Fuel shut off?

[yechave]

I was reading; everything you need to know "Motorcycle Touring", by Dr. Frazier. There were a number of references to shutting off the fuel supply from the tank if the bike went down. Does the R1100RT have a fuel shut off, and if so, where is it?

 

Thanks!

[russell_bynum]

Your RT does not have a fuel shutoff valve (Petcock).

[Ken H.]

Nor does the RT (or any BMW bike that I am aware of) have any type of sensor that shuts off the fuel pump in the event of a tip over or similar.

[Joe Frickin' Friday]

Nor does the RT (or any BMW bike that I am aware of) have any type of sensor that shuts off the fuel pump in the event of a tip over or similar.

 

You're right, there's no tipover sensor. The bike will keep running on its side until the engine seizes from oil starvation.

 

That said, the fuel pump runs only when it is triggered to run for a short period every time there's a blip from the HES (those short run periods overlap to cause continuous fuel pump operation when the engine is actually running). So as soon as the engine stops running, the fuel pump will also stop.

 

A fuel leak will not shut things down unless it is sufficiently large to cause a loss of fuel pressure at the injectors (i.e. starve the engine of fuel). IOW, a nicked fuel line is potentially hazardous since it will keep spraying fuel as long as the engine's running, but a totally severed line will cause a rapid shutdown.

 

The fuel pump is a positive-displacement device, so if it's not running fuel will not drain through that line. Unfortunately the same does not seem to be true of the return line downstream of the pressure regulator: if there's a rupture there, fuel will flow freely. Thankfully, that portion of line is not under pressure, and so the only time you'd expect a failure is from abrasion (haven't seen any issues yet after 125K mile) or a major crash.

 

although it certainly doesn't hurt to shut the fuel supply off on a carburetted bike after a crash, The fuel petcock is not particularly a safety item. It's there to prevent flooding of the carb during storage due to a possibly sticky float needle. Not only is it not necessary on a fuel-injected bike (like your BMW), it could also cause problems if a (hypothetical) petcock were to be accidentally left closed when the fuel pump was turned on (as when turning the key on).

 

Although the fuel plumbing setup on a BMW bike is basically the same as a modern fuel injected car, it's interesting to note that a ruptured return line won't cause a problem on the car (since the fuel in the line will just drain back to the tank, the lowest part of the system) but could potentially empty the bike's entire tank onto the ground.

[NoHeat]

So to answer the question in the OP, the kill switch also serves the role of fuel cutoff. If your bike tips over, hit the kill switch and you will not only turn off the engine, you will also stop the fuel pump. Is that right?

[Joe Frickin' Friday]

So to answer the question in the OP, the kill switch also serves the role of fuel cutoff. If your bike tips over, hit the kill switch and you will not only turn off the engine, you will also stop the fuel pump. Is that right?

 

In a simple tip-over, yes. But if the bike is involved in a crash that ruptures the return line, fuel is gonna leak out and there's not much you can do except retreat to a safe distance and tell people to put their cigarettes out.

 

The one thing I can think of in such a case (i.e. a ruptured return line) would be to leave the bike on its left side. Since the fuel return line is on the right side of the tank, this would eliminate the gravity feed of fuel from the tank to the return line.

[smiller]

The bike will keep running on its side until the engine seizes from oil starvation.

Has anyone retrofitted a lean sensor (say from a Honda) to an oilhead? Seems like an easy mod that might save the engine from damage and would also serve as a fuel cutoff (by stopping the engine, thus the HES pulses.)

[T__]

Actually if they (BMW) tip over hard enough like in a crash the fuel pump usually quits pumping fuel out the pressure line anyway as the pump usually comes loose & breaks the plastic hose outlet fitting off the fuel pump..

 

Don’t ask for a tip over switch as those things are prone to problems as the miles go by.. Have failed the tilt switch on both Harley’s & GoldWings with roadside patch wire required to get going again.. In fact my last ElectraGlide would cut out when leaned way over in a tight turn due to the tilt switch triggering..

 

If it’s a low speed tip over then just hit the kill switch.. If it’s a high speed crash you probably are not still on the bike anyhow so fuel leakage is not a problem for the rider just the insurance company..

 

Twisty