Pincheck
Hi, I've just bought an 851 from 1989 and on filling it with petrol I find the tank breather acts as a siphon and dumps fuel all over the floor. The breather is inside the tank and should (I presume) have some sort of flow restriction or one-way valve at the end (the thing at the end of tube No 5 in the attached diagram). Unfortunately, mine just has an open end. Does anyone know what that part is supposed to be or where I can get one from?
Thanks
nine16
I suspect the more likely culprit is a loose or dislodged line from the cap vent, outgoing, or return.
Pincheck
There is no cap vent as such on my bike. The breather comes in under the tank, via a feed through into the tank and then up to a bracket on the underside of the cap mounting block. On my bike the breather "valve" was a home-made open-ended piece of 15mm copper tube rather than an actual valve. I assume this should be a flow restrictor or one way valve as shown on the diagram. This is the part I'm trying to identify.
mst4
My 1989 model with the alloy tank just vents via a breather tube with no attachments,as far as I rember there's a hose that joins the underside of the filler cap(inside the tank) and it breaths through that?
SP128
I believe "b" and perhaps "a" have one-way valves, while "c" is open. In the tank of my 1990, much the same as the diagram, "5" is a metal pipe feeding the outlet "c" from a drain-off (if fuel present) or breather (perhaps, if not) opening at the top of the tank (about at the cap). An open rubber/nylon fuel line that simply runs down the right-side of the engine, behind the clutch is fitted to the outlet. No fuel comes out of that line, which can probably be run to wherever you prefer, unless the tank is too full--if topped off above the base of the rubber insert below the cap with the bike standing straight. Expect that something--the metal pipe, perhaps--is disconnected or broken below that point, which is allowing fuel to run directly out of outlet "c" from a much lower level.
