Oil from blow back reservoir.

Afternoon all. My 5k mike GRiSO has just started to push out oil from the ‘blow back’ reservoir and spill out down the engine casing. . It appears to be coming from the fat cloth reinforced pipe which is itself soaked in oil.   TBH I am not familiar with this arrangement and am not sure where to start. I have also checked the pipe coming from the air box that exits under the bike and that appears to be full with oil   I have removed the plug and emptied it. There is oil residue on the air box itself that looks to be pushed out by pressure perhaps. Would it be fair to say I have a blockage somewhere and any insight as to where to look first.  Also, do I have to remove the fuel tank to gain access to the blow back reservoir? I have pics but am on my phone and unable to upload them here right now.

Cheers
Steve

Edit.  I have just read Pete’s very helpful description on how it all works on Guzzitech but still wouldn’t mind knowing why it has done this and how much of a ball ache is it for me to fix it. Ta.

Hi Steve; most likely is a cracked/loose rubber pipe (12 or one of 16) or failed condom (17) around the blow-by reservoir - I've had condom fail due to rubbing against the frame & oil dripped onto the cam covers. If you can't see where it comes from with wings off then you will need to remove tank to check. Doubt it's a blockage anywhere; it's normal to see some oil in bottom of air box and even if the drain pipe fills it just means more on air box floor.

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Thanks a lot for the diagram. Really helpful.  And bugger, I’ve got a proper task ahead of me.   I’ve removed the wing and the fabric on pipe 8 is sopping wet with oil but I couldn’t say for sure where it comes from. It looks like it could be the feed (pipe 16) from the LH cylinder pissing down over pipe 8.l, or as you say, the condom. Is that some basic pressure regulator type of thing? It would make sense if that has broken as the pipes all looo pretty secure (as far as I can see). Probably taken it’s time to saturate the cloth and now it’s dripping. Man, I’ve read about the ball ache involved to get the tank off.  It’s only three years old and I’ve found some other rubber that’s perishing too.  Biggest drag for me is that I live in London but have to keep my bikes at my folks as I don’t have anywhere to keep them in town.  I can’t just do it over a few evenings after work

There's no back pressure regulation (it just runs with inlet vacuum pull & blow-by push), condom is just a blanking thing as this connection does something else on other Guzzi variants but not used on GRiSO. You could try getting phone with flash in the space and doing some pics to see layout of land first.

Tank is not too bad once you've done it few times but nyloc connection can be tough first time (spray or lube it before refitting) as it's a 'technique to un-couple...& care needed to avoid pipe kink as you lift tank...some guidance in forum.

Mine is 10 years old and not much perished in pipes yet....seems variable quality. Good luck & let us know any other questions Paul