2015 F800GS misfire

[Kenoath]

Hi all, new on here. I would appreciate some advice if anyone has had a similar issue.

I have a 2015 F800GSA that I took delivery of about a month ago. Km is a bit high at 100k but it was a 1 owner bike in very good condition, and the owner had a record as thick as a bible of everything he has done, including tyre changes and average fuel economy. It was also 40% cheaper than the nearest other F800GSA.

It ran flawless for the first 500km. Low and high speed, traffic and open road. It stood for a week as the weather has been utter shite. I started it up yesterday and about 2km down the road when I twisted the throttle to pass a car it bogged and misfired. I tried again, same story. I limped to the next place I could pull over, stopped, revved the bike and all seems fine. Rode about another 15km and no problems.

The bike switched off for about an hour after I stopped, and when I restarted it the misfire was back but even at idle. After about 5-6km limping home it all but disappeared. First start up this morning and the misfire is there immediately. Tried revving it etc, to no avail. Right hand side exhaust is much colder than left.

I stripped the bike, swopped the coils and same symptoms, now the left hand pipe is cooler than the right. Bike wasn’t covered for the first 2 days and got rained on. I had a cover on it from day 3. I don’t see any signs of water close to the plugs or coils, but have sprayed everything excessively with electrical contact cleaner.

Before I replace the coil, has anyone had something else they would recommend I look at? Or go through an extensive fault finding process and replace parts that aren’t faulty? TIA


Sent from my iPhone using Tapatalk

 

[steve hughes]

Can you post on a local to you bmw forum and see if anyone locally has a GS911 to read the current fault codes? This maybe a more effective way of troubleshooting compared to swapping parts out.

Lastly whilst its a high miler with a documented service history when were the plugs changed last? As you will have realised they are buried under the dummy fuel tank so may have been missed.

 

[Kenoath]

Thanks for the reply. I will try and post locally, there isn’t a lot of BMW’s around here in New Zealand, comparing to other countries. The biking community is fairly small.

Yeah I have the bike stripped down in my garage. Used to sell BMW motorcycles at a dealer back in South Africa from 2009-2012, so have a fairly good idea on them, have done most basic maintenance and PDI’s etc. Plugs was last changed less than 1000km ago, as the owner had done the 100k service before I bought it.

Since posting I have swapped the coils around again and the one pipe is definitely cooler than the other. Swapping the plugs didn’t make a difference to the pipes temp after startup, so I’m about 90% sure the coil is done. The one coil measures in the range of what I could see on some youtube videos, the other one is way low. I have ordered the coil but no one close has stock, and eta is Tuesday next week . Guess I will have to be patient. Will update when I swopped it out and tested it.


Sent from my iPhone using Tapatalk

 

[Kenoath]

Update: I swopped out the coil that I thought was faulty, and it solved the misfire. I also reset the throttle position sensor and the idling has stabilised. Throttle response is spot on, from just above idling right up to redline. It feels more responsive and pulls better as well. Maybe thats just in my mind, but it also could be cause the coil was on its way out from before which caused performance to fall. Fuel economy is also down to 4.1l/100km on the 40km round trip I took, mixed highway and suburban that I normally ride to work and back. I averaged 4.5l/100km before. Thanks for the advice posted.


Sent from my iPhone using Tapatalk

 

[MotoRevive]

Approx 25% of the F800s I work on have one or both coils full of water/gunge/corrosion from people jet washing their bikes and forcing water past the coil seal. Or when the coil hasn't been correcly replaced to form a good seal.

When the coils aren't the issue, it's often the small hoses to the back of the airbox which control idle valve. They're small, go brittle and are often not replaced properly after a valve/plug service.

 

[slparry]

Approx 25% of the F800s I work on have one or both coils full of water/gunge/corrosion from people jet washing their bikes and forcing water past the coil seal. Or when the coil hasn't been correcly replaced to form a good seal.

When the coils aren't the issue, it's often the small hoses to the back of the airbox which control idle valve. They're small, go brittle and are often not replaced properly after a valve/plug service.

Hi Ted

Hows things

 

[MotoRevive]

Hi Ted

Hows things

Working for the Fuhrer

 

[slparry]

Working for the Fuhrer

so I heard I'm over at Triumph, being amused at the parts labels

 

[MotoRevive]

so I heard I'm over at Triumph, being amused at the parts labels

That should make you feel at home.

Ironically, most of the parts we fit to BMW's are probably made in China