My buddy bought an 03 RK, it was well taken care of and had lots of extras but the exhaust and intake appeared stock.

He bought a HD Stage 1 air cleaner system and slip ons. Last night I helped him install the open air cleaner intake and told him the bike may not run well and would probably need at least a flash or PC or whatever.

Well after the install the bike runs perfect, no popping, no missing, sounds great etc. I am wondering if the previous owner already had a download done or what?

At this point since the bike is running so well, I told him to check him gas mileage and consider just leaving it alone. I have never seen a bike run or sound this good after a stage one without fuel/air mgmt.

Is this common? should he tune anyways? Or would you guys just leave it alone?

 

Many great debates over this. will the ECM compensate enough? Most and I agree it does not. It will run lean or leaner than before.Watch the headpipes turn blue. A tune will be required.

 

then again what if the previous owner did the stage 1 tune but removed the cleaner and slip ons and putting the stock ones back on.

 

That is possible...One way to find out is to have his serial number run through the service dept's computer. Everything that was done at any dealership will pop up including the stage one download

 

As others have said, check and see if he does in fact have a tune, and definitely watch it for signs that it's leaning out. It may take a while for the ECM to realize the air cleaner is there and may or may not compensate for it. Personally, if it doesn't have a tune, I'd get it tuned just to be on the safe side, but that's just me. You might get away with it!

 

The bike is a 03 , it does not have O2 sensors and the ECM does not compensate, it is an "open loop" system. It only runs off the MAP that is flashed in it.

Good chance the previous owner removed the slip ons and ac when he sold the bike.

 

We ended up taking it to the dealer and just got a stage 1 download flash. Cost about a hundred bucks and its running even better. Dealer said same thing as you guys that it would run lean and probably have trouble down the road when it got hot.

thanks!!

 

Bear in mind that when talking about the ECM compensating, it is not designed for removing air filters etc! It is designed to let us ride through burning deserts and over freezing mountain passes, so has adaptability built in to do that. IMHO a 'stage 1' involves restoring the air/fuel ratios to optimum, instead of the lean and hot running stock settings. That will probably involve adding a tuner.

I looked into doing that properly (slip-ons, air filter and tuner) when buying my SuperLow and decided against, but I don't think Sportys suffer in the same way the big twins do.