Installed my exhaust and there seems to be a strange sound.

[JuggernautOfWar]

I installed my Yoshi Works Carbon exhaust with the baffle out and no tune so far. The exhaust itself sounds freakin' amazing and I could just sit there listening to it all day, however when riding the bike while using throttle (not coasting) there seems to be an odd sound coming from what seems like the front of the bike like maybe where the headers are or even the engine. Now, I admit this sound I'm hearing may be completely normal for the bike with a less restrictive exhaust on it, but I only have experience with the factory sewing machine exhaust.
 
It's hard to describe the sound, but it almost sounds like a small piece of fabric flapping in the wind right below me as I ride, though of course there is no fabric there. I could describe it as a sort of soft flutter sound, like it's either coming from the engine itself or the headers.
 
This is probably just me actually hearing the engine for a change and not being familiar with it because the factory exhaust I'm still used to made it so hard to hear anything going on.
 
What do you guys think? Am I being overly paranoid?
 

[go4geoff]

I have the yoshi carbon setup as well man, and I admit I have heard this fluttering noise too at times. For me it was more when I quick revved at slow or idle speeds that I'd hear the flutter when the revs would come down. Since I've got the ecu reflashed I don't hear it anymore. But on occasion from a somewhat colder startup/go I'll hear it when I'm first taking the bike out. I think it may have to do with excess gas partially igniting and escaping with the revs due to the new setup making the bike run leaner

[Jeckler]

Did either of you replace the header gaskets?

[JuggernautOfWar]

Interesting thanks for the reply. I should specify this is not the same as the slight "popping" sound when rolling off the throttle and coasting in gear, but a separate sort of "flutter" sound when the throttle is actually applied.
 
How much was your ECU flash? Do you think running lean will hurt the bike at all?
 
 

Did either of you replace the header gaskets?

No the Yoshimura documentation said the factory header gaskets are to be used.
 

[maritan]

You should replace the gaskets with new factory replacements. The fluttering sound you're hearing is likely an exhaust leak.

[JuggernautOfWar]

You should replace the gaskets with new factory replacements. The fluttering sound you're hearing is likely an exhaust leak.

The factory replacements? Yoshimura didn't give me any gasket replacements with the exhaust so where do you get them? 

[Jeckler]

The dealer, or online. 3YF-14613-01-00 It fits about 100 different bikes and ATV's, no joke.

[JuggernautOfWar]

This means I'll have to remove the exhaust to replace the gaskets then reinstall the exhaust again. God dammit, why am I so lazy? I'll do it eventually, but honestly probably not for a little while.
 
Weird that the Yoshi documentation specified the factory gaskets are to be used.
 

[go4geoff]

I had the yoshi pipe put on within 200 miles of owning the bike brand new. So I used the oem gaskets that came on the bike presuming it was so new that it was still useable. @juggernautofwar My ecu flash cost me 175. I had it done local in LA from Graves Motorsports & Bombay Motorsports here in the valley. Running the bike lean will cause the motor to run hotter, especially during the hotter summer days. This adds a bit more wear and tear on the internals over time and will def affect performance for sure. I'm happy to not be running on the California emissions stock ecu cause it felt way underpowered compared to now.

[JuggernautOfWar]

Hmm okay I'll have to call around to see if any local shops can do a tune. Only place I can think of off the top of my head is the Yamaha dealership an hour away, but they'll probably charge a small fortune to do it. Sometimes living in a small university town is annoying. I don't have the spare $200 or so right now for the tune so it will have to wait. I know running lean is a bit more wear and tear on the engine over time, but I hope it's not too bad to run lean for a few months.
 
@go4geoff are you still using the OEM factory gaskets or have you replaced them? I installed my Yoshi exhaust at about 100 miles on my bike so I don't know why I'd need to replace them already. It does however make sense that the flutter sound is coming from an exhaust leak at the header.
 
Is there any way to reliably test the area for exhaust leaks without damaging the "Works" finish on the exhaust? I can't feel wind, air, or much of anything in my hands and forearms from an explosion I was in overseas so I would like to test for an exhaust leak without having to feel for it.
 

[Jeckler]

This means I'll have to remove the exhaust to replace the gaskets then reinstall the exhaust again. God dammit, why am I so lazy? I'll do it eventually, but honestly probably not for a little while. 
Weird that the Yoshi documentation specified the factory gaskets are to be used.

The Yoshi doc says to 'inspect and replace if necessary'. Presumably, if they're obviously damaged, replace them. Sometimes it's hard to tell though. I just put the stock back on and replaced them 'just because'. What you could do is drop the headers and at least inspect them. If there's any black marks across the copper, you'll know they've been leaking. Another thing to try; use a lighter or a match and hold it close to the headers when running and see if the flame flickers. You might think that's crazy, but the technique is used all the time to find all kinds of leaks.

[JuggernautOfWar]

This means I'll have to remove the exhaust to replace the gaskets then reinstall the exhaust again. God dammit, why am I so lazy? I'll do it eventually, but honestly probably not for a little while. 
Weird that the Yoshi documentation specified the factory gaskets are to be used.

The Yoshi doc says to 'inspect and replace if necessary'. Presumably, if they're obviously damaged, replace them. Sometimes it's hard to tell though. I just put the stock back on and replaced them 'just because'. What you could do is drop the headers and at least inspect them. If there's any black marks across the copper, you'll know they've been leaking. Another thing to try; use a lighter or a match and hold it close to the headers when running and see if the flame flickers. You might think that's crazy, but the technique is used all the time to find all kinds of leaks.

I installed the exhaust at only 105 miles on the bike (currently have about 160 miles) so I find it pretty hard to believe the factory gaskets were already worn out. Know of any other way to test for leaks on the exhaust without damaging the "Works" finish? My bike is stored outside with a cover so there is some wind that would naturally make the flame flicker anyway. 

[go4geoff]

@juggernautofwar I'm still using my oem gaskets that came with the stock exhaust. Since my tune I haven't heard the flutter except for when I mentioned earlier. It could just be the excess gas burning off whole running through motor revs. My exhaust still tends to raspy pop when I downshift high in 3rd or 2nd. As the revs come down quick my yoshi will still be a bit poppy. It's odd too cause the bike runs way cooler while running and through the other gears. Perhaps I gotta dyno my tune and see if there is a weird flat spot on the deacceleration curve

[12ival]

gaskets are $8 a piece. a small price to pay rather than risk problems down the road.

[JuggernautOfWar]

gaskets are $8 a piece. a small price to pay rather than risk problems down the road.

Do you know of a good way to test for exhaust leaks outside? I'd rather be sure what I'm hearing is actually an exhaust leak and not something else. 

[sorkyah]

gaskets are $8 a piece. a small price to pay rather than risk problems down the road.

Do you know of a good way to test for exhaust leaks outside? I'd rather be sure what I'm hearing is actually an exhaust leak and not something else.

Soapy water in a spray bottle
or you can take a chunk of heater hose and use it lile a stethoscope to pinpoint the noise
 

[Beemer]

Years ago I'd bought a used, 77' Chevy Blazer that developed a sound just like what you described. I tracked it down and tightened a couple screws on the headers and VOILA, no more funky noise! 

[sansnombre]

Agreed, it's probably an exhaust leak. When Yoshi referenced using OEM gaskets, they were saying that no special gaskets needed, and you could use the standard Yamaha ones - not that the ones currently being used could be re-used. I always replace those gaskets, as they are essentially squish-type gaskets and, similar to a copper crush washer on braking systems, you use them once. Yes, sometimes you can get away with using them again, but you risk . . . well, you already know. Consider using a torque wrench on these nuts - most people over-torque them.
 
You can check EBay as well for gaskets. There are non-OEM gaskets available as well for this bike.
 
You MIGHT be able to get away with loosening/removing the connection at the baffle and just remove the header part of the pipe to reinstall the gaskets. I remember installing this demon and the baffle is where the time is spent.
 
Also, when the bike is running at idle, you can grab a thick shop rag and very briefly (<0.5 second) cover the exhaust exit. If you have a leak, this will exacerbate the sound, and you should be able to confirm you have a leak. Be smart - you're just momentarily covering the hole to hear the hiss. Momentarily.

[hobbs]

Start the bike, momentarily plug the exhaust outlet with your hand (preferably with your riding or work gloves on... so I'm not responsible for you burning yourself), a rag, something... This will force gas out of any leaks.
 
Probably easier with 2 people. Someone plugs the end briefly while you inspect the headers and connections for leaks.
 
I'll stress briefly. Don't plug the end for more than a couple seconds at a time.
 
Edit: guy above beat me to it, follow his advice.

[aaron]

If you smoke cigarettes or cigars take a big drag off of your smoke and blow at the header gasket area. If you see the smoke quickly get blown away you probably have a leak. This is the way the old timers would check for header gasket leaks.

[biggaudi]

Get this guy to come over and help look for leaks!

[maritan]

A sheet of paper held near the header outlets on a calm day will show you if you have a leak. Blip the throttle a little and if the sheet flutters you have a leak.
 
You might not even need to blip the throttle.
 
If you have a leak, don't get lazy. Fix it. A leak is not good since it also means cold air can get in when you shut off the engine. Probably not the best for valve stems etc.

[duenan]

Right after where it says to reuse oem gasket in the instructions, it says inspect and replace as necessary.
 
Unfortunately Yoshi's instructions don't take into account total newbies, so their language isn't the best.
 
But since you did it at 100 miles, I would figure it should still be ok, but who knows... Me, I changed my exhaust at 200 miles but I still installed brand new gaskets anyway.
 

[YZEtc]

Probably had a gasket move out of place as you bolted the head pipe down.
Buy new gaskets and use a bit of high-temp silicone sealant (or grease as shown in the Yamaha Service Manual) to keep the new gaskets in place during attempt No. 2.