On my 09 CVO Fat Bob I had the heads ported, installed Andrews 54H cams and V&H Pro Pipe Chrome. The bike runs great except that the Idle doesn't sound right to me. I'm also lacking slightly on the low end punch. I know I need a tune but the plugs look identicle to my 011 CVO SG which was dyno tuned. I know there will be an improvement when I tune but if I was satisfied or wanted to live with it as is, why tune if the plugs look good?
Gary

 

because the plugs don't tell you crap unless you significantly lean of overly rich.

 

The plugs can only tell you how the engine is running at that exact throttle setting. You'd have to run it at a particular setting, kill the engine and coast to a stop if you want to get a reading for that particular load and throttle setting.

A dyno tune will get it right all the way though the RPM range and under load, just like in the real world.

 

Bro checking the plugs to see if youe bike is running fat or lean has nothing to do with what a tune does.. Running your bike with the mods you just did and no tune your just looking to do damage to the motor if you havent already. I wouldnt ride the bike hard or for a long period of time without any kind of tune.

When you tune a bike a tuner is messing with AFR table, advanced spark, timing, Knock, closed loop ,open loop bro its involved. Etc etc...

Who did the head work and the cam job on your bike?? cause I cant believe they didnt tell you that you absoultely need a tune.. cause there is no way you can leave it as is man...

 

BigBoyz did the heads.
I will have the bike tuned as I have done with other bikes. I guess I'm just curious as to how the plugs can look correct without a tune. I run the bike at a steady 60mph then hit the kill switch before checking the plugs.
Gary

 

I spent the best part of a year messing with the tuning on my Sporty using a combination of dyno time to confirm the HP numbers and my own O2 meter to get the AFR spot on. I also regularly checked the plugs because that's how I used to tune bikes.

What I found was that because of modern fuels its hard to read plugs now. For the base ring to start to show white the AFR has to be consistently lean at around 15:1. To get the ring black and lumpy you need to be around 12:1. Anything in between is pretty much guesswork. And that difference is all the world in tuning.

 

A legitimate question. Your 09 has a closed loop fuel system and can adjust itself within a certain range to be richer or leaner through feedback from the O2 sensors. It does however still correct to get back to the factory fuel/air ratio. If your plugs are burning right, it's an indicator of combustion chamber temperatures, then you should be okay. The only benefit is more power and more emissions if you change the ratio. It will also run cooler but as long as you are within normal temp ranges, it won't help anything to be cooler than normal temp ranges.