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Strange sound after exhaust installation


redwood

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I installed a Yoshimura R77 exhaust without the baffle on my 2019 MT-07. So far I'm absolutely loving it :)

However, I think I might have a minor air leak at the headers. I hear a high pitch sound coming from the front of the bike, seemingly from the headers. The sound remains and has never left during the 3 days I've had the exhaust. Here's what I hear: 

There haven't been any symptoms that would indicate this is a major problem. There's no choppiness in the throttle, no lugging, and the bike has never acted unexpectedly. I commute 40 miles to work so I would've noticed something by now. Also, I have no liquid leaks; no black streaks.

Here are some of my guesses as to what might be the cause:

- Issue with the gaskets because I didn't change the ones that came with the bike (install happened around 1500 miles).

- I didn't tighten the header nuts enough, even though I felt like I might have been overtorquing at the time. The images below show that there might be more tightening I have to do 

- (My hope but unlikely) The engine is running super lean since I don't have the baffle in and the issue will be solved after I get the ECU flashed.

For troubleshooting, I want to start with seeing if there's more tightening I can do to the headers. One concern with that is that I crush the gaskets.

If that doesn't work maybe sealant would be enough since this seems minor?

If all that doesn't work maybe I leave the muffler on, take off the header, and change the gaskets.

And finally, I will be flashing the ECU regardless of what happens. 

 

So anyone have any ideas or critique of my plan?

IMG_20190719_185658.thumb.jpg.f03930c601fa7cb715b66b0b5862171b.jpg

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You can use one of them "long reach" lighters and run the flame around any exhaust joints and see if the flame dances when motor is running... That's my way of finding exhaust leaks...

 

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2015 fz-07- Hordpower Edition...2015 fj-09- 120whp- Graves Exhaust w/Woolich Race Kit- tuned by 2WDW
 

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On ‎7‎/‎20‎/‎2019 at 1:47 AM, norcal616 said:

You can use one of them "long reach" lighters and run the flame around any exhaust joints and see if the flame dances when motor is running... That's my way of finding exhaust leaks...

 

^ What I was going to suggest. If you don't have one of those another old method is you can light a match or a piece of paper and hold it a ways underneath the header connection and then blow out the flame. The smoke will rise up to toward the connection and if there isn't any disturbance in the smoke it should be good.

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Beemer

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Sometimes, if you're not careful, you can actually cock the head of the pipes that should be directly seating in the exhaust ports. If you get it in there just right (wrong), it will appear to seat fully and tightening the nuts will just jam it in there further, while appearing to be seated correctly. Mostly, this is due to the pipe being heavy and trying to rotate the pipe downward as you try to keep the sealing surfaces aligned.

If this is what happened, you might have to replace the gaskets, as they could have been pinched and deformed.

I have done this during an install, but have caught it early enough to re-seat the heads in the port before tightening the nuts fully.

Good luck, but whatever is the problem, it should be relatively easy to locate and fix.

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It's a windy day here so a bit challenging to try the suggestions. But thanks for all the good tips! For now I just used a bic lighter in the areas I could reach and everything appeared okay.

I spoke with a repair shop over the phone and they mentioned the sound was most likely due to not having a power commander installed. I'm getting my ECU flashed regardless so I'll see if that is indeed true. My bike has had no performance issues and the engine temp is normal so at the moment this is the theory I'm running with...because I would like to not have to reinstall the exhaust ;)

So for those keeping score at home, the remedy might be an ECU flash or new gaskets.

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To be honest I don't hear anything that sounds abnormal. Engines make all kinds of little noises but that's normal. Seems we've been here before.

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Beemer

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cornerslider
4 hours ago, Beemer said:

To be honest I don't hear anything that sounds abnormal. Engines make all kinds of little noises but that's normal. Seems we've been here before.

I kinda thought the same thing....

""W.O.T. until you see god, then brake"

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You guys are right about the noise that the video captured...it's just the engine.

It's hard to capture the other sound which can best be described as a locomotive where it sounds like varying air pressure escaping from somewhere. I'm pretty sure it's due to the gaskets I reused, my dealership mentioned the same thing. I've changed the gaskets but have to wait for me ECU to return before firing her up. It's not the most scientific approach but I will report back.

Thanks y'all for staying patient with me through my mechanical adventures!

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Just now, redwood said:

You guys are right about the noise that the video captured...it's just the engine.

It's hard to capture the other sound which can best be described as a locomotive where it sounds like varying air pressure escaping from somewhere. I'm pretty sure it's due to the gaskets I reused, my dealership mentioned the same thing. I've changed the gaskets but have to wait for me ECU to return before firing her up. It's not the most scientific approach but I will report back.

Thanks y'all for staying patient with me through my mechanical adventures!

One thing about the Yosh exhaust I've learned after fooling with a couple dozen of them. The sharp edge of gasket surface of the head tubes can get hung up on the threads of the head bolts a little bit if you're not careful. When you fit up the pipe to the head give er a good solid rap with your fist to seat the the mating surfaces properly.

I also use a dollop of high temp whatever to hold the header gaskets in place while bolting things up. Keeps things from moving when I ain't looking.

Good luck.

 

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