Put Cycle Shack Slip Ons on my 08 Nightster, took out the baffles, do I need to do anything else?

Question

I put the slip ons on after taking out the baffles, and it seems almost too good to be true with the sound I am getting. Basically my question is that it seems like I am running straight pipes out of a fuel injected bike. Do I have to map this and dyno it? Or would it be okay just leaving it as is, although I feel like I am running much too lean. Or, I could always just put the baffles back in there. What do you think?

Answer 1

Or, you could realize the the entire world doesn't like the sound of straight pipes on a HD and put that baffles back in. When we eventually all have to keep the stock exhaust on our bikes, it will be people like you we can thank for it.

Now that I have told you how I feel, I will tell you to go to the Dynojet website and look to see if they have a map listed for your modifications. You can get a Dynojet Power Commander III USB for around $3-400 that will let you make any modifications to you bike you want without worrying about burning a hole in a piston.

Good luck. (Loud pipes don't save lives.)

Edit: You are taking a risk with any intake/exhaust mods without adjusting mixture. Air cooled twins can be a lot more sensitive to lean conditions than a liquid cooled bike. Plus, the narrow band O2 sensor and feedback system that HD uses won't adapt to even minor changes. If you are going to do the slip-ons, the SE aircleaner is a good bet, or you can do a similar job by drilling the inner backing plate of the stock air cleaner.

If you are going to mess with the bike just to be loud, you are a first rate poseur and you are going to do whatever you feel like doing anyway. If you want to get some more power, do it right.

I have used the PCIII USB on my old Roadking ('06) and it was a first quality piece of gear.

If you want to be the kind of douche that wakes up the neighbors and rattles windows, nobody can stop you. It's just that it is steadily ruining it for the rest of us.

I have a Vance & Hines can on my Buell and it gives a nice rumble without being obnoxious. I know what the slip-ons you have sound like. I had the SEIIs on my 1200 Sportster ('05). They are nearly identical to the ones you have. They are perfect with the baffels in, and stupidly loud with them out.

No matter what choice you make, the PCIIIUSB will give you a good way to get your bike tuned up fairly well without paying for dyno time with every modification.

Sn00p, you are a borderline illiterate, and you don't "rejat" an EFI bike. Oh, and my Buell is made in Wisconsin and the company is owned by Harley Davidson. Your loud pipes may well have saved your life, but not your IQ when it comes to motorcycles or the English language.

Answer 2

put them back for now it wil lhave to be remap and get better air also

Answer 3

yes, you should remap.  may as well do a high flow filter, the heavy breather looks real nice on a nightster.  then you only rejat once to compensate for both and save money if you hire it done.  or, yes, buy a power commander.... but plug testing only goes so far, a dyno still gives the best map... i know my way around a bike and i still hire it done instead of buying programmers.

loud pipes save lives and they are also kickass cool too, notice it's the jealous jappcrap rider that c**p on loud pipes because try as they might (and they have) their rice burning pos jappcrap still doesn't sound like a harley much to their little heart's dismay.... and they never will, they just need to buy the harley and give up on trying to turn a pig's ear into a silk purse

Answer 4

Check your timing and the carbs may need re jetted. Simple job if you know what you are doing. You will lose power with this set up you have but this will help.

Answer 5

I think you'd be better off with the baffles in.Bikes run better with some back pressure.Do as one poster said and do a plug check.if your running way lean your going to kill your engine.If your getting any ping off the line or when you whack the throttle while going down the road you better fix it quick.One poster mentioned adding a high flow air cleaner.That will make it worse unless you remap the bike.

Answer 6

Good question! The only way to find out is to take it to a mechanic who is familiar with modified Harleys, and see what he thinks. My first thought is, since you have fuel injection you may not have to re-map it, but you may want to put on a high-flow air filter, since you've changed the exhaust pressure. The engine may need to be able to suck in a little more air. I'd say go have an expert check it out, the last thing you want to do is keep running it too lean.

Answer 7

You'd be wise to do some plug testing.

If you run the bike for 10 or so miles , shut it off w/o idling and inspect the plugs, you should have a light tan colored residue on the portion of the plug that surrounds the electrode.

If the plugs are too light, or worse , clean, you are too lean.

A too lean condition can lead to excessive head temps. and should not be ignored.