Topic: 1 & 4 Cylinder not firing.

[ieism]

My 550 has suddenly started to run on 2 cylinders I can't figure out why.

The only thing I've recently changed is the plugs, I installed Iridiums but the same heatrange as stock (DR7IX). There is no spark from both 1 & 4 wires, even if I try it with an old working plug. It sparks fine on 2 & 3.

If I touch the trottle while doing a sparktest (plug on the engine) there's also some sparks wanting to jump from my trottlehand to the trottle, is that normal?

The bike is stock besides electronic ignition.

I've tried cleaning and putting on the sparkplug caps again, that wasn't it.

I've tried loading the battery, i've checked continuity from the coil to ignition. I can't see anything wrong with the ignition either (although i'm not sure how to determine if it's good or bad, it looks fine).

Is it possible that these new plugs somehow wrecked a coil, and how do I check?
I was thinking of putting 2&3's wires on 1&4's plugs, but that won't really tell me anything.

I have a multimeter, but i'm not sure how to check anything besides continuity with it. Is there anything else I could measure?

ivar

[TwoTired]

What spark gap do the plugs have?

Have you checked the plug cap resistance?

Do you still have the old points to substitute? 

Electronic ignitions can go bad.  Especially if the inductive kick back from higher than normal voltage development in the coils is not handled properly in the electronic ignition module box.

Cheers,

[ieism]

The plugs are iridium, you can't change the gap on them. I've also swapped them back for the old plugs that i was using before, and it doesn't spark at all.

The caps are ok, I have a spare set that i've put on to check. So i'm 99% sure it's not the plugs or caps.

I'm not sure if I still have the old points, I hope I can find them somewhere. That's a pretty good idea to rule out the electronic ignition though.
The electronic ignition is not new, it's been on the bike for 20.000 miles.

[TwoTired]

Okay, you can't change the SP gap.  What IS the gap?  The gap is key to what voltage peak the coils need to develop in order to jump the gap.

The magnitude of a collapsing field and the inductive spike in the primary is directly related to the voltage peak magnitude.

Inductive spikes CAN kill or damage electronic devices.

Hope your electronic module has survived.  Is this a Dyna?

Cheers,

[ieism]

The gap is .028"  So that should be 0.7 mm.  The plug is a DR7EIX.

That's the same gap as a normal D7EA that i've been using for years, and also in the range my manual specifies.

Both the DR7EIX and the D7EA are recommended for my 550F by the partsfinder on NGK's site.

Of course my manual thinks I need a D7ES (gap 0.6 - 0.7mm), but they are not for sale here anymore.

It's not a Dyna ignition, I think it's called Accent. It's a German brand. I'll start by replacing the ignition this weekend with the original, and see if that solves it.

Thanks for the help TwoTired.

[TwoTired]

I see.
Added resistance at the resistor plug, in addition to the spark plug cap resistors can increase the voltage developed in the coils, and thus a higher magnitude inductive kick back on the primary.  But, it is, perhaps, unlikely to be root cause of failure (if, indeed you have a failure).  Could be a contributor, though.

You say one side is working and he other doesn't?

Swap Yellow and Blue sides and ignition leads between 1-4 and 2-3.  Does the problem follow the trigger source?

Cheers,

[BobbyR]

I suspect you could have a high voltage leak somewhere. An old school but effective trick is to run the engine in the dark and look for sparks or flashes. Look around the coils. Alos look to see if the wire leading from the points to the coil is not chafed and shorting. I had that problem.

[Bodain]

Thats an easy one...  1 and 4 fire off one set of points. 2 and 3 fire off he other set of points.

Since both 2 and 3 aren't firing you know it's ignition.... Would not be wise to put 1 an 4 plug wires on 3 and 4... Timing issue you know!

Verify 2 and 3 coil is getting voltage. If it ain't it won't fire...

Verify the two wires that lead to points. There by the brake switch is where they connect up to the points. Maybe the 2 & 3 wire came loose.

Verify 2 & 3 points... Put volt meter or light on it. Turn ignition on. Turn crank by hand. As 2 & 3 open it should go +12 volts... If it doesn't find broke wire.

[TwoTired]

Would not be wise to put 1 an 4 plug wires on 3 and 4... Timing issue you know!

Thats why you swap the Yellow and Blue primary wires, too.  If the problem tracks either, you've found the source.  You don even have to run the bike.

Cheers,

[Clyde]

Firstly check all connections and check the HT leads are not chafed and rubbing against the frame.
Then I would just swap blue and yellow wires, but not ignition leads.
If the problem moves from 1-4 to 2-3 then you most likely have a problem with the inductive(?) pickup on the 1-4 side.
If the problem stays with the 1-4 then you should look at connections to the coils or coils themselves.
Switching the blue and yellow wires means the engine will not run because the timing will be 180 degrees out, but it may backfire, so it would be safer to remove all four plugs to do this.