Topic: Red Stuff on Gas Cap

[kennyle]

So I just got this bike a few weeks ago and its been in the shop since. Anyways, carbs were looked at and now bike is running good. Went to the gas station to fill her up and I noticed hard red stuff on underside of the gas cap. I also looked inside and noticed rust so it looks like I need to clean the gas tank this weekend. I was just wondering what in the world is this solid red build up? Is this what gasoline and oxidation does to it? I just want to scrub this damn thing clean already.

and the tape was to just block things from falling into the tank.

[Stev-o]

That looks odd, is it very hard or soft? If hard, it could be some type of liner that was applied to it.

[kennyle]

its very hard stuff. Have to file this crap off or something. Just noticed it lines the gas tank as well. =/

[kennyle]

I just searched up red liner motorcycle gas tank and something called Red-Kote came up. It might be it...

[chewbacca5000]

I just searched up red liner motorcycle gas tank and something called Red-Kote came up. It might be it...

+1  Make sure that the vent is clear or you could run out of gas going down the road, and have to open the cap to keep the fuel flowing.  Ask me how I know.

[CycleRanger]

Yeah, it's red-kote.  One of the bikes I just bought has that in the tank too.
Looks like crap, especially on the underside of the gas cap.

[carnivorous chicken]

It's Redkote. It's a decent liner, I lined a tank 5 or 6 years ago with it and it's still fine, and easier than POR-15. Doesn't always look the best inside, and can turn filters pink for the first couple of tanks of gas.

But the comment about the vent being clear is a good one -- check that. But I wouldn't worry about the liner.

[kennyle]

It's Redkote. It's a decent liner, I lined a tank 5 or 6 years ago with it and it's still fine, and easier than POR-15. Doesn't always look the best inside, and can turn filters pink for the first couple of tanks of gas.

But the comment about the vent being clear is a good one -- check that. But I wouldn't worry about the liner.

I just searched up red liner motorcycle gas tank and something called Red-Kote came up. It might be it...

+1  Make sure that the vent is clear or you could run out of gas going down the road, and have to open the cap to keep the fuel flowing.  Ask me how I know.

I'm really new to this but after searching it up I think you guys are referring to the vent line coming from the gas tank to the carbs?

[carnivorous chicken]

No, there is a vent under your gas cap that prevent your tank from making a complete seal -- meaning that gas won't flow to your carbs. It's that little nub looking thing on the underside of the cap (that is now colored red). If that gets clogged (by a sealer, for example, or bits of crap get in there somehow) it'll block it and your bike will die due to fuel starvation. You can clear it with a pick tool or even drill another small hole in the underside of the cap (not all the way through the cap -- there is space between the rubber seal that goes around the underside of the cap and the top side of the cap to let air escape. These vent blockages can sometimes become known after you change the gas cap seal -- old, cracked ones don't seal so the vent blockage isn't apparent.

You can test it by firing it up with fuel in the tank and the cap open, then close it. If it dies shortly (a minute or two) then that's your likely culprit. A clear inline fuel filter will also let you see if/how well gas is flowing to the carbs from the tank.

[carnivorous chicken]

just looked at your photo -- you don't have a gas cap seal. The vent I am talking about is on the right hand side of the cap (if you're sitting on the bike, to the right). Get a seal -- Ebay sellers have them for around $10. Then check that vent.

[kennyle]

No, there is a vent under your gas cap that prevent your tank from making a complete seal -- meaning that gas won't flow to your carbs. It's that little nub looking thing on the underside of the cap (that is now colored red). If that gets clogged (by a sealer, for example, or bits of crap get in there somehow) it'll block it and your bike will die due to fuel starvation. You can clear it with a pick tool or even drill another small hole in the underside of the cap (not all the way through the cap -- there is space between the rubber seal that goes around the underside of the cap and the top side of the cap to let air escape. These vent blockages can sometimes become known after you change the gas cap seal -- old, cracked ones don't seal so the vent blockage isn't apparent.

You can test it by firing it up with fuel in the tank and the cap open, then close it. If it dies shortly (a minute or two) then that's your likely culprit. A clear inline fuel filter will also let you see if/how well gas is flowing to the carbs from the tank.

Ahhh damn, I've been on here for only a couple of weeks but I've learned so damn much already because everybody is so helpful. Thank you.

And about the seal, I took it off prior to taking the picture because I was ready to clean the thing but decided to be patient and ask the experts on here just in case its something harmless which in this case was just Red-Kote.

[Mantree]

It looks like crap but seals well

Sent from my ME302KL using Tapatalk

[Johnie]

Looks like whoever put that Red-Kote in dumped it in the tank and shook it around in there. Most guys will protect the cap and vent. You should be able to put your mouth on that vent hole in the underside of the cap and blow through it. That is how I check to be sure mine are clear. If not clear your tank will create a vacuum as you run it and it will impede gas flow to the carbs. The Red-Kote I have in one tank has held up well.

[Scott S]

 You can actually see the gas cap vent in the first pic. It's at about 3 o'clock. It's the little tent shaped piece sticking up. You may be able to run a small pick or pin through it to make sure it's clear.

 And, yes, that's Red-Kote. Pretty decent liner but it looks like someone did a messy job of installing it. This is Red-Kote in my '84 BMW tank. If you dilute it slightly with acetone it spreads better and more evenly. Too late for your tank, but for future reference.