Shocking driving and high irregular idles - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
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Old 07-01-2019, 03:11 PM Thread Starter
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Little less then a week ago I tried to fix a poogs syndrome, I removed the tank and checked the pet cock reassembled it and noticed a piece of the front carb wasn't plugged what I thought was not deep enough in the engine block, I removed one of the air intakes and put the carb in deeper. After taking it for a test spin I noticed it backfired like crazy around 5k rpm its so bad that the bike shocks with shots of power/no power when it does that (its mostly around 5k rpm) to fix this I just switched back to 4th gear and let it sit at 6k+ rpm until today where it did it even when driving slowly, the shocking is so bad you can't drive nicely when I pulled over I noticed the idle made jumps from 1k to 3k to below 500rpm for a while almost as if there isn't a good combusting. Shortly after it hit 0rpm and the engine shut down. Luckily I was at work and waited till I was done to see if it still had the problem. It didn't for about 5-10 min when I went off the highway to check it out, same problem. I waited a couple of minutes and drove home. Does any of you have any idea what this could be? Could it be clogged carb?


Edit: sorry for the crappy writing. I did this on my mobile phone

Last edited by Panarock; 07-02-2019 at 08:37 AM.
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Old 07-01-2019, 03:45 PM
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Sounds like an Air leak between carb and intake.

Carb Boots have alignment marks to help you get them oriented correctly, clamps need to be snug

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Old 07-01-2019, 04:15 PM
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I had the boot come loose from what I guess was the constant vibration. Idle went crazy while I was sitting at a stop light. I was holding in the clutch and it jumped to 3.5k. I’d be lying if I said it didn’t scare me. I managed to reseat it without shutting the bike.
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Old 07-01-2019, 05:13 PM Thread Starter
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Quote:
Originally Posted by TonyO View Post
Sounds like an Air leak between carb and intake.

Carb Boots have alignment marks to help you get them oriented correctly, clamps need to be snug
The boots seem to be plugged in the right way.
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Old 07-01-2019, 06:39 PM
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Check for cracks in the rubber??
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Old 07-02-2019, 08:38 AM Thread Starter
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Quote:
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Check for cracks in the rubber??
I removed the carbs and checked the rubbers. I coulnd find anything. I put them back and the problem still presists

Last edited by Panarock; 07-02-2019 at 05:33 PM.
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Old 07-02-2019, 11:10 AM
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Try some water in a spray bottle, warm the engine fully and spray the boots while listening for changes in how it's running, and steam at the exhaust tips.

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Old 07-02-2019, 11:16 AM
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By "shock" I assume you mean "shake".

Sounds to me like you have one cylinder cutting in and out. Possibly a carb issue but could be electric.

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Old 07-02-2019, 11:32 AM
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I took it to mean a sudden burst of power, which points to dirty carb jets (but could easily be ignition), but the high rpm moments point to an air leak.

Should also check the vacuum line at the left carb, it should be dry at all times.

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Last edited by Spockster; 07-02-2019 at 11:42 AM. Reason: ignition
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Old 07-02-2019, 11:37 AM Thread Starter
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Quote:
Originally Posted by Knifemaker View Post
By "shock" I assume you mean "shake".

Sounds to me like you have one cylinder cutting in and out. Possibly a carb issue but could be electric.
By shock I mean when driving you get a switch between power/no power about 10 times a second resulting in shocking acceleration/no acceleration, acceleration etc
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