Identify this noise - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 5 (permalink) Old 11-03-2018, 09:17 PM Thread Starter
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Identify this noise

Hey guys so as of recent my 95 vn750 has been making a lot of rattle. I can't figure out what it is.

Luckily for you guys I made a YouTube video of it high qulaity.

Here the link: https://youtu.be/PisI032fQM0

The bike has 55k miles on it so I suspect I'll have to part it out or pull the engine.

Let me know what you guys think it could be. I replaced the ACCTs with MTTCs and thought the sound would go away but I was wrong! Seems like a slapping rattle towards the front right side of the bike.
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post #2 of 5 (permalink) Old 11-04-2018, 01:07 AM
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When you got close to the right front, I thought I could hear it. Exhaust leak at the front? It's timed along with the rap from the tailpipes. Up front there's the crush gasket on the pipe, and it seems there should be a gasket where the exhaust manifold meets the head. If you cover that tailpipe and rev it, ... What can you hear? OR Cover the tailpipe, start it cold, and very quickly feel for air around the pipe/manifold seal points before it gets too hot. Usually helps to gently blip the throttle to make the leak more apparent.

Poking around with one of these can really pinpoint noises. $3.99? They used to be around $5 to 5.99. Don't take the black bulb apart to see what's in there! ... ahem ... Despite how it looks, it's not made to come apart. Inside is a metal disc.

https://www.harborfreight.com/mechan...ope-63691.html

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
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post #3 of 5 (permalink) Old 11-06-2018, 09:26 PM
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I'll say exhaust leak also.. notice how the noise coincides with the exhaust ignition note.
Remove the air cleaner and while it's cold spray some soapy water on the header joint. See if it spits out or bubbles?
 
post #4 of 5 (permalink) Old 11-18-2018, 07:10 PM Thread Starter
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Quote:
Originally Posted by [email protected] View Post
I'll say exhaust leak also.. notice how the noise coincides with the exhaust ignition note.
Remove the air cleaner and while it's cold spray some soapy water on the header joint. See if it spits out or bubbles?
Well I've gotten mixed reviews you guys say it could be an exhaust leak but I suspect it's inside the front head. I've gotten a lot of people saying it's the HLA's. I've taken the engine out of the bike and it's inspecting the front valves and rocker arms trying to determine how to tell if I need to replace them.
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post #5 of 5 (permalink) Old 11-20-2018, 11:29 AM
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Quote:
Originally Posted by Milesoffun View Post
Well I've gotten mixed reviews you guys say it could be an exhaust leak but I suspect it's inside the front head. I've gotten a lot of people saying it's the HLA's. I've taken the engine out of the bike and it's inspecting the front valves and rocker arms trying to determine how to tell if I need to replace them.
It's tough to diagnose from a video. Both problems, exhaust leak or collapsed lifter/valve problem could coincide with a change in exhaust note, or cause that change. I wouldn't have touched a bolt until checking the possible leak areas and listening with a stethoscope.

I think if it's a lifter, it should be on one of the exhaust valves (because of the sound in the pipes). But check them all. Remove and bleed the lifters, get them full of oil, then see if one is a lot easier to compress than the others. It may be obvious and the bad lifter is just limp. Compare the height of all the lifters, bad one can be shorter if damaged internally. A good lifter will be very tough to compress by hand (probably will need a tool), the bad one will be easy. You can place a rocker on top and use that to press down.

Rockers - A rocker mated to the bad lifter could have some unique wear patterns compared to the others, from tapping the valve stem or the lifter pocket on the rocker due to excess clearance.

Exhaust leak - Should see where gases have been going past the gasket, a burned area or soot.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf

Last edited by Spockster; 11-20-2018 at 11:36 AM.
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