04 RSVR won't idle below 2,000 rpm

Hello, I had hoped my first post wouldn't be trouble related but unfortunately my just purchased RSV won't idle below 2,000 rpm. I just picked the bike up yesterday and it stalled out as I was leaving the shop where I bought it. I started it again, rode a few feet, and it was sputtering and trying to die. I turned the bike off and started it again and the problem seemed to go away so I rode home for 45 minutes with no issues so I didn't think much of it. Later on that day I took the bike out and it ran fine, then after about 30 minutes of riding it would barely run below 2,000 rpm and would stall at idle.

It is a 2004 RSVR with 6400 miles on it. When I lifted the tank and opened/loosened the airbox, it appears that nothing as been touched since the factory and all factory screws that were marked still have the factory marking intact.

After looking through the forums, I have tried the following:
* Removed and cleaned the IAC solenoid and check for functioning. It powers up and moves when the bike it powered on.
* To eliminate the possibility of anything IAC related, I disconnected the IAC bypass hoses and ran the bike with different diameters of vacuum tubing inserted to set the idle. Same result, won't idle below 2,000 rpm.
* Drained tank and filled with 2 gallons of fresh gas. No change.
* Vacuum hoses seem to be connected with no breaks or kinks.
* Unplugged the TPS connector and inspected - connections look fine.
* Checked EFI self diagnostic via self check on gauge cluster and it returns a code of "0".
* EFI indicator/CEL only came on once after I first discovered the issue and hasn't returned.
* Bike is charging with ~13.8v at idle - 3,000 rpm. I charged the battery overnight just eliminate battery voltage from being a possibility.
* Disconnected the battery for 30 seconds to try to clear any faulty settings the ECU may have learned and performed key/memory procedure after re-connecting
* Checked and cleaned spark plugs

I don't think it's fuel supply (volume/pressure) related because the bike runs fine above 2,000 rpm and cruises/accelerates just fine.

TPS? I've also read about the trim adjusters in the ECU.

Thanks,

Jesse

I'm pretty sure both cylinders are firing although I wouldn't rule out spark plug caps. It doesn't sound like one cylinder is firing when it sputters out, it sounds like both are sputtering and I'm not smelling unburnt fuel when it does. I was originally thinking if spark was bad then high RPM spark would be bad as well (like when you open the throttle off idle then it would misfire). I'll investigate the spark plug caps further.

I talked to a bike mechanic in passing today and he mentioned sometimes a bad R/R can cause idle issues. I considered that but I seem to be getting decent (if not ideal) idle voltage at 13.8v as measured with a volt meter on the battery terminals.

Thanks

Edit: I also accidentally left the MAP sensor unplugged this last time I started it up and it made no difference to the idle condition.

Well, as luck would have it I fired the bike up to take another look before checking out the coil pack. Right after I shut it down I pulled the idle bypass tubes to gain clearance to access to coil pack and noticed fuel and air vapor coming from the tube to the rear cylinder - makes me think that one isn't getting adequate spark at idle.

I think dog78 may be on to something with the bad coil. I unbolted the coil pack to take a look at it and started the bike again. I moved the coils a little and the bike started to idle better. I moved them again and it stalled right out. I fired it up one more time, moved the coils and it stalled out. Since moving the coil pack had a direct effect on the ignition, I have to think that has something to do with it. The only thing I can't understand if this is the case is why a faulty coil would only cause problems below 2,000 rpm. In my past dealings with coils it's usually the opposite - engine runs fine down low but the ignition struggles to keep up at higher rpms and load. I ordered a replacement coil pack which should be here on Wednesday so I'll give that a try along with fresh plugs.

tedyboy, I checked the ECU via the gauge cluster diagnostic and only got a code of "0". I don't have access to a CO monitor to check the fumes but I do have a wideband O2 meter - I just need to figure out a way to plug the second O2 into the exhaust pre-catalyst. Coolant temperature seems to have no effect on the idle (misfire?) situation - cold or hot it acts the same way.

I took a photo of the coils but I can't access photobucket from work - I'll get the pic up tonight. There's not much to see though, they look like a normal Bosch twin coil pack and, unless there is a catastrophic failure due to heat, etc., failed coils will look just like new ones. I tried to measure the resistance but my voltage meter has been acting up and won't measure resistance for some reason.

The Aprilia coil pack is a Bosch 221 503 037. I ordered the Bosch 221 503 035 which appears identical and I can't source the 221 503 037 coil pack in the U.S. (the 035 is available everywhere since it was a common Mercedes coil).

dog78, thanks for the info! I might see if I can source some entirely new spark plug wires/caps, etc. locally. The wires/caps on my bike, which I assume are OEM, are made by NGK. Does anyone know the part number by chance? I think I have a few local options - there's a Polaris/KTM dealer nearby which obviously deals with a variety of Rotax engines.

Question: Is the resistor in the spark plug cap required? I can't find much on it but there was one post where someone mentioned it was redundant with a resistor type spark plug. I'm not worried about low level EM interference but wondering if it is safe for the ECU and coils. I can easily come up with a nice set of MSD wires with quality caps, etc. from the local auto parts store but the resistor type is more difficult to source locally. I'm also wondering if that additional resistor and mounting serves as a point of failure in the OEM cap design.

Fixed it! Brand new plug wires. As I was removing the rear plug wire, the cylinder I suspected of no spark, the plug cap fell right off with maybe 2 lbs of force so I'm sure it was only barely making a connection. Unfortunately, the HT leads got stuck on the new coil pack I purchased so I ended up needing both new wires and caps. There were plenty of plug wire kits available locally but none of them designed for distributorless ignition coil packs, all had leads and crimp terminals for distributors. There is an Aprilia parts distributor about 3 hours drive from me so I was prepping to have to make the drive tomorrow since the local dealer didn't have the HT leads in stock. I could easily source the wires and caps from AF1 racing but I'd be looking at a week for them to arrive and I'll be traveling on business next week.

So I made a trip to the local Harley dealer with my old broken wires and asked if they had anything similar. It turns out that some of the Harley Davidson wires designed for their distributorless ignitions mount right up and work like a charm (part #31992-99B). The long wire is the same length as the OEM long wire but the short one is a little shorter so I picked up two long ones. The best part, they only cost $6.36 each.

I let the bike idle and revved it intermittently for about 15 minutes and so far so good. It's a little late and cold to take it out for a ride tonight but I'll update this weekend on how they're running.

dog78, thanks so much for pointing me in the direction of the ignition cable! I would have taken me forever to finally track down such a simple fix without your advice.

Took it out for an hour today and it seems to be running great! I definitely must have restored some power as well since it has a lot more pull than when I rode it the first day I picked it up. I kept pulling the front tire off the ground today trying to get reacquainted with the throttle.