Tank vent pipe question

davesax36 · Nov 16, 2013

Why does the tank vent pipe have such a tiny restrictor hole on the end? I ask because I sort of filled mine up a bit with Red Kote when I was treating tanks. I guess I let it sit the wrong way a little too long, and the excess didn't drip out of there. I've reamed it out with a violin string, but it doesn't flow too freely. I'm thinking about just cutting it off, removing the Red Kote from the little pipe, and making a new restrictor with jbweld or something. Any thoughts? Will I need to also replace blinker fluiid and have my carb chains rebuilt?

dannymax · Nov 16, 2013

davesax36 said:
Why does the tank vent pipe have such a tiny restrictor hole on the end? I ask because I sort of filled mine up a bit with Red Kote when I was treating tanks. I guess I let it sit the wrong way a little too long, and the excess didn't drip out of there. I've reamed it out with a violin string, but it doesn't flow too freely. I'm thinking about just cutting it off, removing the Red Kote from the little pipe, and making a new restrictor with jbweld or something. Any thoughts? Will I need to also replace blinker fluiid and have my carb chains rebuilt?

Not sure about the blinker fluid but those carb chains were moly-arc'd here at BRC and never need rebuilding.

unk:

tothemax93 · Nov 16, 2013

I know Danny does a good job with the carb chains. I've struggled with finding a good source for blinker fluid. I decided to make my own and its works so much better than any I have gotten from the store. It's so good I've decided to sell it. Its a little pricey, but you get what you pay for. Please send your checks to .........:eusa_dance:

davesax36 · Nov 16, 2013

So I can go ahead and cut the vent pipe?

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Miles Long · Nov 16, 2013

davesax36 said:

Why does the tank vent pipe have such a tiny restrictor hole on the end? I ask because I sort of filled mine up a bit with Red Kote when I was treating tanks. I guess I let it sit the wrong way a little too long, and the excess didn't drip out of there. I've reamed it out with a violin string, but it doesn't flow too freely. I'm thinking about just cutting it off, removing the Red Kote from the little pipe, and making a new restrictor with jbweld or something. Any thoughts?

Click to expand...

davesax36 said:
I removed the restrictor, as well as the attached vent tube and tip-over valve, years ago, as part of an auxiliary gas tank modification.
My only guess as to why the restrictor has such a tiny hole is that Yamaha wanted to limit gas leakage in the event of an upset, even though the tip-over valve works very nicely. Or perhaps the small hole provides redundancy, in the event that the valve fails.
In any event, the design shows how little area is required to vent a tank of this size.
The restrictor is hard to get out. I think I removed the one on my bike by partially tapping the orifice, and then using a slide-hammer arrangement to jar it loose. If you decide to renew the restrictor, perhaps a tight-fitting piece of rubber with a tiny hole drilled into it would be easier than the JB Weld. Or maybe a piece of coaxial wire, with the wire removed.
Cheers!