ecm required with a slip-on?

I just bought a 04 xb12r. The bike is just way too quiet for me so I'm thinking about the jardine slip-on. I think I will go with the race ecm but I dont have the money to buy the muffler and ecm at the same time. Will I be ok to run just the jardine for a couple weeks before I get the ecm or will it run too lean?

if it's just a couple of weeks, wait till you can buy ecm, open airbox & exhaust at the same time

You are supposed to adjust the fuel injection if you modify the performance of the bike at all.

on the big twins if you dont change the air filter just the pipes its ok...i would not think buells are different

I've also heard that if I don't change the air box, I will be ok with the stock ecm.

Yeah you will be fine, if you change the air flow as well as the exhaust then get a new ECM.

You are supposed to adjust the fuel injection if you modify the performance of the bike at all.

Click to expand...

Sorry I do things properly. Yes, you MAY be able to get away with it, but its not the proper way of doing things.

No need to apologize. Just confusing info here. I want to do things properly too. I want to do what is proper, but also not do things unecessary - so that is the difference: not between proper and improper, but between necessary and not necessary.

I go off of the things that I have at my disposal to give my advise on this

The factory tells you it must be done, and from my experience at the dealers I have worked at, things as simple as changing your spark plugs have had bikes coming back with running issues. Another thing too, if you have to reset and zero the TPS at every service just to help the factory computer keep up with the changing parameters its needs while it wears over time, why wouldnt you need to do some sort of adjustment for putting on some sort of modification? Also wouldnt you want to see the most out of the modification by running it in conjunction with some sort of ECM mod? Yes, it will run, but in a lean condition. Depending on how you ride that could cause problems, maybe not right away but it could. If you want to take chances with your however many thousand dollar investment just to save some money, be my guest. I would rather keep it running in tip top condition and do it properly the first time.


maybebuell - yes on some of the big twins, we have seen that you can get away with it just doing mufflers, but not always on those either. I have had several of the people that "heard from their mechanic/buddie they can run them without a tuner/download". They are the same people that come back a short while later buying a tuner because their bike runs hotter and their new pipes blued up. I am just offering my inside insight to help you out. You can choose whether or not you want to do it with your bike or not, but what I am saying is the way that it is supposed to be done.

as already mentioned i'm with BPG on this.

from the experience we had here is that the engine does run lean which causes cooling problems.
piston gets warm, fuel gets spayed on it which causes sudden cooling (metal becomes harder) and then, because of the powerfull compression, BANG! a hole in the piston.

As I said on another post, I so much appreciate BPG. You are an incredible resourse. LeFox - your time in answering has really helped. I came on this board just a few weeks ago and I have scrolled through all of the pages of posts and read every single one on exhausts - many several times - and there has been some conflicting information. I also read my owner's manual, spent hours talking to the one Buell guy at the dealership, etc. You guys have both helped tremendously. Thanks again.

thx, glad to help where i can...

wasnt drummer exhauste the one that said add his clip on muffler and no need to buy or adjust anything....ride with lots of metric efi bikes and harley efi..thats what the dealers tell them...seems not to be a problem for them....tell ya the truth every efi i seen and raced who added a ecm or some kind of power commander ran to rich realy gained nothing and there gas milage sucked......im sure im not the only one to see this

Some drummer pipes you can get away with running their pipe without tuning it. Check with them first. Since they are just basically a redone stock pipe it is possible.

If you're bike is running rich after installing a tuner, you need to do more tuning. Plus optimum performance is achieved by being slightly on the rich side.

best air/fuel ratio is 14.7, but if it's power you want your af should be set round 13.5

so yes, performance is running a bit more on the rich side...

see below for a dyno chart of slipon with standard ecm, keeping in mind that the part that really sucks is the rpm rage you are mostly riding in = not good for your engine!
(lower graph = af ratio)

Thank you LeFox

no prob

i dont see those power numbers with aftermarket ecm and race kits...your making my point

Because they advertise crank horsepower in most ads, not rear wheel corrected horsepower.