Wow, that is some awesome info! I didn't expect to get such great help.

This will likely be a winter project. I live in Canada, so that means really soon! I appreciate the offer on the baffles, but I would really like to tinker with this stuff myself. I have a new welder at home (flux core/mig). I've been puttering around with the flux core as I dont have a bottle of gas to convert it to mig, although mig will be my choice of welding on the pipes. I intend to buy pre-bent pieces of tube, and go from there.

As far as doing 'math' for the back pressure... I'm not really sure what that means? I have a pretty good vision of how to build a baffle now, but not sure how to fine tune it. Do you just go by sound and vibration? Will it backfire if there is too much baffle?

Those are pretty sweet rat rod baffles SF!! Your bike has been an inspiration for sure.

Thanks again guys. I'm sure I'll be back on with more questions soon. Now I just have to get my welding skills up to par.

 

I think the OP has a nice idea on his mind and if he takes his time the pipes will come out cool, but is worrying about back pressure too much IMO. I have no baffles in my Martin Bros pipes and my bike pulls hard form idle to WOT. I do have the PC III tuned for the pipes and AC so that is a big help, but I was running baffleless slip on's with just the stock AC and HD download and was fine, just a small loss of some low end, but was still not bad. I have made some baffles by useing a L bracket and some washer and they do work for back pressure and sound reduction, but I took them out as I love the open pipe sound.

 

[QUOTE=ElGoonski;8838511]Wow, that is some awesome info! I didn't expect to get such great help.

This will likely be a winter project. I live in Canada, so that means really soon! I appreciate the offer on the baffles, but I would really like to tinker with this stuff myself. I have a new welder at home (flux core/mig). I've been puttering around with the flux core as I dont have a bottle of gas to convert it to mig, although mig will be my choice of welding on the pipes. I intend to buy pre-bent pieces of tube, and go from there.


You can actually get some pretty decent welds with FC... just dial the welder in right and practice, practice, practice. I totally agree with wanting to do it yourself, and the offer stands if you get stuck down the road, just PM me if you decide to take me up on it, but I am sure you will be fine. Backfiring is not really an issue with too much back pressure, but it will choke the bike out of too restrictive. Backfiring is more an issue with lean conditions from too little back pressure, you can get what is called decel popping, which is a backfire (actually afterfire) out the exhaust.

 

Isn't afterfire a condition of burning unused fuel in the exhaust fumes once it heats up? I would have assumed this was a engine rich condition?

 

... my old gsxr would shoot 6-8 inch blue flame out of the pipes at night on decel... man it looked/sounded cool!!

 

Well, I was right... I DO have more questions!

What have you guys done with your O2 sensors? It seems familiar to me that you can plug them off, or get rid of them. How does this effect your ECM??

Also, if I was going to drill/tap my own O2 sensor holes, is there a preferred distance from the exhaust port for them?

 

Take a look at your local hardware store such as ACE. They should have some threaded metal bungs that can be welded to the new pipes. You will typically want to mount them in similar distance and location as the old pipes. I would definitely not cut them off, yes it will cause ECM issues, probably cause the bike not to run properly at all.
Lol, may have looked cool,, but can be very damaging.

Engine rich is easily a cause of afterfire, but it can also be an affect of the computer varying in air/fuel sampling. The AFR can spike due to a misread from the O2s creating either lean or rich condition. Any improperly atomized fuel can be unburnt and ignite on it's way out of the motor.