1979 GS1000E Carbs

[Dalisword]

Hi, I have a 1979 GS1000E. I have the same problems posted in the engine drivetrain forum but I was thinking the carb experts could help too. Upon starting my bike it pops like popcorn going off in the exhaust. I have come to the conclusion it is running lean... BUT after riding a measly 100 miles this year (in one afternoon) it suddenly started sounding more like a buzz than anything and it has no power. I think the carbs are plugged so I am going to completely dip and clean everything. The only problem is there is a little confusion on what my carbs actually are. Everything I come across says that my carb should be a Mikuni VM26SS. Every picture of the VM26SS's I find shows a screw on top for the carb body. Mine is 4 bolts which to me seems more consistent with the pictures I have seen of the VM22SS series. the only numbers I can find on the carbs are on the engine side and they say 490 over 20. Can anyone identify what I have? P.S. I measured the head side opening and came up with the measurements for the VM22S's. I'm going nuts trying to figure this one out.
Something else I am curious about. The previous owner put a 4 into 1 exhaust on it but didnt do anything to the carbs so I am thinking about going up a size or 3 to fix the running lean issue. But I cant find any markings on the jets. any suggestions on jet sizes? I also have a foam filter for it but took it off when I did my spring rebuild and replaced it with a paper filter. Any help would be greatly appreciated.
Thanks
-Dali-

I wrote you a novel, and didnt even think about pix... These are my carbs, I just took the pic

[Nessism]

Take photos. Upload to Photobucket.com. Load [img] code here in body of post. Photos will show up in HIGH RESOLUTION, just like magic. Once we can see the photos we will tell you what you have.