Rusty Gas cap/Parts Cleaning

[Peteroo]

Any recommendations for cleaning/cleaning chemicals a crusty bottom of gas cap and petcock? I have an ultrasonic cleaner and thinking i might try some evaporust(will have to look at content to see if its harmful to heat). Petcocks are made of some sort of s**t metal so idk what could harm it. Little worried about all the plastic bits too.

[ricksax]

Evap-o-rust is a mild acid, environmentally friendly. It should work on the gas cap bottom-- just sit it in a dish with a shallow amount for 24 hours. I wouldn't get it in the lock mechanism. Replacing the petcock would be best, I don't know if they are still available.

[mparker]

I think Hord still has Petcocks.

[Zanderk]

Weemoto in the UK also do a full replacement petcock

[DrPMC]

Caustic soda works well with aluminium parts but should be used carefully as it will eventually dissolve them. I wouldn’t use caustic on the petcock as it may be made of a zinc alloy and that very readily dissolves. I’d use wire wool by hand or one of the little scotchbrite type buffing mops with a Dremel. I’ve also found that stainless steel pan scourers work very well for cleaning all sorts of manky metal parts, without being too harsh.

The petcock can be rebuilt, but requires drilling out the rivets and tapping for screws.

It may be that the parts of the fuel cap are also zinc alloy too.

[Peteroo]

im a cheap skate on this build right now, so i might rebuild the pet cock unless i have a spare cb900f petcock leftover. Il tryout the evaporust, looks like its pretty gentle

[Captain 80s]

Don't use Evaporust on the Gas Cap (or anything aluminum). Buddy ruined his using it temporarily while the tank was upside down to clean up the top. Ate the aluminum and fucked up the venting. We watch his gas cap bubble and spit at stops if you flip open the key cover. He can no longer use a tank bag.

[riot]

Regular vinegar works well. You have to let it soak for a long time though (24 hrs at least). Recently used it for a set of carbs and it was great. It's rubber safe and hard to screw up.

Muiratic acid is quicker, but you risk over etching if you leave it too long.

[Peteroo]

ok errored on side of safety and used some vinegar. seemed to help clean it up. Cap is pretty chewed up along the inner ID of the rubber seal but possibly usable. I will let it soak for a while longer. The petcock may be a gonner tho

[ricksax]

Don't use Evaporust on the Gas Cap (or anything aluminum). Buddy ruined his using it temporarily while the tank was upside down to clean up the top. Ate the aluminum and fucked up the venting. We watch his gas cap bubble and spit at stops if you flip open the key cover. He can no longer use a tank bag.

This is my error, sorry. I thought the cap was steel. It certainly feels heavy. I replaced mine with an inexpensive aluminum Chinese version which does not lock.