i have the 85 push button gas cap and it leaks / emits fumes terribly so i need the updated gas filler cap.

send me some photos here or i can PM you my email or tele #

thanks in advance

-K

A replacement gasket kit 16119062461 may go a long way in remedying your issue although they are getting very hard to find. I am in Canada and had to order one from Hap's Cycle in Sarasota, Florida.

elementalfire

elementalfire wrote:A replacement gasket kit 16119062461 may go a long way in remedying your issue although they are getting very hard to find. I am in Canada and had to order one from Hap's Cycle in Sarasota, Florida.

elementalfire

I plan on getting the rubber ring around the cap mount, but from what I've read the 85 push button caps are notorious for leaking and right now a splitting headache from all the fumes.

hi to the k100 group after a very long time! my 86krs has the same prob with fumes coming out of the filler cap and is a major deterrent to riding. Kyle mb did the replacement kit solve your issue ? does everything in the repair kit get used or does it vary by model, it looks like there is a seal in the kit my cap doesn't have ( looks as it goes around the lock area) ? any trick to dissamembling the part with the wide thin seal ,gently pry ?

KyleMB wrote:i have the 85 push button gas cap and it leaks / emits fumes terribly so i need the updated gas filler cap.

send me some photos here or i can PM you my email or tele #

thanks in advance

-K

PM sent.

The replacement kit will help if your seals are bad. In my case I ended up getting a new gas cap.
I kept my original lock so all the keys would still be the same and somehow gas occasionally seeps from the key hole. Not sure how to fix that. So seals there.

HThanks for the input. Out riding today and the auto in front of me was emitting sweet fumes of an unknown origin , say around 4:20. I'm sure I would ride more often if my bike smelled like that. 

I installed the thick foam gasket on the inside top of the gas cap and that has helped some with the fumes. But I would still like to have less, is this possible? Has anyone gone on a search and eliminated fumes elsewhere on the bike?

 My exhaust doesn't seem abnormally loud( I guess it could still be leaky),I replaced the seals around the fuel injectors and the boots on the air box years ago . The bike doesn't smoke, unless it is on the side stand for awhile but that burns off in short order.

Flip2 wrote:I installed the thick foam gasket on the inside top of the gas cap and that has helped some with the fumes. But I would still like to have less, is this possible?

Is your moto's fuel tank vent clogged? That might cause an increase of pressure within the tank that could allow fumes to breach the gasket seal. Blow some compressed air through it via its port attached to the underside of the tank. Does that port dump into a cup on the frame that has a hose attached to it, or does a hose attach to the port directly then exit behind the right foot peg plate?

Forward tubing/nipple- Tank Vent
Rear tubing/nipple- Rain Drain

Do you have 85 push button cap on 85 tank? Its important because earlier cap has a breather, but later tank has a breather tube from fuel pump to cap. 
What happened to me this very hot days? I mounted 86 cap on 84 tank and experienced vapor lock very often. Engine stopped and I had to open cap to vent it. Bike started normally after few minutes. Very inconvenient in city traffic.
Finally I removed 86 cap and mounted first type 84 cap on may 84 tank. No vapor lock any more.

I will add to the confusion.....my 84 K100RT does not have a push button cap and fairly sure it never had. All runs ok and its been running in 35C+ temperatures without any issues.

My new RS does have push button cap......now its good to know about the venting.

I went for 500 km round trip on very hot day - 35 in shade, maybe 50 on the road. I noticed engine run poorly on custom control and on crossroads. I tried to cool with kill switch but it was mistake. After a minute with engine off on traffic lights it didnt restarted. What happened? When switch of engine without fuel recirculating it started to evaporate. No proper cylinder feed. 
After three minutes and several tries and after opening tank cap it started again.
When came home I decided to mount old cap which belonged to 84 tank and try to replicate problem. It never happened again even in dense city traffic. Look to me that tank with old cap was a bit cooler than with 86 cap. 
Regards

92KK 84WW Olaf wrote:I will add to the confusion.....my 84 K100RT does not have a push button cap and fairly sure it never had. All runs ok and its been running in 35C+ temperatures without any issues.

My new RS does have push button cap......now its good to know about the venting.

The push-button cap is not recommended and its foibles are described in this fiche entry.



The recommended cap is this.

Yes, I changed 84 for 86 cap after I saw that warning on the forum. But may experience was opposite. I ll stick to old cap

nino wrote:Do you have 85 push button cap on 85 tank? Its important because earlier cap has a breather, but later tank has a breather tube from fuel pump to cap.

Dobar Dan Nino

Your '84 fuel tank has no breather/vent tube?
Is this a difference between Euro and US models?

My 84 K100RT tank looks like that one, bolted down and with the electrical plug at the front left........but it has the later fuel cap AND the two spigots that come out under the tank........and they are not in that photo either

Does this mean there are two types of early tank....?? Something I was completely unaware of. Need to look under the tank on the RS...

I dont have breather tube which goes from fuel pump filter to cap like on 86 model. My original fuel pump filter wasnt connected by plastic tube with top of the tank.  
I believe early 84 cap has some ventilation.