Akra race, BMC race, PC V w/Dan's map = backfiring?

[djhartm]

Finished the install last night & was surprised to see backfiring w/flames when blipping the throttle.

It seemed to get better as the bike warmed-up, but I though the PC V (and more importantly a good map) eliminated this. Did I miss something?

PC V shows a green power LED lit, but nothing else.

I have not ridden the bike yet as I am still putting her together.

[1000RR]

Dan's map may not be quite optimal (on deceleration) for your bike. You might try another map and see if you get the same back firing.

[djhartm]

Took it out for a short spin today - ran great.

Guess it was a fluke.

[sbs]

Originally Posted by djhartm

Took it out for a short spin today - ran great.

Guess it was a fluke.

It is an amazing setup, isn't it... Have a buddy follow you at night, or through a tunnel while you are flat on the gas and using the quickshifter.... Quite an interesting thing to see....

[Loomis]

Originally Posted by djhartm

Finished the install last night & was surprised to see backfiring w/flames when blipping the throttle.

It seemed to get better as the bike warmed-up, but I though the PC V (and more importantly a good map) eliminated this. Did I miss something?

PC V shows a green power LED lit, but nothing else.

I have not ridden the bike yet as I am still putting her together.

Going to be order mine very soon...

[Poodie]

Originally Posted by sbs

It is an amazing setup, isn't it... Have a buddy follow you at night, or through a tunnel while you are flat on the gas and using the quickshifter.... Quite an interesting thing to see....

My buddy said the same thing to me last night! I pulled away from him on our way home from work and he said it was spitting red/blue flames haha.

[1000RR]

Originally Posted by djhartm

Took it out for a short spin today - ran great.

Guess it was a fluke.

Awesome... I have tried Dan's map (in the past) as well and it ran great, no backfiring at all.

[shashankmittal]

I have the decell popping on mine and when I contacted DJ, here is what they told me:

Decell popping does not necessarily mean that the bike is running lean or rich. It is simply unburnt fuel being released into the exhaust and igniting in the pipe.

Most metric bikes will have a clean air injection system which is pumping fresh air into the exhaust port of the head to inhibit this. Blocking this system off, can help greatly to reduce decell popping.
- already done as per How to Plug/Block the PAIR Valve

Secondly you would want to make sure the bike doesn't have any intake, vacuum, or exhaust leaks as this can also cause popping.
- I am assuming that this is not the case.

After these steps have been made, and you are still getting decell pop, you can add or remove fuel in the decell region of the Power Commander map. This is in the 0% throttle column from 2000rpm to redline. Generally, I will start by putting a 15 in these cells. If it still pops, but is getting better I will increase this number by increments of 5 until the pop is gone or at least minimal. If adding fuel doesn't help, you can also try removing fuel in this same area. When I do this I usually will start with a -60 in the appropriate cells and move down from there.

I started with 15 and now have a value of 35 under 0% throttle in all cells from 2000rpm to 14000rpm in my map. My decel popping has reduced considerably, but still exists. Shall I increase it further or shall I start with -60?

[kismetcapitan]

I am bewildered by these kinds of posts - where people remove the catalytic converter, add a fueling computer...and then think backfiring is a "problem". I suppose you'd also want to complain that you can smell fuel in the exhaust as well?

You tune any engine, you're adding fuel, more than can be burned by the air that the engine is pumping. That fuel exits the tailpipe, and when things are hot enough, you get flames.

If you're popping a lot, maybe add an Autotune. Whenever I make map changes, or the weather changes dramatically, I get more backfiring as the fuel map adjusts, but it's only for a day or two.

I personally think flames shooting out the exhaust pipe is, uh, cool?? A lot of movies have flames added to the exhaust of cars via CGI. But if it isn't your cup of tea, at least understand that it's normal and expected - you've just increased the fuel going to the engine, and eliminated the cat. If you want silent exhaust with no popping, don't modify the stock exhaust and don't add a PCV!

[djhartm]

^Backfiring when blipping the throttle is not a normal result of adding a full system with a dialed-in PC V.