kill switch, starter keeps cranking...

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Herb
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Re: kill switch, starter keeps cranking...

Post by Herb »

Spacecoast wrote:
New thing: after riding awhile 30-60 mins, when I shut bike off, it shuts off, then I get a "whump"-sounding backfire. Its not the loud backfire you usually hear. Too rich?
My bike does this every time I shut it down, as long as it's fully hot. My assumption is that there is some sort of "ignition" going on inside the exhaust system with unburned residual gas, but it is very minor. When I was doing some system checking after purchasing my bike, I created an unintended back-fire. Traveling about 30 mph, I took the heel of my boot and pushed slightly down the kick-stand, just enough to trip the safety switch. I wanted to know if that would cut the ignition (and it did) and upon letting it back up a second later I got a rather loud back-fire since I was still holding the throttle a bit open. Overall, not recommended. My point is that the heat of the exhaust wasn't enough to ignite the raw gas, but once engine ignition was restored, the exhaust flame caused the back-fire. I think the "whump" is more associated with a very mild and lean fuel vapor dump during shut-down, and might be hitting a hot catalytic material, which is designed to burn minor unspent gas. Thus both Herb and Fred and correct. Its a yes and no answer.
The difference is the amount of fuel, how hot it is and the amount of time to allow air to be sucked back into the exhaust.
I can't seem to win the lottery. I think I have used up all of my good luck riding motorcycles.

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Fred
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Re: kill switch, starter keeps cranking...

Post by Fred »

Herb wrote: The difference is the amount of fuel, how hot it is and the amount of time to allow air to be sucked back into the exhaust.
:eek: How does air get sucked back in the exhaust.

Tell all boat owners to immediately change to over waterline exhaust outlets immediately.

I wonder how turbos manage with that --you are making break throughs in Mechanical engineering --wow Ive never heard of this stuff before.

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Herb
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Re: kill switch, starter keeps cranking...

Post by Herb »

Fred wrote:
Herb wrote: The difference is the amount of fuel, how hot it is and the amount of time to allow air to be sucked back into the exhaust.
:eek: How does air get sucked back in the exhaust.

Tell all boat owners to immediately change to over waterline exhaust outlets immediately.

I wonder how turbos manage with that --you are making break throughs in Mechanical engineering --wow Ive never heard of this stuff before.
Don't know much about exhaust systems ie fluid dynamics do you? Oh, that's right, you quit school because they couldn't teach you anything.

Quick down and dirty info about air movement. Not that you will be able to understand, or willing to learn, but someone else might get some good information.

Air, exhaust, moving through a tube with a certain amount of velocity, STOPS being pushed, it continues to move creating a vacuum which then pulls air back into the muffler.
I can't seem to win the lottery. I think I have used up all of my good luck riding motorcycles.

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Fred
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Re: kill switch, starter keeps cranking...

Post by Fred »

Herb wrote:
Fred wrote:
Herb wrote: The difference is the amount of fuel, how hot it is and the amount of time to allow air to be sucked back into the exhaust.
:eek: How does air get sucked back in the exhaust.

Tell all boat owners to immediately change to over waterline exhaust outlets immediately.

I wonder how turbos manage with that --you are making break throughs in Mechanical engineering --wow Ive never heard of this stuff before.
Don't know much about exhaust systems ie fluid dynamics do you? Oh, that's right, you quit school because they couldn't teach you anything.

Quick down and dirty info about air movement. Not that you will be able to understand, or willing to learn, but someone else might get some good information.

Air, exhaust, moving through a tube with a certain amount of velocity, STOPS being pushed, it continues to move creating a vacuum which then pulls air back into the muffler.
You mean reversion.
That is a a tiny bit from sonic or thermal shock not a whole pipe full enough to get to the exhaust valve and combustion chamber.

It is a shock that goes back up the pipe not a flow of air and it goes up on the outside diameter of the pipe which is how you stop it with reversion cones. Not very successful but Harley guys buy them.

At a guess a 5 foot long 2 inch pipe would be about 4 times the capacity of the motor.--- in other words BS

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Herb
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Re: kill switch, starter keeps cranking...

Post by Herb »

Fred wrote:
Herb wrote:
Fred wrote:
Herb wrote: The difference is the amount of fuel, how hot it is and the amount of time to allow air to be sucked back into the exhaust.
:eek: How does air get sucked back in the exhaust.

Tell all boat owners to immediately change to over waterline exhaust outlets immediately.

I wonder how turbos manage with that --you are making break throughs in Mechanical engineering --wow Ive never heard of this stuff before.
Don't know much about exhaust systems ie fluid dynamics do you? Oh, that's right, you quit school because they couldn't teach you anything.

Quick down and dirty info about air movement. Not that you will be able to understand, or willing to learn, but someone else might get some good information.

Air, exhaust, moving through a tube with a certain amount of velocity, STOPS being pushed, it continues to move creating a vacuum which then pulls air back into the muffler.
You mean reversion.
That is a a tiny bit from sonic or thermal shock not a whole pipe full enough to get to the exhaust valve and combustion chamber.

It is a shock that goes back up the pipe not a flow of air and it goes up on the outside diameter of the pipe which is how you stop it with reversion cones. Not very successful but Harley guys buy them.

At a guess a 5 foot long 2 inch pipe would be about 4 times the capacity of the motor.--- in other words BS
Waste of time trying to educate you. Stay ignorant.

Everyone else, the "whump", is normal whenever the engine/exhaust system is hot and the engine is shut off. do what you want with the information.
I can't seem to win the lottery. I think I have used up all of my good luck riding motorcycles.

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Fred
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Re: kill switch, starter keeps cranking...

Post by Fred »

Herb wrote:
Fred wrote:
Herb wrote:
Fred wrote:
Herb wrote: The difference is the amount of fuel, how hot it is and the amount of time to allow air to be sucked back into the exhaust.
:eek: How does air get sucked back in the exhaust.

Tell all boat owners to immediately change to over waterline exhaust outlets immediately.

I wonder how turbos manage with that --you are making break throughs in Mechanical engineering --wow Ive never heard of this stuff before.
Don't know much about exhaust systems ie fluid dynamics do you? Oh, that's right, you quit school because they couldn't teach you anything.

Quick down and dirty info about air movement. Not that you will be able to understand, or willing to learn, but someone else might get some good information.

Air, exhaust, moving through a tube with a certain amount of velocity, STOPS being pushed, it continues to move creating a vacuum which then pulls air back into the muffler.
You mean reversion.
That is a a tiny bit from sonic or thermal shock not a whole pipe full enough to get to the exhaust valve and combustion chamber.

It is a shock that goes back up the pipe not a flow of air and it goes up on the outside diameter of the pipe which is how you stop it with reversion cones. Not very successful but Harley guys buy them.

At a guess a 5 foot long 2 inch pipe would be about 4 times the capacity of the motor.--- in other words BS
Waste of time trying to educate you. Stay ignorant.

Everyone else, the "whump", is normal whenever the engine/exhaust system is hot and the engine is shut off. do what you want with the information.

I got the whump occasionally too but I know what it is not some dreamed up crap about air going back up my exhaust pipe.

Dominiquer
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Re: kill switch, starter keeps cranking...

Post by Dominiquer »

Well, that was more than I'd bargained for! The whump has diminished, very subtle now so I won't worry about it. Thanks to all who contributed.

vagabond83
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Re: kill switch, starter keeps cranking...

Post by vagabond83 »

So back to the original issue for this post. I have had the same issue. I push the starter button and the starter turns over, when i release the button starter continues to turn. I have figured out that my FP relay is feeding power back to my starter button wiring, thru the Y/G wire, that is also connected to the Decomp controller that activates the starter relay. Anyone got some ideas on how to fix this issue or to bypass the FP relay and direct wire the FP.
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Fred
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Re: kill switch, starter keeps cranking...

Post by Fred »

What the f is an FP relay. If you speak English it is highly likely some one will know.

Oh Oh fuel pump!!! as far as I can remember the fuel pump is supplied from the ignition.

Down load a wiring schematic.

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Herb
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Re: kill switch, starter keeps cranking...

Post by Herb »

Fred wrote:What the f is an FP relay. If you speak English it is highly likely some one will know.

Oh Oh fuel pump!!! as far as I can remember the fuel pump is supplied from the ignition.

Down load a wiring schematic.
You need to learn English abbreviations/acronyms.

You also need to get a wiring diagram and recheck that the power flow, the block diagram and fuel system description on page 5-2 of the manual are also helpful to the information challenged. The FP (fuel pump for the information challenged) RELAY is controlled by the ignition system so that unless the front cylinder is firing it doesn't allow the relay to provide power to the FP.

Jumper the yellow/white and the brown/black wires at the FP relay and you will have power at the FP any time the ignition switch and engine stop switch are on.

When my FP relay went bad I did EXACTLY what I described and now anytime I turn the ignition on the FP runs until it reaches the preset pressure.

BTW, for Vagabond, this will completely take the FP relay out of the system.
I can't seem to win the lottery. I think I have used up all of my good luck riding motorcycles.

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Fred
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Re: kill switch, starter keeps cranking...

Post by Fred »

What I did was remove the decomp and delay relay and that fuse was then used for the pump.

With modern batteries and much bigger start cables running as short as possible I have no trouble cranking with out the de comp.

For instance yesterday was the first time I started the bike since my 6 month in UK. The clutch was stuck as normal but this time it would not clear by rocking.

With modern batteries I was able to start the bike in gear numerous times until it finally cleared,--- no decomp.

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Herb
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Re: kill switch, starter keeps cranking...

Post by Herb »

A few months ago my decomp relay quit sending the power to the start relay. Decomp worked but no crank. I jumpered the hot wire from the start button (Y/G) to the start relay input (Y/B0 but left the decomp hooked up. Been starting like a champ. It just doesn't have the .02 sec delay.
I can't seem to win the lottery. I think I have used up all of my good luck riding motorcycles.

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