Dead Sporty in Devon, Help Please.

[Soulee]

Hi Folks,

Im a newby to the site with a slightly ill 96 Sportster 1200 that has been altered by a previous owner, In an effort to sort a pinking problem I have done some further mods and am now having other problems.

The mods that have been done by others are as follows:

Twin spark heads.
Dyna DC6-4 coil
Screaming Eagle Ign. Module
Screaming Eagle Slip Ons

She ran with the above but was pinking on heavy throttle, so my first move was to check the jetting.

I have just done the following mods, some for looks others in a hope to cure pinking.

S&S style air cleaner with K&N filter.
Head Breather Kit
Yost Powervalve
#45 pilot jet
#185 main as per kit
New S/E Plugs
New S/E Leads which dont fit the Dyna terminals(Smaller) so reverted back to old leads.

All above done together so now I have no idea which mod or mods are causing problem.

The problem now is as follows,

She will not start, she turns over fine but will not fire then all of a sudden the rear cyl starts up but not the front? Then the mother of all backfires from the front cyl. Ign straight off

So I check for fuel and all plugs are damp, Plugs are giving nice blue spark and K&N filter?

Am I missing something? Is the obvious staring me right in the face??

Please Help guys,

Lee

[kevscrivener]

The front pot should catch first anyway so don't worry about that; the backfire may well be caused by excess fuel in the system. If you've been cranking it for a while fuel will build up in the exhausts and once the front pot does catch what you describe will happen.

Did it do that just the once or is it persistently starting on one then chiming in on the other?

You need to do a process of elimination now. Try swapping the plugs over first; if no joy go back to the old set; the logic is that they worked OK last time. Wouldn't be the first duff plug I've had straight from the packet.

Try that and let us know how you get on.

[kiwidave]

what are twin spark heads? Are the heads twin-plugged...i.e. you are dealing with four spark plugs?

[Soulee]

Thanks Guys,

will give the 4 plugs a try, hopefully thats all it is.

Sorry Kiwidave, meant to say Twin Plug heads.

Will keep you posted either way.

[b0nio]

On the stock ignition system there is a voes switch, which reduces the advance when the vacum drops under large throttle openings. This is to stop pinking at large throttle openings. I'm not familiar with the SE unit but I guess it uses a similar system.

Probably too easy, but, I had a problem with a misfire on one pot which was due to me pulling the plug wires and the connector going back too far into the rubber boot. The consequence of which was when put back on the plug it left a gap between the connector and the top of the plug.

[kiwidave]

I hope it is something as simple as that because I fear you won't find a lot of hands-on experience with that set-up. It is a very unusual mod on any Harley since 1984........you could even argue ''pointless''.

Twin-plugging was only usually done to pre-Evos because of the dome-shaped pistons preventing the flame from one plug on one side accessing all areas of the combustion chamber, as it were.

Even then, some people wiith Shovels etc who have had it done are doubtful of the added value in terms of horsepower, etc.

[Kernow]

I seem to recall that there were twin plugged 1200 Sporties around in the late nineties as Production machines, may be wrong though, but I still reckon there were some about, certainly not Pre-Evo.

[robbiemac]

the 1200S or Sport had a twin plug head as standard. cannot remember when it was introduced though.
Not touched one for ages but i would do the checks for connections and plugs etc.

[Ming the Merciless]

Originally Posted by Kernow

I seem to recall that there were twin plugged 1200 Sporties around in the late nineties

Your memory is correct Ian - the Evo XL 1200S Sportster Sport had twin plug heads, twin front discs and suspension adjustable for preload, compression and rebound.

Identifiable by the chequered flag tank decal and a pair of coils located forward of the front pot (under the headstock), the model ran until 2003, the 100th anniversary year. See here

[kiwidave]

good to learn....didn't know that!