engine knock - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 10 (permalink) Old 05-31-2011, 12:54 PM Thread Starter
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Question engine knock

I am looking at buying another 750 - why? - 2 is better than one right? - at any rate the bike is a 2002 with about 4000 miles on it and the owner says that it has a bad knock in the front part of the motor - he also states that it is not the ACCT - before I jump in and throw cash down a hole - i was wondering if anyone has some ideas on what could be a possible issue? I am going up to check out the bike this week if I can make my schedule work out.

That can't be my bike - it aint movin'
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post #2 of 10 (permalink) Old 05-31-2011, 02:46 PM
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My first thought is the Hydralic Lifter Assembly (HLA) may need bleeding to remove air from system. ??

This is #8 from roach`s vn750 engine rebuild series of videos:
http://www.youtube.com/watch?v=h2UurZjkfxE


Roaches video thread:
https://www.vn750.com/forum/showthread.php?t=18289

Gordon

1991 VN 750 -"Cosmic Lady" or "Bad Girl"?
Purchased May 16, 2008
Approx.19,300km (12,000 miles)

H-D windshield
Relocated R/R
MF-AGM battery
Fiamm Freeway Blaster horns
F&S luggage rack and engine guard
Kury Offset Hiway pegs
July 13, 2016, Riding on the DARKSIDE now, Classic Radial 165/80-15


TOP TEN THINGS A NEW RIDER/OWNER SHOULD DO. Click on link.
https://www.vn750.com/forum/11-vn750-general-discussion/9127-top-ten-items-you-would-suggest-new-owner-do-his-new-ride.html

Last edited by OlHossCanada; 05-31-2011 at 02:58 PM. Reason: add link
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post #3 of 10 (permalink) Old 05-31-2011, 03:09 PM
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Even if he states that it isn't the HLA I would still check them out and make sure the springs are in good condition and holds the tension. It's just a saef idea to look there first cause that is the easiest fix out of everything.

1990 Kawasaki Vulcan 750
12,000
English Version

ACCT to MCCT conversion video
https://www.vn750.com/forum/showthread.php?t=18235

ACCT to MCCT Conversion Thread created by wib714
https://www.vn750.com/forum/showthread.php?t=17917

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post #4 of 10 (permalink) Old 05-31-2011, 05:17 PM Thread Starter
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this might be a silly question - but - do you have to pull the motor to check the HLA - or is it easily accessible with the motor in - meaning the valve of course

That can't be my bike - it aint movin'

Last edited by trekbiker; 05-31-2011 at 05:19 PM. Reason: left off part of the post
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post #5 of 10 (permalink) Old 05-31-2011, 05:54 PM
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Quote:
Originally Posted by trekbiker View Post
this might be a silly question - but - do you have to pull the motor to check the HLA - or is it easily accessible with the motor in - meaning the valve of course
The engine has to come out and the head removed to get to the HLA.

STOP -- DON`T DO IT YET!!

Do a 5 minute "Grambo" trick to make sure the ACCT is ok before tearing into the HLA.

******And get another opinion on the HLA before going on mine alone. I`m just brainstorming.*******

Grambo trick is no cost, quick and easy.
https://www.vn750.com/forum/showthread.php?t=1076

Take the little cap bolt off the top of the front ACCT.

Stick a SMALL screwdriver inside and back the adjuster off a turn or two, then pull back and let the spring snap back into place.

Start the engine and listen to it. Does it still knock?

Stick the screwdriver back in and apply a little pressure.
Does the knocking stop? If so you found the problem.

THE FIX:---

Get the TOC Manufacturing replacement ACCT springs ($35 for a set of 2 springs with 4 O-ring seals and installation kit),

OR the TOC Manual CCT (~$50 each),

OR do the $4 ACCT to MCCT conversion that wib has in his sigline.

Gordon

1991 VN 750 -"Cosmic Lady" or "Bad Girl"?
Purchased May 16, 2008
Approx.19,300km (12,000 miles)

H-D windshield
Relocated R/R
MF-AGM battery
Fiamm Freeway Blaster horns
F&S luggage rack and engine guard
Kury Offset Hiway pegs
July 13, 2016, Riding on the DARKSIDE now, Classic Radial 165/80-15


TOP TEN THINGS A NEW RIDER/OWNER SHOULD DO. Click on link.
https://www.vn750.com/forum/showthread.php?t=9127

Last edited by OlHossCanada; 05-31-2011 at 05:57 PM.
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post #6 of 10 (permalink) Old 05-31-2011, 11:35 PM Thread Starter
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don't worry - i am not about to jump in there yet - i am hoping to have a look at the bike this week - i was trying to figure out what to look for - so I could make a value judgement on whether to buy it or not. I am up for any ideas that you guys throw at me - thanks!!

That can't be my bike - it aint movin'
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post #7 of 10 (permalink) Old 06-19-2011, 06:58 AM
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Hi!
I have a strange knock in my 750 engine.I thought it was the ACCT, but I did the Grambo trick and the tensioners are o.k.
Digging deeper in Internet I found some gay, who said that this noise may come from worn bushings on the harmonic balancer.Has anybody heard about something like that?
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post #8 of 10 (permalink) Old 06-19-2011, 09:40 AM
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Trek and Rikardo, an easy way to determine where the knock is coming from is to use a screwdriver or similar as stethoscope. Stick one end in your ear(use the non-metal end...lol), and place the other in different spots around the engine case. You'll be able to pinpoint the source of the problem. A common cause of knocking - especially a deep "thrum" sound - is indeed the balancer. You'll hear the sound coming from the front left side of the engine. Cheap to replace the worn bushings, although it does require an engine pull to get to 'em. However, lots of help available here if you need to tackle that on your own.

C
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post #9 of 10 (permalink) Old 06-19-2011, 11:29 AM
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Thanks man.Yes, the sound comes from the left side of engine.How hard is to replace the bushings?Has anybody did it before?
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post #10 of 10 (permalink) Old 06-19-2011, 05:38 PM
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It's easy once you get in there - pull the two pieces of the balancer apart, put the new parts it, etc. But you have to pull the engine to do that. If you have some garage space and a lot of patience, folks here can walk you through the process. Or pick up a Clymer's repair manual and you can do the job on your own, no problem.

C
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