Help Diagnose My Engine Noise! [video]

[MotoDeebs]

Hi Guys,

Video here: https://www.youtube.com/watch?v=Ro0IAEh9kTI

Just bought a 2007 GS500F a few weeks ago. Loving everything about it except this stubborn ticking noise!

A little about the noise: It only happens under load (during acceleration) after about 4200rpm. It does not happen in neutral when the engine is at idle or revved past 4200rpm.

There are only a handful of things I dug up that I think it could be:
1. Valve clearances (re-shimmed a few days ago... all clearances now in spec but the noise is still present)
2. Loose/faulty cam chain tensioner (saving this for last because I've heard that a loose cam chain ticking noise will be loudest at idle & generally get quieter with increasing rpm... my ticking noise does the opposite... my noise isn't present during idle, and only becomes apparent @ 4200rpm under load) Also... im not really sure if i can just take off the tensioner without risking the chain jumping. People talk loosely about putting it in top dead center (which doesn't make sense to me... since there are two cylinders... which one should be in TDC?? etc etc) before taking it off... Having a hard time finding clear instructions on this... also I'm not 100% sure how the tensioner works... either way... this will be the next step...
3. Loose starter clutch bolts. I currently have the stator cover off & can only see the starter clutch bolts from the back side... i dont think they are loose, see a photo here: http://imgur.com/seYpnIK .... do you guys thing i should tear down further to make sure the bolts aren't loose? Its kind of a pain to get the clutch assembly off...

Any insight WILL be helpful! Thanks Guys!!

 

[Nessism]

I think you are on the right track with checking the cam chain tensioner. You can buy one off ebay for cheap to learn how they work before going after yours.

Before removing the tensioner I'd put the engine at TDC for the number 1 cylinder. After reinstalling the tensioner check the cam chain timing to make sure it hasn't moved. Some paint marks on the cam chain and cam sprockets will make it easy to see if the engine jumped a tooth or whatever.

 

[MotoDeebs]

Instead of pulling everything apart again (tank, petcock, valve cover etc) , could I just put it in TDC via lining up the RT mark with pickup and looking thru the spark plug hole to make sure I've got the correct cylinder in TDC? I'd replace the tensioner and rotate the crank 2 revolutions with a wrench to make sure of valve clearance? Any reason this would be more dangerous than pulling the valve cover off to check correct timing?

thanks for the feedback!

 

[Charlie G]

No! What Nessism is suggesting is pecisely checking the engine time by seeing if the piston is colliding with the valves. This done by placing a particular piston at the top dead center mark and checking that marks on the cam chain and sprockets align with points/marks under the valve cover. It's not hard, but you will need a manual to identify the correct marks/points.

cg

 

[tkent02]

Hard to tell from the recording, but I have heard similar noises from engines that have had a bad connecting rod bearing. Certainly check the easier stuff first but it is a possibility.

Doesn't sound like a cam chain to me, don't think a valve can hit a piston over and over again without breaking. Not sure what else it can be.

 

[MotoDeebs]

I had a similar noise in my car a few years ago and this is exactly what it was... I hope its not this... Thanks

 

[Nessism]

If the cam chain is too loose it may be fluttering at higher rpm. Not sure of course, but I do know the noise is not from the valves hitting the piston, although that could happen if the chain gets too loose and jumps cam sprocket teeth.

 

[tkent02]

If the cam chain is too loose it may be fluttering at higher rpm.

Any cam chain tensioner problems I have heard sounded like a paint can full of rocks on a paint shaker. Have never heard one as rhythmic and even as this noise.

Sounds like a loose rod bearing.

 

[Guest]

Any cam chain tensioner problems I have heard sounded like a paint can full of rocks on a paint shaker. Have never heard one as rhythmic and even as this noise.

Sounds like a loose rod bearing.

The ignition moves to full advance at about 4000 rpm which would tend to make a loose rod or wrist pin bearing knock. Given the nature of GS wrist pins, I'd think the rod bearing is the likely culprit. Not a diagnosis with a happy ending, and you want to cover the other possibilities like loose exhaust system parts which can do the same, but those noises aren't load sensitive.

 

[MotoDeebs]

Check out this clip: https://m.youtube.com/watch?v=P3hqgZx5WUQ

recorded yesterday. Running on one cylinder at a time.

noise is only present when running on the left cylinder only.... Would lead me to believe it's something like the left cylinder connecting rod, and not anything to do with the top end.

if it were top end related, I'd think it should happen no matter which cylinder was firing.