Aftermarket Fuel Cap - Venting Issue?

[Jb40k]

Afternoon all,

I recently fitted an aftermarket keyless fuel cap, the CNC type from Road and Race (link to pictures of the same cap on eBay), installation was straight forward enough; however when I open the cap to refuel I get a burble and splutter of fuel splashing up.

I reused the stock rubber gaskets so presumed the tank would vent the same, has anybody else had similar issues? There are two small allen screws fitted, do I need to release them? Does anybody a little more technically minded know what might be going on?

Thanks, Lee

 

[TownsendsFJR1300]

I know it shouldn't be burbling or doing anything when you open the cap..

Doesn't sound like its venting.

I'm assuming you didn't have the tank up and possibly kink the vent hoses exiting from the tank?

That allan head screw appears it may be a drain for any water that gets into there.

You may want to get ahold of the manufacturer if its not addressed in the installation instructions..

 

[FinalImpact]

One observation is this. The ball shown in the picture, if it depresses, it may be that unseating the set screw next to it allows air to enter the tank as fuel leave. But while seated, it blocks air? IDK!

The oem cap/valve assembly has a tip over check valve to prevent fuel from spilling should you park the bike upside down from a tree.
Does the new part say anything about a check valve?

You might just see if the ball is stuck (press on it) or if the set screw being loosend allows air to pass to the tanks vent. If the ball is fixed and doesn't move. This could be a problem.

Again, a great place for a syringe. Shove syringe into vent hoses under bike and try to suck air through them (extract plunger). One drains water from the cap, the other lets air into the tank as fuel is consumed. If blocked, the engine could run lean from fuel starvation.

Could result in engine damage or fuel tank implosion. Do some checking ASAP.

 

[FinalImpact]

WELL - snooped at the other pictures posted. It appears there is NO CHECK BALL as I had thought above but what we are seeing is the end of the set screw from both directions (top & bottom). Is that correct? Auctiva Image Hosting

Auctiva Image Hosting

That said, it appears that unseating them ** may ** allow air to enter the tank. The downside is there is NO SAFETY CHECK VALVE to prevent a spill should the bike not remain in its upright position. It will simply rely on gravity and the hoses being skyward.

Look at the OEM cap and notice that little orange seal to the lid and tank. It vents there through the cap.

 

[Jb40k]

Thanks for the feedback! A quick update, I've dropped Road and Race a quick email to ask if they have any more info on the installation; awaiting a reply from them. However in the mean time, I've removed one of the screws and it seems to have reduced the 'fizzing' when removing the cap... Having read your thoughts on the cut off, I'm inclined to refit the stock cap and perhaps have it powder coated instead... I'll update again if I get anymore info.

Thanks again!