G'day Fellas.
1988 FXST pretty much standard. I've been battling inlet air leaks for a while now ( https://www.hdforums.com/forum/carbu...fter-fall.html ) and am sure it's all fixed. But a problem still persists.
Copied from my last post in that thread. I'm a one finger typist !
From dead cold she will start on full "choke" and after about 20 seconds will take 1/2 "choke". Starts to sound rich so close the "choke" and will idle. After another 20 seconds she cuts out (doesn't sound like not getting fuel). She will start up again and idle but cuts out after 15-20 seconds. Will start again straight away and cut out again after 15 seconds. Each time she cuts out she will start straight away but the time till cut out gets shorter. I tried starting with a WOT, she started and revved up to about 4K then backfired and shot flames out the exhaust. Again she fired up and idled for 10-15 seconds.
I'm starting to think it might be electrickel so I disconnected the voes, no change, replaced the coil (new 2.5ohm duel fire) no change, bridged the main and ignition circuit beakers, no change. Checked all the connections at the ignition switch, all good. Could this problem be the ignition module?
At my whits end.
Cheers

 

Some will not run correct till they are totally warmed up - Harley knew this and installed a finger adjustment under the throttle - so when and after you start it up you set the engine speed higher

then go and put your stuff on and let it warm up a bit - what causes it - camshaft might be stock emissions **** - low speed jet has a tiny clog or it is a tad bit too small - engine compression has a play as the volumetric efficiency is not as strong when the engine is worn - not shot just worn in good

 

G'day John.
It's spark cut out that's stopping her. She was starting from cold on full choke and wasn't long before the choke was off and idling (carb is rich) then cut out. Start again and run for 15 seconds and cut out. after 20 or so times she wouldn't start so checked the plugs and no spark. Come back an hour or two later she started and did the same twice then again no spark. An hour later still no spark so I think the ignition has died.
I'm pretty sure it's the original 36 year old ignition that's only done 22,000 miles.
Cheers

 

If oem, then pull cam nose cone cover, and take a look at cam sensor to see if melting of not.
If melting, then scribe V in old sensor to inside of nose cone cover, and replace sensor with it's V at the same slot as the old sensor.
As for sensor, after market MC-SPA1.

As for cover, if still riveted in place, center drill out old rivets, tap back plate channels to 10-32 where rivets went through, and reinstall plate with allen pan head SS bolts, that you have chucked in a drill, to use 400 sand paper to gleam the heads, with a touch of blue loctite on the threads when installing the cover plate back on.

 

G'day Dano.
I had pulled the cover a couple of days ago and all looked good. What I did notice is the wires just past the connector had gone stiff where they went around the frame tube.
Another question, I replaced the original HD coil with an after market one. Neither had + or - on the poles. The two white wires to the bottom pole and the blue wire to the top (just as my wiring diagram says) but in another thread here says the other way around. She has run like this for the 4 years I've owned her.
Cheers

 

The early sensors do not melt, only '96 thru '98. When those earlier modules went bad, they die, dead.

Here's the sensor and module checks but just do the module sensor (first section).


https://www.hdforums.com/forum/ignit...l#post18851776

 

G'day T150.
Thanks mate, coming to the rescue again. I've printed it out and will do the test tonight. Just a mongrel of a place to put the module under the oil tank!
Cheers

 

I agree, that ignition module is a PITA to get to under the oil bag. As far as your intake leak those rubber compliance fittings often crack causing the issue and it’s important to get it right. I eventually put a solid manifold on my ‘88 flst.

 

G'day Corpus.
I have converted to solid mount. It just took a while to realize I had to use S&S type rubbers with the V-Twin (S&S copy) manifold.
What a PITA to get the oil tank out. 2 hours last night and it's lose but not out. Any tips?
Yesterday I ordered a Ultima programmable system with single fire coil. Should be here tomorrow. If I get that bl@@dy tank out!
Cheers

 

I wish I could remember some tips for you but I think it was at least 20 years ago that I switched to a DynaS single fire ignition. It’s not as tune-able (is that a word?) as the Ultima but it’s certainly held up over the years.

I think the hardest part of the job was the tight access to the bolts holding the tank in and I think it was even harder going back in if I’m not mistaken (sorry). There are quite a few excellent wrenches on these boards, hopefully one of them will chime in with some helpful tips.