Meh, broken down

[greg]

Was riding fairly sedately and I heard a horrible mechanical noise, thought it was from the traffic at first. Pulled over and it's definitely my bike. Turned it off and tried to restart only to hear a good awful noise, so stopped that immediately.

Think my timing chain has slipped a tooth. Any idea how bad the damage will be? I guess I should have checked the tensioner sooner...

 

[aclayonb]

Depends on what actually occurred. Hopefully, the pistons didn't come in contact with the valves or anything crazy.

I was just starting to feel overly paranoid about having put a MCCT on my bike too.... Now I'm somewhat reassured.

 

[greg]

Got it recovered to my local garage. The mechanic says that as soon as you hear them making noise it's time to change it, it's been a little rattly for a while now, so it's overdue. Bike had around 34k miles on the clock and I've been meaning to check it for ages :/

 

[FinalImpact]

Sorry to hear that Greg. Are you sure it was the top end of the engine and maybe not something lower?

If you go at it yourself I'd dump the oil into clean pan and open the filter looking for small parts. After that its pull the plugs and RS cover for TDC setup and chain inspection. Although you could do that first if thats where the noise was.

Keep us posted.

 

[greg]

left it in the capable hands of my mechanic, I don't really have the time or experience for this kind of stuff.

I'm 99% sure it's the timing chain, I'll know in a few das for sure. I'm just hoping I didn't make it worse by trying to start the bike after I stopped. (I killed the bike, it didn't die by itself). At first I thought there was a rock in the fan, as power didn't seem too affected, but I was only going slow.

 

[greg]

here's video of the sound it was making, didn't have my camera on when I tried to start (I wish I hadn't now)

https://www.youtube.com/watch?v=MOdDJY5zuu4

 

[FinalImpact]

here's video of the sound it was making, didn't have my camera on when I tried to start (I wish I hadn't now)

https://www.youtube.com/watch?v=MOdDJY5zuu4

Didn't happen to occur right after a shift did it? Its very much CRANK speed vs CAM speed which is 1/2 of crank speed. However, its very hard to tell from those few seconds but maybe your clutch or something down low let go???

I say this as it seems it was:
Still running
Somewhat stable RPM wise

However - while coasting (it seemed like you were coasting in??) it had a bit of surge to it then but the actual idle once stopped seemed rather stable.

How did the clutch feel & function in those last few seconds?

 

[greg]

I've got a slightly longer video, but I didn't feel like it added much

Frequency of the sound was proportional to engine speed.

I can't be sure if it occurred after I changed gear as there was a lot of background/wind noise.

Engine power didn't seem to be affected, but I didn't test it. Clutching in made no difference to the sound. The surge might just have been me slipping the clutch and using a bit of engine power to move the bike.

 

[greg]

I reverted the youtube video, so it's a bit longer (59seconds), than it was before, not sure how helpful it is though.

 

[FinalImpact]

JM2C - but the fact that its running ** near** stable at the end is a positive note regarding the health of the valves in that they likely did not contact the piston(s). Once that happens the idles goes to crap instantly. You know as part of the TB balance first thing to do is confirm valve clearance as one being open too long or to short makes it near impossible to get a steady vacuum reading (TB balance win).

I could speculate tell the cows come home and it won't add a lick of value. Lets see what they find.

This bike has the self wound stator right? So the left side has been apart. Anything else ever apart?

 

[greg]

This bike has the self wound stator right? So the left side has been apart. Anything else ever apart?

The one I wound ended up failing last year, so I replaced it with an OEM spare that I bought from here.

I did try and start the bike (I naively thought that maybe I had a rock in the fan), it made a god awful noise, so I stopped straight away. I'm hoping I didn't damage it further doing this.

I'll post an update once my mechanic takes a look at it next week.

 

[Cloggy]

Sorry to hear this Greg, I really hope it's not that bad.

 

[greg]

sort of good news, no bent valves

still a new tensioner is £90+, plus a new chain is £20, plus labour, plus vat, etc.

Still not going to be cheap

 

[FinalImpact]

sort of good news, no bent valves

still a new tensioner is £90+, plus a new chain is £20, plus labour, plus vat, etc.

Still not going to be cheap

Are you saying the timing chain spit a link out or what was the conclusion? What made the noise?

 

[TownsendsFJR1300]

So did the cam chain jump a tooth? Or just the CCT fail and chain flopping about in the case?

I too, am curious as to the noise..

BTW, that rear guide, (that the CCT pushes on), I would replace that while he's there. It takes the brunt of the chain tension, isn't terribly expensive and its right there(woun't take 5 seconds to R&R with the cover off and everything apart)

 

[greg]

The tensioner unwound itself apparently.

Are the guides worth replacing, he said the front one had a little wear it but looked ok, couldn't see back one. It was going to add another £60 or so onto the price.

Not sure of the exact cause the noise, I'll ask next time i speak to him, it was quite a bad line

 

[TownsendsFJR1300]

The tensioner unwound itself apparently.

Are the guides worth replacing, he said the front one had a little wear it but looked ok, couldn't see back one. It was going to add another £60 or so onto the price.

Not sure of the exact cause the noise, I'll ask next time i speak to him, it was quite a bad line

If it un-wound itself (the spring likely broke) the chain was flopping about inside the engine case with NO tension. That alone would make a heck of a racket!!!

How it didn't jump a tooth, you need to buy a lottery ticket...

Re the guides, the front, rarely wears as the front run of the chain is (normally) taught. The rear guide, the CCT (that failed), literally puts ALL its tension to that rear GUIDE which in turn puts pressure on the rear run of the cam chain keeping it taught. The chain, 100% of the time, runs up against it. It will wear. With the new rear guide, it alone will take up some play in the chain (depending on how worn it is). With your mileage, I would definitly replace it.

Open the below link, you'll see how much of it the chain actually rides on it(quite a bit):

Part #12, just sits on a dowel: 2005 Yamaha FZ6 (FZS6T) Camshaft Chain | Babbitts Yamaha Parts House (Less than $50.00 US)

 

[Motogiro]

VEGASRIDER (Kenny) had badly worn cam chain and guides and it eventually allowed the chain to have enough slack that it contacted the Crankshaft Position Sensor.
This resulted in the #12 error code and the motor would not start because of lack of CPS to the ECU.

Fortunately it seems like your pistons and valves didn't kiss!

Have your tech pull the right side cover and inspect the CPS for damage because that would likely also make the same noise with loose cam chain. Hopefully the chain did not cut the sending unit. The ECU may have thrown a #12 and that would confirm that CPS contact suspicion. It seemed like your idle was normal in the video. I would think if you had jumped a tooth the idle would have been abnormal.
New chain and new guides. Why not check valve lash while the cover is off?

 

[greg]

update from the mechanic, the guides look to be in decent condition, and it would take 2 weeks to order new ones in, so I'm going to stick with the old ones. He's fitting a new chain, the failed tensioner wasn't at full extension, so everything should be nice and tight when it's fitted. Mechanic said he'd be happy to run his bike like this.

I did ask him to check the valve clearances, and do an oil change. I originally planned on getting this all done over winter, but it didn't snow, so I didn't lay my bike up. Apparently my rear brake pad is shot too, so getting that replaced, I think this is the 3rd one I've been though :spank:

Think I'll take my brakes apart and give them a good clean up one weekend.

 

[TownsendsFJR1300]

Have your tech pull the right side cover and inspect the CPS for damage because that would likely also make the same noise with loose cam chain. Hopefully the chain did not cut the sending unit. The ECU may have thrown a #12 and that would confirm that CPS contact suspicion. It seemed like your idle was normal in the video. I would think if you had jumped a tooth the idle would have been abnormal.
New chain and new guides. Why not check valve lash while the cover is off?

That PU sensor is right there attached to the cam chain cover, so the cover is off anyway (hanging there but a real good idea).


Just a suggestion for your mechainic if he hasn't already done so:

Right now, before any valve lash changes, just check for any EXCESSIVE GAPS between the valve(s) and cams. If there's any valve way out (super loose), you have a bent valve that's NOT CLOSING FULLY (thus, the larger gap). Hopefully the gaps will be good.


**Also, if he follows the Yamaha shop manual to the letter, it has a "TYPO" having him turn the crankshaft COUNTER CLOCKWISE (BACKWARDS), vs the correct forward, Clockwise direction. He likely already knows that.

Shouldn't take too long to put back together (short of waiting on parts).