Once cat is removed from a 2010 SG, can you run with stock pipe setup and no other mods as long as you don't upgrade the AC?
I have a stock 2010, just gutted the cat, and threw on a thunderheader slip on. I have a PCV and SE AC coming later this week but would like to know if its ok to ride it as is until those items come in. I did a test ride around the neighborhood and it sounded GREAT! however there was some popping when i let off the throttle so wondering if its running too lean and if i should just wait.

Also, MGR at local dealership says slip on thunderheader with de catted stock pipe will lose HP, and that I need to add a pipe inside header to build back pressure. Not sure he knows what hes talking about as he also said I would lose HP on stage 1 upgrade, when the service dept says Ill get increased gains across the board.

Thanks for any feedback on this.

 

You can run it like that indef as long as the AC is untouched. I have been for 2k miles and I actually picked up more juice at the top end. I used to need to drop down to 5th gear to pass on the highway but after decatting I can stay in 6th gear. I took a ride this weekend with a buddy from this forum m2az that still has his cat and he tells me he needed to drop down into 5th when we passed vehicles cuz 6th was somewhat flat. My 6th still had plenty of chitspa to get er done, it didn't before I took it out.

 

Removed cat on my 2010 sg, I run a SE thunder stick, i have had no problems at all, no loss of power, I think it runs better imo. a lot cooler, doing the rest this winter.

 

Hay TUCCI, bigdogx, thanks for the info. Ive heard from some folks that it should be fine as long as ac stays stock, but that popping on decel is a sign its running too lean or something is wrong. Are you using stock muffler? I am using a thunderheader slipon and wonder if that has any change to the equation.

 

Regardless of manufacturer, it is a wise idea to add a tuner when modifying or replacing headpipes. The cats create a lot of back pressure and once removed, depending on the slipons, you could create a situation where there is not enough back pressure for the narrow band O2 sensors to operate properly. As the old saying goes tuning is not always required but it's always recommended. Usually if you do intake and exhaust upgrades, you will not see the full power increase the upgrades are capable of until you add a properly tuned fuel management system.
Keeping the AC stock will increase your chance of not requiring tuning, but like I said before it's always recommended.
Popping (loud backfire, not just a flutter) is a sign you should have things checked out. This usually means you have an exhaust leak or it's running lean.
-Ryan

 

Hay Ryan, thanks for the info. I plan on going back over the work completed so far after work today as it was a late night last night when I finished up the pipe swap. Probably need to double check the exhaust head bolts and muffler clamp to make sure I wasn't too easy on it. When it comes to exhaust head bolts im very gun shy as Ive snapped them off in past on older bikes and that is one road I do not want to go down again.

 

No I stuck the stock mufflers back on and I rarely hear any decel popping....once in awhile I do but not enough to make me worry about running too lean. I was heavy into jetting carbs on my metric before coming back to HDs and I can tell by the exhaust ends, the plugs as well as the sound it makes when I'm decelerating that the 02s are keeping the mix where it needs to be.

 

Ok, got my pcv and ac yesterday. Install was pretty straightforward and easy. Installed pcv to proper plugs and tucked in front of battery. Disconnected o2 sensors on rt side panel. Then removed stock ac and installed se ac. Started up and sounded good enough. Took her for a ride today and man, nasty backfirin all the way home. It's in the 60's here which is unusually cool. I thought fed sure plugs would be white or very lean and they are tannish on top and sooty on threads. I'll post pics in just a few.
Any ideas on why she's back firing on decel so bad?

 

Attached are pics of plugs. 535 is front cyl, 536 is rear.

 

Well if we were dealing with carburetors I'd say to increase the PMS (Primary mixture screw) 1/4 turn out. But I'm not sure how you do it on a FI. If I could paste a pic of my stock plugs I could show you how they look identical. I only hear popping once in a great while. Not enough for me to agree that stock bikes are running too lean.