High rpm deceleration popping

[James t]

Hi all I've had a problem for a while I just can't figure it out, I'm getting popping at high RPM for my exhaust when the engine is hot, it doesn't seem to do it when the engine is cold all of my exhaust clamps and fittings are tight I don't have any exhaust leaks or intake leaks all boots are new, my question is is this a sign of a lean condition or a rich condition I've heard it both ways your thoughts please thanks

 

[Redrum]

Since you asked thoughts. I would worry about something else and not the fact you annoyed an old lady at the crosswalk with some popping.

If it goes fast when you hit the throttle and stops I'd say good!

Mine sometimes "sneezes" at low RPM's. I usually don't live there so no worries on my part.

 

[James t]

It runs like a ***** ape ,idles smooth no issues at all now that I got the carburetors all figured out and it's synced right, it just bugs the hell out of me because I know it shouldn't be doing it , but is it doing it because it's rich or because it's lean

 

[one2dmax]

A lot of decell popping is generally attributed to a bad coasting enrichener (under the quarter sized round covers on the sides of the carbs).

 

[James t]

Carburetors were just rebuilt 1 month ago all diaphragms and gaskets replaced, popping was there before I rebuilt the carburetors no change after

 

[Sniffbooger]

I've pulled my carbs off at least ten times the last year, and every time I put them back together and sync them, it runs different! I only changed the jets a couple times, but it seems like they are sensitive to the proper type of gaskets used, idle mixture screw settings, how clean you get them, and also don't forget the many different sized O-rings in various places. Most likely popping on deceleration is a lean mixture. I put richer low speed jets in my bike and it never backfired on deceleration, but the mpg dropped to around 22mpg...I re-jetted them back to stock, plus I put 147.5 main jets, and now I'm getting about 40mpg hwy, with occasional mild popping at decel.

 

[Tom Determan]

"No change in behavior between before and after" applies to all sorts of things in life and common examples are a transmission repair and another is a Vmax carb repair ! Many times the reason is there also was "no change" in the system between the "before and after" due to misdiagnosis, improper repair or faulty part among other reasons. I'd suggest you dig into the coasting enrichener as One2dmax suggested and look for a cocked spring, torn or improperly seated diaphragm, clogged orifice or whatever. There's 4 chances for this problem.

 

[James t]

I know the diaphragms are good and I know the springs are in place , I don't want to pull the carburetors off right now because the bike runs too good I'll just deal with the popping for now and figure it out eventually thanks

 

[dannymax]

What do you have for exhaust?

 

[James t]

My bike is all stock and original all jetting is stock, I always thought popping from the exhaust was a rich condition because it was unburnt fuel hitting the hot exhaust

 

[dannymax]

It can be either....high rpm when hot sounds like lean. Supported by the bike running strong, VMax likes lean.
Did you try adjusting the mixture screws?

 

[James t]

I have tried adjusting the mixture screws and it does seem to help a little, it seems like my back right carburetor if I adjust it only about a half turn out it seems to almost take it away, but that imply it was running rich on that cylinder, I can live with it I just am the type of person where I like to figure things out and I like to know why, I haven't really gone past three turns out on my mixture screws but I hear some guys have gone as far out as five turns