I own a new XL1200n. This was my first Harley, and I wanted the Harly sound so I knocked out my baffles. The bike sounds great!, but after a couple hundred miles i pulled my plugs and they are white. I went to the local harley shop and asked for a down load to re-map my computer and they said i had to by a stage 1 kit. My question is, will running my bike in this condition be harmful. If so can I just get my 1200 re-mapped with out installig a stag one kit.

 

First off the plugs should be white....thats a sign your burning everything in the combustion chamber. However there should be a fuel ring (like a halo) around the white ceramic tip, if this fuel ringisn't present the AFR is too lean....if it is then the AFR is really close to perfect.

I you install a SE air filter the bike will need theAFR altered for sure

 

Thank you for the reply. I will go and check.

 

The halo is there.

 

Doc,

I've never heard of this halo, so am interested in this. You learn something new every day here though.

Is this halo right at the far end of the ceramic next to the base of the electrode? What color should this halo be? I know in the past i've heard this area should be a light tan if running properly.

 

The plugs ceramic insulator can incicate a rich or a lean condition. The tip of the insulator and most of it down to almost whereit joins the plug's outer shell should be natural white or VERY SLIGHTLY grey in color. When you look down into the plug, there should be a hint of a light tan fuel ringat the insulator's base where it connects to the plug shell. If the insulator is all or entirely white the AFR is too lean (no ring). If the ring is dark brown or the insulator is completely colored, the mixture is too rich. The closer the fuel ring is located to the bottom (where it meets the plug shell) of the insulator the leaner the mixture. The closer to the nose of the insulator the richer the mixture. So to answer your question I like to see the fuel ring between the base and the nose of the insulator.
The main thing tolook for is; isthere a fuel ring or not....if not richen up the mixture. If there is a fuel ring, no matter if it's at the base or the nose, the fuel is so close to perfect you can rest at ease your ok. We get real picky where the fuel line is in race motors because we are looking for every edge we can get while at the track....but for the street just having the fuel ring will do.

 

Hey Doc

Thanks for the excellent info on the "fuel rings". It makes perfect sense. I know there are many different methods on when/where/how to check your plugs but how do YOU check yours. after an extended high RPM run?? I'm pretty sure you don't check after an extended period of idleing right?? Please advise.

Thanks

P.S. I'm installing Rush slip ons with 1.75 baffles with no other mods. No A/C and no re-map so I'm going to be checking my plugs often as an indicator that everything is O.K.

 

Well Randy there are several things a plug will tell you such as:
Fuel ratio
Preignition
Timing
How Hot the engine is running (Thermal Efficiency)
Detonation
Oil in the Combustion Chamber

I put together some lecture notes on reading spark plugs with some drawings....I don't know how to get them to attach here on the forum, but if I'll try.

No I don't let the bike idle unless I am checking the idle circuit. If your checking the mid range hole the throttle open, going down the road, between 1/4 and 3/4 open for a couple of miles then turn off the bike pull the clutch in ( or vice versa) and check the plug. Same holds true for the main jet but the throttle has to be open between 3/4 to full throttle,(you better do that on a closed track...lol)