I have a 2006 with 6000 miles. shortly before 6000 miles it would randomly misfire while cruising down the free way at 65-75mph. It acts as if someone cut off the ignition switch for 1/2 a second. It usually afterfires (backfire) when it resumes. The 6000 mile valve adjustment has been done. but it still does this. There might be a slight correlation to slightly slowing down, but more or less it's while at constant speed. I'm fairly certain it's not a fuel problem because it afterfires when it resumes running indicating that it ignites fuel that's been sucked into the engine, but not burned as it should. Any thoughts as to what could be cutting out the ignition at freeway speeds?
My first inclination is that you could be experiencing a symptom of the intermittent battery connection issues that seem to be so common with the 500's.
I don't know, but when I first started riding my 2006 500, I occasionally experienced a momentary falter (sputter) and I concluded that it was when I was in 6th gear when I really should not have been (i.e. I was lugging the bike and it was objecting by sputtering one quick hickup). The only other time my bike has faltered like that I'm convinced that it was sucking hard on a tank that was not venting enough to allow the fuel to comply, but that time the symptom was persistant and increasingly severe until I did something (like stop and eventually open the fuel tank cap). Loose electrical connections should be considered but don't ignore the fact that is hard to tell where you are in the shift gradient because we have such quiet bikes. 'Tom
All valid points, but if he's really running the 65-75mph he indicated in the first post, he can't be lugging it (unless he's pointed up a fairly steep hill at full throttle).
I've got a tach. Roughly between 5 and 6k RPM at constant speed on the freeway is when it happens. Northwest Ohio is as flat as a sheet of glass. I'm not lugging it. Due to the very occasional nature of the .... we'll call it a "hiccup" I'm inclined to think it's electrical. On a 16 mile ride it hiccuped only 3 maybe 4 times. I'll check my battery connections this weekend. I find it odd that it only happens on the freeway though. Also FWIW it doesn't happen every time I ride.
Not to complicate the scenario, but your hic-ups sound like some of the symptoms I've observed, and I was pointed uphill maybe at mid throttle in 6th gear. Hardly an idle but still possibly geared to high for the conditions I was in. In response to the situation, I tended to use 5th at anything less than 60 mph and the hic-ups were fewer.
When I described the symptom to my mechanic, he suggested that some of the orifices in the carb could be partially occluded and the bike was slightly starved for gas. His solution was to run a tank of Lucas injector cleaner through the bike to clean up things in the carb. I'm in the process of finishing that first tank with the Lucas in it so I can't report success or failure. Subsequent to the occasional hicups I had one spell where I was more inclined to considering a vent problem with the tank but I'm still working on that hypothesis too. Keep after it and something will present an answer. Tom
Jablonsky, Yes, that was one of the other suggestions that was put forth by my local mechanic. Such a crack could only appear when you hit a bump or reached a certain speed. Worth checking. tom
Did anyone solve this? I just finished restoring a 91 for a friend. It has exactly the same problem. Starts fine, accelerates fine, good throttle response. Runs good enough, I considered keeping it for myself. But it does have that occaisional stutter at cruise speed especially at 50 or above. The owner noticed it the first time she rode it. It runs better than it did when she bought it, but still there's that stutter. Any help?
an old thread, but here's a suggestion nonetheless.
"Service" the spark plug caps....unthread each from the spark plug lead, cut that back 1/8" for a "fresh start"
Then unthread the brass lug, remove the resistor and spring...clean the inside wall of the cap and rubber boot bright and shiny before reassembling and tightening.
I'll wager you'll find the caps loaded with grimy spooge.
Because of the location of the plugs down deep in the head recess water boils off the head, vapors into the cap...kind of causing a "junk trap" and an easier path to ground for the spark.
Also, if you are so motivated...remove the orange silicone vent breather discs within the fuel cap. Eventually will clog and mimic running out of fuel, even though fuel in tank.
250 and 500 Ninjas have the same vent arrangement, same problem, same solution.
The Vulcan crowd has named the condition "phantom out of gas syndrome" or Poogs.
OP here. I guess I never did respond with the solution. I only vaguely remember the solution. I think it was loose battery terminals. It was as if someone turned off the ignition for a second or two. As a side note It is also possible to pinch one of the vent hoses with the seat but that mimics the stuck vent in the gas cap as in the bike simply acts like it has run out of gas until the partial vacuum in the gas tank has been corrected.
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