back firing

[bustamove]

im running a 2inch air box snorkel up front, now im pretty sure it didn't back fire before,(its been backfireing for awhile) but recently its has been getting alot worse, before it was every other time. when i am cruising,or full throttle runs its fine runs like a champ. but if i am coming down steep hills letting the engine brakes work between about 10 to 25mph, it back fires like crazy, and latley when im cruising at 45mph then come to a stop it will backfire at least once or twice only when i get down to about 10 to 25mph mark, to the point where im pretty sure i blown a gasket or something in the exhaust or baffle. its gotten louder.

now i realise its probably beacuse of the snorkle, but is it a lean pop or a backfire cuz its too rich??

[NMKAWIERIDER]

Originally Posted by bustamove

im running a 2inch air box snorkel up front, now im pretty sure it didn't back fire before,(its been backfireing for awhile) but recently its has been getting alot worse, before it was every other time. when i am cruising,or full throttle runs its fine runs like a champ. but if i am coming down steep hills letting the engine brakes work between about 10 to 25mph, it back fires like crazy, and latley when im cruising at 45mph then come to a stop it will backfire at least once or twice only when i get down to about 10 to 25mph mark, to the point where im pretty sure i blown a gasket or something in the exhaust or baffle. its gotten louder.

now i realise its probably beacuse of the snorkle, but is it a lean pop or a backfire cuz its too rich??

You have an 08 so I am surprised there is a leaning or richening problem with the EFI to have a problem like that. You do however have the same valves I do, and if an exhaust valve starts leaking, they can cause back firing because part of the air/fuel charge during the compression stroke leaks off into the exhaust then when the condition is right, it detonates. Most times it just just burns and gets expelled, but other times...BOOM. Also, the longer it leaks, the more it leaks and the face erodes and the worse and more often it gets.

Probably better check at least the exhaust valve lashes and if they are OK, take a compression test to see if one has less then the other.