I had an inline filter get caught on the valve cover in such a way where it pinched the fuel line enough to cause exactly the same symptoms. Took off the filter and problem solved.
On 7/6/10, Scott McKinley <[email protected]> wrote: > After rebuilding the fuel valve on a '83 550, I applied a slight vacuum via > a hose and 60 cc medical syringe. You can observe the flow of fuel if > connected to the tank or "jerry rig" a fuel source. I recall hearing a > slight sound of the diaphragm as it moved back and forth. See attachment. > Scott > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of David Cummings > Sent: Tuesday, July 06, 2010 2:52 PM > To: [email protected] > Subject: Re: [Nighthawk Lovers] Re: Replacement petcock? > > I'm leaning towards the diaphragm being the issue - it still runs fine > at lower speeds - so not sure about the trash issue. > > I'll probably order the kit and pull it apart this weekend. Wondering > if I should coat the tank at the same time... > > -Dave > > On Tue, Jul 6, 2010 at 5:40 PM, surfswab <[email protected]> wrote: >> Sounds like the sustained high speed might have sucked some trash into >> it. Or there's hole in the diaphragm. Its purpose is to hold a >> "valve" open so fuel will flow for as long as there's vacumn applied >> to it. Insufficient vacumn, no -- or slow -- fuel flow. >> >> I would pull the tank and drain it, pull the petcock and disassemble >> and inspect the parts very carefully. Use a magnifying glass if >> neccessary to inspect the diaphragm for a split, a pinhole, or a >> tear. >> >> Clean the nylon screens meticulously. There are two -- one in the >> bowl and a "sleeve" that fits over the feed tube. And inspect the o- >> rings, also two -- one in the bowl and the other secures the sleeve at >> its base in the throat of the petcock. >> >> Check the vacumn supply tube from the engine to the petcock for >> leaks. And clean everything twice. Regardless of what you do or >> don't find, I'd install a rebuild kit. They're about $20. Your >> bike's 30 years old and the rubber's tired. >> >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups > "Nighthawk Motorcycle Lovers!" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to > [email protected]. >> For more options, visit this group at > http://groups.google.com/group/nighthawk_lovers?hl=en. >> >> > > -- > You received this message because you are subscribed to the Google Groups > "Nighthawk Motorcycle Lovers!" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/nighthawk_lovers?hl=en. > > -- > You received this message because you are subscribed to the Google Groups > "Nighthawk Motorcycle Lovers!" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/nighthawk_lovers?hl=en. > > -- Sent from my mobile device -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en.
