sachimore Posted June 12, 2022 Share Posted June 12, 2022 Need some advice guys. Have a 2002 Silverbird with 65K on it, well maintained and has never had "any issue" of any kind. Garaged and loved for 20 years. Recently noticed that at idle it is no longer the smooth no move tach needle at 1,100 RPM. It bumps. Every few seconds it’s like one of the combustion cycles is a little stronger than the others and the needle can bump up a couple of hundred RPM and immediately drop. Then hit again and again. You can feel the bump in the seat. Few days ago I started to get a low RPM type burble when pulling away from a stop sign. A miss kinda. By 1,600 or 1,700 RPM smooth. The next day worse, the burble turned to a low RPM power loss as it leaned to actually cutting out. Smooth out moved to around 2,000. Next day worse in all directions but now I have an occasional feint back fire while the RPMs rise. But after 2,400 smooth as silk. Whatever it is it is happening fast. I’m a decent mechanic but not electrical which this feels like. Any ideas appreciated as I have no idea. Or at least where to start. Thanks Sach Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted June 12, 2022 Share Posted June 12, 2022 Fuel pressure regulator? Thoughts? Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted June 12, 2022 Share Posted June 12, 2022 Have you checked the spark plugs to see if one looks different from the others and their condition in general? Quote Link to comment Share on other sites More sharing options...
SwampNut Posted June 12, 2022 Share Posted June 12, 2022 2 hours ago, blackhawkxx said: Have you checked the spark plugs to see if one looks different from the others and their condition in general? Adding to this, and agreeing, but also what's the other maintenance like? Air filter? Quote Link to comment Share on other sites More sharing options...
XXitanium Posted June 13, 2022 Share Posted June 13, 2022 2002 - sticky injector? Quote Link to comment Share on other sites More sharing options...
tomek Posted June 13, 2022 Share Posted June 13, 2022 (edited) Often overlooked are vacuum lines. Those little things attached to throttle bodies and fuel pressure regulator. If even one of them is cracked it is gonna effect fuel pressure. XX has a reference FPR. Referenced to vacuum in intake tracks. The easiest way to do it is to replace them all at once or it will take forever to figure out what line goes where etc. Get foot or two of appropriate I.D. from Auto Zone, razor blade, and replace them piece by piece. Edited June 13, 2022 by tomek Quote Link to comment Share on other sites More sharing options...
ironmike Posted June 13, 2022 Share Posted June 13, 2022 Agree that vacuum lines are suspect--especially it they're the original at 20yrs old--find any raw fuel in one and your FPR merits replacement as well. Fortunately, these are relatively easy fixes. Quote Link to comment Share on other sites More sharing options...
sachimore Posted June 13, 2022 Author Share Posted June 13, 2022 Plugs and filter all new 5K ago. Rebuilt the entire bike 3 years ago except for the engine and trans. Did not see any need to touch them. Some great thoughts here and will follow up. Thanks guys Sach 1 Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted June 14, 2022 Share Posted June 14, 2022 First thing I'd check is the FPR (fuel pressure regulator). I think you can get to the vacuum hose without disassembling stuff, but it's been a long time. Pull the hose off and if there's gas in it it's done. If there's no gas turn the key on to pressurize, if still no gas then it's probably fine. My second thought is the test connector corrosion issue. Quote Link to comment Share on other sites More sharing options...
XXitanium Posted June 14, 2022 Share Posted June 14, 2022 Yeah, sketchy ground too? Quote Link to comment Share on other sites More sharing options...
sachimore Posted June 18, 2022 Author Share Posted June 18, 2022 Can somebody tell me where the fuel pressure sensor is? I have a phone book sized tech manual and it's not listed in the index. Thanks Sach Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted June 18, 2022 Share Posted June 18, 2022 1 hour ago, sachimore said: Can somebody tell me where the fuel pressure sensor is There isn't one. The fuel pressure regulator is at the right side of the fuel rail. Quote Link to comment Share on other sites More sharing options...
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