Mikuni BS34: plugs covering pilot jets missing

Yesterday I received a set of Mikuni BS34 carbs for spare parts for my '82 KZ750R. Upon disassembly I found that the plugs covering the tubes where the pilot jets are located (for the lack of a better description) are missing. Pilot and main jets are the original sizes (37.5 and 110).
Is there any point in such a 'modification'? How is the tune of the carbs affected by this? I guess I'm going to replace those plugs anyway but your input is highly appreciated!

Greetings from Germany,
Stephan

I have similar type plugs covering the pilots on the Keihin CV34s on my 750 and I would'nt even bother using the carbs without the plugs. Just by replacing the O rings on those plugs and making them fit better gave me better running.

I dont know why someone would remove them.

Welcome to the forum !!!

Thanks a lot for your input! And this was indeed my first post on this forum. As KZ750- and carburettor-newbie the sheer amount of carb-related postings on this board threw me off when I first started to look around here... Should have taken that as a sign but after all I start to catch up on things.

Stephan

Some versions of the BS34 have the pilot jets drawing gas via a side passageway into the main jet well. These must have a plug to ensure the pilot system doesn't run rich. Perhaps plugs are available as part of rebuilt kits. I am not sure. Keep in mind that these plugs need no fit really tight as there is a stop fitting inside the float bowl that puts pressure on the plug when the bowl is fitted in place. Suzuki models use rubber plugs and I suspect these would work fine on your bike and the rubber plugs are available via places like www.z1enterprises.com - You will likely have to contact them directly as they may not list them on their website.

Thanks for further clarifying the topic. It seems my BS34s are drawing fuel via those passageways into the main jets like you wrote. This would explain the previous owner setting the mixture screws way to the lean side to compensate for the missing plugs. And he was telling me, his bike ran great. Yeah well, I guess I better fit those plugs anyways
Thanks a lot!