[oakparkpete]

I've a 650 exec with 34,000 miles and a blown yoshi muffler... it backfired often... what should be adjusted so that I don't blow out the new yoshi now being installed??

 

[miken6mz]

I don't know anything about aftermarket exhausts, but I do know that a 650 with its computerized fuel injection should never backfire.

 

[Desert Rat]

I don't know anything about aftermarket exhausts, but I do know that a 650 with its computerized fuel injection should never backfire.

Never had my 09 650 Exc backfire, for all that goes never had my 07 400 do it either.

 

[NormanB]

Was it backfiring with the OEM muffler? Or was it only with the Yoshi?

Can you guess where I am gong with this? .

 

[TechArtGuy]

Alot of the aftermarket exhausts don't do well at hiding the sound that the pair reed valve makes when injecting air into the exhaust loop to ignite unburnt gases when the throttle is closed when decelerating. So you could try running with the end baffle pipe, closing the reed valve intake or switch back to stock.

 

[Pelicanman58]

Just a small point of lexicography; "Backfire" is when the ignited fuel comes back up the intake system. When the ignited fuel pops when entering the exhaust to early and not fully ignited till it is in the exhaust, that is called "Afterfire". Most people switch the two, thinking afterfire is backfire because it comes out the back. Big difference, though, when speaking with a mechanic. Have a great day!