riding to work after a exceptionall damp night resulted in savage misfiring and cutting out , the bike (1985 k100rs) would tick over as normal and run fine then suddenly drop onto what felt like 1 cylinder and stagger along at 20mph for variable distances. Closing the throttle seemed to clear the problem then as i re open it the cutting out returns. I have recently put the bike back on the road and it smoked quite smelly as if burning very old fuel so i added a fuel stabiliser in the hope that would clear the problem. Also the fuel cap rubber seal wasnt centrally mounted so i think 2 possible problems, i either disturbed some crap in the fuel system or water has got in the tank or ignition.....

If anyone has experienced similar id be intrested to hear,

Jez

hi jes ,,,welcome to the forum

sounds like you need a good cleanout of the fuel system at least .

condensation is quite likely inside the tank ...but in addition to that best to check all the fuel rubber , including the rubber inside the tank ...we have seen colapsed fuel lines which has all sorts of consequences including ruining fuel pumps (expensive) a new fuel filter wouldnt go astray after possibly replacing all the lines if rubber is noticed on your fingers from handling the rubber inside the tank ...worth mentioning is the fuel pump suspension rubber in the fuel tank ...

there have been lots of posts in here about this ....and you might search for some of them using the search feature .

electrical connections are always an issue on bikes of this age ..and should be checked and cleaned throughout ....start with the ignition coils ..secondary leads ...and all the stuff under the tank ...

i wouldnt be surprised if there are a number of issues that need to be found ...

we love a product in here called deoxit ...great for cleaning all the connectors ...look it up you wont be disapointed

hope that helps some ....and good luck ...

thanks charlie thats great stuff and it all helps , i noticed a similar post on the k75 section all suggesting similar things and mentioning the loom connector that runs alongside the right front corner off the battery so ill give that a re-wire too

jez

Hi Jez,
Worth also checking the condition of the ignition leads. I generally give the inside of the metal spark plug connectors a good spray with the aerosol silicone to help repel water and also to stop the rubber in the boot sticking to the ceramic of the spark plug.
Regards,
K-BIKE

Sounds like a fuel starvation problem to me so the pump, filter and maybe even the injectors need some attention. Condensation in the tank results in water gathering right where the pump draws from and those pumps don't like water one little bit.

dont forget to check the fuel supply connector ...under the righthand side cover.... if its corroded clean it up and check that it is a tight fit

thanks fellas its all really as i suspected but the specific experiences off you all helps a lot , the loom under the right panel infront off the right front corner off the battery has been re-connected with bulletconnectors and looks very suspect... ill repeat its only a damp weather problem so far , the motors as smooth as frank sinatra in the dry way beyond 1*0 mph......

thanks to all who replied , Jez