2004 Yamaha FZ6: misfire or rough idle

Filed May 16, 2006 · Electrical · 12,800 miles · VA · crash · 1 injury

At 9m miles, my 2004 yamaha fz6 began to exhibit the following: 1) after approximately 30 minutes of operation, erratic and prolonged periods of rough idle at 500 rpms instead of the normal 1300 rpms 2) motor would stall during gear changes, even at highway speeds 3) during these times, the smell of gasoline was noticeable. Changing the spark plugs seemed to fix the problem temporarily, but they soon reappeared. At 12m miles, the bike was taken to the yamaha dealer to be fixed but they could find nothing wrong with it. I went next to an independent motorcycle mechanic who also could find nothing wrong. He suggested that it was probably an electrical problem and could be expensive to fix and I should take it to a different dealer. He also questioned if the "check-engine" light had come on which would have registered specific trouble codes, but I told him that they had not. At 12800 miles, while pulling onto the roadway, the bike stalled unexpectedly in a turn at low speed, locked the back tire and went down. I sustained minor injuries, and the bike lost a mirror, foot peg, front fairing, and generally got bummed up. Since then, I have found numerous reports of "throttle positioning sensor" defects that have created similar problems with this make and model of motorcycle. And yet, the dealers seem to know nothing about it! Installing a new tps may or may not fix the problem. But for now I'm stuck with a bike that I can't trust, has little resale or trade-in value, and probably isn't safe to ride. After reading the numerous and similar sounding complaints, this may well be a manufacturing defect that should result in a recall.

Filed Sep 15, 2005 · Fuel system · 4,900 miles · TX

Bike idle drops (600-850 RPM) when clutch pulled in causing vehicle to stall at red lights, exiting driveways etc... Poor fuel mileage and rough idle. Upon cycling the ignition key off and on, symptom will temporarily rectify itself only to return later. I am fearful of a rear-end impact from another vehicle at intersections as a result of this problem. It seems that the "throttle sensor assy" part no. 5fl-85885-05-00 is the major culprit per other owners experiences with this vehicle and same symptoms.

Filed Sep 5, 2005 · Fuel system · 7,400 miles · OR

Trottle chunky/delayed/erratic, making motorcycle difficult to control in corners. Stalls at stops, a dangerous situation in city traffic. Does not idle, I need to keep the throttle slightly rolled on. Runs rough, smells of gas, seems to miss. Problems started with throttle delay at 7000 miles, stalling started at 7400 miles.

Filed Aug 31, 2005 · Fuel system · 5,615 miles · CA

Riding home from work on a 2004 yamaha fz6, with just over 5k miles on it. The bike began to surge by itself and would either go to a full open throttle (without any user input) or would hold a constant RPM (regardless of user input). The first surge was very violent (wheelie style throttle input) and nearly kicked me off the back. Lost grip with my throttle hand, but was able to grab clutch and avoid an accident. Very inconsistent throttle response the rest of the ride home (~4 miles). Sound from exhaust had also dies down and was very quiet. Upon arrival at home, I parked the bike and felt the exhaust and idle - everything was normal. Upon the slightest throttle input above idle, there would be no pressure from the tail pipe and the air around the exhaust would become instantly super heated. I had the bike towed to a repair shop (del amo motorsports) to have it looked at. They ran diagnostics and found no errors. How can there be no errors when the bike drove around with a mind of its own? The bike is still at the dealer, will update the report later. Have had all service checks, bike has been doing fine, except for a rough idle, diagnosed as a tps problem by texas yamaha south outside of houston, tx. This was done around the 700 and again around the 1200 mile mark. Problem (associated with tps, as diag. By tys) stopped around 1400 miles then showed up around 4700 and has been doing it ever since.

Filed Apr 30, 2005 · Fuel system · TX

At about 6200 miles while pulling up to a light of a steady run my motorcycle would die. Restart it, and it would be misfire real badly and die again. Take key out and back in it would fire up just fine, for the time being. First time this happened I was about to take a turn, had the clutch in down shift, then braked for an oncoming car, as I started to lean I was letting the clutch out, when low and behold the engine died. So it just locked up. Luckily, I was able to get that clutch in before it went over. Took it to the dealer and they had it a couple days and said there were no codes, and they could not duplicate the complaint. It acted up when ever it felt like. Sometimes it ran fine for weeks, then sometimes it messes up a bunch in 1 week. I've researched this topic online, and found many others with same problem.

Filed Apr 28, 2005 · Fuel system · 7,200 miles · CA

My motorcycle will stall and/or run rough occasionally, and not idle without additional throttle input. If I turn the ignition off and restart the motorcycle it will fix the problem for a period of time. I am very concerned that the motorcycle will encounter this problem while turning and causing instability that might contribute to a crash. In addition, I do not like having the thought of this problem in my mind everytime I am riding, as it takes enough concentration to avoid other vehicles and monitor road conditions. I have not repaired the problem yet. Thank you for your time.