Real 'tinny' exhaust noise?

[CampX]

My '05 EC300 just started making a funny exhaust noise, but only at certain times.
1)Hitting 'false' second (rarely, thank god)
2)Jumping logs or rocks
In both these cases, RPMs go full-pinned for a split second. Then the exhaust gets a real tinny ping-ping-ping to it, maybe 10 seconds worth, til it clears out......then its back to its grunty normal exhaust note.
Any ideas?
Jetting seems to be bang on, except that its smokin hot here right now in southern BC, like 40C/100F degrees.. And the first time it happened I was riding at 5300ft ASL, I normally ride around 3000ft. But she's running really good otherwise, just put on a 4 hour ride yesterday, just about stroked out from heat exhaustion!
Thanks!

[twowheels]

Originally Posted by CampX

My '05 EC300 just started making a funny exhaust noise, but only at certain times.
1)Hitting 'false' second (rarely, thank god)
2)Jumping logs or rocks
In both these cases, RPMs go full-pinned for a split second. Then the exhaust gets a real tinny ping-ping-ping to it, maybe 10 seconds worth, til it clears out......then its back to its grunty normal exhaust note.
Any ideas?
Jetting seems to be bang on, except that its smokin hot here right now in southern BC, like 40C/100F degrees.. And the first time it happened I was riding at 5300ft ASL, I normally ride around 3000ft. But she's running really good otherwise, just put on a 4 hour ride yesterday, just about stroked out from heat exhaustion!
Thanks!

Sounds like you're lean in the needle and main - the ring-ting sound is your warning.

[CampX]

Even if the tinny noise is only after these instances? Happened twice in 4 hours yesterday. Funny thing is, my jetting was bang-on, as far as I can tell, when the weather was way cooler. Should it not be running richer now, if anything?
Running a 175 main, 40 pilot.

[twowheels]

Originally Posted by CampX

Even if the tinny noise is only after these instances? Happened twice in 4 hours yesterday. Funny thing is, my jetting was bang-on, as far as I can tell, when the weather was way cooler. Should it not be running richer now, if anything?
Running a 175 main, 40 pilot.

You stated that in both instances it was coming down from high rpm. Easy to try to replicate - just wind the throttle open and allow it to snap closed. Try adjusting the needle clip to see what happens.

[CampX]

Good idea. Thanks. Definitely don't wanna lean out my engine........

[rosco]

Make sure your powervalve isn't sticking open. They get a real tinny sound when that happens but It shouldn't make your rpms hang up unless you are lean on your jetting.

[Jakobi]

Originally Posted by rosco

Make sure your powervalve isn't sticking open. They get a real tinny sound when that happens but It shouldn't make your rpms hang up unless you are lean on your jetting.

This is where I'd be looking

[threehundy]

I have the same problem when I land hard jumps it sounds like the pipe has a hole in it loss of power until I can rev the sound away then all goes back to normal.... my 2011 300 did it and my 2014 300 does it.... very annoying and extremely hard to troubleshoot.

[fasteddy]

Originally Posted by rosco

Make sure your powervalve isn't sticking open. They get a real tinny sound when that happens but It shouldn't make your rpms hang up unless you are lean on your jetting.

100% its your power valve sticking open, mine is doing the same exact thing, will repair when I do a piston change next week..

Ed...