Fuel tank question, riding on the street

Here's maybe a weird question: my R is set up for supermoto and riden almost all on the street. I was doing some work on it the other day, had the fuel tank off, and noticed how deep each of the tank's side-chambers are, on either side of the center channel (where the bike's frame passes through the center of the tank).

It occured to me that without a lot of bouncing and side to side motion, fuel from one side-chamber would not be able to "slosh over" to the side of the tank where the fuel petcock is.

So here's the Wierd-question-of-the-week: will a street riden R go need to be prematurely switched to reserve, even though the other side of the tank was still almost full of fuel? Seems to me that would happen unless the bike saw a lot of side to side / bouncing motion (like you'd normally have offroad). Is that true or am I missing something?

I ask because several times when I've been out on a ride I've had to shift the fuel cock to reserve, when I didn't think I had riden that many miles...

If this is true then obviously all you'd need to do is give the bike a couple of good shakes to move the fuel into the right-side chamber....

[i said it was a weird question.]


"Perplexed in Pennsylvania"

Dude I got the big IMS tank on mine I think its like 4.7 gal, and its sloshes some when riding offroad but when Im on reserve and its almost out of gas I literally have to lean the bike way over to the ground on the right side to get the half gallon on the left to the petcock side

I've run out of gas three times on the same fill up. Going to reserve, laying it on it's side and then I turned her completely upside down and rubbed her belly. This was good for another 10 miles.

It can happen.Once I ran out of gas even after switching to reserve,I managed to get a couple more miles by laying it down on its side.Good insurance tough.

I am begining to think you are right. I ran mine out of gas and ran on the reserve for a good 10+- miles. When i went to the pump to fill up it only took 1.9 gallons to fill. Theroretically it should have took 2.2-2.5 gallons.

That is if the stock tank is 2 gallons plus a .6 gallon reserve.

Have the same problem with my 650L and its IMS tank.

I've run out of gas three times on the same fill up. Going to reserve, laying it on it's side and then I turned her completely upside down and rubbed her belly. This was good for another 10 miles.


I think you have to lay the bike on it’s right side to get the fuel over to the petcock side. I have the IMS 7.0 gal tank and it has fuel lines from both sides that go to a vacuum pump that pumps the gas to a chamber where it can gravity feed to the carburetor. The petcock is located in the same place as the stock tank.

This means that the fuel is actually carried lower and you don’t ‘loose’ the capacity on the left side of the tank while running. Of course, it also has three times the capacity if you fill it to the top.



This tank also works with the Baja Designs Dualsport directional signals and if properly braced at the bottom front mounts will protect the radiators. You don’t have to fill it all the way up, just put in the amount you need and the bike will actually ‘feel’ lighter than stock.

With the IMS 4.7 (actually holds 5+) it is VERY difficult to get every last bit of fuel out of the left side of the tank. The other day I was almost empty--rolled the bike onto a curb and leaned the bike over onto the low side. Basically I was able to get the bike completely flat with the ground. I still couldn't get all the gas over to the right side of the tank. I think you'd darn near have to turn the thing upside down to get that last 1/4 or 1/8 gallon or so. Or siphon it out...

Thanks to all that replied. I guess I was not crazy with my thinking at least on THIS one... :thumbsup:

Ride safe. :thumbsup:

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