Damn missfire again

[dolphaxel]

So I went for a couple of rides this week and to my dismay my misfire issue seems to be coming back. It sounds like a click and you hear the engine stumble for a split second. You can feel it in the throttle as well.

Before I rebuild the bike it would happen fairly regularly riding around town, but after the rebuild and having the bike tuned it seemed to mostly go away. It would only happen every now and again at very low rpm. I was told by the tuner that it was a "lean miss" and that he had tuned it out. I have replaced the coils and plugs, but that been a while ago. If it was simply a tuning issue wouldn't it not come back over time? Im thinking maybe I have some other issues that I have not addressed some place. Maybe injectors or fuel pump?

Regardless it really pisses me off when I go around a corner and " click click click". When it happens it looses smooth power for a brief second and makes things a bit jerky. I don't need any help looking like a retard when I'm riding so this has got to stop! thanks.

Last note. I was thinking of trying some Iridium plugs. Does anyone know the NGK number. Their site only lists standard NGK R plugs for my bike.

[Raux]

I'm no expert by far.

but starting from the start of the electrical system to the plugs
generator... going bad?
regulator... going bad?
flywheel sensor... gap set correctly?
coils... replacements good?
wires... broken?
plugs... lean coloration?

on the fuel side
pump... low fuel pressure resulting in lean condition? but click click click isn't explained
injectors... click clik click.. fire with no fuel?


these would be all the items I would check

[Speeddog]

It's backfiring through the intake.

That's the click you hear, and you can feel it in the throttle because it flips the butterfly.

How long ago were the valve clearances adjusted, and what were they set to?

TB sync done?

[dolphaxel]

valves done 3k ago. I don't know what the valves were set at. Motocorsa in portland did it. Plugs had about 3k on them and they had good color to them. Haven't checked the throttle sync yet, but I need to get some tooling to do so. The charging system puts out good voltage. Maybe I have a loose closer?

[Speeddog]

Possibly.

You mention engine rebuild.....
Can you provide a little more info regarding that?
Miles on engine before and after, what was done, etc.
Link to a thread is fine if you've detailed it elsewhere...

[dolphaxel]

I rebuilt the bike, but the engine stayed closed. The engine hasnt been messed with at all other than maintenance. It got the valves done and belts changed at 7k. also got dyno tuned at about 8k. The only power accessories are PC3 and spark high mounts. The headers are coated. Its a long jacked up story, but I'm the fourth owner and I have been riding the bike since it had 5k on it. Its always done this to some degree and It's starting to bug the shit out of me. I know all but the first owner and the middle two never rode it. Im close to 11K as of today. Seems like low milage to have issues like this, but I'm hoping there is just something simple that has been over looked.

[brad black]

if it had a pc3 fitted and tuned it shouldn't be lean.  have you tried richening it up?

[dolphaxel]

when It was tuned he tried to tune it all out. The F/A ration was good all over the map and he did dual maps as well. As far as power and power curve it runs way better than it did before. Again the strangest thing is that it had settled down, but seems to be getting worse.

[Speeddog]

Have you downloaded the map?

See what it's got in the low throttle% and low rpm boxes.

[dolphaxel]

thats on my list. Unfortunately I don't own a windows based computer and the software that I have is only for windows. Hopefully I can get that squared away soon so I can see whats going on. The tuner is 150 miles away over a snowy pass at the moment so I probably won't make it over there any time soon.