Bike (mysteriously) won't start...again...3rd time.

[Fitz]

Preamble: I had reason to believe that my air filter was in need of some attention. In order to check it, I had to remove the tank. I did this by simply unbolting the rear mount and spinning it around to rest on the area where the seat normally resides. Check the air filter, it was dirty, ordered a new one, cleaned and re-installed the old one (for the time being).

I put everything more or less back together and started the motorbike just to be sure. It started and I let it run for a couple of seconds.

The next day, I attempt to start it. It hesitates and doesn't really start. Removed the seat, etc. and unbolted the tank to see if anything was amiss. When I removed the breather hose with the check valve(?) attached to it, there was a distinct hissing noise. I think maybe I reversed the breather hoses (there are two, one with the check valve and one without) and possibly fuel was not flowing. Attempt to start and still nothing (starter is turning over, engine is not "catching"). I removed both breather hoses and attempted to start that way.

Twice before I have had no-start issues due to the tip over sensor. Therefore, I'm thinking this is rearing it's head again. On a 2006 Sprint, where is the tip over sensor located and are there any distinctive markings on it (e.g. part number)?

Before you ask; the kill switch is on, the clutch is disengaged and it's in neutral. The starter would not engage otherwise. There is a full tank of gas.

Suggestions?

Thanks in advance.

[Calliway]

Sounds like your two breather hoses that are on the bottom of the tank are either off or reversed.

[iceman]

... the front fitting breather hose vents the tank and has the valve in it.It stops your tank emptying out if the bike is laid down.
The other hose is the drain from around the filler opening - water, spilled fuel.
The vent hoses being off wont stop the bike from starting.
The hissing sound is interesting - you should be able to suck and blow through the tank vent hose as long as the valve is in the vertical position.
There have been instances of kinked hoses - I had one

Grant

[Triple Ripple]

I noticed when my hose was kinked or pinched that it proved very hard to open the gas cap due to the partial vacuum inside. There was a great sucking of air when I finally got it open. Just a guess on my part that maybe you have a kink or a blocked line and the low air pressure is affecting the fuel pressure. Though I don't recall any performance issues when this happened.

[Fitz]

Triple, I've had the sucking noise from the tank also when opening the gas cap. But that was right after the bike was running (i.e. pulling into a gas station).

Calliway. Thanks for clarifying the hose location. I think they pulled off when I moved the tank initially and I wasn't sure which went where.

As for the tip over sensor. Where is it located and what does it look like?

[Fitz]

Er, rather, Iceman, thanks for clarifying.

[CLB]

The tip sensor mounts to the underside of the front tank bracket with two through bolts.

Do you hear the pump prime for several seconds when you switch the ignition on or is all quiet? If you hear the pump prime you can ignore the following:

Your first post reads like you spun the tank around without disconnecting wires and hoses first. If so, you may have pulled a wire or unseated a connector. The pump wires are barely long enough to reach with everything in place. Try unplugging and reseating the pump connector on the underside of the tank. Check the pump fuse as well. Make sure the fuel line fittings are fully seated.

[Fitz]

CLB,

Yup, the pump is priming. That's why I suspect the tip sensor since this has happened before (twice).

Thanks for the location on the tip sensor. Maybe I disturbed it when I fiddled with the tank. I would really like to remove this useless piece of electrolica from the bike. It is normally open or normally closed.

I was a bit ham handed when I first spun the tank, but, other than the breather fittings, I'm quite sure I attached everything else (only one electrical connection needed to be disconnected to move the tank).

[CLB]

Ya know...

I wouldn't think the pump would prime if the tip sensor were stuck. It's there to avoid fuel spillage if the bike assumes a horizontal attitude. It seems a bit counter productive to prime if the bike's on its side.
I don't plan on testing that for you.

Unplug the sensor, hook everything else up and see if the pump still primes. If it doesn't, you are looking in the wrong direction.

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Also...

That it's happened twice and you had to ask where the switch was leads me to the conclusion that the prior diagnosis and repair was done by the dealer.

That it's happened twice on one bike and I haven't heard of this failure elsewhere leads me to a conclusion that the dealer incorrectly diagnosed an intermittent.

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As for the tip sensor...

It's a 3 wire device as opposed to a simple SPST switch.
It's tied into the TPS reference voltage and the signal ground for the MAP, Ambient Pressure, Coolant Temp, Throttle Position, IAT, Fuel Level and Lambda sensors.
I advise not messing with it.

Another small issue at hand is that I would prefer to avoid meeting with your widow's legal representation after posting instructions for disabling safety features.
I'm sort of shy that way.

[Fitz]

CLB,

I appreciate the advice and understand your reluctance to advise further.

This is the first bike I have ever owned with a tip sensor. Personally, I don't see the need for one. I'm just saying....