2005 f650gs sudden increase in revs & loss of power

[chloechrisSA2011]

We are currently in Chile (on our way to Vancouver) and we have developed a little problem with one of our F650gs.

While cruising, usually around the 4000rpm mark, Chloe's bike has developed a little problem when she opens the throttle to accelerate quickly i.e. when over-taking. What happens is the bike looses power and the revs shoot up to 8000rpm but the bike DOES NOT respond with an increase in speed. It feels (and looks like) it jolts just before it looses power, the revs then hit 8000rpm. After it has hit 8000rpm they stay high and once the bike has pulled over and idles it revs at 3000rpm.
Turning off the engine and starting it again clears up the problem but it will happen the next time we try to accelerate quickly.
Today is the first time this has happened, the bike is ridable but the issue prevents us from riding in a normal manner.
Recently, we had a 'minor' problem when the bike ended up on its side in a river, we drained all of the water and got it running to get us home. We changed the oil (3 times) and are now running with low quality oil (to clear the rest of the water) which will be changed after . . say 1000km. This was 5 days ago and since then the bike has been running fine.
I am tempted to swap the injection units between the bikes to see if the problem jumps, other than that im a little stumped?

Ideas greatly appreciated, thanks in advance.

Chris & Chloe
BUENOS AIRES to VANCOUVER | Chris, Chloe & two motorbikes across South, Central & North America

[palace15]

Sounds like clutch slip, check the free play at the lever and then on the clutch adjuster, good luck

[bubbla]

....might also be caused by using this low quality oil, which just does not work with your clutch. A regular car oil does not have the the neccessary additives to operate a wet clutch.

Good luck!

[chloechrisSA2011]

. . .the poor oil we are using is looking more and more like the cause of the fault, its being changed as soon as possible and hopefully the new oil will have the necessaries to free up any problems we are having with the clutch.

As soon as I have a solution (or not) I will be straight back with the results.

Many thanks guys.
Chris.