Knock knock

[fZling]

Hi All,

Long time reader, first time poster.:Lurking:

I was hoping the wise Fz6 community could help me out in a very awkward jam.

I've been riding a 2006 Fz6 which I bought with about 6000 miles on it and have had a joy after riding for about 500miles, but recently noticed a subtle knocking noise coming from the engine around 4-6krpm. After hearing this noise, I quickly researched and found it could be a faulty cam chain tensioner. Okay, installed an APE tensioner, no real change in the amount of knocking.

Now, after letting the bike sit for about a week, I decided to take it for a spin on the local highway. On my way home, a TERRIBLE knocking/rattling between metal. Luckily I was REAL close to home and coasted it to the garage. Now the noise is pretty damn loud and happens at any rpm. Just to get a sense of how bad it is, I do NOT want to start the bike with the problem. Maybe an example of the sound would be smacking a metal can with a drum stick.. :banghead:

Time to take the bike apart

The first thing I checked was the oil and anti freeze, perfectly clean. No metal debris. Ok :thumbup:

Then off comes the valve cover, hmm, the cam timing is perfect. The timing chain is fine and no debris anywhere in the engine. The engine turns easily using the crankshaft bolt. :rockon:

And this is where I ask you guys/gals. Any suggestions on what could possibly be wrong? I feel like if something was broken metal debris would spit out in the oil or antifreeze, but nothing.

Any suggestions would be great, or perhaps a link to a similar post. Couldn't seem to find anything similar myself.

 

[TownsendsFJR1300]

Did you pull the oil filter and pour it out looking for metal? Did you let the oil drain from the engine or just peek at the dip stick... Emptying the engine of oil will show any shiny metal. I'd probably cut the filter open too and see if there's anything in there...

I assume when you checked the cam timing you were at the TDC mark on the rotor with the cam chain cover off as well, not just the cams lining up with each other. If the cam chain jumped a tooth at the rotor (cams still in sync), it could cause the valves to hit the pistons.. Also, if you have the valve cover off again, check gently for any play in the cams and head

If you blew a rod bearing, (should be more like a double knock), pull the spark plugs, turn the engine forward and stop with the piston (for each cylinder) half ways up. Then push DOWNWARDS with a screwdriver (or such) on the piston. There should be NO PLAY. If there's movement you have a rod going south.

Could you tell what area of the engine the noise came from? If you thought the noise was initially coming from the cam chain tensioner (right side) the clutch is adjacent to that, perhaps there's a problem under there... Worn bushings/clutch basket slopping about hitting the case?

Anything else you can post would help..

I have an FZ6 manual for an 07 as a PDF file if needed. PM me...

Good luck...

 

[fZling]

First, thanks for the detailed reply Townsend. I really appreciate it.

To answer your questions.

I did let all the oil drain, including all radiator fluid. The oil looked completely clean.

I'm going to double check to make sure I evaluated the timing chain correctly, but there was not much play between the heads.

From my best guess it sounded like the noise was coming from the lower end of the engine. Thus leading me to believe it COULD possibly be a rod problem, but I'm going to get back to work on it this weekend.

I'll be sure to update this thread this Saturday after I finish working on it again.

 

[616ah]

In addition, I'm just wondering if, for the work involved, would it be easier to just pull the oil pan for a look/wiggle if you suspect a spun bearing? I often see auto engines that the drained oil looks "ok" after a spun bearing, but after pulling the pan, the pile of bearing chips are still sitting in there...

I think an experienced ear could possibly save you big in the way of unnecessary work/unintentional damage/time invested in your situation. It bothers me that the FZ6 oiling system doesn't seem to have a pressure sensor, just a level sensor, although in reality I guess it doesn't matter - the end result is the same.

To totally put the cart before the horse here, I find myself wondering if I were in your shoes and it IS a major engine mechanical failure at that milage, it would seem probable that this engine has had a questionable past... (overspeed, neglected/improper maint, mechanical failure, etc). Chances are it most likley wouldn't make financial sense to even fix that motor. I would be tempted to put oil back in it, idle it and try to pindown the source. Chances are enough (too much) damage is already done...

Sorry to be so pesimistic...

 

[TownsendsFJR1300]

In addition, I'm just wondering if, for the work involved, would it be easier to just pull the oil pan for a look/wiggle if you suspect a spun bearing? I often see auto engines that the drained oil looks "ok" after a spun bearing, but after pulling the pan, the pile of bearing chips are still sitting in there...

I think an experienced ear could possibly save you big in the way of unnecessary work/unintentional damage/time invested in your situation. It bothers me that the FZ6 oiling system doesn't seem to have a pressure sensor, just a level sensor, although in reality I guess it doesn't matter - the end result is the same.

To totally put the cart before the horse here, I find myself wondering if I were in your shoes and it IS a major engine mechanical failure at that milage, it would seem probable that this engine has had a questionable past... (overspeed, neglected/improper maint, mechanical failure, etc). Chances are it most likley wouldn't make financial sense to even fix that motor. I would be tempted to put oil back in it, idle it and try to pindown the source. Chances are enough (too much) damage is already done...

Sorry to be so pesimistic...

To pull the pan isn't that hard and probably isn't a bad idea. Pull the header, then the pan. I agree with the low mileage, it was probably abused alot/oil not changed, etc..

I'd personally start pulling it apart, find the problem, then determine wether a new/used engine is in order...

Something from the old car days, if a rod IS IN FACT knocking, if you pull the plug wire (use the correct tool and ground the coil wire) to that cylinder while running the knock noise generally decreases significantly...

 

[fZling]

Just started working on the bike again. This is what I did :

1) Took the clutch apart and spun the input shaft. No noise.

2) Put the bike in gear and spun the rear wheel. No noise out of the transmission. Went through all 6 gears.

3) Took the oil cooler off, no debris at all. Was unable to take off oil pan.

4) Checked the piston half way up the stroke. No play at all

It looks like an engine with 6k miles on. Nothing is wore, acting weird or funny noises.

Now going to put the bike back together and see if the noise is still there.

 

[RJ2112]

Did you hear the noises only when moving? As the internals seem to be checking out, have you looked at the drive line components? Specifically, the primary sprocket? The front sprocket retaining nut is not the most secure setup out there.... if a previous owner replaced the front sprocket with a lower tooth count set up, it's possible the sprocket is loose on the shaft.

Take off the front sprocket cover and inspect. The nut is supposed to be held in place by a washer with one ear bent up alongside a facing surface of the retaining nut. If the retaining nut has backed off, all heck can break loose.......

 

[Motogiro]

Before you pull the pan.
You might pull the stator cover and check to see if something has changed in that area which may be resulting in the noise.

I know a guy that has a 600rr that gets a funny rattling noise only when there is an electrical load like his directionals/4 ways or tail light. He's got something loose in the stator/rotor area.
Also since our bikes don't use a bendix type setup for the starter it uses a sprag clutch. This is another area that might fail and you may end up with noise.

 

[fZling]

Hey, thanks for the replies all I think I might have found the problem,

After looking similar problems on youtube I believe I've narrowed it down. The knocking is most likely caused because of spun rod bearing. I'll probably end up doing an engine rebuilt, but worst case scenario, replace it with a used engine.

I'll be sure to update on how the repairs are going for future use. Not to mention a couple video clips of the bike in action :Sport:

 

[dstaffx]

Hey, thanks for the replies all I think I might have found the problem,

After looking similar problems on youtube I believe I've narrowed it down. The knocking is most likely caused because of spun rod bearing. I'll probably end up doing an engine rebuilt, but worst case scenario, replace it with a used engine.

I'll be sure to update on how the repairs are going for future use. Not to mention a couple video clips of the bike in action :Sport:

Sorry to hear that on such a new engine. Best of luck and hope you get it sorted out.
:thumbup:

 

[RJ2112]

Hey, thanks for the replies all I think I might have found the problem,

After looking similar problems on youtube I believe I've narrowed it down. The knocking is most likely caused because of spun rod bearing. I'll probably end up doing an engine rebuilt, but worst case scenario, replace it with a used engine.

I'll be sure to update on how the repairs are going for future use. Not to mention a couple video clips of the bike in action :Sport:

At this point, I would make the effort to pull the pan, and inspect the rod bearings from the bottom. If you don't see metal chips in the bottom of the pan, and do not feel any play in the rods, you would save yourself engine removal from the frame. It's not terribly difficult to pull the rod cap, and physically inspect the bearing faces. Just make sure and put the caps back on the right piston rod, with the same orientation as previous. And the right torque....

If it IS a spun bearing, you haven't added any time to the tear down. All the things you need to take off to remove the motor still have to come off, the only change would be the pan being off the bike.....

 

[fZling]

At this point, I would make the effort to pull the pan, and inspect the rod bearings from the bottom. If you don't see metal chips in the bottom of the pan, and do not feel any play in the rods, you would save yourself engine removal from the frame. It's not terribly difficult to pull the rod cap, and physically inspect the bearing faces. Just make sure and put the caps back on the right piston rod, with the same orientation as previous. And the right torque....

If it IS a spun bearing, you haven't added any time to the tear down. All the things you need to take off to remove the motor still have to come off, the only change would be the pan being off the bike.....

Right, I got the oil pan off, but was curious if it's possible to remove a crank with the engine still in the frame?

 

[RJ2112]

Right, I got the oil pan off, but was curious if it's possible to remove a crank with the engine still in the frame?

I'd assume no; but I don't have the shop manual for reference. There's anecdotal evidence that you can do work like that, I remember a story of a warranty job authorized by one of the Big Four.... the shops got a specific amount for labor, and found they could do the job much more quickly if they put the bike upside down and worked on the bottom end with the engine in the frame.

Not saying that's a good option, simply that if there is a will there is a way. Trust the shop manual for a known method that will get you the results you want and expect. If you have the time and money to look for another way have at it. :cheer:

 

[TownsendsFJR1300]

Right, I got the oil pan off, but was curious if it's possible to remove a crank with the engine still in the frame?

Looking at the shop manual for my 07, I suspect it would be possible however extremly difficult. With the cases split, the transmission main shaft will fall out (it doesn't have main caps/bolts holding it in, just the cases as they split horizontally). There are also numerous chains (for oil pump, cam chain, etc) that need to be dealt with.

For the extra couple of hours removing the engine, trying it fipped upside down may be the way to go..

Besides the crank being torqued down properly, the cases also need torqing/sealant properly applied. There are numerous bolts holding the split cases together as well..

As posted above, you can pull the oil pan and each rod cap and check the rod bearings with the engine in the frame. With the rod cap removed, if the bearing is spun, the piston/connecting rod needs to come out for machining/replacement anyway... I, personally would start there..

Good luck..

 

[Nelly]

This engine is known to be pretty bullet proof and it’s rare to hear of any significant problems. What causes the rod bearing to fail? Especially with such low mileage.
Good luck with the re-build at least you have the technical ability to attempt it yourself. Please keep us posted.
Nelly:thumbup:

 

[616ah]

Not sure if this will be much help or not, as you seem to have a fairly systematic direction going here. I understand what you are doing pulling the crank, but I (again jumping to conclusions) wonder if it might give a dose of reality to find the failure and then price a few parts before diving right in to a big mess. Did you find much indicating a bearing failure (loose shreds of metal in the crank case and the pickup screen)? From the noise you describe you shouldn't have much trouble locating the failed component just by wiggling a few things after gaining access. Generally (speaking from automotive experience) the deciding factor of salvagable or not is if the main bearings have spun in the case.

If you end up needing a complete crank, bearings, gasket set, conecting rods, oil pump, + massive time investment, etc... And still not really having a cause (ie hidden damage - and not knowing if it could happen again). A good used assembly starts to look really apealing in so many ways.

It is possible to have a rod bearing failure for a number of reasons, even something as simple as flooding or improper storage prep can hydrolock a cylinder enough to cause a slight bend and over time wipe out a bearing, but who knows...

 

[fZling]

Thanks for all the ideas!

Instead of putting the bike upside down I'm going to attempt removing the crank by putting the bike on it's side. If I'm able to find a bad connecting rod bearing I'll go ahead and proceed to take the motor out of the frame. I'm just trying to do the most amount of work I can do without having to take the motor out. Updates on the repairs will be coming this Saturday.

 

[616ah]

Thanks for all the ideas!

Instead of putting the bike upside down I'm going to attempt removing the crank by putting the bike on it's side. If I'm able to find a bad connecting rod bearing I'll go ahead and proceed to take the motor out of the frame. I'm just trying to do the most amount of work I can do without having to take the motor out. Updates on the repairs will be coming this Saturday.

I guess you could... but that sounds really difficult and a bit backward here. Is there no easy way to verify the rods without spliting the case? Generally if a rod bearing fails, the rod hits the scrap pile and things start going down hill from there. If there is a rod failure does it make financial sense to go deeper? At some point, the way it sounds, wouldn't it be easier to pull the whole motor out knowing it either needs rebuilt or replaced, after verifying a component failure? Wouldn't this be a whole lot easier had you not had the sense to shut it off and just let it totally gernade to pieces? :BLAA:

Just some random thoughts based on my assumptions. (One thing I've learned - Never assume).

 

[fZling]

Updates with some pictures. Decided to just remove the engine from the frame, and stopped the dissembling right when I got to the throttle bodies.

 

[FinalImpact]

Re: Knock knock \\ Look inside before you go further!

I'm late in the game but have a few suggestions:
When exactly did the noise start?
Idle:
Under load:
While decelerating:
Coasting - all the time:

With a good load of bad gas and/or a real lean condition from a bad fuel pump, injector issues, plugged fuel pick up, anything making a super lean condition these will make a horrible piston knock which would be prominent during start up, acceleration, under load.

Again - cutting the oil filter open now, will show you the damage. If the filter is clean, tell us about the last load of gas! Poor some out and run in it your lawn mower if you have too. how old is it? How did it run the last time you road it? Was ran out of oil? What are your OC intervals?

If the Oil filter is full of copper and lead looking material, you lost a bearing. If not, I'd inspect the fuel filter and gas.

Tell us everything you know!