Hey Gang,

I've got a real problem and mixed opinions from Harley mechanics. My '04 Fat Boy set-up includes the 95ci kit, high compression cast pistons, 251 (midrange) cam, SE airkit, SE Ignition control module (ICM), Mikuni carb and V&H Big Shots.

The bike has been running great until this season. Two problems started this season. First the turnsignal/security module threw a code and needed replacement as the bike would shut down or not start at all. The module was replaced and this problem was corrected.

Second problem: The bike will be running great and then suddenly begin to run like crap. It sounds as though there is pre-ignition. Not just a 'ping' but more like someone dumped a handfull of ball bearings in the crankcase, or there are 3 Stooges in there with hammers!...I'm talking BAD!!!. I am compelled to shut down the bike immediately to avoid engine-valve damage from preignition. The problem starts immediately without warning. It may be a heat-related problem as it usually occurs on hot days and resolves temporarily when you let the bike cool down.

My dealer said it was the ICM and replaced it. A month later, the problem started again. Last Saturday, I was running great for the first 30 miles. Stopped at a light....idle was fine initially, and then suddenly the motor went into the preignition/meltdown mode while I was sitting there at idle. The problem usually occurs while running at speed. On this day, the weather was clear in the low-mid 80's...not a real hot or humid day for the NE. I can't underestimate the horrible, metal knocking sound the motor makes when this happens. Most of the noise seems to be coming from the left side of the motor. It can't be a mechanical problem or it would be doing it all the time...all mechanics agree on this point.

So I'm thinking it's a heat-related malfunction of a component that has something to do with ignition timing. First the mechanics said it was the ICM (BUT... the problem persists with the new ICM!!!). Some mechanics are saying Crank position sensor....others are saying manifold pressure sensor....some say "I don't know". Frankly, I don't think any of them know for sure...and I don't want to end up with a stockroom full of spare, working parts while they try to figure this out on my parts/labor dime. Dealers are reluctant to call the motor company for tech support because the bike was modified (with Harley parts by the dealer of purchase!!!).

I love the bike. The bike runs like a demon when the problem is not occurring...but I can't depend on it. I have a trip coming up...I don't know whether to take the Fat Boy or my Schwinn...I'll probably go farther on the Schwinn.

I am very frustrated and disappointed with the lack of dealer mechanic consensus on the cause of the problem. Can anyone help?? Thanks...

Regards
AlbertG

 

I would think a bad sensor would give you an error code or shut down the bike. did you check your oil system? I hope you figure it out soon let us know.

 

Thanks BigThunder.

What about the oil system?? Everything seems OK in that department.

The problem is intermittent and probably heat related. I get no codes. One mechanic told me I should get a code with crank or manifold pressure sensors.

I think I got a ignition timing component that malfunctions when it gets hot. When it happens, the bike runs rough like the ignition timing went to hell...sounds like a loose wrench rattling around in the crankcase...preignition blues...what else could it be?? When it cools down...it's back to normal and runs great..

But right now...a Schwinn is more reliable...

Anyone other suggestions are appreciated...I'm all ears...

Regards

 

A. Put an oil cooler on there for one. Since your running iron lined cylinders, it sure will help with oil temps alot.

B. Swap out that SE ignition module for a higher quality daytona twin tec unit. The SE modules are known to be built rather cheaply and around here in my neck of the woods there have been alot of known issues with them dieing prematurely from heat and vibration related issues.

Daytona Twin tec is known as one of the best companies for Harley ignition/ECM components on the market. Screamin Eagle products are poor in comparison.

 

BUMP....anybody with some advice???

Thanks
Regards

 

04 Fat Boy Meltdown update here.....

Well gang, the problem persists after replacing the ICM, MAP and Crank position sensors. The problem now occurs almost everytime I ride the bike. This past weekend I was about 15 miles out...got to an open by-pass and accelerated to ~75 mph...went a few miles and then started decelerating as I was going up an exit ramp and then the problem started again. It's a dry, shearing-type, (pre-ignition??) noise coming from the lower left side of the motor. (Yes, the primary chain compartment has already been checked, adjusted and torqued.)

I let the bike cool...I restarted the bike at 30 minute intervals but the noise/problem persisted...I could not ride the damn thing! By this time my friend who is a master car mechanic arrived to give me a ride home. Finally after 2 hours of cooling, I started the bike....the shearing noise was immediate for about the first 3 seconds and then suddenly stopped. Oil was checked before the ride. My mechanic friend described the noise as "a dry, shearing-type noise", but he only heard it for a few seconds. He thinks one possibility might be a loose/worn cam timing chain causing timing problems. This problem has occurred at idle, at speed, with hot and cold ambient temps. The bike will be runnning great and then suddenly go into this meltdown mode. I got a ride home...then returned with my PU and ramps to pickup my bike...a real fun Sunday night overall....

I am very disappointed in the bike and the certified Harley mechanics that don't have a clue to this problem...25K invested...and only 18K non-abusive miles later.... and it's done. More than 3 trips back and forth to the dealer for this problem.

What conditions do I need to meet for a Lemon lawsuit??? Anyone know??

Sorry for the vent...I love my Fat Boy but it ain't lovin me back... I got to take a hard look at it's "value" here......at $22K original investment with 95 kit, cam, etc, installed on a brand new '04 bike...plus another 3-4K in tires, accessories and maintenance the past few years....and it's damn worthless at 18K miles...not much value in this Harley when you do the dollars vs miles math...

I'm dying to hear what the Forum has to say about this problem....and I'm way past fed up with the bike...my entire riding season here in eastern US has been spent stranded in front of Wawa's waiting for the bike to cool down, and if I'm real lucky, limp the 15 miles home after having to cancel on meeting friends and the days ride...

I’m ready for the “C-4” Power Commander option and then follow-up with an insurance claim…!!!

Help from anyone who knows is sincerely appreciated…

Regards

 

Well lets see thing to check if you havn't already.
spark plugs
plug cables
faulty ignition coil,module, or sensor
battery (or charging system)
Damaged wire or looseconnectionat battery terminals,coil or plugbetween ignition sensor and module.
fuel tank vent plugged carb vent line closed off
air leak at intake manifold or air cleaner
clogged fuel injectores
dirty ignition coil module or ecm connector
faulty sensores MAP orCKP incorrect valve timing
weak or broken valve springs damaged intake or exhaust valve
excessive carbon deposit on piston or combustion chamber
ignition timing advanced due to faulty sensor inputs
low oil pressure caused by oil feed pump not functioning properly or oil passages obstructed
faulty hydraulic lifters
bent push rod
incorrect push rod length
rocker arm binding on shaft
valve sticking in guide
chain tension spring or shoe worn
All out of service manual

 

Sound like it's detonating from a carbon buildup or something glowing in the combustion chamber. Get the highest octain you can find and add boost to it also. If it won't do it then, you are faced with some kind of carbon removal method. Personally, I'd go the water injection method. The sound on the bottom left may just be a byproduct of spastic power impulses driving the compensator nuts. Fix the cause and it should be quiet after that.
Ron

 

If it was mine and I had to take a wild guess, I would change the plug wires first and if that didn't help, put in a new ignition coil. I had an ignition coil go bad on a car. The car would run great when it was first started, until it ran for 20 minutes or so then a lot of the problems you are having would start.
Good luck,
Tom

 

does it have a power comander?have seen those go bad and act like that.