I am close to completing a rebuild of a 1976 Guzzi T3 but found this bit in one of my boxes of bits I took off it and which I cannot remember where it goes.
It has a Single ball bearing in it as if it is something to do with venting the engine or gearbox  It is a collard aluminium tube about 20mm long and about 15mm dis
Anybody got any ideas, I have a photo but cannot attach it Doh !!!Â
It’s for the engine breather and goes in the pipe sticking out of the top of the engine block before the breather hose goes on. Not all come apart for cleaning and you need to make sure it moves freely.
I would have thought difficult to put in upside down but I guess someone would try! It drops into the large metal pipe and the outer rim at top edge holds it up.Â
I’m guessing yours may have a plate with a square hole at the top? Pic John showed is the ‘new improved’ style.
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A word of warning, if you are using a le mans style air box instead of the original set up, make sure you bend up the flap valve at the top of the big inlet pipe on the air box or you will have venting problems.