I recently bought a '98 f3 that came from Arizona originally now resides in Colorado. When I took it to get rejetted for the altitude the mechanic noticed tiny holes in the carborator shutters...He told me that sometimes when you get an aftermarket jet you need to drill holes in the butterfly valves. The OTHER side where the wholes are...
On my bike you can see there are approx 24 holes on the first carb and approx 15 on the next one... prolly the dude figured out that he was doing it wrong. There are no holes on my butterfly valves.
Has anyone heard of this or come across this? I fixed the holes by filling them with epoxy and there is not issue now...

 

With your fix, do they slide in and out good?

 

The fix works great. I used JB Weld from Lowes... great $4 fix. Just had to sand the crap out of it but you can't tell there were holes there now.