Engine oil level and crankcase thread kinda

I have read as many threads as I can find that talk about the engine oil level and its effect on the blow by getting into the air cleaner box. I bought a new to 2015 Grisso with 1600 miles on it and unfortunately got into a mountain bike accident and won’t be riding for at least another six months due to broken everything, so that gives me time to come up with a solution because from what I read, even when the engine oil level is at an appropriate level, there still will be blow by an oil will accumulate in the air cleaner box and will drip out of the air cleaner, box and onto the engine Because The box is a sandwich oil seeps out between the seams. My big question is; has anybody ever found a mini oil catch can and installed it in line between the crank case vent outlet and the Air filter box. I have one of these on my 2022 GMC 6.2 L truck and it works great especially considering that the truck is direct injected so there is no fuel wash over the intake valves to clean that oil off. So back to the mini catch can approach, I’ve only seen big billet units that are used on Harleys, but I’m looking for something small and lightweight that I can mount Somewhere convenient for servicing. If nobody has done this and I move forward with it and it works I’ll post here and let you guys know.

Well, there will always be a small amount of particulate oil that will be expelled with the gas vented from the crankcase. If the level is kept correct and there is nothing wrong with the motor though it will be caught and recondensed into liquid form in the breather box located behind the steering head and drain back to the sump through the condensate return hose that enters the sump next to the oil drain plug.

Yes, there will be some tiny amount that will still get into the airbox and then be burnt but it is infinitesimally small and in reality barely dampens the entry point on the upper right hand corner of the airbox.

If the sump is repeatedly over-filled it will keep pumping the excess out and this will end up in the airbox but the forward, central, drain is there to allow any excess condensate to drain into the hose, which is clear so it’s visible, down by the right hand foot peg which is capped so that, as well as preventing the ingress of dirty air, also allows it to act as a reservoir for the excess condensate.

Putting in a catch bottle is basically unnecessary. On the 1400 Mark added another condensor tank but it’s real purpose is mainly to increase crankcase volume so the pressure differentials at higher RPM are less pronounced resulting in less particulate matter being expelled. Worrying about carbon build up on the back of valves is unwarranted unless you chronically over-fill your sump.

Pete I can’t thank you enough for the detailed explanation I was unaware there is a system to accept and return oil to the sump. I was under the impression all of the vented oil/particulates went only to the airbox and there was no return to the sump. The bike is on its service stand in the garage and I will be doing a full service because it has been stored for many years and while doing so I will make sure to fill the sump properly and clean out the air box and drain the plugged lines below. I should be Good to go. Again thank you because I am new to a GRiSO. I owned V-11 sport and 74 Eldorado (should have never sold) and a Quota. Then got off track to Ducati so I am happy to be back home with a Guzzi. Can’t wait to ride it in a few months. Now it is time to make it my own as it sits and looks at me.

If your bike has been inactive for long periods it is well worth checking the condition of all the hoses as they are prone to cracking and degradation, especially in hot and dry environments.

There are two from the back of the heads to the condensor box, the one from the condensor box to the sump, one from the condensor box to the airbox and the condensor box also has a rubber ‘Condom’ on a redundant spigot that is prone to degradation and leakage. There is also a hose from the airbox to the stepper motor.

The airbox also has two clear drain hoses that are fracture prone as they are made out of crap. One from a central spigot in the middle of the front of the airbox and one from a spigot at the rear on the left hand side that can be seen exiting a cutaway in the ‘Under-mudguard’ just behind the shock. Both these hoses should be installed, unbroken, correctly routed to a clip just inboard of the riders right hand footpeg and capped to prevent undress of dirty air to the ‘Clean’ side of the airbox.

Thanks much I will add to my list of to do items over the next couple months. No riding so it will all get done before it’s maiden run.