Join Date: Feb 2010
Location: Maleny, Queensland, Australia
Fast idle adjustment 2005 650
The fast idle circuit has stopped working on my K5 650 (116,000km) and I would like some help from people knowledge about fuel injection.
The Secondary Throttle Valves turn easily by hand, but from the open position only do a quick stutter and stay open with the ignition first turned on and do not do the full open/close sweep.
I have tried to follow the manual (for a K4 which should be identical) and disconnected the STVA coupler (STV valve fully open) and measured the TP output voltage (R and b/br) wires at 4.92V.
The manual says the TP voltage should be 1.21v for this test and the fast idle adjusting screw should be used to bring the TP voltage to spec. I must admit that I could not identify the fast idle adjusting screw from my fuzzy workshop manual picture but wonder if the large range from 4.92V to 1.21 could be reached using this adjustment screw.
While the STVA coupler was disconnected I measured the STP sensor voltage at 5.2V with the valves open and this exceeded the manual's minimum value of 4.8V as required.
With everything connected but the STValves fully closed, turning on the ignition makes the valves open fully so while the STVA operates to this extent do I still suspect a malfunctioning STVA.
The bike is running perfectly otherwise with hot idle set at 1300rpm so I could just ignore the problem by manually keeping the revs up on cold start but I would prefer to fix the problem.
2005 DL 650 - 120,000km
1972 Suzuki T350 - about 105,000 miles (including 2 Castrol 6 Hour Races)
1982 Honda CX500EC - 261,500km
All owned from new