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Fuel Tank Removal Question

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Hi all,

So I'm about to rejet my '11 400s this weekend, which requires the removal of the fuel tank. In looking at the petcock, there is no "off"position, just On, Res, and Prime. So, my question is should I run the tank down/drain it prior to removing it? Otherwise it would stand to reason that fuel is just going to come spewing out everywhere. Am I correct in thinking this, or is there something I'm missing?

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The stock petcock is a vacuum petcock. Leave it in the "on" position, disconnected the fuel and vacuum lines, unbolt and lift off the tank, it will be fine. It won't leak. When the engine runs the vacuum created allows fuel to flow through the petcock. With the engine off the fuel won't flow (unless the diaphragm is shot)

Edited by Drz Charlie

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The stock petcock is a vacuum petcock. Leave it in the "on" position, disconnected the fuel and vacuum lines, unbolt and lift off the tank, it will be fine. It won't leak. When the engine runs the vacuum created allows fuel to flow through the petcock. With the engine off the fuel won't flow (unless the diaphragm is shot)

Sweet. I've never dealt with a vaccum petcock before, wondered how this was all going to pan out. Wish me luck, I've never done a jet change before, but based on the instructions on here I'm sure it's going to go well with minimum cursing. Unlike the tire change.

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It should be a piece of cake, no worries. As said above, disconnect all the lines and it shouldn't leak. That is one of the main drivers for many people getting a manual petcock because when they do fail, if they do fail, you will have a bigger issue on your plate.

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when they do fail, if they do fail, you will have a bigger issue on your plate.

That's a good point. I've been reading that people have issues finding ones that don't interfere with the choke knob or have the nipples in the wrong place.

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Look into Brown Family Racing or get a Yamaha Raptor Petcock or several other capable manual petcocks that fit. I plan to purchase a new tank for my bike soon and I will put a manual one on. I just like to minimize the what ifs (petcock, loctite fixes, mcct, etc)

Edited by UFboostedgator

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You can leave the shrouds on the tank when you do it also , saves undoing more bolts . But you will have to undo the 2 bolts that hold the seat on and remove that , then there are 2 bolts at the back of the tank . Once you have these out and have undone the 2 that hold the shrouds to the radiators , then remove the hoses , one for vacuum and the one for fuel . And you are good to go . If you haven`t already , I would consider the 3x3 mod while you do your rejet , it will make the bike run better and save pulling it all apart again , greg

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ya i would do the 3x3 mod since youll have it all aparrt, its easy i just used a house hold steak knife (im sure something sharper like an exacto blade would be even easier)and heated it up with a lighter, the hotter the knife the easier the cut/slice.. i did it in under 10minutes

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Guys quick q -

a couple of months back my friend was installing my trail tech vapor which required fuel tank removal. I have an SM - when we disconnected the lines, fuel came spilling out and we had to put a plug in it. I cannot remember which position the petcock was in when we disconnected the lines, but if it's a vacuum petcock doesnt that mean fuel will stay put?

The fact that fuel came out - does this mean something is wrong with my petcock?

Edited by dh0licious

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Guys quick q -

a couple of months back my friend was installing my trail tech vapor which required fuel tank removal. I have an SM - when we disconnected the lines, fuel came spilling out and we had to put a plug in it. I cannot remember which position the petcock was in when we disconnected the lines, but if it's a vacuum petcock doesnt that mean fuel will stay put?

The fact that fuel came out - does this mean something is wrong with my petcock?

Seeing you live in australia maybe he had an E model, I dont think they have the valcuum operated petcock from memory so it would have to be switched to off, if it was a SM it would have to be on prime for fuel to come out. Also you can expect a tiny bit of fuel to come out but it wouldnt be more than a shot glass.

Edited by Romie

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Seeing you live in australia maybe he had an E model, I dont think they have the valcuum operated petcock from memory so it would have to be switched to off, if it was a SM it would have to be on prime for fuel to come out. Also you can expect a tiny bit of fuel to come out but it wouldnt be more than a shot glass.

He has a SM and his friend was installing it? I think that is correct.

So, he should have just turned it off (horizontal).

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