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What is this sound?


schlageter

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Hello guys, I'm pretty much new with the VFRs, I just purchase this bike for a really low price, the previous owner got pregnant and they needed the money, they were doing an stetical modification but I know there is some maintenance that need to be done.

 

Now here comes the cherry of this cake...

 

What you guys think it could be the sound of it? I heard people saying that is the camshaft, the valve caps that need calibration and other things... But I would like to hear your opinions.

Thank you! :D

 

Btw, this is a VFR 750 1990 and I hope to be the one conducting all the maintenance and repairs on it

WhatsApp Video 2017-11-10 at 6.27.23 PM.mp4

WhatsApp Video 2017-11-10 at 6.27.19 PM.mp4

WhatsApp Video 2017-11-10 at 6.27.15 PM.mp4

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  • Member Contributer

Without being able to determine where it is coming from, I'm at a bit of a disadvantage.

Could be valve train related but it reminded me more of rod knock, especially the intermittent nature of both the pitch of the sound and the frequency it occurs.

 

You'll have to tear into the engine regardless, I can think of no external failures that make a noise like that  Could be something loose hitting the engine, but I wouldn't bet on it.

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Cam chain tensioners? I can't tell what year of bike it is and whether or not it has gear driven cam or cam chain. Sounds like the clacking of a cam chain which I had on my 2005. Pretty easy fix and about 200 bucks. The sound would go away on mine off idle or under tension.

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The fact that it seems intermittent and relatively light would make me think top end?  I'd pull the valve covers and check for something amiss.  

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Cam chain tensioners? I can't tell what year of bike it is and whether or not it has gear driven cam or cam chain. Sounds like the clacking of a cam chain which I had on my 2005. Pretty easy fix and about 200 bucks. The sound would go away on mine off idle or under tension.
The bike is a vfr750 1990, the sound is coming more from the engine than from any other place, and as you can hear, it is LOUUUDD :'(

This is a gear driven cam, and I hope I don't have to replace a camshaft

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Your location says, "COL".  I'm uncertain whether that means the country of Columbia or the U.S. state of Colorado?

 

If your location is actually Colorado you can go to Harbor Freight and get a "Mechanic's Stethoscope" (really cheap, just a few dollars).  The mechanic's stethoscope is a great tool for tracking down the location/cause of an engine noise.  It allows you to be very precise when listening.  At normal idle engine speed you can easily determine whether or not the noise is coming from something in the valve train (the noise occurs at 1/2 crankshaft speed) or whether it's coming from something crankshaft related (the noise matches the engine idle speed).  That can give you a good start and some direction to go in to correct the problem.

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Your location says, "COL".  I'm uncertain whether that means the country of Columbia or the U.S. state of Colorado?
 
If your location is actually Colorado you can go to Harbor Freight and get a "Mechanic's Stethoscope" (really cheap, just a few dollars).  The mechanic's stethoscope is a great tool for tracking down the location/cause of an engine noise.  It allows you to be very precise when listening.  At normal idle engine speed you can easily determine whether or not the noise is coming from something in the valve train (the noise occurs at 1/2 crankshaft speed) or whether it's coming from something crankshaft related (the noise matches the engine idle speed).  That can give you a good start and some direction to go in to correct the problem.
Hahahaha it is a bit more far than that, I'm actually in Colombia, but still it is a good idea to purchase that tool, I still can order it and get it delivered here, I'll definitely check it out :D

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  • 5 months later...

Hello everybody!

As a follow-up on this thread, I can tell you guys what I finally found wrong with the engine... Partially rotated rod bearing

Soo basically, the tube in charge to suck the oil from the bottom of the engine was loose, generating a low oil pressure.

The previous retarded owner, removed a lot of the frontal electrical system, including the oil pressure light.

Because there was not enough oil running through the crankshaft, one of the rod bearings got overheated and was partially rotated and half destroyed in the process.

How do I fix it? The crankshaft has scratches on, the same as the rod so I have to replace both, plus all the crankshaft and rod bearings, but I am afraid of the new setup of new bearings thickness and rod selection since there are some configuration preset on the crankcase

Any suggestions?

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  • Member Contributer

Not sure how plentiful they are in your part of the world, but I would search for a good used engine ( or a whole bike) first. That's probably going to be the quickest and maybe even cheapest route.

Good luck.

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  • Member Contributer

 

 

Knipsel.thumb.JPG.07d64d1294b731f952a6d0b7b6281485.JPG

 

 

 

 

A friend is replacing head and camshaft :-(

 

 

 

 

 

As stated, best find a complete engine; here in NL that would cost you ~200 euro....

 

 

 

 

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