Looks Can Be Deceiving? Rebuilt or NOT? Mikuni BS38 innards - PHOTOS

Im still contemplating whether i will rebuild these carbs. took them off the bike today and had a look at the floats, float height, etc. Im not expert, but these look CLEEEAN to me? Anyone care to differ?

Prior to removal, the bike was surging, then that stopped. Now it just sounds a bit boggy when I ride, not clear, but the spark plugs look ok. Maybe the needles and seats are shot?
 

Look into the bowls where the pilot and main jets are.



 

Clean as a whistle:
This is how the bowl looks when I took it off. I did not wipe it clean or anything. Came out as is.

See the scale crud on the overflow pipe?  That same crap is quite likely inside the internal passages on the carbs.  NOT CLEAN.

Ah, thanks so much for your guidance. I thought clean bowls = clean carbs.

Also, in the second foto you can see quite a bit of scale on the carb body, especially above the left side of the float.

what causes that to accumulate? is there any additive I can use to stop that from happening?

Unless you live next to an ocean, all you need to do is get the carbs really clean to start with, then just ride the thing regularly.

between me and the previous owner. these carbs havent been cleaned/changed in 5 years. not bad Id say! I do let the bike sit sometimes but not longer than a month/2 weeks. I put MMO in the fuel too and somes the Lucas fuel additive. Ive heard about star tron to or whatever its called.