Recoated my gas tank

[Mobrules]

I was advised to get some POR 15 and recoat my tank. There was a lot of crap in it. Glad I did it. It was a pretty easy process, following the instructions and a lot of rolling the tank around.
The only problem I have is there are 2 places to connect hoses, one is obviously the fuel supply. Not sure what the other one is for, but I might have plugged it up when I sealed the tank. Could someone explain the function of this hose and what problems I might encounter if it is plugged? And if there is an easy solution.

 

[marsmax85]

small hole is the drain and bigger holes fuel sender

 

[Mobrules]

Might need more descrpition. There are 2 tubes on top of the tank. 1 connects to the fuel filter, the other one is smaller and goes to the carbs i assume, didnt really look. any way the smaller metal tube on the top of the tank, toward the rear on my 86 vmax may be plugged after recoating the tank. While I was coating I tried to make sure it did not get plugged. The hole in the end is very small. I blew air through it to make sure it was flowing, but by the time the sealer hardened I was not able to blow air through.

Not sure if I should use a drill and drill it out or what

 

[marsmax85]

you have a rollover tube also ..

 

[marsmax85]

Also on boats.net you can look at parts breakdown on the vmax Click on yamaha parts

 

[Mobrules]

May have found the answer to my problem. The tube i have been referring to is the vent/rollover line. I believe there is a check valve in the end of the tube where the hose connects. Not sure if it will cause any issues but I am not going to drill it. Instead I will try not to free up the valve, which is going to be a pain if the tank sealer is plugging it. If it becomes an issue with my bike running properly I will look for another solution. Maybe I can drill it out and find a replacement check valve some where
Thanks for your replies

 

[[email protected]]

On top you have the fuel pickup and the tank vent. The vent has what looks like a brass bushing pressed into the end of it. The brass part has a small orifice in it to allow the tank to vent. It attaches to the rubber tubing that routes down the front of the battery box, thru a check valve, and eventually ends in a spring holder attached to the oil pan.

The breather needs to function or else the fuel won't flow to the carbs. I'm not sure what size the orifice is. You may be able to poke thru there with a needle. If not, a tiny drill. I've never heard of anyone trying to replace the brass part so I'm not sure how it comes out of the tube or where to get a replacement. Worse comes to worse I'm sure the tube could be cut closer to the tank and you could fab some kind of restrictor.

 

[[email protected]]

May have found the answer to my problem. The tube i have been referring to is the vent/rollover line. I believe there is a check valve in the end of the tube where the hose connects. Not sure if it will cause any issues but I am not going to drill it. Instead I will try not to free up the valve, which is going to be a pain if the tank sealer is plugging it. If it becomes an issue with my bike running properly I will look for another solution. Maybe I can drill it out and find a replacement check valve some where
Thanks for your replies

We must have been posting @ the same time.

There is a check valve but it is located in front of the battery box. It has rubber hose on both ends. One end goes to the tank, the other end to atmosphere near the oil pan.

The tank has a restrictor in the metal vent line. The restrictor has a small orifice in it. It needs to be open.

 

[Mobrules]

Thank you, that makes sense. I'll see what I can do to get it open.

 

[marsmax85]

maybe thick strand of piano wire on end of a drill to bore hole thru coating

 

[davesax36]

I poked a violin string through mine. I know air can travel, but I'm sure it's reduced from normal. I don't think it really matters as long as the pressure can be released. It shouldn't change that fast.

 

[[email protected]]

I poked a violin string through mine. I know air can travel, but I'm sure it's reduced from normal. I don't think it really matters as long as the pressure can be released. It shouldn't change that fast.

Pressure release is just one part of the need. The breather also needs to allow air in to replace the empty volume left as the fuel is pumped out.

Every try to use a fuel transfer pump in a 55 gallon drum without removing the breather cap? The pump tries to implode the can as it creates a vacuum inside. The pump will strain and get hot and output is dramatically decreased. Eventually, there will be no output and the pump will fail and the 55 gallon drum will look like it was attacked with a sledge hammer.