QuestionQUESTION: Hello Mike,
I have a 2K1 Fatboy w/ 95 overbore, Rinehart 2into1, Mikuni HSR42 (properly jetted), 302cams, and Screamin' Eagle Ignition module. This bike damn near refuses to start when hot!! I've been to a hundred harley shops, no real 'technical' problem, BUT....I'm now to the point where I think I'm suffering what one 'expert' called a classic voltage drop when cranking. This bike backfires out the exhause, the intake, or both, seems to crank REALLY hard, and just refuses to start until cranked several times when hot. From a cold start, it will start on the first crank with no problems. But, HOT....it's a bitch!! Anyway, I seem to recall running across a 'fix' for this by adding a relay to the ignition circuit and bypassing a lot of harness wiring, and running the coil straight off the battery. Are you aware of such a modification, and if so, does this sound plausible to you? Any help would be appreciated. Thanks, Tom
ANSWER: Pull youor plugs and let me know what color they are. Also, are you running solid lifters?
mike
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QUESTION: Hi again Mike,
First....running the 'stock' lifters. I will say that I have had the stock cams back in the bike, and still had the same problem, so I reinstalled the 302s again. Everything remained the same. This problem has existed since prior to the overbore, the exhaust change, and I've been thru 3 ignitions modules including the Daytona Twin-tec module, all in an attempt to correct the issue. I've played with the Mikuni jetting as well, and had it so lean I could get nearly 50 mpg! I've also run it so rich it seemed to drink a tank of gas between here and the end of the block. NONE of this changed the character of the 'hard-start-hot' problem. As for the plugs, I'd characterize them as being grayish in color. Not quite coco brown, and definitely NOT clean-white. I've lived with this problem for 3 seasons now since acquiring the bike. I've even resorted to re-installing the Kehin for a spell. I think I've pretty much eliminated everything 'installed' on the bike in the way of up-grades, as well as ruled out issues like bad plugs, plug wires (changed 3 times), carb and jetting, enrichment issues, etc. I've even changed the crank sensor. As I said, it backfires first from one end, then the other. Or, perhaps first from the exhaust, then out the intake....or vice versa. Then, it will just crank over as if it had no spark at all. The worst is that it often will reverse-fire without a true back-fire out the intake or exhaust, but it will cause the compensator on the crank to rotate in reverse while the starter is trying to crank the engine foreward......and this makes a TERRIBLE sound! Then, it will just start up like nothing at all was ever wrong!! Frankly, if NOTHING else....IT's EMBARRASSING!!! I had hoped the replacement of the ignition module would correct the problem. Since my letter of a couple of days ago, I've found the wiring set-up I'd asked you about. It is from Crane Ignitions, and it's for their Fireball Start Boost Relay. It's just a simply Bosch 30 amp relay wired between the battery and the coil, triggered by the ignition 'on' circuit. I'm going to give that a try....and perhaps one more thing.....a NEW battery!! Ya know, that may have been the problem all along! (DUH!!!) I did just check my battery.....and it's delivering 425 CCA at 13.8 volts according to my Midtronics Battery tester. Spec is only 275 CCA.....so I do NOT think it's a battery problem, but, still .....who knows??? Could be the starter has too much draw and kills the voltage enough when hot to be causing this problem. Thus, the relay 'may' solve the issue. We'll see. One last thing; This bike was acquired by me under some sad circumstances involving a fatal accident by a neighbor while riding the bike. The 'wreck' sat in a field for a year while awaiting the court to finalize the case. The bike was I believe 4 years old at the time, and acquired it in '05. It took me a season to restore it, and I basically started riding it full-time in '06. The problem has pretty much been present since I started using the bike. I will also mention that I have an '00 Dyna and an '04 Softail....and NEITHER bike has any problems, and I've done similar mods to both of them. So, this one stands alone with this issue. I've even thought of voltage drop across the handlebar switch...but that does not seem to be the case either. So....there you have it. Again, any help or suggestions would be appreciated! Thanks Mike. Tom D.
AnswerIt sounds like the problem is the starter drawing to much voltage. When this happens it kills the battery and has trouble turning over the motor. You can try adding the wiring setup from Crane and see if that helps, but you will still have a voltage drop from the starter and over time it might get worse. There are a few reasons for the starter killing the battery. Bad positive wire to the starter, bad ground, or the starter itself, bad brushes or armature.
Good luck and happy riding
Mike
