hi fellow riders,After a ride if I open the petrol cap there is a lot of pressure that escapes is this normal or should this be venting through the breather pipes etc cheers .

Hi Rddragon,
The tank should vent, from memory early K's have a vent line fixed at the rear to a pipe which can get blocked. Later k's have a tun dish assembly which sits under the naked vent pipe and allows any fuel which by chance comes out to drain away and because it is open it stops the vent getting blocked.
Regards,
K- Bike

Hi there
Some models (IE for California) have a vent line to the crank case with a check valve, that opens at ? presure. So wen you open the tank youll feel the pressure release. There is a bulletin in the down load section with instructions to eliminate the crank case connection an the risk of oil contamination with fuel in warm weathers.
Best regards
JAP

Thanks for all your advice,been busy today fitting a alarm winterproof all conections I'm amazed what a good job the Germans made of building the k100 considering how old it is ,also I've taken the speedo apart to dry out all the moisture inside ,maplan do a large tube of anti corrosion non insulating grease so used it in all the conections and it's only £6 , tank was a bummer to remove fuel pipes very short hard to get access due to the fairing back to it tommorow .

RD,
On your bike year you have a vent pipe under the tank that hangs down.
I am sure you will find it is trapped closing the rubber pipe.
I had experienced this myself.
Ajays

Thanks for you advice Ajay will be posting pics of the new bike soon ,Ps us old ones have to stick together lol I'm 53 cheers Ian.