Rusty needle valves?

[Pendulum]

I'm giving my carbs one last attempt before I send them off to chef... And I just pulled the bowls to adjust floats and all 4 of the needle valves were rusty. There was no rust found the 1st time I tore them down.

Just curious about the causes of the rust, so I can prevent it.

[Nessism]

Rust in your gas tank.

[Pendulum]

Rust in your gas tank.

That was my 1st thought too, but I never had rust in the carbs before and there's no rust in the bowls or anywhere else, even now. The needle valves themselves are rusting. I've also got a brand new fuel filter and it's rust free. I don't see any rust in the portions of the tank that I can see, either.

[Nessism]

Crappy aftermarket needle valves from "carb kits" (not the original Mikuni parts)?

[Pendulum]

Crappy aftermarket needle valves from "carb kits" (not the original Mikuni parts)?

I believe you're on to something. As usual.

I used the needles from my K&L kits, because I foolishly thought that they were so simple they couldn't possibly have messed them up. ugh. This is probably why my bowls are overflowing really badly, as well.

[Lulu7404]

For me, the overflowing float bowls was due to the float needle sticking in the valve. I squeezed a little too hard taking them out to clean and they deformed just enough to have the needle stick and not close the hole to stop fuel flow. Had to replace 3/4.
I've been reading here long enough to agree with the above, not to use anything but Mikuni parts.

[GateKeeper]

Are needle valves steel ? I thought they were brass ? which is why I don't understnad how a needle valve can get rusty. I thought when I tore my carbs apart all needles and jets and so on were brass, I guess I didn't look close enough..

[tkent02]

The body is brass, the pointy part is some form of steel.
Maybe the Mikuni ones are stainless and the others aren't.

[Pendulum]

The body is brass, the pointy part is some form of steel.
Maybe the Mikuni ones are stainless and the others aren't.

Yeah, that's the odd part... The pointy part is squeaky clean. The body of my needle valves is what's rusty.