Reserve didn't work as expected

[MisterMagoo]

Wanted to see how much gas I would have after reserve, only problem is once I ran out of gas and put the petcock to reserve, bike wouldn't start, looked in tank couldn't see or hear a drop, 2017 yz 250x , any suggestiins on what i did wrong or what happend?

[505 YZ125]

Your question is confusing. You wanted to see how much gas you had left BEFORE reserve? But completely ran out of gas before you could use reserve? And then it wouldn't start?

[MisterMagoo]

Sorry I wrote it confusing 

i just wanted to see how much or far I could go on the reserve tank

so when I ran out of gas , I flipped it to reserve and nothing, gas was completely empty, simply there was no reserve to use

[ronbuell]

Usually one side of the tank will have some gas trapped in it.  Just lay the bike onto the petcock side (left) for a few seconds to move the gas from the right side to the left side.  Older WRs have a deep sump on the right side that will never drain to the left.  YZs have a smaller amount over there, but that petcock doesn't have a reserve.

[MisterMagoo]

I actually did lean the bike on it's side, perhaps not enough. Also this is a yz 250x the two stroke not a four stroke as I see the topic was moved

[mlatour]

With the bike level on a stand, here's a quick test:

 

Pull the fuel line off the carb and have it drain in a container of adequate capacity.

Starting with an empty fuel tank, leave the petcock in the 'ON' position and slowly add 

gas to the tank until it start to flow from the fuel line. When it flows, shut it off.

Drain the tank and measure how much gas you poured in.

 

If the value is much less than the bike's 'reserve' capacity specs listed,

suspect the petcock , pick up tube / filter assy etc. isn't assembled properly.

 

 

Edited July 2, 2017 by mlatour

[Vintage Not Pimpage]

Sounds like you had the fuel tap on reserve the whole time...