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Rough running R1150RT

scootrp125x

They call me Gort
Rough running 04 R1150RT

I was riding home from work last night and about 5 minutes into a 20 minute commute the bike started running rough. I was able to get off the interstate and stop at a well lit self service gas station. I couldn't find anything loose or leaking with a flashlight. This was probably the third or fourth ride since the bike came out of the garage after winter storage. I probably had 1/4 of a tank of gas left but just in case I was running out of gas I pushed the bike over to the pumps and put about 4 gallons of fresh 93 octane in the tank.

I was barely able to get the bike started again and keep it running by keeping the rpm's up. The engine was still running rough but seemed to be stable enough to try to ride it home. I made it home but the bike continued to run rough and seemed to be very loud, even with my ear plugs in.

This morning I removed the fairings parts and inspected the exhaust for any loose bolts or leaking seals and I couldn't find anything. I don't see any evidence of leaking engine gaskets or seals. I do most of my own maintenance including valve and throttle body adjustments. Last fall I did the valves, throttle bodies, oil and brake fluid change. I changed the fuel filter a couple of years ago at 25k and the bike now has 36k.

I rode the bike a few more times before putting the bike away for the winter and took a long afternoon ride a few weeks ago. I have not had any problems of this kind but I have thought the exhaust sounded a bit more throaty in the last few years. I'm may be barking up the wrong tree but it sounded like my exhaust had fallen off while I was riding home. Would an exhaust leak cause such a sudden and pronounced problem?

Thanks for any suggestions,

Mark
 
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Just a thought. Have you ever replaced the stick ignition coils??? Mine would not act up until the engine was warm. You could be running on just the lower spark plugs. One of mine was still good. I kept it as a spare on the bike.
 
stick coils?

I replaced both stick coils a couple of years ago that seemed to cure an intermittent and very minor erratic idle problem. I still have the old ones and at least one of them was good, I could never figure out which one was bad. I will try replacing them one at a time with the old ones and see if that helps. I replaced the spark plugs last year and they ran fine. Thanks for the tip.
 
I have never had a problem with water in the gas from winter storage. I have a great heated garage, not too warm, not too cold. I use stabilizer and have ridden a few times this year. I believe water sinks to the bottom of the tank and the problem would have appeared before now.

I'm hoping the problem is the stick coil. My BMW 530XI car has the same stick coil technology as my motorcycle. A couple of years ago my car began running rough very much like the bike last night. I drove the car to the dealer the next day and they correctly diagnosed a bad stick coil. The car ran rough with 5 cylinders firing correctly so a bad stick coil on the bike with only 1 cylinder firing would be even worse. I pulled the left valve cover off the bike last month. The oil cap was turning in the valve cover. I had to pull the stick coil off of the left spark plug. The coil may have been damaged during the removal process and it finally started to misfire. I will try the coils that I removed from the bike a couple of years ago and see if they make a difference.


Water in the gas, perhaps?
Because of sitting over the winter.
 
You didn't say you did anything with the gas tank or throttle bodies. Have you checked that the throttle cables are properly set in the (thingy) that they set into? BTDT and it acts as you described, except it did that from the start, not in the middle of a ride.
 
You didn't say you did anything with the gas tank or throttle bodies. Have you checked that the throttle cables are properly set in the (thingy) that they set into? BTDT and it acts as you described, except it did that from the start, not in the middle of a ride.

The throttle body cables are properly seated and nothing appears amiss with the gas tank or fuel lines.

This morning I took out the left spark plug and inspected it for any signs of uneven firing or wetness. I replaced the left stick coil with one of my spare stick coils and the problem did not go away. I did the same for the right side and no luck. Both spark plugs were dry and looked normal. The bike still wont start with both of the coils replaced.

I also checked the air filter while I was working on the bike and everything looks normal, no evidence of mice that might have built a nest over the winter.

I'm wondering if it could be the Hall Sensor although I know very little about them except that they seem to fail while the bike is in operation and the engine runs rough or wont run at all. I could not even get the bike cranked this morning.
 
Since we have two sparkplugs per cylinder, the "bad" side will still run if any coil goes bad. And, because it's still running on the "good" plug, the "bad" plug will still show a decent color, it will NOT show "rich" or be wet.

The lower/bottom/outer plug on both sides is fired from the dual-output coil under the tank, by the frame's neck. If you clip an inductive timing light on to those wires, that may point to the issue.

Also, inspect very closely the plug wires where they pass through the clips that route them along the frame - I had damaged insulation because the clips were too tight.

If you replaced a suspect stick coil with a used coil, that's no guarantee that you'll have a better spark.
 
Since we have two sparkplugs per cylinder, the "bad" side will still run if any coil goes bad. And, because it's still running on the "good" plug, the "bad" plug will still show a decent color, it will NOT show "rich" or be wet.

The lower/bottom/outer plug on both sides is fired from the dual-output coil under the tank, by the frame's neck. If you clip an inductive timing light on to those wires, that may point to the issue.

Also, inspect very closely the plug wires where they pass through the clips that route them along the frame - I had damaged insulation because the clips were too tight.

If you replaced a suspect stick coil with a used coil, that's no guarantee that you'll have a better spark.

Thanks for the tips. I am confident that the used stick coils are working well enough that the bike would have cranked.

I am interested in checking the dual-output coil under the tank. I was just on the phone talking to the service manager at my local dealer. He also mentioned the coil under the tank. He cant get the bike into the shop for a few weeks. I will check all the wires while I am waiting.
 
Update

This week was the appointment at my dealer. The left cylinder showed low compression and the leak down test confirmed the problem. They suspect a bad valve and will remove the cylinder and send it to a machine shop. It will take a couple more weeks to get everything done and put back together.
 
Success!

I picked up the bike Thursday and it runs great. Here is a picture of the broken valve.
 

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I have been wondering how this happened so I searched the internet for "broken oilhead exhaust valve" and found a post from 2006 on the BMW Sport Touring website. The information suggested that a chunk of the valve probably didn't break off but that the valve was slowly burned away by an area on the valve that began as a tiny leak and progressed over time to a large hole which affected the performance of the cylinder, sounds logical to me.

Here is the post by RFW in Vancouver:
"Probably not a chunk that was "missing", but simply a burned exhaust valve. When exhaust valves burn out, the high velocity, high temperature gases that leak by in one area start eroding the valve at the point where it is not seating. This erosion causes more hot combustion gases to leak past at supersonic speeds, causing more erosion and so the cycle repeats until the valve has a big notch in it.

The result is that the valve ends up looking like it has a big notch or chunk taken out of it. I have never seen an exhaust valve that had an actual piece broken off (nor are there significant mechanical stress on one small area of the valve that would cause this). But I HAVE seen lots of burned out exhaust valves (some from my own motors over the years) that suffered the typical damage described above.

What is the cause? Inevitably, the cause is that the valve clearance has decreased to zero at some point. Note that the hotter the motor gets, the more the clearance decreases. This is normal, and is why it is better to have a slightly wider gap when cold, than one that is too narrow."

Once the clearance decreases to zero, the valve will burn out in only a few miles as several thousand degree combustion gases race past the seat at supersonic speeds like a supersonic cutting torch.
 
A chunk of carbon lodging between the valve and seat will start the burn process. It happens very fast.
Higher mileage engines that use oil (broken in too lightly) seem to suffer from this once in a while.
 
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