One of the managers said the plug was way lean. hes in sales though. I don't detect any exhaust leakage. I don't hear anything out of the ordinary and don't see any signs of a leak. Is there a good way to detect a leak otherwise?

 

Plugs:

An experienced eye can get an indication from the plug -BUT modern fuel additive packages and mixtures tend for a lighter looking plug, compared to the cars fo the 70's.
--- this is why current repair manuals no longer include sparkplug pictures... carbs went away on cars in 1987


The plug in the pic looks a little sooty- but that doesn't matter because it indicates nothing about how the the fuel air mixture is at various rpms.

It could be horribly rich at idle and lean enough to burn the motor at speed-- there is no way the rider can tell looking at the plug- cause it could just as well be lean at idle and rich at 4000 rpm

"in the old days" plug readings may be taken like this:

Ride the bike down the street to the freeway service road/ onramp- get motor to temp.
install new plug with antiseize
start and idle motor- pull plug look at it- make any adjustments.

if plug is sooty, replace it.

start motor, immediately get up to speed, say 4000 rpm. Hold at that rpm for a few miles. hit kill switch.

get over to shoulder.

pull plug

adjust or not.

if adjusted, check 4000 rpm again. if good

install new plug, and test again at the next rpm range of interest say 3000 rpm


and so on.- this could take a dozen or more plugs to get dialed in- and maybe a full day with a pocket full of jets and needles and tools

what I'm getting at is that unless you control for rpm range, you have no idea what is influencing the appearance of the plug.


In the early 90's I started tuning my bikes with an o2 sensor in the headers and a voltmeter taped to my bars- i now had instant feedback on the mixture at all rpms ranges, all throttle positions and load conditions- and could use that info to base adjustments.

this is what the bike is capable of- hundreds of times a second



I'd hate to see the OP get all tangled up in sparkplugs, when there could be other things to look at.

I would :

restore the motor to stock ecm

and run it to see if the condition changes

if not- look at the header seals- high vacuum in the motor can suck in nice fresh burnable air into the exhaust system

( exhaust leaks can often be found by holding a cigarette near the pipe, and watching the smoke from the end.)

if it does- then

reinstall PC and check ( some problems are poor pin connections)

if the problem is still there, it is a mapping/tuning problem

and these are not for the novice, it takes a deep understanding of how the motor is running under various conditions and how various parameters interact.




--make sure you aways use antisieze on plug threads, always start the plug with your hand 3 or 4 or more turns), careful not to cross-thread. If your can't get you hand to start the plug, slip a piece of fuel line hose over the end


and like any internet forum, it is difficult to know the experience or expertise of the person typing somewhere- I've seen some ****-eyed suggestions from guys who can't get through an oil change with out blaming Harley for put 2 similarly sized drain plugs under the bike




Mike