is this a tank of bad gas or something else?

[zeke]

Filled up on the way home yesterday. 4.5 gallons. 2 mile ride home was uneventful. The morning commute to the office sucked. Rough idle. Unstable idle. Stalling out. I had to engage the fast idle lever to prevent stalling out when stopped . Idle would flux from 1500 RPM to as low as 900 and also as high as 2100, but generally would bounce about +/- 300 RPM from 1500. It was strange to sit at a light and watch the idle flux up and down. Also it ran horribly at speed. Sluggish to respond to the throttle, and just did not want to accelerate. Plan to drop some Seafoam in there, hopefully that does the trick. The ride home also sucked.

But is this a sign of some other problem? Should I check something else? I suppose the battery may be due for replacement, but would that impact at speed riding? Just had new tires put on, which are working out great so far.
Bike details
2004 r1150r
31000 odo
Last value an adjustment was at 24000.
fuel filter replaced and dot4 flush brake and clutch at 24000 also
Just changed the oil, gear, and fd last week.

Thanks.

[AZBMWRIDER]

Chances of getting bad fuel from a station these days is not as common as it has been in the past .
About the only thing you can do, is to drain the tank and refill it and see if it helps at all .
My first question would be, how old is your battery ???
I've had two instances where a battery in it's dying stage, caused odd engine running issues, idle was the worst, had to put the 'choke ' on in heavy traffic to keep it running .
The second question is, how old are your spark plug wires ???
I had the original wires give me engine running problems at about 7 years of age .

[towerworker]

A sudden change in running characteristics would point to the only "new" addition----which seems to be the fuel. I would certainly fully drain the tank and refill with a good brand of non-ethanol 93 octane (or highest octane in your area. The other thing that could cause this kind of running would be a stick coil failing. But I'd do the fuel thing first. Keep us updated and we'll try to help where we can.


Wayne

[zeke]

Worked through half the tank with the help of some Seafoam. Topped off with premium from another station. Running better, a bit rough, still hard to start, but stalling has reduced. Throttle response is better but not back to normal. Hopefully I'm on the way back to normalcy.

Just of of curiosity how much wrest the spark plug wires? Can you do that work yourself?

Thanks. I'll continue to keep you posted if things go sideways.

[towerworker]

I assume you're asking about the plug coils. The '04 R is a "dual spark" engine meaning it has two spark plugs per cylinder. The primary plug is the one that is on the very end of the jug and has a plastic cover over it and the wire that feeds it. That is the one with an integrated coil/plug cap. We refer to those as "stick coils". It's been a while since I've priced them but last I heard they were $130-$140 each. And yes it's a simple replacement, just unplug the harness connector and plug in the new. Hopefully you have with your BMW tool-kit that came with the bike the black plastic tool that is used to unplug the stick coil from the spark plug. But it sounds like your problem was the fuel (which is good!) and you won't need to replace the coils. The secondary plugs are on the bottom side of the jug and are covered by a small black plastic cover held on with two small bolts I believe. They are conventional with a standard plug wire and the coil is up under the tank. I've never heard of one failing though since that is old tried and true technology.

[CycleRob]

zeke,
Your description of events does point to stale or water laden fuel. The fact it noticeably improved immediately after your half tank fill-up from a different station proves it likely is not a bad stick coil. The problem with premium grade fuel is that so few customers are using it. That means the premium fuel you buy will have more calendar weeks in storage to absorb water from humid air and degrade as its volatile elements are lost or decompose. The 10% Ethanol in our fuels makes the stored fuel more eager to absorb water and degrade faster with age. Ethanol based fuels degrade in as little as 3 months. Cars and bikes like my F800St that "recommend" using premium grade gasoline can safely be run on regular grade gas "with reduced performance", so many more drivers are doing just that as the price approaches $4/gallon. It is only cars/bikes that say "premium fuel only" that cannot use the lower grade fuels. In your case, using a dry-gas product to help digest the entrapped water may have been better than using SeaFoam.

Time was when premium grade fuel had system cleaning detergents and regular grade did not. Not anymore. All grades seem to have it now. IMEO the best fuel brands are the 2 that contain the very effective Techron brand fuel additive; Chevron and Texaco, that share the same fuels and corporation. They are also among the less expensive major brand fuels.

[Rags]

I always use Techron after fueling in Baja... takes out all the wrinkles

Rags