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Please ID these carbs!!!

  • Thread starter Thread starter jeepenstein
  • Start date Start date
J

jeepenstein

Guest
Hi guys and girls, my recently purchased 1980 GS 1100 E apparently does not have the OEM carbs on it. I ordered a set of K & N filters for my bike and low and behold they are huuuuge compared to the inlet side of my carbs. The ones you see in the attached pic are 44mm on the inlet side. I don't know much else about them. Take a look at the pic and please help me ID them! Can anyone tell me what bike they originally came from?

Thanks! BUBBA

DSCN1616.jpg
 
Those look just like the carbs on my '79 GS550L, which are the stock VM carbs.
 
Hi,

Definitely Mikuni VM carbs, but what size? VM29?


Thank you for your indulgence,

BassCliff
 
They look like VM29's. Do the float bowls have a 17mm hex head drain plug?

Assuming they are VM29's, they are far better than the stock carbs. They were not stock on any motorcycle, just sold separately as a performance option from Mikuni.

Have a look at this link - halfway down the page are pictures of the VM29's from different angles.
http://www.z1enterprises.com/reference/z1-carb-guide.aspx
 
Ok that's a good start! How would I go about Identifying the actual model of the carb? Any specific things I can go by? Like bore size etc? They seem to run fine, Plugs are a nice tan color and no lagging and/or bogging. How do these compare to the OEM performance wise? Are they better than OEM flow wise etc? The previous owners of this bike have done a few odd things here and there that I am sorting out as I go. This is one of those things.. haha.. Thanks again guys!

BUBBA
 
The GS1100's were all equipped with Mikuni BS34 CV carbs, it is quite unusual to install a rack of smaller VM29's smoothbores on a GS1100. The person who performed this operation also installed a different intake manifold boot to make things line up. He must have preferred 29's because the normal performance carb upgrade was a set of VM33's s/b.
 
Last edited:
Yep, they have the drain plug as mentioned... Thanks for the link also.. That appears to be what I have.. Thanks guys!


BUBBA
 
srsupertrap said:
The GS1100's were all equipped with Mikuni BS34 CV carbs, it is quite unusual to install a rack of smaller VM29's smoothbores on a GS1100. The person who performed this operation also installed a different intake manifold boot to make things line up. He must have preferred 29's because the normal performance carb upgrade was a set of VM33's s/b.
Click to expand...

If it's a stock GS1100, the 29's are probably the better choice. They give crisper throttle response in the lower RPM. On the drag strip, the 33's will get you down the track faster, but talking with many customers, the 33's seem to suffer with poor transition through the lower RPM range on most bikes.

Once you get over 1100cc, the VM29's are really too small.
 
I intend to strip the bike down this winter and do some "upgrading" in the process. A larger bore and some mild head work is in the plans... I guess New carbs will be a requisite as well.. haha..

BUBBA
 
they are deffinitely VMs..take them off and measure the inside diameter of the throat thats towards the engine and that will tell ya what MM they are..then they would be VMxx...whatever they meausre.
 
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