Shovelhead Electrical Problem

I have a 75 / 2007 custom shovelhead just built with about 3500 miles on it. While riding home the other day on the hwy about 55 or 60 mph, it just quit. It was like I turned the ignition switch off. It still has power, gas, and plugs are good. When trying to start it, it just turns over and over and then POW, a loud backfire. Thats all it will do. Anybody know what it might be? Coil, electronic ignition, jumped timing?

plug wires, coil

It seems to me like it jumped its timing, brought a flashback of some of the old rattletraps i used to drive.:witsend: If you have electronic ignition check to see if the plate came loose and moved, or if one with mechanical advance the spring and weight may have let go and broke a wire.

Thanks man. I do have a Crane HI-4 electronic ignition and already checked the plate and wires. All appears to be good. I think I am down to a coil or the ignition module. If anything else comes to mind, let me know.

Yeh, checked the wires but don't have a way to check the coil. Getting a very spuratic spark in the plugs. Only sparks every now and then when turning it over. I am thinking the coil. Thanks

Yea, I agree. I do have electronic ignition. When turning it over, the plugs spark every now and then, not constantly every time like it should. Still have to check the wire to the coil, but I don't have a meter to see if there is spark from the electronic ignition module to the coil. With running out of options, I think I am down to the coil or the ignition module. Any more help would be appreciated. Thanks!

You mentioned you have a Crane HI-4 & I've got one in one application - never had a problem with it. You'll want to buy a good test meter & you'll find a lot more uses for it than just this situation. I have a Triplett Model 9310 & the 9320 has even more features, but there are other good ones on the market too, like Fluke (funny name for a good meter). It may be as simple as a bad connection & even if you've checked 'em all before, do it again. But one thing the meter will really help you with is checking the wires - they can break inside the insulation & you won't see it - spark plug wires are especially bad about that.

Thanks, I will check that out. Will that meter check the continuity in the plug wires also?

Yes. And what you want to do is hook it up so you can wiggle the wires & see if there's any change in continuity.

Got it! Thanks

I had a buddy who kept burnning coils until we figured out we had the wrong omhs coil for the ignition system we had.

Viking

Thanks man. Already checked the coil and it is a 3 ohm as recommended by Crane for the HI 4 Ignition. Still don't know what it is, either the coil or the ignition. Changed wires and that did not fix it. Have 12 volts from the ignition to the coil, but don't know if it still could be the ignition anyway. Ya know of any way to check the ignition or the coil?

There is a ohm's test for the coil,there is primary resistance and secondary resistance,I have the crane HI 4 single fire ignition on my bike,I could pull my coil off and take the reading and let you know what they are ,if that would be any help to you...Good luck....

do you know anyone with a coil the same that would let you give theirs a try just to see if that is your problem.It may be your module I had one go bad on my 82 sturgis.It back fired and would not take its gas.Also check your ignition switch and the wires going to it to make sure they are tight.

Yea, had already checked the switch, nothing there, I'll have to see if anyone has a coil to try. Thanks

To check your coil, read the resistance on the primary circuit and secondary circuit(where plug wires go) the primary should read 2.5-3.1 ohms and the secondary should be 11,350-13,750 ohms. Fluke are the best, I've got an idiot proof one , put it on the battery,reads voltage. On the coil it reads resistance.No settings just use it.:devil:

Thanks, but I need a little help. I have a Fluke meter borrowed from a friend. Can you walk me through this? I don't know electrics. I have checked the battery with the DC setting and am getting 12v. To check the coil, on the ohm setting, where do I put the ground and where do I put the hot lead from the meter to get the readings you mentioned? I think I need to check the top of the coil where the plug wire goes in and then the bottom where the plug goes in, but again, which wires on the meter go where? I assume I have to turn the switch on. If you can get back to me that would be great. Thanks

Sure thing, On the primary circuit put the setting at Rx1 and put the leads on the studs for the ignition. On the secondary set the meter to Rx1K and put the leads in where the plugwires go. This is how you do it for the dual fire setup which I think you have it at on the Crane ign. Your coil only has 2 studs for Ignition leads,right? . If you find the coil is toast, I'd change it over to single fire. It's a Crane Hi4, correct? They have a switch for single fire and duel fire. the coil for single fire has 3 studs for ignition wires.Single fire will take some shake outta the shovel,only fires on cyl that is on compression stroke, duel fires both all the time. If you're running single fire I'll have to take a run up the garage and see if I can get the Res. specs for single fire:devil: Good luck

No, you don't need switch on. Disconnect the all the wires from the coil, you're testing Resistance.
You should get a little more than 12 volts across the battery. Put it on the charger while you're checking the circuits.