When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I am stumped. My 87 FXSTC runs absolutely fantastic...until it doesn't. Very randomly, usually under acceleration, it will just die like the switch is turned off. I can somewhat keep it running by really giving it gas. It will run for a short time at high RPM, but if I let off, it will just die. I let it rest, then it will do it again, sometimes in as short of distance as 100 yards. I figured the coil was getting hot so I replaced it. No difference. I recently went on a vacation for 5 weeks and left it at an indy to look into. They drove it around and could not get it to fail. I picked it up yesterday and rode it home, about 5 miles. Ran great. I run a Dyna S ignition. I hear that the advance springs are the weak point. Could that be the problem? When it failed, I pulled the plugs and they were getting spark, but looked weak to me. I pulled the gas line and it was getting gas. Any ideas how to diagnose this sporadic issue? Thanks!!!
Did the indy check the advance mechanism? I've seen the pins the flyweights ride on wear enough that the weights hit the points cover on a Shovel engine. Also seen them so gummed up that they flyweights could barely swing out from the full retard position. The advance setup in your '87 is the same mechanical flyweight system. If it fails to always advance, or do it as intended, it screws the timing by always being retarded to some degree. A complete advance setup is relatively inexpensive and easy to change out.
Well it is about the age where tank lining will break loose and can plug the petcock screen. Stop and it falls away then gets sucked onto the screen again. If you're sure the screen is clean and nothing (randomly) restricting fuel flow...
Dyna S was always known to be near bullet proof with the advance mechanism being the only thing that gives trouble and requires service. But, I have been reading lately about several cases of the rotor coming apart, magnet falling out or something to that effect. Might want to look closely at that.
I have considered the advance timing mechanism and understand that it is a regular maintenance item. How is it serviced? Oil the springs? It is easy to get to and unless it has grenaded, or something, can it just be lubed and serviced? I assume to have to check the springs for tension, too, etc. Thanks for your replies!!!!
I have considered the advance timing mechanism and understand that it is a regular maintenance item. How is it serviced? Oil the springs? It is easy to get to and unless it has grenaded, or something, can it just be lubed and serviced? I assume to have to check the springs for tension, too, etc. Thanks for your replies!!!!
The pins where the weights swivel need to be lubed regularly. Both those points are where they wear and bind. Factory assemblies were barely decent, some of the aftermarket units (which it likely has) were junk, others are good. Just have to remove the ignition plate to get in there and look and feel.
If the ignition checks out okay, try dropping the float bowl and looking for little bits of crud that could be clogging up your carb. Had that issue on my shovel and the symptoms were just like you are describing
Have you tried to take the gas cap off while its dieing to make sure the gas cap is venting? how long did you let the fuel run when removing the hose? I've had a non vacuum petcock run fuel really well for like 10 seconds the slowly die down and stop, even after I removed it from the tank cleaned screen and blew through it, had to replace petcock
Quick update. I removed the ignition advance set up and took to my indy. He said it was in great shape. Springs were good and no rubbing and looked well lubed. So, we are back to a fuel delivery problem. I am going to check the carb bowl next. His thinking was that something got into the carb and interfered with the fuel flow. When I goosed it real good and it would run at high RPM, that was the accelerator pump action. The float bowl was probably empty when that happened. Makes sense to me. More investigation to follow. Putting in an inline filter next in the meantime.
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.
Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.
Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.
87 Softail cutting out/dying
