06 S2R800 bogging, surging and backfiring

[faolan01]

My 2006 S2R800 has developed a couple of issues that I was wondering if anyone had any ideas about before she goes in to the shop to be looked at next week.

1) This season there are a lot of times where the idle seems really low to me, hovering around 500 RPM when in neutral while fully warmed up, but sort of pulsing up towards 700-800 at times. There have been a couple of times where she has stalled out from the RPM being too low while either holding the clutch in waiting for a light or sitting in neutral.

2) She has developed a flat spot around 5000 RPM when I crank the throttle open. She'll race up to 5000, then suddenly bog down. If I back off the throttle she'll start speeding up again.

3) This past weekend I took to my parents' place to store her in their garage and protect her from Irene. On both the ride there and after picking her up again the other night she was bogging down a lot more, with the RPMs suddenly dropping from just over 6000 to between 4500 and 5000 then randomly racing back up to 6500 or so. This was with the throttle held steady, not attempting to modulate it at all while trying to figure out what was going on. There was one fairly loud backfire on the ride to the garage, and two smaller ones on the ride back.

The engine, airbox, exhaust and ECU are all stock.
Any thoughts?

[Dirty Duc]

Vacuum leak?

TPS?

Fuel filter?

Fuel pump? (this could include bad voltage to the pump).

Something wrong with the coils?

[EEL]

Keep us updated. I'm having similar issues, though not that random.

[Ducatiloo]

I had a similar issue.  I found 3 issues.  My fuel fuel was partially blocked and the connection of the spark plug to the wire was loose just enough on one cylinder that at it would vibrate at 6k rpm.   It runs like a champ now. 

[faolan01]

I'll update after I drop her off to be looked at Friday. Really hoping it's something relatively simple (and inexpensive) that they'll be able to take care of right away. European Bike Day at Larz Anderson Museum is next Sunday, and I'd much rather take her than drive to it!

[Ohm3d]

mine backfires huge at 4000rpm on deceleration after hard acceleration... people behind me say they see a flame.. I am getting mine dyno'd with a PC in the next few weeks, I'll see if that makes a difference

[faolan01]

well I just got the call with the final verdict...there was "significant water" in the fuel system, the throttle bodies badly needed to be synched, and the injectors were fouled. They flushed out the water, synched the throttle bodies and cleaned the injectors and that has cured all the issues but one. They said on the test rides it was stumbling a bit in the 6500-8000 RPM range at full throttle and the codes the ECU was kicking out indicate an issue with the ECU at the top end. Since I generally shift before 6500 unless I'm really accelerating hard, I'm going to leave that alone for now (not exactly in the budget at the moment anyway.)

[faolan01]

also, my spark plugs needed to be replaced and they started a claim for me for the expanding gas tank issue.

They showed me what they drained from the gas tank and fuel lines. They weren't kidding about the water! I'd say around a quart had somehow managed to build up.