My 2012 twin has become a single....

CappoUK

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I've had my 2012 R1200RT since 2016, and until the pandemic arrived I commuted into London on it just about every day, come rain or shine. Generally it was really reliable.

After lockdown started, the bike didn't get used much for a year or so (certainly not the mileage I had been putting on it previously) but I used it a few times this year, and did a 100 mile round trip about 4 weeks ago. About 2 weeks ago, I got it out to go out, and it wouldn't run properly at all. Coughed and spluttered and if it ever tried to run, it was only running on one cylinder. It also smelt really heavily of fuel from the exhaust.

I've had someone plug in a GS911 reader but that didn't show up any faults at all. I can tell that it's the RH cylinder (as you sit on it) that isn't firing as the other exhaust gets warm when it tries to run but the RH one doesn't. I've had both plugs out of that cylinder and they are both sparking, and at one point when I was testing that, it coughed into life on the other pot and there was high-pressure fuel/air shooting out of the empty plug hole.

I'm stuck now and have no idea where to go next with it. As above, it ran fine the time I used it before, and now it's half dead. I think I'm going to have to put it into someone (Mark Holden hopefully) to look at it but wondered whether anyone had another ideas before I do?

Thanks for reading.
 
Swop over the coil caps from left to right and vice versa, and see if the problem moves to the other cylinder.
 
Thanks, I'll give that a shot.

If one coil was faulty, would it still run just on one coil/plug?
 
Thankfully you had both plugs out or you could have had a flamethrower!!!

in theory it should run on the lower stick coil?

What colour were the sparks ??

If Anything but a CRISP SHARP Violet or Deep Blue the plugs are ballixed and not firing when under compression

If you have a big fat Orange, Yellow, white, green, spark then your plugs are goosed

Were you possibly running the engine for short periods to keep the oil moving around etc etc ?
 
Thanks, I'll give that a shot.

If one coil was faulty, would it still run just on one coil/plug?

It should. But all depends on how long the main coil cap (it's the main 90% of the time) has been out. If it's not been working for a while the bottom plug starts to fail as it's doing all the work.
You may get a good spark when testing out of the engine, but they can struggle when under compression in the engine. .

Also a failed coil cap doesn't throw up a fault code on the diagnostics.
 
Thankfully you had both plugs out or you could have had a flamethrower!!!

in theory it should run on the lower stick coil?

What colour were the sparks ??

If Anything but a CRISP SHARP Violet or Deep Blue the plugs are ballixed and not firing when under compression

If you have a big fat Orange, Yellow, white, green, spark then your plugs are goosed

Were you possibly running the engine for short periods to keep the oil moving around etc etc ?

I don't think the sparks were all that great to be honest. Maybe time to change them? What with the smell of fuel, duff plugs would certainly make sense.

Are the coils "binary" in function, i.e. if there is a spark at all then the coils are working?

I can certainly swap side to side and see what happens, although that may be next week now before I get to it.

Yes, I did run it occasionally when it was standing, but usually left it to run up to temp. I realise that's not the best thing for any motor but equally didn't want to leave it standing without running. Does that knacker the plugs then?
 
That all makes sense then! I'll get some plugs ordered up and report back.
 
Just to update and close this one off. I carried on searching and testing, but eventually threw in the towel and handed it to a local specialist. The final verdict: the fuel had a significant amount of water in it. How, I don’t know. The bike has stood outside in all weathers for the past 5 or 6 years and never had this before. Whether I picked up some bad fuel, whether it was the ethanol effect, or what, I don’t know. Anyway, a tank drain and a flush through with 98RON and we’re back in business!
 


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