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re: "Surge Free" spark plugs

Steve -

What Parker did, I'd guess, was set your TPS richer - maybe back to 
spec or maybe richer than spec. By twisting the TPS a hair clockwise, 
you fool the ECU into thinking the butterfly is more open than it 
really is.... and so needs more gas.

Whatever means you use to set your TPS, when you are sitting with the 
power-on but engine still, it should end up reading around .375. Higher 
and you'll get popping noises, lower and you are back to stock 

This logic applies to all the Oilheads, as far as I know (which is 
definitely limited).

We fool with our spark plugs because it is easy to do. Few problems 
arise from a spark plug which is in the rough ballpark. Having said 
that, a cold plug and too much city lugging will lead to bad running 
which is cured by a few miles on the open road - I run a "7" which is 
coolish and gets clogged so Parker's choice of a hotter "6" may be 
cogent. (When doing mods, I like to err on the side of cold.)

But the Oilheads do seem to have chamber deficiencies, odd in such an 
otherwise evolved bike, as evidenced by the value of dual-plugging, a 
fix traditional in two-valve Airheads. This is exacerbated by the silly 
choice of 3-electrode plugs initially made by The Factory, later moved 
to 2-electrode... and that is Parker's secret plug, the NGK equivalent 
to present factory recommendation!!!

Lots of plugs will work fine. I use a trick iridium plug because it is 
extended tip and being precious metal, NGK carved away both the centre 
and side electrodes thus supporting better mixture swirl around the 
spark and unshrouding the spark from the mixture - BKR7EIX. Next time 
(which will be a few years) I'll just get the platinum equivalent and 
save a few bucks. This is the opposite of using multi-electrode plugs 
whose ONLY advantage is keeping their spark gap longer than real cheap 
plugs... not a big advantage in any sense

The straightforward appropriate fix for surging in a mostly stock bike 
is a Techlusion 259 or, if you have mods, a Techlusion 1031. This gives 
you a little box with four adjustments which add enrichment to the 
mixture as much or as little as you like and if you set it to their 
recommendation, you'll be happy.