Crank, crank, crank: no fire

[Danno]

Happy Spring everybody from Minnesota. The snow is gone here and the riding season has begun. After replacing the fuel, changing oil etc., I got about 50 miles ridden and everything was great until this morning. All it will do is crank. No inkling of firing at all. I'll start troubleshooting after work tonight with the usual suspects. It's an 84 and I don't have a lot of history on it as I've only had this one a year or so.

Danno

[nhmaf]

It sounds like you're not getting any spark @ the plugs, but first I'd just check to see that you're getting gas into the cylinders - after cranking it for a bit pull each plug out to see that it smells of gasoline and may be moist with fuel.  If that is the case, then it's time to go through the rest of the usual route:  A few questions:
1) Does this still have the original coil?  IF so, is it "grey" in color?
2) Have the plugs/plug wires been changed lately?
3) Have the valves been adjusted?
4) Have you removed the float bowls on the carbs to see where the fuel level is in each bowl?
5) Did you notice any skipping/misfiring or high idle while riding the bike?

[drewboid]

Gas - out of gas - fuel line clogged - carb jet clogged? - drop the fuel bowl and check for gas / dirt.  Try a squirt of ether starting fluid if you do have a spark after the spark test.

Spark - coils ending in -200 were noted to crack - change the plugs - remove a plug and hold it against the cylinder and crank to see if you get a spark (you may want to use something insulating to hold it)

Good luck - let us know what you find

[Danno]

Good fuel.
Spark plugs wet and no spark
Have 12 volts to coil
Coil # is: 0 221 500 203

Ran fine 12 hours ago.

Danno

[Bob_Roller]

If you have a multimeter, check the primary windings of the coil, resistance should be around 1.5 ohms, secondary winding resistance should be around 11-13k ohms.

If it is the original OEM black and gray coil, good chance it's failed.

My original coil gave me no warning, engine quit 2 blocks from home at a traffic light, after removing it, it had no cracks in the plastic case, but the secondary winding was open.

[Danno]

Primary looks okay but secondary appears open. I assume this is a new one since the nipples are a reddish orange. I'm going to go ahead and get one ordered anyway. Best to stay OEM or any aftermarket anyone recommend?

Dan

[Bob_Roller]

There is a popular replacement, the Dyna 'Brown' coil, 1.5 ohm primary resistance.

Motorrad Elektrik has the coil, plus an adapter bracket for $90 plus $6 Priority Mail shipping.

http://www.motoelekt.com/

[Danno]

Thanks, Got a new one on it's way along with wires.

Dan

[nhmaf]

Sounds like ya got it, then.  The "203" coil was supposed to be a later one without the cracking problem, but again, anything electrical can go bad, and usually does, all of a sudden.

Teamwork !!!
 

The Dyna Brown coil I have installed in my bike has works very well, and even takes up a bit less room.   I am very happy with it.

[Justin B.]

Hopefully it's not the bean-can or ICU...

[montmil]

Hopefully it's not the bean-can or ICU...

Checking bean can (ignition trigger unit) function is easy. All you need is a spark plug wrench.

Pull a plug, reattach the coil lead and ground the plug to the cylinder head. I usually use an Irwin QuickClamp, or similar. You do not want the plug to be ungrounded for the test.

Ignition on. Toggle the kill switch on the right-hand switch assembly... you will see a spark at the plug if the can is operational.

Quick and easy confirmation.  [smiley=thumbup.gif]

The Dyna coil is great. I had no issues with the 83's coil but went ahead with an order to Rick at Motorrad.

Monte

[Danno]

Learn something every day. I did know about the diode board sensitivity but not the bean can. Sure hope I had the spark plug grounded when I checked for spark. Of course it's absolutely beautiful today and I'm looking at the bike instead of riding

Dan

[ambrose78]

Ignition on. Toggle the kill switch on the right-hand switch assembly... you will see a spark at the plug if the can is operational.
 

If your tacho works you should also notice the tacho "flicks" once about 2-3 seconds after turning the ignition on.

Though I'm not sure this indicates whether the Bean can is working or not - It seems to be that the ICU has a quick power on 'self check' after it is switched on. I got that spark with the bean can disconnected but after the ignition switched on. I can't confirm whether this happens if the coil is/isn't working. Mine coil was working.

The only way to really check the bean can is operational is to pull the bean can (following all precautionary advice such as disconnecting battery when removing cover) and then manually rotate it by hand when it is connected to the loom with ignition on. You should get lots of sparks and the tacho moving as though the engine is running. If not likely case that either bean can hall effect sensor or ICU.

The other test is to see if the icu is behaving from the hall effect signal. which involves pulling the bean can plug and earthing the middle terminal on the wiring loom side. Each time it is earthed, you should see a spark (and tacho movement). Again precation about where you earth the circuit  - away from diode board is best.

Good luck with it

[Bob_Roller]

I've noticed on occasion, that when I turn the ignition key  to the on position, I can hear an odd noise from the engine, it must be the fuel/air mixture in the cylinder igniting with a valve open when the spark plug fires off.

It's kind of a whistle/wheeze type of sound.

[Justin B.]

It's easy to test the bean-can by building a simple tester with the information available here: http://robfrankham.co.uk/bike/vane_switch_tester.htm