FZ6 2006 knokcing sound when rPMs go down

[baha]

Hi guys,

I am hearing a knocking sound from the left side of the engine. The sound can be heard after revving the engine and the rPMs start to decrease/ go down after 4000 to idle. When i'm revving the bike and the rPMs go up, I can't hear the sound.

You can hear what I hear in this video:

[video=youtube;6MhLvQgZ_dA]https://www.youtube.com/watch?v=6MhLvQgZ_dA&feature=youtu.be[/video] on 0:25 sec.

It's not a sound from the chain tensioner or the valves. The alternator is ok as well. There is a doubt that it could be the rod bearing or piston pin, but why do I hear it only when rPMs goes down?

 

[TownsendsFJR1300]

That video would be MUCH more helpful if the throttle wasn't revved SO FAST and the microphone held closer to the engine on the predominate side so we can hear it.

Taking a stethoscope or long screwdriver from the engine to ear will also help pin point down the area.

 

[baha]

Well, I actually didn't shoot the video. That's the guy I bought the bike from. I will make a new, close to the engine longer video with different rev speed.

I didn't get the point of the stethoscope/ screwdriver... What do you mean?

 

[bpchura]

I honestly couldn't hear much in the video. I would recommend doing exactly what Townsends said and see if you can isolate the sound to a definite area on the bike. As for not hearing it at a higher RPM, it most likely is just at too high of a frequency. That plus the additional noise from the engine drowns it out. If you can, drop the oil and cut open the oil filter. Check for metal flakes that would indicate a bearing failure. Thats the easiest and most definitive way to tell if a bearing is toast.

 

[TownsendsFJR1300]

I didn't get the point of the stethoscope/ screwdriver... What do you mean?

If you put a long handled screwdriver direct to your ear and then on different area's of the engine, it'll help pin point where the noise is coming from (depending on what it is). IE, if it was a valve tapping, you'd hear the noise thru the screw driver MUCH MORE when touched up against the valve cover.

A stethoscope is MUCH more accurate.

Depending on the noise, internal engine noises tend to echo and scatter thru out the internal block. Your trying to narrow it down.

Besides checking the oil and oil filter, sending out a sample of oil for analysis will often show if a bearing is toast, etc... A bit cheaper / easier before a complete tear down...

But yes, a new video, preferably on the side its coming from and revving, etc, when its the worst, will be the most helpful.

 

[baha]

Here's the new video. The sound can be heard in the low rpms, right before idling. The sound appears only when the engine gets hot. I don't hear anything while cold, right after starting.

[video=youtube;xUGJXthe_W4]https://www.youtube.com/watch?v=xUGJXthe_W4[/video]

 

[TownsendsFJR1300]

I honestly don't hear any anything unusual.

Were you able to narrow down the noise to the RS or LS using a screw driver or stethoscope?


I gather this noise is new from "normal" operation??

 

[baha]

The rattle can be best heard btw 3500- 1500 decelerating rpms in the left lower part of the engine- in or a bit above the oil pan, where the crank and all the bearings are. I changed the oil & filter and put synthetic 15W50 (previous was 10W40). I think the noise decreased along with the whole engine operation noise (around 2db according to my phone's db meter) with this ticker oil, but it's still there. The filter and the oil were clean and I couldn't locate metal flakes even with a magnet.

This is a video of another guy with R6 engine and a sound very similar to mine, heard on rpms decelerating:

[video=youtube;6N-bK8OvKhs]https://www.youtube.com/watch?v=6N-bK8OvKhs[/video]

Could it be a sound coming behind the alternator cover? It might be a bearing, but I'm not sure if it's a rod or main as there were no metal flakes in the oil. I only hear it when engine gets warm. Is there a magnet in the oil pan or is just the drain bold that is a magnet?

 

[Motogiro]

Since this seems evident when the engine is warm and not when it's cold...... Is the thermostat rattling?
I suggest you pull the stator cover and inspect the stator flywheel for damage, a lost magnet and running true. Inspect the stator winding for damage and clearance issues.

 

[TownsendsFJR1300]

Since this seems evident when the engine is warm and not when it's cold...... Is the thermostat rattling?
I suggest you pull the stator cover and inspect the stator flywheel for damage, a lost magnet and running true. Inspect the stator winding for damage and clearance issues.

I remember reading something here about a loose stator or something under the cover. It may have been for another bike, its been awhile..

I know the stator is held on with super duty loctite which needed a heat gun to remove...

 

[baha]

Should I drain the oil before removing the cover? Is it full of oil there?
[MENTION=2579]Motogiro[/MENTION], what do you mean with the thermostat rattling, it's in the upper side of the engine and I can't imagine it rattling along with the rpms.

 

[baha]

Do I need to drain the oil before removing the cover?

[MENTION=2579]Motogiro[/MENTION], what did you mean with the thermostat rattling?

 

[TownsendsFJR1300]

If on the center stand, you can pull the cover W/O draining the oil.

The level is lower than the cover





ADMIN, my e-mail notification showed a question:

"Should I drain the oil before removing the cover? Is it full of oil there?"

the OP posted, BUT the actual post is NOT here for some reason...

 

[baha]

Yes, the replying of the post went somewhat wrong...
[MENTION=2579]Motogiro[/MENTION], what do you mean with that thermostat rattling?

I will pull the cover while the bike's on a stand and check for anything unusual.

 

[FinalImpact]

FWIW: The bearings of the ROD and CRANK journals are some form of lead material (soft and they wear) then there is a copper layer and the shell is steel. So you won't find anything with a magnet until the engine makes horrifying sounds from the clearances opening up and the oil not providing its boundary layer of protection.
If you have that old oil filter; gutting it and looking in the pleats (folds) may show something.

As stated; get a wooden dowel, a screw driver, or something and listen to the engine from many places. It will be noisy and there will be sounds. But try to isolate it to the one this thread is about.

 

[baha]

So I removed the cover and find nothing suspicious.

[MENTION=15974]FinalImpact[/MENTION], 2 questions:

1. I can't hear anything before the engine gets to operating temperature. Why is that? The clearances gets bigger?
2. Why is the sound heard only while rpms decelerate? I can't hear the noise at 4k or 8k rpms when reving. Only heard btw 3500 and idle.Low oil pressure in these rpms?

 

[FinalImpact]

Those are possible. Have you ever heard the Rods Rattle on deceleration on someones video? It is a very distinct sound.
Anyway - the left side of the engine has a plug and you could check and verify the oil pressure. How many miles on the engine?

Things I'm reading that are not in your favor:
It does it when its hot and when it is decelerating. If it is rod bearing that is how it begins but we are jumping to conclusions.

Watch this... On the surface it looks harmless enough except High RPM and Force have trapped the oil in the engine and its NOT in the oil pan, coupled with what IS in the OIL PAN, well it wasn't enough and the engine was starved of oil under load and the bearings DID what they are supposed to do and gave way to keep the crank alive. Not ideal but its happens...

Cookies and Rod Bearings - Oppsss

 

[baha]

Well I haven't heard similar noise only on deceleration. I had a problem with a car's engine rod bearing but it was knocking all the time at all rpms and it lasted 2- 3 years before the connecting rod teared the engine block.

It is possible that it's a starting stage of a bad bearing, as there were no visible metal flakes and the sound can only be heared while decelerating. That's why I put synth 15W50. And after I can't hear hear the rattle in the higher rpms, that means the oil and the pump are doing their job.

 

[TownsendsFJR1300]

With the proper tool, you can check the oil pressure and rule that in or out.

Under the stator cover is a port to screw in a pressure gauge.

If it is low, address it ASAP to prevent any damage, additional damage..

34.1 PSI at 6,600 RPM's

 

[FinalImpact]

So I removed the cover and find nothing suspicious.

[MENTION=15974]FinalImpact[/MENTION], 2 questions:

1. I can't hear anything before the engine gets to operating temperature. Why is that? The clearances gets bigger?
2. Why is the sound heard only while rpms decelerate? I can't hear the noise at 4k or 8k rpms when reving. Only heard btw 3500 and idle.Low oil pressure in these rpms?

I suspect its more oil related than clearances changing.

Decel; you have to think in terms of engine load or more specifically piston/rod work being done. When you open the throttle the net effect is accelerating the crank so the load on the piston and rod is all the fuel burning pushing it down the cylinder. This keeps upper end of the rods crank journal in contact w the crank and you don't hear bad noises.
When deceleration is under way there is little fuel being added, no work forcing the piston down the hole so the rod bearing is having to pull the pisti downward. At bottom of the stroke you hear the rod actually slap the crank during the transistions of pulling to pushing. As the bearing wears it simply gets worse until you loose more oil pressure and have more participant's chiming in.