early 1977 carb question plus K&N filter question (not the pod filters)

[willycrash]

I'm newish around these parts, but anyway... I have a early 1977 GS 750 which already seems to run a bit lean with the stock pipes and filter. While I have been considering putting a 844 kit in it while replacing it's leaky head basket, I have already bought a V&H pipe and a K&N filter for the stock air box (sounds like pods aren't very easy to tune). From what I understand, my bike has the earliest set of carbs, which lack adjustable air screws that can be accessed by drilling or what not, so even if I can shim the needles with washers, I may already have issues trying to jet my carbs to the filter and pipe, much less if I went up on displacement or opened up the air box.

My guess is I might want to get a set of carbs from a later model, but hoping to avoid CV carbs or giving the bike an anachronistic look by putting obviously modern parts on it. That would seem to indicate looking for stock carbs from a 1978 model. It does occurs to me that I may be over thinking this, as V&H instruction sheet only mention going to 115 main jets and the K&N may not make all that much difference over oiled foam, but I think I remember that jet kits of the day always came with a drill bit for accessing the air screws, as well as pilots and adjustable needles.

It also occurred to me that there might be a more modern set of carbs that could still use the stock air box that wouldn't be overkill and would be easier to jet while still using the stock throttle cables i've already had shortened for the new super bike bars. My admittedly brief search of the archives doesn't seem to reveal any simple fix, but I would appreciate any advice.

My other question is, I wonder if there is any reason not to cut the backfire screen out of the stock filter frame that the K&N still uses?

 

[hannibal]

I'm pretty sure all Suzuki VM carbs came with adjustable air screws. My GS built in November 1976 has them. Can you post a pic of your carbs?

Pods work well on VM carbs, not BS carbs.

 

[Chuck78]

You may have KZ1000 VM26 carbs on there if they only have 1 set of air or fuel screws not both. Accelerator pump? What are the #'S faintly stamped into the carb near the choke plunger on the flange next to where they mount to the rack? Should be some like:
45
010

or
45
020

My June 1976 GS750 carbs here have both pilot fuel and pilot air screws, as should all of them 77-79

 

[Jyoungblood]

My ‘77 factory manual shows vm26 carbs. The breakdown shows the air screw on the outboard side on top of each carb. The fuel needle is not shown, only says “do not touch” And points to the screw head on a photo (it is on the bottom of the float bowl). I hear factory is 5/8 back on fuel and know that it is 1-1/4 back on air.

i know its an oldie, this is for others with the same issue.

 

[allojohn]

With stock airbox that’ll be about right.