Knocking Noise From Engine

[SoCalFJR1300]

Had a little scare last Saturday.

Went out in the morning and started the bike and was lettting it idle/warm while I was getting my gear on and all of a sudden I heard this knocking coming from the engine!

Knocking lasted about 10-15 seconds then stopped.......bike seemed to run fine, not knocking anymore so far?

Talked to a FJR mech and he thinks the Cam chain may have adjusted itself?

He says since the sound started and then went away it must be part that can adjust?

You guys have any ideas?

2008, only 8,000 miles....bike did sit a lot in it's life. I bought it last February with only 2,900 miles. It's run great this whole time and since that knocking incident it's been fine.

Was just wondering what you FJR experts thought?

Thanks in advance (even for the smart ass comments)

 

[petey]

I wouldn't let your machanic work on my bike. "Cam chain may have adjusted itself"?? .....UNLIKELY...

since the cam chain is on sprockets.

 

[SoCalFJR1300]

I wouldn't let your machanic work on my bike. "Cam chain may have adjusted itself"?? .....UNLIKELY...

since the cam chain is on sprockets.

Didn't say he was "my" mechanic, said I talked to "a" FJR mechanic.

I just called a dealer.

It's on sprockets but their's adjustment right?

Something was abviously stuck or hanging up or something??

Was just wondering if anyone else ever experienced a knocking that started then went away within less than a minute.

 

[Ignacio]

It's on sprockets but their's adjustment right?

Nope! There's no adjustment.

....unless you consider moving the chain one full sprocket tooth a valid adjustment parameter....which I certainly don't....and don't know anybody else that thinks so either...on this particular engine.

I believe the only thing that "adjusts" is cam chain tension. Maybe that's why they call that CCT thing a cam chain tensioner? And maybe that's why it has so many threads rehashed on this forum about it? Maybe that's what "a FJR mechanic" (not "your FJR mechanic") meant. It has a history of getting weaker over the miles unless, supposedly, embellished by the Yamaha gods with a special blue dot of pigment.

I suggest you go read up on the MANY existing CCT threads and see if your symptoms match up.

 

[ionbeam]

Hmmm, there is knocking and then there is knocking and then there is KNOCKING.

If you had KNOCKING like metal parts hammering, it's time to park it until you can have it diagnosed. This kind of noise can be caused by plane bearings being loose or a dead CCT, but a dead CCT will let the chain continue to slap around and you would know it.

if you had knocking that sounded like metal parts, it could indeed be caused by the CCT. The CCT in the FJR is designed to be self adjusting. I believe what Yamaha wanted to say was that your knocking was caused by light pressure on the cam chain because the CCT had not self adjusted, then as the warm-up continued the CCT did adjust itself. I have seen motorcycle shops get a bike in that had a rattling cam chain then rev the snot out of the engine to get the CCT to self adjust.

If you had knocking which I suspect you had, you were probably hearing lean misfire from a cold engine. It will indeed sound like a knock and will usually be associated with a misfire -- this is not uncommon in all Gens. Also, when the engine is cold (thermostat hasn't opened yet) the Air Injection System will be active and injecting fresh air into the exhaust ports in the cylinder head. This can cause popping in the exhaust. Next time you drive away with a cold engine (no bars) go up to 30-40 mph and chop the throttle OFF and listen to the popping you will hear.

 

[SoCalFJR1300]

It's on sprockets but their's adjustment right?

Nope! There's no adjustment.

....unless you consider moving the chain one full sprocket tooth a valid adjustment parameter....which I certainly don't....and don't know anybody else that thinks so either...on this particular engine.

I believe the only thing that "adjusts" is cam chain tension. Maybe that's why they call that CCT thing a cam chain tensioner? And maybe that's why it has so many threads rehashed on this forum about it? Maybe that's what "a FJR mechanic" (not "your FJR mechanic") meant. It has a history of getting weaker over the miles unless, supposedly, embellished by the Yamaha gods with a special blue dot of pigment.

I suggest you go read up on the MANY existing CCT threads and see if your symptoms match up.

Thats fine if you don't think it's the CCT, I'm just trying to get ideas of what it "could" have been or if anyone else has had pronounced knocking that went away after a short time.

 

[SoCalFJR1300]

Hmmm, there is knocking and then there is knocking and then there is KNOCKING.
If you had KNOCKING like metal parts hammering, it's time to park it until you can have it diagnosed. This kind of noise can be caused by plane bearings being loose or a dead CCT, but a dead CCT will let the chain continue to slap around and you would know it.

if you had knocking that sounded like metal parts, it could indeed be caused by the CCT. The CCT in the FJR is designed to be self adjusting. I believe what Yamaha wanted to say was that your knocking was caused by light pressure on the cam chain because the CCT had not self adjusted, then as the warm-up continued the CCT did adjust itself. I have seen motorcycle shops get a bike in that had a rattling cam chain then rev the snot out of the engine to get the CCT to self adjust.

If you had knocking which I suspect you had, you were probably hearing lean misfire from a cold engine. It will indeed sound like a knock and will usually be associated with a misfire -- this is not uncommon in all Gens. Also, when the engine is cold (thermostat hasn't opened yet) the Air Injection System will be active and injecting fresh air into the exhaust ports in the cylinder head. This can cause popping in the exhaust. Next time you drive away with a cold engine (no bars) go up to 30-40 mph and chop the throttle OFF and listen to the popping you will hear.

Thanks for the response but you and Ignacio are confusing me, I do appreciate both of your input though!

Ignacio says there's NO adjustment to speak of, you say there IS and it could cause a KNOCKING sound?

It was a fairly loud knock, I heard it from about 3 feet away as I was putting on my gear.

I think if it was serious the knocking wouldn't have went away, just trying to get some ideas though.

 

[ionbeam]

Thats fine if you don't think it's the CCT, I'm just trying to get ideas of what it "could" have been or if anyone else has had pronounced knocking that went away after a short time.

Ahh, the clues are becoming more refined. That was what I was meaning, there are different levels of knocking. This kind of noise is consistent with the CCT, you need to look and see if you have a blue dot CCT. Do you feel that there is no way it could have been lean misfire when cold?

 

[SoCalFJR1300]

Thats fine if you don't think it's the CCT, I'm just trying to get ideas of what it "could" have been or if anyone else has had pronounced knocking that went away after a short time.

Ahh, the clues are becoming more refined. That was what I was meaning, there are different levels of knocking. This kind of noise is consistent with the CCT, you need to look and see if you have a blue dot CCT. Do you feel that there is no way it could have been lean misfire when cold?

Sorry, yeah it was a fairly loud metal to metal sounding knock like a bearing or ROD knock on a car.

It was a warm morning...about 70, and I've started the bike in MUCH colder weather and not had any knocking so I would say no on the lean misfire when cold.

 

[SoCalFJR1300]

Gotta run...it's taking forever for these posts to load.....again......worked fine for about a month or so, just too hard to communicate this way, Thanks for the inputs guys I'll check back in tonight.

 

[ionbeam]

I see you're post arrived about one minute before I clicked POST. The CCT self adjusts, there is nothing you can do to adjust it. Both the old and new CCT are installed then the plunger is released and the internal spring pushes the plunger against the rear cam chain slipper.

If your FJR has had the valves checked there is an outside chance that either the front or rear cam chain slipper did not go back onto the dowels correctly. There was one Forumite that didn't get the rear slipper back on correctly and never knew it until he went back into the engine to change the CCT to the new blue dot CCT.

 

[Ignacio]

Thats fine if you don't think it's the CCT,

I have no idea where you got that from ..... I sure didn't say anything like that.

If anything, I'd wager a CCT for a win/place/show....hence the suggestion of reviewing CCT threads. I wouldn't wager on detonation/lean stuff or hard parts disintegrating unless it was a box exacta with super great odds.

 

[RadioHowie]

Ignutz,

I'd put danger money on "Cold Engine Misfire" before I'd think mechanical issues.

 

[ionbeam]

I'd put danger money on "Cold Engine Misfire" before I'd think mechanical issues.

Put 10 people around a FJR and let them listen to a particular noise. Now, have them each write a post to the Forum describing the noise and any observations that may go along with the noise (noise is in synch with a tach needle bobble, lights flicker, black smoke out the exhaust, etc). I'm willing to bet that it would read like 10 different problems.

What a difference a video or sound clip could make. Given the model year (without stated elapsed mileage) I wouldn't suspect the CCT as the root cause of the observed noise and I'm really sensitive to CCT issues

or even rumors of CCT issues. I would also mention that I have heard cold engine misfire even when the weather is warm. I wonder what a few tablespoons of water from the bottom of the gas tank would sound like as it gets shot into the engine...

 

[Fred W]

The noise from a loose cam chain isn't really a "knocking" sound, more of a marbles in a can sort of rattle. And I don't think it would come on suddenly and then subside equally as suddenly with no outside input.

I'm inclined to agree with Radio Howie that the OP was getting some of the dreaded cold start misfiring that the inferior second gens are apt to produce. Some folks call it klunking, knocking, what have you. It seems to emanate from the normal drive-train slop's bouncing around after these cold start misfires.

The 1st gens do not seem to ever exhibit this trait, but the seconds do somewhat commonly, though intermittently. It seems to be caused by a too lean fueling (during cold starts) coupled with a too low idle speed during the cold start. It is well documented that the second gen cold idle speed is just too low, most likely due to the design requirements of the AEs.

Theories have been floated that raising the cold idle speed (via the cold idle adjustments screw, inconveniently hidden in the bowels of the intake manifold) might alleviate some of that cold start misfiring.

Could this be what you observed?

 

[FJRBluesman]

Can I play? I'm guessing like a counter balance thing, but not sure there is one on the bike. So I'll say either the clutch / clutch damper noise or possible transmission slack or some goofy thing. Don't know why it would start then stop. Just my 2 cents.

CCT either makes noise or doesn't I know, RPM plays a factor, but I don't believe a CCT would be quiet then make noise then be quiet again all while idling. Cam chain noise is distinct (to me) compared to a clanking noise.

I also like Fred W's post.

Let us know, good luck.

 

[dcarver]

The ?? I have is - all the time or just some of the time? Just once?

 

[rPGoatBoy]

If you have an inspection mirror, you can see if your CCT is the blue dot version. If you can make an audio recording, even a video recording with a cell phone, that would help considerably if the problem is repeatable. If not, and you're confident you can make the 45 mile trip up to Chino without damaging the motor, I can help you diagnose. If it stumps us both, I can make a video and post it for the world to see. Sound good?

 

[RaYzerman19]

Hard to say without a sound byte or more info or what your definition of a minute is. Hard to say if it was CCT or the cold start/lean fuel thing (would not "knock" in my definition), or if it was like a con-rod-like knock noise, or if it was a clutch noise. If this bike has been sitting a long time, chances are all the oil has drained off parts or leaked out of con-rod bearings so there isn't the full oil cushion between crankshaft and bearings/piston pins and bearings/pistons in the bores/camshaft and bearing caps, etc. Also, if there's the Yamma recommended 20W40 in the crankcase, upon start-up it's going to take a bit to get all the parts lubed properly as oil pressure builds so they don't have the hammer noise. In this case, the hard knock should have diminished significantly in a few seconds, but the general noise may continue for a minute until things warm up a bit. I've never heard a%2