Petcock is easy enough to test. Disconnect the fuel line from the carbs and the vacuum line. Use a syringe to apply gentle pressure to the petcock, see if it flows, see if it holds the vacuum or if it slowly goes away.
-Kyle On Thu, Aug 26, 2010 at 10:06 AM, Kurt Nolte <[email protected]>wrote: > Javier, > > It could still work with the "leaking petcock diaphragm" theory. When > you let the bike sit for a while, a slow leak has a chance to put out > enough gas to cause a starting problem. Once that gas is dealt with by > your initial difficult start, subsequent starts without a long wait > will be "problemless" because the leak hasn't had a chance to move > enough gas. > > If you don't have the problem again when you go home from work > (several hours from now, unless I'm mistaken), then you indeed have a > somewhat confusing issue. > > It's possible that suddenly having to use the petcock more often could > have caused a small tear in your diaphragm... thus the sudden onset of > the problem without much warning. > > That help at all? > > -Kurt > > On Thu, Aug 26, 2010 at 10:39 AM, Javier Garcia <[email protected]> > wrote: > > Hi guys, > > thanks a lot for such educational answers. Now I am a bit more confused > than > > yesterday. This morning I checked again for leaking. Nothing. Engine, > parts, > > and garage floor all very clean. I went to start the same way I always > do, > > no choke (at least not this time of the year), and no gas. It tried to > fire > > up a couple of times, but not quite there yet. I had to give it a bit of > gas > > and then went on. Just a bit rough at the beginning, but mostly from > being > > cold. Putted my gear on and the bike is idleling perfect as usual. Took > it > > outside and I turned off because I forgot something inside the house. > Came > > back, hit the start, and fire up without giving any gas. Lucky I guess. > Came > > to work, and I did not experience any of the symptoms from yesterday. > Pulled > > over in the parking lot. Turned off. Hit start and it fired up > immediately > > as usual. Tried 4 or 5 times consecutively. The same. The problem is > gone. > > > > Now, according to the general consensus, the diaphram in the petcook > could > > be responsable for this issue. How does this scenario fits now? I > actually > > was thinking what I have done differently recently, and one thing is that > > since my speedometer cable broke, I cannot calculate the gas level, and > thus > > now I wait until I am empty and I have to change to reserve to go to the > > station and fill up the tank. The difference now is that I am using the > > petcook more often, swiching between tank and reserve. Before, I pretty > much > > never touched it. > > > > Could it be also that going to reserve I just picked up some dirt > deposited > > at the bottom of the tank, and then when to the carbs. I guess I could > try > > Seafoam as well, just as a sanity check. > > I will let you know how it behaves when I get off work. > > > > Thanks again for your opinions. > > Javier. > > > > > > On Thu, Aug 26, 2010 at 8:55 AM, Kurt Nolte <[email protected]> > > wrote: > >> > >> After that, start wondering about float valve seats. Well, if it still > >> gives you problems after you've made sure that the carburetors weren't > >> at some point adjusted for a slight fuel leak into the intake, that > >> is. > >> > >> On Thu, Aug 26, 2010 at 8:39 AM, [email protected] > >> <[email protected]> wrote: > >> > I agree with replacing the petcock diaphram, i would even go as far to > >> > not check it, just replace it.... After that look at your vac lines, > then i > >> > dont know after that.... > >> > > >> > Good luck > >> > > >> > > >> > -----Original Message----- > >> > Date: Thursday, August 26, 2010 6:40:24 am > >> > To: "Nighthawk Motorcycle Lovers!" <[email protected] > > > >> > From: "jaybird248" <[email protected]> > >> > Subject: [Nighthawk Lovers] Re: Fuel related problem > >> > > >> > Javier, the reason you have to give it lots of throttle to start is > >> > that it's flooded. Opening the throttle lets in more air, diluting the > >> > accumulated gas to the proper mixture. Then the engine can fire up. > >> > > >> > I also had this symptom due to a torn petcock diaphragm. > >> > > >> > Jay S > >> > 92 NH750 > >> > South Florida > >> > > >> > On Aug 26, 5:39 am, jaybird248 <[email protected]> wrote: > >> >> Absolutely check the petcock, as surfswab says. These symptoms are > >> >> exactly like what happened on my bike and it turned out to be a small > >> >> hole worn in the diaphragm. When I replaced the defective unit, not > >> >> only did the symptoms clear up, my gas mileage went from the 40s into > >> >> the 50s. > >> >> > >> >> Jay S > >> >> 92 NH750 > >> >> South Florida > >> >> > >> >> quoted text - > >> > > >> > -- > >> > 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]<nighthawk_lovers%[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]<nighthawk_lovers%[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]<nighthawk_lovers%[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]<nighthawk_lovers%[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]<nighthawk_lovers%[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. 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