Whirring noise

[pajukoo]

My bike is a 2007 FZ6-N S2, 38000 km on the clock. Recently it’s been making a whirring/winding noise in 3rd gear under drive when moving at 43-50 kph (26-31 mph), rising in pitch, until it disappears after 50 kph. The noise happens only when on the throttle, and goes away when clutched in. And only in 3rd gear. Oh, and it seems to come and go, apparently depending on engine temp. It’s most noticeable when cold or very hot, but less audible when at a nice 76-84 C (168-184 F).

Chain is lubed and properly tensioned, oil changed about 1000km ago (Yamalube 10W40) and checked frequently.

Could it be a transmission bearing issue? Seems unlikely as it only occurs in 3rd gear, right? Worn cogs? It’s kind of driving me nuts, as I don’t want to take it to a mechanic as splitting the case is an expensive job.

 

[TownsendsFJR1300]

The transmissions are pretty much bullet proof un-less you literally blow up the clutch and fragments get stuck between certain gears.

How many miles on the drive chain and exactly, how are you setting chain (slack, on the taughest spot, reference where on the chain).

Original sprockets?

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[pajukoo]

I don’t actually know the mileage on the chain, as I bought the bike in May. The chain was pretty tight when I bought it, with about 1” of slack. The front sprocket is new, I switched it out for a rubber-damped one because of chain noise. The chain was also really dirty, and I cleaned it thoroughly. The rear sprocket looks to be in good shape, and isn’t original.

I adjusted the chain at the tightest spot, and set the slack to 2”, and I measured it just behind the chain guide.

 

[Gary in NJ]

Wheel bearing

 

[TownsendsFJR1300]

As the chain was obviously too tight and apparently not maintained for it's life, I'd be looking hard at that.

The OEM chain is continuous loop with no master link. The swing arm has to partially come off to replace.

Un-less replaced with an OEM chain, you'll see either a clip or one link with 2 center pins "dimpled" in..

.

 

[pajukoo]

I’ll check the chain, but I have a feeling it’s not the original one. What’s bothering me though, is that the chain would make noise in any gear? Or could it be some harmonic from a worn chain and a certain rpm at a certain speed?

The chain doesn’t have any links that are stuck, and the tightest spot doesn’t differ much from the slackest one.

I’m just worried it might a bearing issue due to the chain having been overtight for however long the previous owner might have had it that way. Although the output shaft bearing didn’t make any noises when I checked it while changing the front sprocket, and the seal hadn’t leaked oil, and the shaft didn’t have any play and it turned smoothly.

As for the wheel bearing, how would I check if it’s okay or worn?

 

[bryancraftyhands]

Just for fun and to see what the outcome might show if anything, lift the rear, put the bike in gear and roll the wheel with the engine off. Shift through them, feel and listen as you roll for anything to change. I would mark the chain and make at least one full revolution of it before shifting to another gear if there is concern that it may be the chain.

 

[TownsendsFJR1300]

Being that output shaft is nice and tight, no play, no leaking seal is a VERY good thing..
Sounds like the over tightness didn't damage that bearing.

As for wheel bearings, pull each wheel off. With a finger (or two), spin each bearing feeling for smoothness/ notchiness, etc. There's also a bearing in the rear sprocket carrier..

Chains, are about the most abused (not maintained) item on the FZ... They can /will make a odd noises if worn.

As for 3rd gear only, dunno. Hopefully just a chain , wheel bearing, anything but inside the cases..

.

 

[Gary in NJ]

Just for fun and to see what the outcome might show if anything, lift the rear, put the bike in gear and roll the wheel with the engine off. Shift through them, feel and listen as you roll for anything to change. I would mark the chain and make at least one full revolution of it before shifting to another gear if there is concern that it may be the chain.

I’d like to learn more about how you spin the rear wheel with the bike in gear with the engine off. You must have arms like Popeye.

 

[Gary in NJ]

As for the wheel bearing, how would I check if it’s okay or worn?

You can remove the chain and spin the wheel, listening for grinding and feeling for roughness. Try to move the wheel from side-by-side noting any movement - that would be a badly worn (damaged) bearing.

 

[bryancraftyhands]

I’d like to learn more about how you spin the rear wheel with the bike in gear with the engine off. You must have arms like Popeye.

Well... Now that you mention it. (aw, that's not fun, I inserted a flexing arm and laughing emoji there. they don't show up)
Good point. Clutch disengaged / pulled. We're concerned about the wheel, chain and transmission here and not the engine so much, yet. Pull the handle, use something to hold it while doing the spinning.

 

[pajukoo]

I tried putting it in gear and turning the back wheel with the clutch pulled in. All I could hear was a faint clicking of the gears meshing and the dogs engaging. No grinding noises.

 

[bryancraftyhands]

No change in feel either? Not even in 3rd? That is the odd thing about your symptom. Most any whirring would be constant in all speeds and gears if it were chain, bearings, or tire. By any chance did your roll it backwards too?
Perhaps if you can get a recording of it and post it on YouTube or a cloud file share / drive service and post the link, maybe we can listen and someone might be able to pin it or at last narrow the options down.

 

[pajukoo]

I'll try to get a recording of the sound somehow The specificity of it happening only in third when on the throttle and no weird noise when turning the wheel in gear either, even in third. I'm almost leaning toward it being some harmonic in the transmission in third gear when the oil is at a certain temperature.

 

[Gary in NJ]

The harmonic (sympathetic vibration) is a very real possibility. It could be as simple as a lose bolt on a fairing.

 

[bryancraftyhands]

Recording of the sound could be a problem of course. If on the ground, you will be traveling and there will be wind noise, otherwise, mics with wind buffers placed where you think it's coming from wired into a recorder might work well. (Don't you wish you saved all the mics from all the old cassette recorders you threw out?)
You could attempt to do it while the bike is on a stand. Make sure it's not going to move itself off as best as possible. Vibration and torque is a problem when revving up on one. Use either straps, helpers or both to hold with you.
If it's not on the ground and not under load, the sound may not appear. This could be an indicator in itself of course. If you have a dyno available to use, would be best.
Have you had the chain checked for being stretched? I mention this because if you are letting off the throttle some for more of a cruising speed, the tension being let off the chain some could be why the sound disappears after third or after a speed. The speeds needed to create the sound audibily not being achieved yet in fist and second? I don't know how you are accelerating, if this is across all ranges of acceleration etc. I know when I first tighten a chain, I get a bit of a hum for a week or two. Cold temps would lead to thicker lubrication, hotter to thinner. These things could affect it.
How is your water pump and oil looking? Going by your kilometers and age, your mechanical seal inside the water pump may be going. The bearing inside may start making some noise if water is getting to it. Look into that as a possibility as well. Check under your weep hold for drips or if you manage to park in the same spot, look for a stain starting to form under that area.

 

[pajukoo]

Here's a link to a video with the noise: FZ6 Noise

As to the water pump, I'm going to flush the coolant at some point, and will take a look at it then. Haven't noticed any leaks, though. The oil's almost brand new, Yamalube 10W40 with about 1000km on it, and when I changed the oil, there was no glitter in it.

 

[bryancraftyhands]

I hear the engine, the wind, and one sound that isn't changing much in pitch or frequency and I think that's just the chain. I'm just running on some earbuds and a laptop for sound though. Hopefully someone else can determine better.

 

[Gary in NJ]

The only oddity I hear is wind whistle.

 

[pajukoo]

Well, that’s a bit of a relief. I guess I’ll think less and ride more!