have an "completish" 1979 engine of unknown history.


Which way would you go? Preferences please

Regards
Staple

[tkent02]

Where do you live? If you ride at only one elevation, VM carbs are the way to go. If you live or ride around large changes in elevation CVs are great.

[JJ]

If it's a '79 engine, with '79 heads, you are pretty much stuck with using VM carbs without making some semi-major mods to the intake tract.

[Staple]

Well CV is better then, any seconds on that? , I live in manchester UK, which has some pretty big riding hills up north, the lake district

Bit more detail
I have most of the bits for both systems - cylinder heads and all. Really only missing VM26SS carbs (+ engine boots) and the CV air box. ( people dont seem to chuck these very often - also I think the VM airbox is different inside so I cant just switch the boots.)

Cheers

[tkent02]

Well CV is better then, any seconds on that? , I live in manchester UK, which has some pretty big riding hills up north, the lake district

Bit more detail
I have most of the bits for both systems - cylinder heads and all. Really only missing VM26SS carbs (+ engine boots) and the CV air box. ( people dont seem to chuck these very often - also I think the VM airbox is different inside so I cant just switch the boots.)

Cheers

Don't think any of your roads are high enough for the elevation to matter much. 2500' or so tops? Doesn't matter.

[Staple]

My last 2 posts didnt appear . Have to use my phone.

True its nothing on what u can do in the USA , 125-3000ft is nothing on pikes peak 14000ft.

anybody remember which 1970s bikes used vm26's?

[Grimly]

Hello guys,

I'm new here and have done alot of reading through and searching and don’t think this has come up in exacly this form. (sorry if it has)

Essentially I have most of the parts for an 8v VM or CV carb system and have an "completish" 1979 engine of unknown history.


Which way would you go? Preferences please

Regards
Staple

I quite liked the VM carbs on my 79, preferring them to the CVs on the 80. Only thing I found was the tendency of VMs to waste fuel it you open them up too rapidly, but I soon developed the technique of pacing my twist action with what the engine could do. In contrast, the CVs felt a bit wooly.

[JTGS850GL]

Grimly: Care to define the word "wooly"? Just not up on that term.

Staple: If you have a 79 then the VM's are the way to go. They're period correct and would require no head exchanges with the engine you have. I wish you were in the US since I have a fresh set of VM26SS rebuilt and ready to go. You didn't say what size engine these would go on. The 26mm VMs were used on GS750, GS850 and GS1000s. As for what years used the VM v/s the CV. In the US the VMs were used up to 1980 at which point they all switch to CVs. In other parts of the world the VM were used for several years afterwards up to 1983 I think. US emissions required the change. Personally I like the smooth throttle, more predictable, response of the CVs but that's another discussion.

[Grimly]

Grimly: Care to define the word "wooly"? Just not up on that term.

The VMs were sharper off the mark than the CVs - not much, but hopping from one bike to the other on a regular basis, it was noticeable.

[uk gs nut]

VM carbs are all you will need around Manchester area, not much elevation change to worry about. I have ridden my GS1000 all over uk with VM carbs no problems.