Engine knock, Please help what to do?

[ManaMane808]

Hey I hope you all are doing well, this is my first time posting on this forum. I’m gonna try to be as detailed as possible so hopefully I can get some help from some more experienced fz6r owners…

I picked up a 2012 FZ6R 10 days ago with a little under 25k miles for 2k as my first street bike, which I thought was a good deal at the time. The bike isn’t perfect but it started right up and rode great with plenty of power, I heard these bikes are bulletproof so I wasn’t too worried about the mileage. The previous owner was a father who barely used it in his two years of ownership but he at least did an oil change. I’ve put around 250 miles on the bike so far.

All was well and i was loving the bike up until a few days ago when I noticed a slight knocking sound when I let off the throttle at low rpm’s. I kinda noticed it before but I thought it was my loose chain slapping a bit. Then I tried listening with the bike stationary and when the rpm’s are coming down from 3-5k you can still hear it so it’s something internal.

I used a mechanics stethoscope to try pinpoint where the sound is coming from and I can hear the knocking pretty much anywhere I put it but It is loudest at the left side of the oil pan by the drain bolt…I can feel the slight vibration of each knock even at idle with the stethoscope.

I’m really bummed because I was just starting to fall in love with the bike and street riding, I’ve been wanting a Japanese inline 4 fully faired street bike for a long time now and this thing checked all the boxes :/

So my question is what do you guys think I should do? Do you think it could possibly be something other than rod knock? Has anyone else’s bike done this?

Here’s a video of the noise, you gotta listen closely…

The three options I’m considering are: A- Run this motor until it blows and risk getting a used motor from a reputable seller on eBay with as low miles as I can find and swap it…not sure how difficult that would be, I have mechanical experience but I’m thinking it’d be a lot easier and possibly even cheaper than replacing the crank and bearings…and even though it sounds like the early stages of rod knock the rest of the motor is probably already damaged by fine metal particles if it is indeed rod knock… B- dig deeper into this motor, ie take off the oil pan and inspect crank. I also want to at least remove the stator cover because it is the second loudest place I can hear the knocking and someone obviously took it off and put too much rtv sealant when putting it back together so that could possibly point to a botched job inside… Or C- Sell the bike while it still runs…but I really don’t want to do that I think this bike is perfect for my skill level with my prior dirt bike experience and it also seems perfect for the relatively small island I live on where there’s not a whole lot of room to go faster than the fz6r top speed, I think it’d take me awhile to really grow out of this bike if ever.

What’s your guys opinions?

Heres some more details…

Right after I got the bike I started to notice on cold starts the bike would make what sounds like a lifter tick noise coming from the head area that went away when the bike started to get up to temp. After reading forums it seems that it is normal for a lot of bikes to do that. Although my bike is due for a valve adjustment but I don’t think the tick is an issue

I did an oil change a few days ago with 3 quarts of mobile 1 10w40 racing 4T oil and a K&N oil filter before I really noticed the knocking. The old oil was dirty but didn’t seem horrible, the old filter said Yamaha on it so I’m hoping it wasn’t the original one but when I cut it open it seemed really clean and not even that dark so I don’t think so.

Also the other day the bike was intermittently cranking but no start, it had two bars on the fuel gauge and seemed to have a decent amount in the tank when I looked but I figured I’d try filling it up just in case and that seemed to fix it for the most part… it starts every time now but it did randomly shut off on me once since then after running for a few seconds. And before all of that one time the bike started but the screen and tachometer were dead until I restarted it so I thought that was a weird hiccup…I’m hoping this points to a botched job underneath the stator cover that explains the knocking and these weird seemingly electrical issues…I kinda doubt it though since the noise is loudest near the drain bolt but the stator cover is right above that so I’m not ruling it out.

I’m gonna try inspecting under the stator cover today and probably the oil pan aswell, hopefully I can find something…I’ll post an update when I’m done. Any advice would be very much appreciated.

Thank you if you’ve read into my post this far I greatly appreciate it! Keep two down!

 

[ManaMane808]

A few details I forgot to mention…the knocking doesn’t change whether the clutch is in or out or if the bike is in gear or not. The sound also seems to become more apparent once the bike is up to temp…both symptoms pointing towards rod knock…

It’s still just hard for me to believe that it’s knocking at 25k miles when I hear everyone saying these bikes are super reliable and can reach 100k miles… I guess my bike could’ve been severely neglected and abused but I feel like it was at least decently maintained since it only has very minor body damage doesn’t look like it was ever laid down just tip overs in the garage. It also has a few aftermarket pieces that show someone cared for it and from what I know it was garage kept by the past two owners.

I’ll post an update after looking into my bike more

 

[Marthy]

Hard to tell. I would change oil and filter and inspect for metal having or something not normal. 25K miles you're due for a valve adjustment too... Could be the chain/sprockets too, I won't worry too much but check your bases.

 

[ManaMane808]

Hard to tell. I would change oil and filter and inspect for metal having or something not normal. 25K miles you're due for a valve adjustment too... Could be the chain/sprockets too, I won't worry too much but check your bases.

Thanks for the reply, I already changed the oil but I’ll try draining some out and inspect it because I wasn’t paying much attention when I drained it the first time.

I’ve never heard valves make a knocking noise like this it’s usually a tapping noise. After watching half click ups videos he went way past when he was supposed to adjust his valves and he didn’t have any tapping noise apparently, just hard time starting in cold weather.

Are you talking about drive chain and sprockets or timing chain and sprockets? It’s not the drive chain because it makes the knocking while stationary too…and I doubt it’s the timing chain because the noise seems to be coming from the opposite side of the motor…I’ll give an update when I inspect the oil…

 

[ManaMane808]

Well I drained a small amount of my oil into a pan and looked at it in the sunlight…there are some very small metal flakes in the oil I just changed around 100 miles ago probably.

After seeing this I’m not even gonna tear into the engine at all because no matter where the metal flakes are coming from it’s not good, and I’m almost positive it’s coming from the rod bearings due to the noise…so I’ve been looking on eBay for a low mileage engine for a good deal and think I’ve found a couple possible options, maybe once I get a new engine I’ll try looking into this one.

For now I’m just gonna throw some Lucas oil stabilizer in and hope that quiets the noise and makes this motor last me awhile, since the knock isn’t that bad yet. I’ve seen it work on cars with mild rod knock so it should work to give me some more life out of this motor aswell.

If anyone is curious to see what my oil looks like I can try taking a video. I’ll also post an update of how much the oil stabilizer helps and how long it makes this motor last. I’m praying for another few thousand miles, that would be great, I’ve heard of cars going much further with mild knock and oil stabilizer so I’m hoping for the best.