MUSKIE
TY 4 Stroke Junkie
I tore down sled today [ after backfire and FLAMES yesterday] and found 2 donuts on left side are junk and donuts on right side still ok BUT the top of flangs both broke off. NO parts till the end of MARCH anywhere !!!!!! 
i need help ...!!
i need help ...!!
apltx08
TY 4 Stroke God
ttt
MUSKIE
TY 4 Stroke Junkie
ttt = ????
ReX
TY 4 Stroke God
To The Top - a post specifically for the purpost of bringing this thread to the top of the forum.
JTD0314 said:
My RTX has been fine since this episode. Could water in the gas cause backfiring upon decel?
ReX
TY 4 Stroke God
You'll find that once in a while they will backfire when there is absolutely nothing wrong with them.
Usually if there are no leaks, the backfires will not be extremely loud and you'll shoot big flames out the back. With big exhaust leaks, the backfires can be extremely loud and the fire/explosion occurs inside the exhaust (often igniting at the y-pipe).
The reason for this is these sleds run too rich upon deceleration. If the exhaust is hot enough to ignite the overly rich mixture, it will ignite as soon as enough oxygen mixes with the exhaust gasses. If there is a leak, the oxygen gets added early in the exhaust so you get a big BANG. Without a leak, the oxygen gets added through the tailpipes.
It also takes a long hard run for the pipes to be hot enough to ignite the exhaust mixture and that is why you'll typically only get the explosions with a tight exhaust system after a hard run.
Usually if there are no leaks, the backfires will not be extremely loud and you'll shoot big flames out the back. With big exhaust leaks, the backfires can be extremely loud and the fire/explosion occurs inside the exhaust (often igniting at the y-pipe).
The reason for this is these sleds run too rich upon deceleration. If the exhaust is hot enough to ignite the overly rich mixture, it will ignite as soon as enough oxygen mixes with the exhaust gasses. If there is a leak, the oxygen gets added early in the exhaust so you get a big BANG. Without a leak, the oxygen gets added through the tailpipes.
It also takes a long hard run for the pipes to be hot enough to ignite the exhaust mixture and that is why you'll typically only get the explosions with a tight exhaust system after a hard run.
Bullitt GT 07
Veteran
ATTN ALL US APEX OWNERS
I just got off the phone with Yamaha USA Customer relations. I told the rep of my concern with my new 07 Apex GT hand warmer and Exhaust issues. I want to make sure it's documented and my sled only has 800 miles. She said, to date, there have been no known issues with either the exhaust or the hand warmers, documented through consumer relations. My suggestion, if she wasn't lying. is that everyone that owns an Apex in the U.s with any of those two issues, call and register the complaint. Don't know if it'll help but it's worth a try.
Jim
I just got off the phone with Yamaha USA Customer relations. I told the rep of my concern with my new 07 Apex GT hand warmer and Exhaust issues. I want to make sure it's documented and my sled only has 800 miles. She said, to date, there have been no known issues with either the exhaust or the hand warmers, documented through consumer relations. My suggestion, if she wasn't lying. is that everyone that owns an Apex in the U.s with any of those two issues, call and register the complaint. Don't know if it'll help but it's worth a try.
Jim
