New Black Pipe

[The Spaceman_imp]

My understanding is that those pops on deceleration are an indication that the bike is running lean.

I don't see how it couldn't be more lean; the huge change in backpressure (far less) is bound to thin the mixture. Actually that's why I removed the 2Bros from my bike for now. It was so lean it didn't run good enough to suit me except at WOT or close to it.

When I can get a PC, I'll put it back on. If I don't sell it first....

[cbfan_imp]

Every picture tells a story. For those about to change exhaust before the change pull a couple spark plugs and take a good photo of the tips. After new system is installed take a good ride/hundred or so miles pull the plugs and compare them to the photos. Plugs are a good indication as to what is going on.
Also sound db's is something you can use to a certain extent. If your new system db's are close to stock db's then you can figure back press could be close to same.........all systems are different.

[HondaJon_imp]

Power Commander V will solve your lean issues, even with the "Stock" map that comes with the unit.



Popping on decel is indicative of a lean condition or an air leak on the intake or exhaust.

[Deanohh_imp]

Power Commander V will solve your lean issues, even with the "Stock" map that comes with the unit.



Popping on decel is indicative of a lean condition or an air leak on the intake or exhaust.

the pair system is a controlled exhaust leak that by design causes popping. The stock exhaust is so quiet that usually you don't hear it.

[Guth_imp]

My understanding is that those pops on deceleration are an indication that the bike is running lean.

there's about the same amount of mis-information out there on this as with oil, octane, and Harleys......... Enough to take this thread out to 100 pages. I'm not taking the bait, oops.

there's about the same amount of mis-information out there on this as with oil, octane, and Harleys......... Enough to take this thread out to 100 pages. I'm not taking the bait, oops.
Deanohh,

Certainly not intended as "bait". I did see your subsequent post regarding the PAIR system, which I was not familiar with. I did some reading on this and I still don't totally understand the mechanics behind it from a total system standpoint. In other words, could the bike not be popping because of the PAIR system, in addition to the the motor running lean? Not trying to argue, just trying to better understand.

All the best,
Guth

[Deanohh_imp]

That was tongue in cheek because of all the theories on mufflers, mapping, air fuel ratios, popping, etc and their fixes. Lean would certainly account for running crappy but decel popping may be from something else.

the pair system at certain times lets filtered air flow via the pair valve into the exhaust so that the extra o2 can allow some of the incompletely burned gasses to finish burning. You hear this combustion as pops during decel. Can be other reasons for pops too. Usually pops that become more noticeable with a louder aftermarket pipe can be greatly reduced by blocking the pair hose(s) but this may cause more emissions and cause acid rain, melting of the north pole, dead whales, depletion of the Brazilian rain forest, etc.

The PCV did eliminate the running crappy at low speed but I would never eliminate almost all the popping with my Staintune by finding the hose from the air box to the pair valve, disconnecting the hose at the very front of the valve which is right below the tank between the 2 center spark plugs, jamming a short tight fitting socket head capscrew (16mm dia bolt head) into the hose and reattaching the hose so that no air could pass through the valve. Because if I did that it would be tampering with the emission control system which is not allowed.

[Guth_imp]

[Utah1_imp]

Kinda like some yahoo running a race only pipe without a federally mandated catalytic converter in place?? Top end feels quicker, my simple solution for slow speed issues is to just drive faster!