Sudden/random loss of power - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 26 (permalink) Old 08-15-2016, 05:38 PM Thread Starter
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Sudden/random loss of power

The day of otherness I was riding on the freeway and something strange happened. I didnít check my speed, but I was looking at the rpms. I going around 6K rpm in 5th gear and then suddenly the rpm dropped to 2K and went back up to 6k. This happened in the span of 1-2 seconds.

The bike behaved similar to when you brake very hard quickly or when you let go of the throttle and it engine brakes except it was way stronger. This wasnít because I let go of the throttle because I had my hand on the throttle the whole time and I was maintaining speed. I tried to replicated it after it happened by letting go of the throttle, but it was nowhere as strong. I probably had about 25 to 30 miles to go until I needed to switch to reserve.
Any ideas what could have caused this? Is this a symptom of something?

Don't take my word for it. I'm just a foolish newbie.
When in doubt, just know that I am only joking around.

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Blacked out engine
Dry rusty splines finally lubed for the first time
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post #2 of 26 (permalink) Old 08-15-2016, 11:16 PM
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Maybe the puck in the ignition switch needs some attention. Loose wire on the back of the switch.

Can try nudging the key and see if it stalls, same with wiggling the harness and plugs near the bars and forks.
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post #3 of 26 (permalink) Old 08-16-2016, 07:58 AM
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If you were going or coming off an incline with that low of gas the petcock filter sits pretty high in the tank. It's possible you tilted it just below the available fuel supply. If it doesn't do it again or only when you are near an incline you may want to remove the petcock and check the filter for slime or contaminants. I wouldn't do it until it becomes an issue you can replicate once you figure out the potential cause.

If you were running for a long time at a constant speed vapor lock in the tank is a possibility as well. Check your tank vent for obstruction.
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post #4 of 26 (permalink) Old 08-17-2016, 03:16 PM
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Quote:
Originally Posted by Spockster View Post
Maybe the puck in the ignition switch needs some attention. Loose wire on the back of the switch.

Can try nudging the key and see if it stalls, same with wiggling the harness and plugs near the bars and forks.
X2 on that. If it at all felt like the whole thing just turned off for a second, that's the puck. Soon it will leave you hangin. Happened ot me several times, on the highway in rush hour no less.

After you clean it, gorilla glue and tie wraps.
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post #5 of 26 (permalink) Old 08-17-2016, 03:56 PM Thread Starter
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Damn you guys are good.

My ignition switch is faulty. If I turn the key too much to the right in the on position then it won't turn on. I have to turn it left a little so that it will turn on. Also if I turn the handle bar all the way to the right, then the bike dies. I know I have to take a look at the ignition switch, but I'm just too lazy.

Also I think I was going up an incline when it happened. My tank used to be rusty and I cleaned it out with vinegar/rust remover so I think there may still be some flakes of rust in the tank. I have in-line fuel filters and I can see the red flakes in there. My previous petcock didn't have the filters on the petcock so it let the flakes through the petcock and into the in-line filter. The petcock I have now does have a filter on it.

Another important thing I forgot to mentioned is that there was an incident before the power loss mentioned above. My bike had a minor power loss and stumbled similar to being out of gas. This random stumbling has happened before twice and once more after. It only seems to happen when there is less than 1/4 gas.

Don't take my word for it. I'm just a foolish newbie.
When in doubt, just know that I am only joking around.

95 VN750
Top speed is 112 mph at ~7900 rpm
Blacked out engine
Dry rusty splines finally lubed for the first time
R/R relocated to the side of fuse box
Rust removed from tank
Marbled
In line fuel filter, 23-28 micron rating
Voltmeter
Gear indicator
LED turn signals & brake light
16 color LED engine light up & underglow
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post #6 of 26 (permalink) Old 08-17-2016, 11:48 PM
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post #7 of 26 (permalink) Old 08-18-2016, 10:07 AM
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Quote:
Originally Posted by evulcannibal View Post
Damn you guys are good.

My ignition switch is faulty. I know I have to take a look at the ignition switch, but I'm just too lazy.
Should look into it, sudden stalls in a sharp turn can put you on the ground, or get you run over.

2003-19k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Me and Cinderella, we put it all together, we can drive it home, with one headlight.
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post #8 of 26 (permalink) Old 08-18-2016, 10:36 AM
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Quote:
Originally Posted by Spockster View Post
Should look into it, sudden stalls in a sharp turn can put you on the ground, or get you run over.
Neither one is an option I'd prefer

ONE RATS ASS GIVEN PER POST
Support your local FREEBIRDS MC
1986/5 Vn700/750 Frankenfook cross eyed bitch "Mellisa Fayhe"
I am a BIKER and i'm proud.FREEBIRDS MC CENTRAL NY
earshaved
lowered with progessive 412 10" shocks
rejetted for K/N Pods part#rc 2340
sportster seat
BOO

'I didn't lose my mind.i gave it away

BRING BACK WOLFIE.
"And I'm free...as a bird"John Lennon Free as a Bird
"I only carry when I have my pants on"Joe Robinson aka Old Dog
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post #9 of 26 (permalink) Old 08-18-2016, 10:42 AM
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Quote:
Originally Posted by OleDirtyDoc View Post
Neither one is an option I'd prefer
Aye .. yi-yi!

I quit riding mine with the plugged pilot jet because the power would come on unpredictably while making low speed turns.

2003-19k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Me and Cinderella, we put it all together, we can drive it home, with one headlight.
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post #10 of 26 (permalink) Old 08-18-2016, 01:21 PM Thread Starter
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Quote:
Originally Posted by Spockster View Post
Should look into it, sudden stalls in a sharp turn can put you on the ground, or get you run over.
Well thankfully I haven't experience that yet. The only time when I turn my handle bars to the right fully is when I am off the bike and pulling the bike out of the garage.

Don't take my word for it. I'm just a foolish newbie.
When in doubt, just know that I am only joking around.

95 VN750
Top speed is 112 mph at ~7900 rpm
Blacked out engine
Dry rusty splines finally lubed for the first time
R/R relocated to the side of fuse box
Rust removed from tank
Marbled
In line fuel filter, 23-28 micron rating
Voltmeter
Gear indicator
LED turn signals & brake light
16 color LED engine light up & underglow
evulcannibal is offline  
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brake , freeway , jerk , loss of power , stop

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