petcock issues???

[lncoln]

I used to hit reserve when the gauge needle touched the red. Now, the past 3 fill ups, i hit reserve when the gauge reads half a tank...yes i visually verified this, bike is running the same, no kinks in lines, and vacuum is good. It also has rained...and my cover is only water resistant (gas cap is brand new, and seals properly), but my bike still gets a little wet.

Could this be my petcock going out? Or do i have contaminants in my tank that are heavier than gas? Any input is appreciated.

[92xjunker]

It is possible have you tested it or tested the fuel for water?

[Kreylyn]

I used to hit reserve when the gauge needle touched the red. Now, the past 3 fill ups, i hit reserve when the gauge reads half a tank...yes i visually verified this, bike is running the same, no kinks in lines, and vacuum is good. It also has rained...and my cover is only water resistant (gas cap is brand new, and seals properly), but my bike still gets a little wet.

Could this be my petcock going out? Or do i have contaminants in my tank that are heavier than gas? Any input is appreciated.

Your petcock has 2 inlets side by side. Switching to reserve simple switches with inlet it uses to allow fuel to flow. The reserve inlet is just lower.


It works something like this petcock (Just an example, not a Katana petcock!)





If you switch to reserve, you ARE pulling from lower in the tank.


The most likely issue is that your having a flow issue. This could be the petcock is not opening enough, or there is a partial blockage in the fuel lines, or you have an in line fuel filter that is partially blocked (or the wrong one).


The reason; The full tank puts enough pressure to flow fuel faster... as the pressure is reduced by the lower level, fuel flow slows down till it can not keep up with the use by the engine. Switch to reserve, you are pulling from a lower point, increases the pressure again.


Krey

[lncoln]

No, i haven't tested the fuel for water.

I threw the inline filters away when i first bought the bike lol...as for the fuel draw, maybe my filter in the tank is clogged on the top portion? As your explanation implies...makes sense. I'll pull the petcock and check the filter. I'll also drain the tank.

Thanks guys.

[Kreylyn]

No, i haven't tested the fuel for water.

I threw the inline filters away when i first bought the bike lol...as for the fuel draw, maybe my filter in the tank is clogged on the top portion? As your explanation implies...makes sense. I'll pull the petcock and check the filter. I'll also drain the tank.

Thanks guys.

Fuel is going to get past the screen where ever it can. If the screen was partially clogged, it would be all over. I'm doubting that's the issue but an easy check.


I would check the fuel lines and confirm they are re-enforced fuel lines, and not vacuum lines. Vacuum lines will collapse when hot, and reduce the fuel flow.


Kinks in the fuel lines will reduce flow.


Reduced flow = higher pressure will push more through but that decreases as the tank level goes down.


I would also check your petcock diaphragm is not damaged, and the petcock is functioning properly. If you have a hole in the diaphragm, that would release some of the vacuum and not allow the petcock to fully open = reduced fuel flow.


Finally confirm your vacuum line is not damaged or kinked, and is properly sealing. Again, vacuum leak there will cause reduced flow.




Krey

[lncoln]

Fuel lines are reinforced triple walled...made sure when i replaced em after purchase, they would last. Vacuum line is brand new, and thick walled...no leaks or kinks in it.

I'll check the petcock fully...bike has 50k on it, so I'm sure it's all original.