hi guys,,i have become the owner of a gsxr 400 that needs some tlc,,its the old model gsxr 73 type i think,,anyway my problem is i took the carbs off today to clean them out and whilst cleaning i lost one of the rubber bung type things that sits over the idel jet,,are these rubber bung important for the bike to run right or would i getaway with one of them missing,iv never seen these in other carburettors before so i duno wot the consequences or affect it woud have running the bike without it,cheers for looking guys

Hi Kev,
You can try it with no bungs and see how it runs. They are designed to make the pilot jet get its fuel from the main system, not the float bowl- stops fuel surge under acceleration and braking so it maybe ok.

thanks for the quick reply variablevalve ,,, in the mean time since i posted this i put a spot of gasket sealer over the missing bung to seal it up just to have it right looking anyway ,,if the bike dont run right with that done il strip back the carbs again and remove all the bungs and see how it goes without them and post back results,,

gasket sealant will react with the fuel after a short period of immersion and will block the fuel flow. I would suggest you remove the sealant or you will have problems. Although they should run ok without the bung you may find it runs a little rich at idle aswell as what variablevalvessuck says

cheers stripes,,if i remove all the bungs,,is there a possibility i coiud foul the plugs on start up as i had similar trouble with a cbr nc23 lately,it was running rich on idel and was a fooker for fouling plugs ,,im only dreading the taught and the de ja vu that im after buying meself more trouble again lol

In my honest opinion i wouldn't remove the 3 you have remaining. I would leave the 3 you have got in and leave out the 1 you haven't. If possible i would leave it out of a middle cylinder as they run hotter than the outer cylinders so less likely to be affected by running slightly rich. If you can get me a picture of the bit you are missing and next time i am at my parents i'll see if i can find the old set of 73 carbs i have as spares there and i'll pull out what you need.