Let me start off with, I have had nothing but good experiences with my Indy...but, I have a small concern.

After much discussion with the Indy shop about breathers, slipons, and exhuasts, the general practice for them regarding tuning is as follow:

(Based on what changes they are making)

They do not have a dynojet, so they use the color of the plugs.
- light grey is good
- white bad
- black bad

Install part, install new plugs, ride bike, based on how engine runs, and color of plugs indicates if tuning is needed.




First I had slipons installed (i was not there to observe process)
They said no need for any tuning/tuner (they Recommend PCV when needed)

Months later I had the High 5 Mach II Breather (this time I observed installation and "eval" of tuning need)

They installed the breather, started it, revved it a few times, shut it off, told me it was good.

Now I am replacing my slipons with V&H Big Radius 2-1...they say "it may" need the PCV, but until they install and "test" it they won't be sure.

I am more than willing to have the PCV installed.

I am just doubting this method of testing if the engine (air/fuel mixture) is tuned or needs tuning?

Is this common practice for those shops without a dynojet?

 

I don't have a dyno, and have been looking at plugs since I was 6 and my dad taught me how. That many changes and I would put the PCV on it, then it can be tuned right. Dynos are not mandatory.

 

One of the old timers at the track tunes by plugs alone. Seems to work great for him and his cars.

 

With the new gas they are using today and the fuel injection trying to read plugs is iffy at best. Before you flame me let me try to explain. If the bike is already lean from the factory (which we all know it is) the plugs are going to be white / tan anyway. By adding the open breather and the free flowing exhaust you have now made a lean condition even leaner.

With fuel injection you have no way of knowing what the AFR is unless you have it hooked up to a testor and run it thru the rpm ranges. Air fuel ratio (AFR) is everyting to a feul injected motor. It may be fine at idle and be lean as heck above 2000 rpm. You have to be able to see what the AFR is doing at all rpm ranges in order to avoid putting the motor in an over lean or over rich condition. Both of which is bad for the motor. Every motor is different and you won't be able to tell by listening unless it's pinging really bad or blowing black smoke.

On a carbed bike you have 3 different circuits that can be adjusted that will give indications of which jet is causing a problem. If it stumbles or bogs you can more easily pinpoint the problem area based on rpm. But for the best tune you still need to ride the bike and see which jet gives you the best acceleration and smoothest operation. On fuel injection it's not that simple as the injectors will just keep dumping fuel depending on were the throttle position is and what the O2 sensors tell the computer.

Bottom line, for me anyway is to take to a shop with a dyno and have it set up properly and you will have a much better running scooter that will last a long time. As always this is just my .02

 

The method works, but it is not the most accurate or efficient method.

There is a difference between optimal and acceptable, no way this method gives optimal results.

 

As the Sarge stated, with FI it's hard to really know what's going on thoughout the RPM range by looking at the plugs, other than possibly identifying extreme lean or rich conditions. Based on what you've stated regarding the air cleaner and pipes, if you haven't had a Stage 1 ECM flash from an H-D dealer, then you are running lean, even if it seems to be running OK, you will run hotter. Get a tuner; either with a canned map, one that can be set up with a dyno (dynamometer by the way), or one that sets itself up as you ride. Your bike will perform better and run cooler.

 

I have a couple of 'what if' questions/scenarios regarding EFI had dyno tuning:

What if someone lives and does most of their riding above 5k ft elevation, but the only dyno tuners in the area are at sea level? I know that EFI is supposed to automatically compensate for atmospheric pressure change, but would a tune done at sea level still be an 'optimum' tune above 5k ft (vs doing a dyno tune at the same elevation)?

Along the same lines, if you ride mostly in hot humid weather, but had a dyno tune done in cool humid conditions, would you still have an optimal tune for hot dry weather (vs having the dyno tune done in hot dry conditions)?