Rear cylinder not firing on '09 RS - any ideas?

[Jombie626]

Hello all, new here and looking for some help. I have an '09 RS SE5 and the rear cylinder is not firing. I have checked all the basics, injection pulse, spark, and compression are good. I have taken the valve cover off and there is no visible damage to the cams and the valves appear to be moving as they should. I think this model has stability control, but I can't find any info on how it works or what it does. Is it possible that has failed and is causing the cylinder not to fire? Any ideas would be greatly appreciated, thank you.

[BajaRon]

Are you sure you're getting spark under compression? A weak spark may fire with the spark plug out of the head. But under compression, fail. The 998 has a high compression.

Do you still have the original wires and plugs? The original wires are of very poor construction and materials and will definitely fail.

If you have spark and fuel, then it has to fire unless you've lost compression or the timing is off quite a bit. What is compression in both cylinders?

What lead up to this situation? You don't usually get a dead cylinder just like that with spark and fuel present.

[Gwolf]

Hello all, new here and looking for some help. I have an 09 rs se5 and the rear cylinder is not firing. I have checked all the basics, injection pulse, spark and compression are good. i have taken the valve cover off and there is no visible damage to the cams and the valves appear to be moving as they should. I think this model has stability control but i cant find any info on how it works or what it does. Is it possible that has failed and causing the cylinder not to fire? Any ideas would be greatly appreciated, thank you

You have posted that the cylinder is not firing, and also that you checked spark and compression as good. How did you check the spark? Is there a nice, fat blue spark visible or did you check with some instrument where you could not see the spark? Where did you check the spark? At the tip of the spark plug is the only place that would eliminate the plug wire as the culprit.

Finding the problem is a process of elimination. Is there a spark as you stated, or do you just assume there is a spark? If there is a spark, is it strong eough to fire under compression?

[Peter Aawen]

Welcome to the Forum & posting Jombie.

Your Spyder DEFINITELY has Stability Control included amongst all the various computer-controlled systems (is it 6, or 7??) that collectively, we affectionately call 'the Nanny' (which you won't really ever see anything much of besides the castellated 'tone rings' on each wheel & the sensors that use those rings to determine the individual wheel rotational speeds & report that back to the 'black boxes' that carry and do all the smart stuff! ) but unless you can see an Orange warning of some sort (usually 'Limp Home') showing on the dash pretty much all the time the ignition is on, then it's very unlikely (if not downright impossible! ) for the Nanny be involved in what you're reporting. That does sound faaarrr more likely to be a failing plug lead &/or plug, which the V-Twin engined Spyders of the same vintage as yours (& mine ) are renowned for!

Before all this started, had you done any work under the tupperware recently?? Been anywhere near the plug leads &/or plugs?? Or is it just due for a service/changing plugs & leads??

[Jombie626]

I have not done any work to it underneath before this happened, there is only 8k miles on it. There are no codes and no limp home light. I have changed both plugs and injectors already hoping it was something simple. At this point im just trying to avoid tearing down the engine

I have replaced both plugs and tested it with a tester the goes between the wire and plug, with it running there is a good strong light from the tool

[Jombie626]

Yes, I used a spark tester that goes between the plug and wire. This was the first attempted ride of the season, my wife was riding and I was behind her, we were on our way to fill the tanks when she stopped and said it wasn't running right. The timing marks are correct, I checked after I took the valve cover off.

[BajaRon]

If you manipulated the spark plug wires. It is very likely that this is your problem. I have no explanation as to why the testing light is showing good spark. But I would replace the ignition wires with a good quality set before I went any further. It's the best way to eliminate these as the cause of your issue.

Early on in my Spyder life. I replaced the spark plugs because my engine was running badly. When I was done, it barely ran at all. It wasn't the spark plugs. It was the wires all along.