R80 electronic ignition issue

[David M]

Hi all, I'm new around here but have been browsing for quite some time so I hope you don't mind me jumping in and asking for a little insight on an issue I'm having with getting my Airhead started.

First, a little background. The bike has sat for about a year and never has had an issue starting apart from the battery being flat. I connected a jump starter to it and had it running but everytime I disconnected it it cut out. So I tried this a few times and kept it running with the jump starter attached for more than few minutes reving a little here and there to see if it would not cut out.

The bike is a custom build and has been made into a bobber, so it has a somewhat unusual layout. For example, to change the battery I have to take one of the exhausts off as it sits in a space inbetween both exhausts. Its unusual, but not an issue as long as the battery doesn't need changing.

Because it has sat for a while (House renovations got in the way of ridining for a while) I needed to change the battery and therefore remove the left exhaust. Once the battery was changed and the exhaust all fitted back together the bike had power, everything lit up. All lights and horn worked, but the bike wouldn't start.

I changed the spark plugs and still no start. So I checked to see if I had spark with the brand new plugs both grounded to the fins and neither side was sparking. The bike runs a dynatek green, dual coil. So with this in mind and spark not going to either plug I changed the coil for the same model but still had no spark.

I noticed that the starter button was working but not springing back, so I wondered if the fault could lie there, but I've just changed this and I still don't have spark. There's never been a kill switch on the bike so that can't be the issue

The bike has an electronic starting kit by Enduralast and that's the last thing on my list to replace (and probably the most expensive) however, I know very little about mechanics and electronics so I'm just muddling through and quite enjoying it apart from the frustrations of failure! The engine is spinning on start but not sparking, does this mean that with what has been replaced, that the electronic ignition is working? (I'm not sure if the initial spin is from the ignition system or not, please forgive my ignorance) or is it probably fried and I need to replace parts of it or is there anything else I should be looking for? As I say the bike was faultless before taking the exhaust off and I've checked all grounding and loose wires etc.

A link to view current starting situation can be viewed: https://we.tl/t-s1pDzLzgeq

Thanks for yoru help on this and sorry for the long first post
David

[Rob Frankham]

Firstly, I tried your link and all I got was a sign up page for an App that I don't want so I can't see what you have uploaded.

Anyway... the joys of aftermarket electronics... great when they work but a real PITA when they don't because there is often not the background body of knowledge to trouble shoot effectively. I'm afraid I don't know the Enduralast setup but a few points in ana attempt to help you get to the bottom of the issue.

1) When the engine is turning over on the start, there should be a visible spark at the spark plugs. If not the engine can't start. No spark implies a fault with the ignition system or the wiring surrounding it.

2) The ignition system consists of a number of parts, any of which might cause the problem. In partiocular, there is a sensor attached to the alternator under the front cover. It would be a good idea to check the condition of this before jumping to conclusions about the ignition unit. You also have to think about the coils and general wiring.

3) Before digging into the ignition system, check for power and earth at the ignition unit. You should have 12v on connection 6 and ground on connection 2. The problem could be caused by the ignition switch, the kill switch or simply a wiring fault.

4) You can donwload the Enduralast fitting instructions in pdf format here. This may make it easier to see what's wrong and it has a troubleshooting guide.

Good luck with this problem... if you are in difficulty with electronics, you might need to find someone who knows a bit more.

Rob

[David M]

Hi Rob, thanks for the reply. The link should take you to a wetransfer link to a video I took with my phone just to show how the bike is turning on startup.

I totally agree on the after market parts, I've found a fair bit of info on the original starting elements, but not much on this one. I've changed the coil to a brand new one, so I suspect that's not the issue and as there's no spark on either plug (both plugged in to a 3ohm dual dynatek coil) I've also replaced the ignition switch, and it's turning the engine, so this is leading me to think it could be the sensor. So that is probably my next port of call.

I appreciate your advice on this. I'm sure it's something simple. Step by step I'll get it fixed.

David

[SteveD]

Is the 3ohm the correct one? That's usually the points coil spec. EI oem is 1.5 and other aftermarket EI units use 0.7ohm.
You should still get spark regardless with it unless the new coil is coincidently kaputski.

[David M]

Hi Steve, the coil is the same as what came off the bike originally and it's ran like a dream for years. It's a dual output and I've read in a few places that it's the right setup. I'm pretty certain the coil is not the issue. I think it may be the ignition unit or a component, or all the connections need looking at for rust etc

But beyond that I haven't a clue!

[SteveD]

Hi Steve, the coil is the same as what came off the bike originally and it's ran like a dream for years. It's a dual output and I've read in a few places that it's the right setup. I'm pretty certain the coil is not the issue. I think it may be the ignition unit or a component, or all the connections need looking at for rust etc

But beyond that I haven't a clue!

Yeah, the pre 9/80 models used a 3.0ohm dual coil setup. I'm not suggesting it's your issue, just that it seems an anomaly to use it with EI.

[Rob Frankham]

The Enduralast installation instructions confirm that the unit must be used with a coil (or coil combination) having a (combined) primary resistance of between 2 and 4 Ohms. They specifically state that the dual coil found on later airheads, with a primary resistance of 0.7 Ohms) is NOT compatible.

Rob

[SteveD]

The Enduralast installation instructions confirm that the unit must be used with a coil (or coil combination) having a (combined) primary resistance of between 2 and 4 Ohms. They specifically state that the dual coil found on later airheads, with a primary resistance of 0.7 Ohms) is NOT compatible.

Rob

Good clarification Rob. Thanks.
I've always known the pre 81 points models to use the 3ohm coils and the post 80 EI models to use 1.5ohm and some aftermarket EI eg Wedgetail suggest the 0.7ohm.

Is the use of the 3ohm here due to other aftermarket electronics used on the bike?

[Rob Frankham]

The Enduralast installation instructions confirm that the unit must be used with a coil (or coil combination) having a (combined) primary resistance of between 2 and 4 Ohms. They specifically state that the dual coil found on later airheads, with a primary resistance of 0.7 Ohms) is NOT compatible.

Rob

Good clarification Rob. Thanks.
I've always known the pre 81 points models to use the 3ohm coils and the post 80 EI models to use 1.5ohm and some aftermarket EI eg Wedgetail suggest the 0.7ohm.

Is the use of the 3ohm here due to other aftermarket electronics used on the bike?

Quite so.

It's important to understand that coils (and electronic ignition units for that matter) are not stand alone items but are designed to work together. Unless you are a real techie, it is always wise to use the coil recommended by the ignition system manufacturer (or one having the same spec). It is also important to realise that the ruling specification isn't the primary resistance.

The performance of a coil is set by a number of parameters including the promary resistance, the number of windings in the primary coil, the secondary resistance and the number of windings in the secondary coil (especially the ratio of primary to secondary windings) as well as a number of other factors. A coil with a (e.g. 3 ohm primary may have completely different characteristics to another coil with a 3 ohm primary but different winding ratio. Also because of their physical and electrical construction some coils, otherwise similar, might display different characterisitics in different rev ranges.

Of course, most automotive ignition coils will work, for a given value of work, in most situations but to get the best results and the longest life, you will want to use the correct coil for your ignition system.

Things to bear in mind about primary resistance...

If you use a coil with the primary resistance too low:

a) If you're using electronic ignition, it may well cause the components in the igntion system to overheat. It may not fail completely or immediately but it is likely to reduce it's service life.

b) If you use one with points, they will arc and you are likely to burn out the points more quickly.

c) The current drain on the battery from the coill will be high and this might have an effect on battery life and starting.

If you use a coil with primary resistance too high.

i) igntion voltage is likely to be low and this may make starting difficult.

ii) you will lose the benefits of hgher spark energy and duration which will effect performance and fuel efficiency... if not a lot.

Coils look simple but they aren't. Just to emphasis the point, you will not go wrong using a coil recommended by the ignition system manufacturer.

Rob

[JohnT]

Have found this very interesting and agree that using the manufacturers recommended parts is the obvious solution as they will have spent much time and money developing.
Now I used to run a 1985 R80 with electronic ignition which had an intermittent ignition fault that I could not find. As it was my daily commuter I needed a quick fix with parts to hand so fitted a points bean can and a K100 coil. It worked and the temporary fix became permanent. I never bothered to find out if they really were compatible.