Hi This bastard leaks. I think it's because of this little bastard hole. Happens with very full tank on hard acceleration. Never had a fuel cap like this before. Q's: Are they supposed to have this hole (must do). Breathing? Is something missing? Is it just a design fault? Do racers only use 2/3 tank of fuel?
The mounting, in the tank itself, that plate. There is a hole, it looks like a small hole. There is supposed to be some small tube thingy on it. The cap closes onto it.
When the cap screws down it is a long way off sealing the hole. Is that hole there to let air IN as the fuel goes down? The tubing should be on the inside?
When you take the cap off is the tank pressurised ?,is there a rubber o ring on the screw cap ?.I blocked the breather hole on my Panigale and the cap leaked,i had put the gasket on the wrong way round,i also kinked the breather pipe and the tank pressurised,nearly blew the cap out of my hand.
Is it national tank day today or summat? Three different convos today on tanks WTF... OK see where I'm pointing to on this 999 tank - there is supposed to be some kinda weird little kinda mushroom tubey thing attached to the top of that pipe I'm pointing to. You know the fuel builds up a lot of gas inside the tank innit?
Got something like that on the OEM fuel cap. This cap has nothing like that. The screw down cap is way off the hole internally as can be seen with this hex key stuffed in. And on the outside So it all fits together like this And you can see the hole. So with a full tank when I accelerate hard the fuel sloshed up and goes through the hole into the well in the tank the cap sits in and sloshes about and then eats my paint.
So maybe there should be a small tube that connects this hole to that vent with the rubber bit? Is that what you're explaining to me?
Yes that what I was trying to say - that ring thingy on your OEM cam goes over that tube in the base. I can't tell from the photos whether you'd have enough room to route a small hose to it. What's also strange is that hole in the filler neck, my guess is that's their way of venting it, I dunno? it's strange because with your OEM vent the gas escapes via that ring/mushroom thing but the petrol doesn't. I guess the tank would have to be pretty full though for the petrol to come out of it. What I originally thought was that you'd omitted to fit that ring thing, but even if you did that the fuel would still escape from where it already is... you could see if you could route a pipe to it but then how would the gas escape??
Ah! Is the front tube blocked?? I think the front one is a drain into the tank, when you have had a leak and take the cap off does the front 'well' have fuel in it??
...so the excess fuel comes out of that hole in your cap, drains into that well and back into the tank instead of out over the front of the tank
No, never been to Bruno. This is the hole, 3mm I think. This is how it fits in the tank. This is my tank stripped.
Ah mate I'm sorry but I can't help, I've a few different racing 999 caps but none of them fit like your one I'm afraid, I assumed that hole faced forward. Very odd indeed! Do you who made that cap? My only suggestion would be to contact the manufacturer and ask them.
I found a similar one on eBay from a German store.messaged them earlier but not holding out much hope..... You think the hole should let air out or in or both?
I think the hole on the side is a pressure release thingy and the hole at the front is to drain any excess fuel around the cap area, or overspill from filling, back into the tank, if they are unblocked of course.
