weird noises from cylinders. - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 9 (permalink) Old 05-21-2014, 12:38 PM Thread Starter
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Exclamation weird noises from cylinders.

So I just bought my 1995 vn750 a couple months ago and I can't remember my bike making these noises but I think I'm getting more accustomed to the sound and feel of it.

The front cylinder/s making a low volume knocking noise and the rear cylinder/s making a low, but abit louder thumping noise(like pushing compressed air). I remember hearing a slight tick when I bought it but I don't remember these sounds.

I was having an issue with the carbs running too lean so I quit riding it until I can get them rebuilt and adjusted. I am just hoping I didn't do any damage by riding it with the carbs out of sorts.
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post #2 of 9 (permalink) Old 05-23-2014, 04:08 AM Thread Starter
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post #3 of 9 (permalink) Old 05-23-2014, 09:03 AM
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I'm no expert but I will chime in. Get the carbs working correctly first as I think unbalanced carbs can affect how smooth the engine runs. Why do you think one is running lean? The cam chain tensioners are a common cause of engine ticks. Search ACCT and GRAMBO TRICK on this site and you will find a lot of information.

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post #4 of 9 (permalink) Old 05-23-2014, 09:41 AM
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Is the bike too lean at an idle, is that what you are saying? If so, why do you think that?

My crystal ball has a failed acct, with out symptoms, I doubt I will be able to help much.

My bike makes a lot of noise, but only when it is running.

OP, not a lot to go on in your post.
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post #5 of 9 (permalink) Old 05-23-2014, 09:54 AM
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Can you do a video?

I doubt there's any major damage from being lean, unless you were doing long, high rpm runs or hard pulls.

Noise at idle or all the time? Idle needs to be 1100 rpm, +/- 50rpm, they thump a bit more if idling too slow.

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post #6 of 9 (permalink) Old 05-23-2014, 11:23 AM
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My two cents... keep it simple man....

It sure looks like it is time to find yourself a great wrench that is close to you.
I would personally look on YELP.COM and start researching the reviews.

Have found a couple of bike shops in the Houston area that way because I have limited wrenching desire and abilities.
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post #7 of 9 (permalink) Old 05-23-2014, 10:25 PM
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My engine was making a bit of a "whumping" sound and I couldn't figure it out. Checked for vacuum leaks ect. Took it to a mechanic friend and he discovered a leak where the carb boot connects to the engine causing one cylinder to run much stronger than the other.

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post #8 of 9 (permalink) Old 05-30-2014, 01:39 PM Thread Starter
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Now that the weather has become nicer I will try and get a video of the sounds in question. As for the lean carburetor, that is just what I have been told by five or so wrenches. Plus the symptoms are spot on in the book I have.
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post #9 of 9 (permalink) Old 05-30-2014, 09:47 PM
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Only plug condition will give ya a full pic of rich/lean (unless its a hitech shop that has an exhaust analizer).....

I suggest checking yer plug condition before anything, and if one cyl seems a bit lean, open up the low speed mixture screw 1/2 turn.....there is a misconception as to what RPM the low jet regulates too...

If you are running standard plugs...check the gap....if running too lean, open the gap a little....that produces a colder same inversely......

Last edited by Wolfie; 05-30-2014 at 09:49 PM.
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