Hi everyone,

I noticed that two of the exhaust pipes from cylinder 1 & 4 were wet, while the other two are completely dry. Not sure if it just oil or a combination of oil and gasoline.  The bike has been parked for 5 month on the center stand and 4 weeks ago all fluids were drained. Does this mean that there is a problem with these two cylinders? Thanks!

bmwk100rs wrote:Hi everyone,

this mean that there is a problem with these two cylinders? Thanks!

Obviously. It could also result from a coolant leak or leaking injectors, but the most common problem is from rings and cylinder wear.
But as it affects the pair of cylinders sharing the same coil, misfiring could get to this result also.

+1 on the coil hypothesis.

Me  too on coils Change coils over and see if fault transfers as well

Thanks on the coil suggestion. Is there a way to test it without starting the bike? I cannot do that at this moment.  Otherwise, I will have to wait until I put it back together before I order new coil, if happens to be the problem.

bmwk100rs wrote:Thanks on the coil suggestion. Is there a way to test it without starting the bike?

Click on the Tech Page link after clicking on the Portal tab at the top of this page. Go to the document Troubleshooting the EFI. Scroll through it to find the coil primary and secondary resistance tests. If you don't read French and would like to learn some, split the screen on your computer, open the French text on one side, the English on the other then translate simultaneously. 

Laitch wrote:Scroll through it to find the coil primary and secondary resistance tests.

Thanks Laicth for this info.  The English version has pictures showing on how to test the coil.  The resistance measured at both primary coils was about 2.6Ω for both of my units. However, the resistance measured between the 2 high voltage terminals was about 10.6KΩ for both instead of the 12.6Ω mentioned in the troubleshooting document.  Not sure if that is still acceptable or if the coils need to be replaced since the doc doesn't say anything about the min/max Ω.  Unless I missed something, the Coil theory can probably be discarded unfortunately.

When was the last time it ran? has it spent time on the side stand prior to 5 months ago? When will you have the bike in a condition you can try and start it?

If the fluid has been there for months the to me it is either glycol or oil. Glycol is sweet oil is not.

Since you don't mention running the bike I have to assume it is a non runner and you are doing a tear down with out investigation of the engines condition before take it apart?

Have you or can you still do a compression test on it?

gorio wrote:When was the last time it ran? has it spent time on the side stand prior to 5 months ago? When will you have the bike in a condition you can try and start it?

If the fluid has been there for months the to me it is either glycol or oil. Glycol is sweet oil is not.

Since you don't mention running the bike I have to assume it is a non runner and you are doing a tear down with out investigation of the engines condition before take it apart?

Have you or can you still do a compression test on it?

The last time it ran was Dec 11, 2020.  It started perfectly cold and hot, and drove it for a couple of miles without issues. Since then, it has been parked on the center stand waiting for me to work on it. The bike only has 53K miles, and it was registered as not operational since 2007 because the previous owner could not ride it anymore. The owner's son sold it to me, but he was not able to tell me how often it was kept on side stand or started during that time.

I should be able to start it in 2-3 weeks. Right now, I'm just replacing all the fluids, worn parts, etc.

With the coil theory out of the picture, I will run a compression test as soon as I can start it.

Sounds good. Once you are at place where you can start it again you will have much better idea there are problems. If it started and ran fine before you started cleaning it up then I would be to concerned at this point.
A compression test is always a good basic starting point if you have concerns. I assume the cooling system was full before you drained it? If that's the case then you can likely rule out a coolant leak as over time it would have likely lowered the level.
My thoughts have always been if it running decent ride it. You can always worry about the details latter.