Slight subtle knocking on decel and rough running.

[Kaisersoze]

hi all,


Bought bike a couple weeks ago. Just changed the coolant and plugs on 06' FZ6 at 20400k miles. Also degreased chain and relubed (more like bathed it) with clear Bel ray chain lube, then adjusted. Bike was running smooth as butter. Warmed engine up and took it out for some highway riding. First time I brought it over 11k rpm. Picked up wifey on bike and noticed a choppy decel when coming to stop signs. Listened carefully and heard small knock from engine (cant tell if top end or low end).

Knocking seems more pronounced today after riding and the bike is not as smooth on accel.

No engine light, and self-diag seemed fine when check all settings. TPS fine.

Hoping to get input on what ya'll think it could be. Valve adjustment? Spark plug gaps wrong? (bought plugs from shop and match what manual says, look pre-gaped.)

Hoping I didnt spin a bearing or something..*gulp*

Thanks all,

- Marc

 

[Nelly]

If its a ticking / tapping noise that last from about 3500 - 4700 rpm it's likely to be the injectors. There shouldn't be any noticeable performance issues though.
Have you adjusted your throttle cables and is the idle rpm set correctly.

Nelly

 

[GTPAddict]

Man, I'm getting scared for you. Seems I've read several more posts about bottom end problems then I'd like to. I hope you don't have rod bearing problems.

OP: Not trying to thread jack here, this may help you as well...

Does anyone know how hard it is to get the rod caps off with the engine in the bike? I am an auto tech, when you have the oil pan off of an automotive engine, the rods are usually just looking at you. If it's not too hard, would it be a good idea to replace the rod bearings as a preventative maintenance thing?

 

[Kaisersoze]

Thanks for the response. The injectors sounded fine on the self-diag. But would that explain the choppy decel at low rpm? Exhaust valves maybe?

If its a ticking / tapping noise that last from about 3500 - 4700 rpm it's likely to be the injectors. There shouldn't be any noticeable performance issues though.
Have you adjusted your throttle cables and is the idle rpm set correctly.

Nelly

 

[Kaisersoze]

Just went to change the oil on the bike and the threads on the oilpan feel apart as i was taking the drain bolt out...I guess the previous owner cross-threaded the drain plug and filled it with some putty or something to get it to stay in. :spank:

any advice on how to get it re-threaded or do I need a new oil pan?



*************EDIT***************

Just saw a couple of threads on re-tapping the oil pan. Gonna try to go that route and will take off oil pan to clean out chips.

This site is amazing.

thank you.

 

[Kaisersoze]

Saw a couple posts about spun bearings but I dont think thats what this is. Just getting bogged down on acceleration. Sounds like something is just missing. Going to sync throttle bodies and clean injectors to see if that helps. Checked plugs today and they were fine. Lets see what happens next. :thumbup:

Man, I'm getting scared for you. Seems I've read several more posts about bottom end problems then I'd like to. I hope you don't have rod bearing problems.

OP: Not trying to thread jack here, this may help you as well...

Does anyone know how hard it is to get the rod caps off with the engine in the bike? I am an auto tech, when you have the oil pan off of an automotive engine, the rods are usually just looking at you. If it's not too hard, would it be a good idea to replace the rod bearings as a preventative maintenance thing?

 

[Shamus McFeeley]

Man, I'm getting scared for you. Seems I've read several more posts about bottom end problems then I'd like to. I hope you don't have rod bearing problems.

OP: Not trying to thread jack here, this may help you as well...

Does anyone know how hard it is to get the rod caps off with the engine in the bike? I am an auto tech, when you have the oil pan off of an automotive engine, the rods are usually just looking at you. If it's not too hard, would it be a good idea to replace the rod bearings as a preventative maintenance thing?

Most of the inline 4s I've worked on do not allow you access to the rod caps through the oil pan. I don't know that this engine is any different.

 

[RJ2112]

Saw a couple posts about spun bearings but I dont think thats what this is. Just getting bogged down on acceleration. Sounds like something is just missing. Going to sync throttle bodies and clean injectors to see if that helps. Checked plugs today and they were fine. Lets see what happens next. :thumbup:

As one of the things you did before you noticed the issue was clean the chain.........

Before you tear into the engine, you may want to replace the chain and sprockets. If the OEM chain is still on that bike, it is at or past the end of it's useful life. If the chain has been replaced with aftermarket parts, it's actually more likely to be a problem.

When a chain wears out, it does so by uneven lengthening. Some links will elongate the holes that carry the pins the rollers ride on. That starts a train wreck sort of deal, and you end up with 1/3 or more of your chain that's looser than the rest. Every time that goes over the sprockets, you get a slight 'jerk' or shudder.

 

[Kaisersoze]

I will look into that as well, thank you.

But even when I have the bike warmed up and sitting there, if I give it throttle and hold it steady the engine breaks up slightly like something is missing.

I checked the plugs this past weekend and they were fine, not oily or full of fuel/ and all the pipes got hot so I know all the pistons are firing.

Gonna buy a vacuum gauge and compression test kit and check throttle body sync and whether Im leaking out valves or past rings.

I heard that before you burn a valve they usually start getting quiet as they tighten and then all hell breaks loose when they burn out. My symptoms are a little less drastic than what the burnt valve descriptions sound like but my worry is that if it is the valves, than everything Im reading says its too late and im looking at possibly rebuilding the top end. (Kind of a bummer cause I was about to sell my car and go pure FZ6 till Mid-November.)

As one of the things you did before you noticed the issue was clean the chain.........

Before you tear into the engine, you may want to replace the chain and sprockets. If the OEM chain is still on that bike, it is at or past the end of it's useful life. If the chain has been replaced with aftermarket parts, it's actually more likely to be a problem.

When a chain wears out, it does so by uneven lengthening. Some links will elongate the holes that carry the pins the rollers ride on. That starts a train wreck sort of deal, and you end up with 1/3 or more of your chain that's looser than the rest. Every time that goes over the sprockets, you get a slight 'jerk' or shudder.

 

[Kaisersoze]

Forgot to add that I am going to disconnect battery and let ECU reset. I dunno if new plugs threw the computer off. But figured its worth a shot.

Thanks again to everyone for the awesome advice! :thumbup:

 

[iSteve]

So the bike was running good then you changed the plugs and now you have a problem. Check the plug wires and boots. Make sure the plugs are seating in the boot properly. As for the drain plug you can get a thread insert kit or just drill and tap it and use a bigger bolt.

 

[FinalImpact]

Oil pan:
buy a heli-coil kit. Most will come with everything you need to install it and then you use the standard bolt. This will last a life time! They come with the proper sized drill, a tap, helicoils, a tool and guide to insert helicoil plus instructions.

As for the noise:
What everyone needs to understand is that the camshaft of a 4 stroke engine turn at half the speed of the crankshaft. As such, a stethoscope or a long metal screw driver with a large plastic end placed to the ear and you can hear what's going on inside an engine. The valve train has allot going on, plus the cam and its chain at a rough idle can make a good deal of noise.

Listen to the bottom of the engine. Listen to the top. The tic of loose valve will be at half the rate of rod slap, piston slap, or lower rod bearing noise. Try to discern one from the other.

A rough idle will be noisy! Why? Chains are meant to be pulled, not pushed as they don't push! So, if the crank is not holding a steady RPM it is up the chain tensioner to eliminate those pulses being delivered to the cam. So the chain is going rattle and touch the guides inconsistently during rough idles. This will make noise!

Tic Vs Tap:
Fuel injectors tic. Loose valves having excessive lash, free play, clearance etc. tap. So, get a stethoscope in there and listen. Most people will never here an injector Tic over all the noise the valves, headers, and exhaust make.

SO; listen to the exhaust headers, both sides of the head plus front and back and around the chain, listen to the bottom end. Listen to the trans. The noises will be alarming. Now try to separate what you heard at idle vs that on the road.

Also: if you really have doubts about rods going bad, cut open the oil filter and spread the pleated element out and examine the contents with a microscope or 10X to 15X magnifying lens with a good light.

 

[Kaisersoze]

***********UPDATE*************

Okay, so I checked compression and all four cylinders at 220Psi which, according to manual, is spot on.

Replaced new plugs with old plugs to no avail.

Checked gap on new plugs with feeler gauge and they were good.

Tried to sync throttle bodies with a vaccuum gauge but i nubbed it and screwed it up. Currently waiting on a motion pro sync tool to fix that blunder. (when i hooked up vacuum gauge to any of the vacuum hoses it was bouncing between 0 - 15 inHg the entire time at idle when its suppossed to hold around 8.6 inHg.)

Decided while i was waiting to use seafoam to clean out the bikes guts and see if it just need to clear its throat. Warmed engine to temperature. Put 1/3 bottle into full tank o' gas and mixed it up with a little rocking, put a little in vacuum hose to throttle bodies from airbox and poured some into the throttle bodies themselves with engine off and throttle open so that it sat a little on the intake valves and the cylinder head. Saw bubbling, which i assume is the reaction to carbon deposits, on the valves. i DID notice that in cylinder one, it was really pooling on the valves, in 2, 3, and 4 a teaspoon of the stuff sat on the valve head so you could see it there, in 1 it seemed to seep by and go into the cylinder. Valve not sealing properly?

Lastly, I waited five - 10 minutes and started her up with a little throttle. She sang loud and gave a nice smoke show when i noticed that i had a leak in the exhaust at the joint right before the mufflers.

Could that leak cause poor performance and and idle problems?

Attached picks: it was puffing pretty good but hard to capture in a still photo.

Thanks all for your awesome help.

 

[Kaisersoze]

bought stethoscope to listen to engine. Not a bottom end noise so I doubt bearing trouble :rockon:

The oil pan problem worked itself out with some teflon-tape around the bolt. There was enough thread on the pan to grab it and seal properly. no leaks so all is well with that.

thanks for the help.

Oil pan:
buy a heli-coil kit. Most will come with everything you need to install it and then you use the standard bolt. This will last a life time! They come with the proper sized drill, a tap, helicoils, a tool and guide to insert helicoil plus instructions.

As for the noise:
What everyone needs to understand is that the camshaft of a 4 stroke engine turn at half the speed of the crankshaft. As such, a stethoscope or a long metal screw driver with a large plastic end placed to the ear and you can hear what's going on inside an engine. The valve train has allot going on, plus the cam and its chain at a rough idle can make a good deal of noise.

Listen to the bottom of the engine. Listen to the top. The tic of loose valve will be at half the rate of rod slap, piston slap, or lower rod bearing noise. Try to discern one from the other.

A rough idle will be noisy! Why? Chains are meant to be pulled, not pushed as they don't push! So, if the crank is not holding a steady RPM it is up the chain tensioner to eliminate those pulses being delivered to the cam. So the chain is going rattle and touch the guides inconsistently during rough idles. This will make noise!

Tic Vs Tap:
Fuel injectors tic. Loose valves having excessive lash, free play, clearance etc. tap. So, get a stethoscope in there and listen. Most people will never here an injector Tic over all the noise the valves, headers, and exhaust make.

SO; listen to the exhaust headers, both sides of the head plus front and back and around the chain, listen to the bottom end. Listen to the trans. The noises will be alarming. Now try to separate what you heard at idle vs that on the road.

Also: if you really have doubts about rods going bad, cut open the oil filter and spread the pleated element out and examine the contents with a microscope or 10X to 15X magnifying lens with a good light.

 

[FinalImpact]

Can you feel it on your finger tips at idle? If no, then I'd think not especially because its after the CAT and O2 sensor. 99% of all the exhaust likely makes it out the tail pipe, but it could cause it to backfire ever so slightly when decelerating down a long grade and getting back on the gas.

Ideally it would have no leaks, so you might loosen the rear section up and try and slide it forward and re-tighten everything.

So, what else did you hear? Could you isolate the noise?

 

[Kaisersoze]

Okay so it seems that the exhaust is a non-issue then because i dont feel anything with finger tips. Took the stethoscope to the engine once again and I definitely hear a noise in cylinder 1. Like metal tapping sound. Same cylinder that didnt seem to seal right with seafoam.

So now its a matter of, intake valve or exhaust valve not sealing right and why? Option a) Carbon deposits b) stuck spring c) bent valve d) worn valve head

I didnt want to have to get into taking the head off to see the valves but lookings like i need to grab those feeler gauges and a torque wrench and start rippin' her apart. :disapprove:

Can you feel it on your finger tips at idle? If no, then I'd think not especially because its after the CAT and O2 sensor. 99% of all the exhaust likely makes it out the tail pipe, but it could cause it to backfire ever so slightly when decelerating down a long grade and getting back on the gas.

Ideally it would have no leaks, so you might loosen the rear section up and try and slide it forward and re-tighten everything.

So, what else did you hear? Could you isolate the noise?

 

[FinalImpact]

Took the stethoscope to the engine once again and I definitely hear a noise in cylinder 1. Like metal tapping sound. Same cylinder that didnt seem to seal right with seafoam.

So now its a matter of, intake valve or exhaust valve not sealing right and why? Option a) Carbon deposits b) stuck spring c) bent valve d) worn valve head

I didnt want to have to get into taking the head off to see the valves but lookings like i need to grab those feeler gauges and a torque wrench and start rippin' her apart. :disapprove:

Lets clear something up:
So you added Seafoam to the carbs and watched it settle and disappear and it did so at different rates, (yes?).

This is normal and would be expected. Why?
The camshaft internal to the engine is such that some valves will be open while others are closed.

Example:
At Top Dead Center (TDC) of the #1 firing stroke the 4 valves of cylinder one are all closed. The crankshaft rotates as follows (degrees) before the valves of 2, 3, and 4 are closed.

Cylinder #2 180°
Cylinder #4 360°
Cylinder #3 540°

So what else could you hear using the new scope? What made number one sound different? Cylinder #4 has the timing chain and tensioner next to it and it likely makes a good deal of noise. Add to that if the engine runs rough, the chain will be making allot more noise the the firing pulses deliver to the crank are not equally balanced.

Tell us more about what you hear and know!

 

[FinalImpact]

I will look into that as well, thank you.

But even when I have the bike warmed up and sitting there, if I give it throttle and hold it steady the engine breaks up slightly like something is missing.

I checked the plugs this past weekend and they were fine, not oily or full of fuel/ and all the pipes got hot so I know all the pistons are firing.

Gonna buy a vacuum gauge and compression test kit and check throttle body sync and whether Im leaking out valves or past rings.

I heard that before you burn a valve they usually start getting quiet as they tighten and then all hell breaks loose when they burn out. My symptoms are a little less drastic than what the burnt valve descriptions sound like but my worry is that if it is the valves, than everything Im reading says its too late and im looking at possibly rebuilding the top end. (Kind of a bummer cause I was about to sell my car and go pure FZ6 till Mid-November.)

Also - your compression check says no, its not an open or burned valve. If the vacuum gauge to the carbs during sync hold steady than I would say that's additional proof that the valves are OK. If the needle bounces around non stop, then I'd go after checking the valve clearance.

Edit: just re-read your posts to find the throttle sync did bounce all over! 0 - 15, so before getting to carried away there, there may be reason for it. What is the gauges intended use? Is it just a multipurpose vacuum gauge OR is it for automotive engine work?
If its not designed for checking engine vacuum then it could easily bounce as you describe. For auto use the gauge needs a tiny orifice or a restrictor like a 0.010" opening or less (**guess**) or the signal is so strong the needle bounces. Think of using a garden hose to empty a balloon or a straw. A large hole will change the feed signal to the gauge making it react instantly. We don't want this.

But - if the needle only bounced one cylinder, now we have something to go on. Was it one or all of them?

 

[Kaisersoze]

Whew, lol...alot to answer.

It was NOT the proper vacuum gauge and it did not have a restrictor. Recieved Motion Pro Carb Sync tool and sync the throttle bodies. Idle is smoother but you can def. hear it missing still.

As far as the sound goes, (I put the stethoscope to the exhaust manifold where it meets cylinder) I heard the clattering of cam chain and such in cyclinder 4 so I knew that was fine. 2 and 3 sounded identical and just heard the normal sounds i would hear without stethoscope, just amplified. With cyclinder 1# it sounded like metal tapping against metal in the frequency of the normal valve tick/tap in other cylinders but much louder and it was in sync with the throttle so if i increased throttle the frequency of the noise increased.

New Symptom: Smell of fuel in the oil.

Removed crankcase cap above dipstick to look inside (at idle so nothing spit all over me) and I smelt fuel. Removed dipstick and smelt that to confirm. It was strong but not like i stuck my nose in the gas tank.

I guess next step is a compression leak-down test on cylinders?

Also - your compression check says no, its not an open or burned valve. If the vacuum gauge to the carbs during sync hold steady than I would say that's additional proof that the valves are OK. If the needle bounces around non stop, then I'd go after checking the valve clearance.

Edit: just re-read your posts to find the throttle sync did bounce all over! 0 - 15, so before getting to carried away there, there may be reason for it. What is the gauges intended use? Is it just a multipurpose vacuum gauge OR is it for automotive engine work?
If its not designed for checking engine vacuum then it could easily bounce as you describe. For auto use the gauge needs a tiny orifice or a restrictor like a 0.010" opening or less (**guess**) or the signal is so strong the needle bounces. Think of using a garden hose to empty a balloon or a straw. A large hole will change the feed signal to the gauge making it react instantly. We don't want this.

But - if the needle only bounced one cylinder, now we have something to go on. Was it one or all of them?

 

[FinalImpact]

From what you describe it sounds like the lash is excessive on one or more of the valves in cylinder #1. The exhaust valves are subject to intense heat and often change clearance before the intakes do as the intakes get a nice cool charge of furl/air during each valve opening.

So, with your scope, try to probe both sides of the head at the same locations. Chances are its louder near the exhaust.

What did the needles do on the new sync gauge? Stable and steady PLUS equally balanced among all 4 cyl?

This bothers you enough to notice it, investigate, and post, so it concerns you. From this I'd guess its time inspect the valves clearances. Do you have the service manual handy. Read it through and ask questions before you get the bike apart.

Lastly: title says "knocking". Is it fair to say we have deduced this to a sharp tapping sound and that it IS NOT currently affecting the bikes performance off idle? Or can you hear it miss at all ALL RPMs? Have pulled the spark plugs? If not, now is a good time to inspect them.

Did you listen to the injectors? Those make a tic and its nothing like the tap in the head. True?