My 800GS needs a ring job. It was an engine I put in that had been sitting around too long, and we speculate that a little rust may have damaged the rings. What I would like to know before the mechannic starts is whether or not the engine needs to come out to do the job. pk
Has the engine been fully warmed up to normal operating temperature, and then run under load at high speed ?
Stuck ring? Back when I used to work on small block chevy's, the cure for a stuck ring was adding transmission fluid through the carb. Made more smoke than a mosquito fogger, but often times that's all it took, which is not to suggest that you do that with your F800 engine, because I'm sure someone out there will come up with all the reasons why you shouldn't do that. :) Another thing we used to do with a engine that was full of sludge was to add a quart of kerosene to the engine oil....and then stand by to change your oil filter often. :) That's what you did back on a farm in Kansas. People were resourceful. These days we take things to the shop and bitch about how much it cost. :)
OK PK, I see you survived the trip on the other bike? So rather than question your question and ask Grandpa what he used to do on the old farm trucks and tractors, I'll try to answer you. Yes. The pistons come out the top after you remove the cylinder head. There's barely enough room to remove the valve cover let alone the cyl head. Since you don't know exactly what happened, you'll probably end up needing to remove it anyway. Wish you were closer, I'd like to see the autopsy.
Here are some pictures that might help you and google translate is your friend ;o). http://gsfr.forumactif.com/t28427-f800-gs-refection-du-moteur-1ere-partie http://gsfr.forumactif.com/t28666-f800-gs-refection-du-moteur-2eme-partie
Grandpa:eek1 I represent that remark. We used diesel fuel to unstick rings, valves and constipation. I would still do that first, if that dam thing will start. You are going to drop the engine anyway.
I'm not a grandpa yet and actually still sleeping with teenagers but I can confirm diesel works great for unsticking rings. There is no posibility of rust causing this problem as there is no ferrous metal in the combustion chamber. The valves are glass filled TI The seats are an alloy that doesent rust, same with rings. The cylinders are AL and are nik-sil coated. Pistons are aluminum magnesium alloy. Your mechanic likely thinks you have steel lined bores. If that's his thinking he's either a Harley mechanic, 1970's mechanic, or not familiar with modern technology. Ring jobs on NIK-SIL engines is different then iron or steel bores. Use the methods you would use with old technology and you will need a new block. You might want to investigate if your mechanic is up to this job. P.S. My professional guess would be that your engine is smoking because the air injection gasket is blown between the valve cover and head which takes less then an hour and $40 in parts to fix. My second guess would be that someone used shit gas and the piston lands are broken and likely engine hosed. A distant third would be that the rings are stuck which idling with a 1 fourth mixture of diesel in the oil will fix. At worst pull the plugs and pour 100ccs of diesel directly in, soak overnight then blow out by operating starter with plugs still out. It's possible that this engine can and must be repaired by replacing the rings, but if so it's the first I've seen and I've seen a lot. Good luck
Any of the tree problems I listed will cause oil usage. It could also be damaged rings or a problem with the head, I've just never seen or heard through official channels of those problems. One other thing to check. Idle the bite forever until the fan turns on and off several times. Turn the engine off then immediately pull the dipstick and check oil level and if the oil is foamed. Foamed oil can be from it being over full or clutch cover gasket being blown allowing air to be inducted through main oil line. The foamed oil ends up in air box and is atomized and sucked into induction headers. Good luck.
I offend people all the time but I don't actually mean to. I'm also 40 so can side with youth or old timers to some extent lol.