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R1150 sputter, hesitation upon restart

Hi,

Last summer my 2002, R1150RS developed an issue when starting off from a stop. At low rpms, the engine will cough and sputter, and almost stall as if its not getting enough fuel. Pulling in the clutch and blipping or holding the throttle open for a few seconds resolves the issue. What makes it curious is that it only occurs at certain temperatures. For example, on the first start of the day, when the engine is cold, there is no problem. If I stop for fuel, and I restart shortly afterwards while the engine is still hot, there is no problem. On the other hand, if I were to take a 15 minute break during the fuel stop, the problem will definitely pop up. In fact anytime the RID temperature display is between 1 to 4 bars upon restart, it happens. Once underway, even under heavy load, there is never a hiccup or misfire. Having to stop and at a traffic light, no issue getting underway again. The bike has always run smoothly, it never has had any surging issue. Mileage is great, the same as when it was much younger. ( I am anal about this and have tracked fuel use since the beginning of time) It is a high mileage bike, but has been meticulously maintained. The usual tune up items have been looked after. New plugs, check valves, sync throttle bodies. Fuel lines are relatively new, replaced in the last three years. The BB screw has been removed and the TBs flushed. I have run a quite few tanks of fuel injection cleaner. My next step is to inspect and reseat the connectors for the various sensors. Oxygen, temperature, air. My internet searching has not uncovered any symptoms like this reported. Any ideas out there?
 
If you have twin plug heads, have you ever checked or replaced your stick coils? I had a somewhat-similar problem a couple years ago which replacing both stick coils solved. I must say the bike wasn't running totally smoothly prior to replacement so you might file this suggestion under Wild Assed Guess. :D
 
Stick coils is better than just a WAG, the symptoms are right. Also verify that the little connectors at their tops are fully seated, those plastic snap clip clips may lose tension or break; also get a magnifying glass on the very ends of those connectors to check for cracks or a deformed contact. This is common enough that a "spark plug harness repair kit" is available.
Speaking of plugs & wires - closely examine the little spring clips that guide the secondary plug wires from the dual coil under the tank to the "lower" plugs - I've seen a few cases of these things damaging the insulation because they were manufactured to be very tight.
Another possibility - the temperature sensor itself.
 
From the parts fiche, stick coils were implemented starting 12/02, so '02 is the "transition" year... and bikes were probably assembled before they got labeled and paperworked for sale... Hey OP, just fer grins, what's your date of manufacture and do you have the "sticks"?
At least my other two ideas still hold...
 
BJS, After helping debug a number of Motronic driveability problems, one route that often prevents a lot of wasted parts replacement is to take a riding realtime value log to CSV file. Do you have or can you borrow a GS-911? That will surely let you know what the sensors are doing.

Also, do you have any mods to the bike which effect fueling?

You might be getting some fuel percolation in the fuel distributor or leaking at an injector. Try turning the key on five times to purge the system, then restart.
 
BJS, After helping debug a number of Motronic driveability problems, one route that often prevents a lot of wasted parts replacement is to take a riding realtime value log to CSV file. Do you have or can you borrow a GS-911? That will surely let you know what the sensors are doing.

Also, do you have any mods to the bike which effect fueling?

You might be getting some fuel percolation in the fuel distributor or leaking at an injector. Try turning the key on five times to purge the system, then restart.

I have never heard of the keyx5 trick. What does it do?
 
It’s only a suggestion based on the symptoms.

I think this makes a lot of sense. With the bike sitting for a period of time after being fully warmed up, I can see the fuel tank and other assorted systems being heated up to the point where the fuel in the lines/pump/associated items is percolated. If your suggestion works, what's the solution Roger?
 
I've recommended trying it because it's easy and needs no instrumentation. If the test works it might indicate a leaking injector, poor pressure regulator or maybe a problem in the fuel pump's check valve. I would rather be able to look at the CSV file of all realtime values during a riding trip where the problem occurs.
 
BJS, After helping debug a number of Motronic driveability problems, one route that often prevents a lot of wasted parts replacement is to take a riding realtime value log to CSV file. Do you have or can you borrow a GS-911? That will surely let you know what the sensors are doing.

Also, do you have any mods to the bike which effect fueling?

You might be getting some fuel percolation in the fuel distributor or leaking at an injector. Try turning the key on five times to purge the system, then restart.

Hi Roger,

I have made no mods to the engine or fuel system. Unless you include aftermarket metal fuel disconnects. Fuel pump, injectors and distributor are all original. Mileage is 202000 kKM. I do in fact have a GS911, but I have never used it. Never had to! Collecting these logs sounds like a great idea, but I have no idea how. I would expect one must drive with a laptop connected to the GS911?
Hmmm, very interesting. I had not put much though into the fuel system.
 
If you have a GS-911 Bluetooth you can log to an Android phone and if you have a GS-911 Wifi it has an internal logging memory. If you have a standard unit you've got to ride with a notebook in the rear case or strapped to the seat behind you. When I did that I set the notebook to never-sleep and to not power down with the lid closed, then ran a bungee cord inside the notebook at the hinge and closed the lid.

Open the GS-911 application, find realtime values and select all, then select log to CSV file, select the turbo logging speed. Ideally you turn the key on, set this up and then start the motorcycle. That way you get a cold-start log which usually has some interesting data. After you've ridden, before you turn the key off, stop logging the CSV file. It will be saved somewhere on your computer, usually in the documents folder.

Once you get the hang of it it's easy.
 
If you have a GS-911 Bluetooth you can log to an Android phone and if you have a GS-911 Wifi it has an internal logging memory. If you have a standard unit you've got to ride with a notebook in the rear case or strapped to the seat behind you. When I did that I set the notebook to never-sleep and to not power down with the lid closed, then ran a bungee cord inside the notebook at the hinge and closed the lid.

Open the GS-911 application, find realtime values and select all, then select log to CSV file, select the turbo logging speed. Ideally you turn the key on, set this up and then start the motorcycle. That way you get a cold-start log which usually has some interesting data. After you've ridden, before you turn the key off, stop logging the CSV file. It will be saved somewhere on your computer, usually in the documents folder.

Once you get the hang of it it's easy.


I do have the GS-911 Wifi. Its as simple as plugging it in and it logs to internal memory. It sounds too easy! Its a long time until spring until the testing can begin. I will give the on off trick a try as well.
 
Here is an update to close this off for anyone still interested. This past month the weather turned hot, and I was able to get away for a week tour in the mountains. Interestingly, the issue has not re-occurred at all this season. Last summer it was very consistent in hot weather. What did I do to resolve it? A clutch spline lube and inspection over the winter. In the disassembly of the bike to remove the transmission, I had to disconnect the air box temperature sensor, and the oxygen sensor. My best guess is that one of these two had a poor connection. (high resistance) Re-seating the connector must have resolved it.
 
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