[HaylessHorse]

Hey,

I've just starting getting a little popping at 4000 miles. Was checking for an exhaust leak and there is quite a bit of air coming out of a little hole at the end of both headers. Looks like someone put this hole there on purpose but does anyone know why? Emissions again?

Thanks,
Scott

 

[geospencer]

Are you talking about a bolt hole? I think that there is a hole in both headers. One is for a lambda sensor (oxygen sensor) and the other should have a bolt in it. When your bike is serviced I think that both holes are used for analysis equipment. (I might have made that up. )

 

[GTRossi]

if it's a gt the headers are double-walled to keep the stainless from discoloring. i'm pretty sure there's a small drain/air bleed hole in the outer wall (i seem to recall a thread that dietrich started quite some time back about this) but you shouldn't be getting blowback out of this hole unless you have a bad seal somewhere in the system...

unfortunately i no longer have my gt so i can't verify this - do a search for this and include dietrich's name, or maybe he'll chime in... dp?? hello???

 

[dietrichpfeifer]

Yup- Mine puffs air out of those drain holes like nobody's business. There are no seals or joints in that section of pipe (joining a section of double wall pipe) so the only thing I can come up with is it's expanding air from heat (strange that it would pulse with engine firing though) or therea a hole in one of the welds somewhere internal to the double wall. No bother, it's such a small amount of exhaust that it doesn't make the bike any louder, doesn't leave any soot on the hole, and I just used a power commander to tune for the difference.

 

[HaylessHorse]

Thanks, yes, it's the small drain holes. Just after I posted, I found the old post and then the bike quit popping. The forum is like magic