Somebody edumacate me on this

[marcmorrison]

I think this must be where unburned exhaust in the rocker arm/valve cover is routed vis-a-vis a fuel type hose away from that area...however, I can't find anything that specifically identifies its function and just wondering what it is???  I've been replacing various fuel lines on a '99 Bassa, came across this hose (actually one to each cylinder), but it looks like they simply connect to the frame; went ahead and replaced both hoses while i was there, but now curious as to what they might be???

[bmc5733946]

Oil breather.

Brian

[Scout63]

Looks like a breather line port.  Routes excess rocker arm oil back to the sump via the air box if it’s anything like an old small block. Smarter folks will come along.

[lucky phil]

I think this must be where unburned exhaust in the rocker arm/valve cover is routed vis-a-vis a fuel type hose away from that area...however, I can't find anything that specifically identifies its function and just wondering what it is???  I've been replacing various fuel lines on a '99 Bassa, came across this hose (actually one to each cylinder), but it looks like they simply connect to the frame; went ahead and replaced both hoses while i was there, but now curious as to what they might be???

As others have pointed out it's the rocker area breather hose.

Ciao

[marcmorrison]

Guess I was on the right track...sorta llike a PCV valve, but what struck me as somewhat odd was that that hose routes back (attached) to the frame.  What does this ultimately accomplish if those exhausts simply end at that point and are not routed back to the air box for recycling??  Am I missing something here??  My "inquiring mind" at work!!

[lucky phil]

Guess I was on the right track...sorta llike a PCV valve, but what struck me as somewhat odd was that that hose routes back (attached) to the frame.  What does this ultimately accomplish if those exhausts simply end at that point and are not routed back to the air box for recycling??  Am I missing something here??  My "inquiring mind" at work!!

Not really, more like a vent for the rocker area to evacuate moisture laden air from the high point of the engine and help prevent "mayo" forming there. On a spine frame bike it vents back to the main crankcase which in turn vents to the frame backbone which vents to the airbox and any separated oil drains back into the sump from the spine.
A PCV system draws crankcase cylinder blow-by and depending on the engine configuration crankcase volume fluctuations back into the inlet manifold on closed and partial throttle and not so much on full throttle and not at all "on boost" for turbo/supercharged engines and recycles it.

Ciao

[aklawok]

 Is it possible that this is actually an air intake for crankcase ventilation and not an exhaust? makes more sense.

[lucky phil]

Is it possible that this is actually an air intake for crankcase ventilation and not an exhaust? makes more sense.

Nope

Ciao

[Scout63]

Is it possible that this is actually an air intake for crankcase ventilation and not an exhaust? makes more sense.

You don’t really want air going into your crankcase since the downward stroke of the piston is pressuring the case and if not released tends to blow seals (not those kind). A one way PCV valve or breather valve allows air out but not in. On the big blocks it can be in the breather box or a ball valve coming out of the case. The rocker arm breathers are sometimes blocked off by owners - I keep them as built by the factory.

[marcmorrison]

Thanks for enlightening me....I feel much better now!!

[Tom H]

They also let the oil drain back into the engine from the frame.

I have had mayo in those lines. PITA to clean them out.

Tom

[jacksonracingcomau]

They also let the oil drain back into the engine from the frame.

I have had mayo in those lines. PITA to clean them out.

Tom

What he said

Other Guzzis have oil return to sump (behind clutch on roundies, external on spinies and small blocks)
90’s cali’s don’t, the only place for condensate to settle is at the lowest point, let’s call it a water trap

For OP in Texas, shouldn’t be a problem but pages and pages of mayo posts on this forum to read if interested

[marcmorrison]

A water trap inside the frame doesn't sound like there will be a good outcome.....hopeful ly that will not occur during my ownership

[Chet Rugg]

on Bassa it starts at the crankcase vents up  large  S shaped hose to frame up front goes down inside of frame goes to small lines that go to rockers.  crank case vent returns back into rockers simple.   Oh yea ball valve at bottom of  S hose where it hooks to crankcase letting it vent one way







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