dyna coils - did I burn them out? edited solved

[lazlokovacs]

Ok, at a bit of a loss here..

New to me LM2, came somewhat disassembled. All went back together easily. I took her for a ride, was very pleasantly surprised, engine running really nicely.

However, the brakes were terrible and the ignition switch kept cutting power to the headlights.

So... De-linked the brakes over the weekend, new M/Cs etc. All good.

Replaced ignition switch, but managed to mess it up. I had the coils hooked up to the terminal that has power through it when switch is in 'parking light' mode.

I didn't even realise this switch had a parking setting and duly left the bike overnight a couple of times with the power on to the coils.

Went to fire it up today and got plenty of backfiring and not much else, the engine would fire but wouldn't idle.

coils primary and secondary resistance checks out fine. Also get a fat blue spark with the plugs grounded on the case.

coils are Dynatek (properly mounted with both ends securely fastened to a purpose built bracket that served me well for many miles on a previous machine)

and the ignition is the crank mounted Sachse unit (also a known working unit)

seeing as nothing else has changed since it was running well, I feel it must be the coils or the ignition unit.

Anyone BTDT or have any ideas?


cheers

[Antietam Classic Cycle]

If they're green Dyna coils, then they may have overheated and cracked.

[Old Jock]

Can't be much help but when you asked about the coils, were they hot to the touch?

Perhaps you didn't check, but I've got a crank mounted Sachse on an LM1000 engine and AFAIK if the coils don't get grounded within 3 seconds then the ignition unit cuts power to the coils.

I'm a bit counfounded that leaving power to the Sachse unit would damage it too.

However from your description it sounds like a timing issue i.e. more likely to be the electronic ignition than the coils, besides your tests indicate the coils are good, at least when cold.

I'd check the Sachse timing and all the dip switches on the box, if it's Ok then I'm guessing it's the Sachse box that's the problem, but it's only a guess.

Oh minimum primary resistance on the Sachse unit is 3 Ohm, but I use 5, less current and Guzzis don't need fast saturation time on the coils

[lazlokovacs]

yeah - I use 5k for the same reason

interesting that the sachse cuts power to the coils, so it's unlikely to be the coils that are down.

already checked the timing, the sachse disk is in the right spot.

I do have a spare sachse box and pick up on hand

Before I dive in, it would be great to know what is the more likely culprit though.

I'm leaning towards the sachse box itself, the lights are going on and off as they should on the pickup . but why??? I can't see how/why a 1év feed to that black box would cause any damage?

a head scratcher

[lazlokovacs]

double checked the sachse unit, firing on time. firing on test mode, but not a big spark and slightly erratic.

also had a quick check, the sachse unit doesn't cut the juice to the coils after a set time...

so coils are back to prime culprit, got some more on order will swap em out and fingers crossed that'll be it

[Chuck in Indiana]

double checked the sachse unit, firing on time. firing on test mode, but not a big spark and slightly erratic.

also had a quick check, the sachse unit doesn't cut the juice to the coils after a set time...

so coils are back to prime culprit, got some more on order will swap em out and fingers crossed that'll be it

If I were a betting man.. I'd bet a dollar it is.

[lazlokovacs]

if only a pair of coils cost a dollar!!!!!!!!!!!

Will let you know

[Old Jock]

Interesting my Sachse system has to be 10 years old and although I've never tested it the instructions state that the system cuts the feed to the coils

The system I've got is the combined R/R and electronic ignition but the instructions state it on the ZDG3 pamphlet (the igntion only unit).

Apologies for the bum steer, if I have a moment I'll test my unit to check.

If you've want an electronic copy of the instructions for the ZDG3 PM me.

[lazlokovacs]

I had time to swap out both the sachse ignition box and the pickup today, no change.

Chick's bet is starting to look good, assuming it's not something else totally unrelated that I've overlooked!

[lazlokovacs]

new coils in

went to start it, no joy, same as before. hmmmm

checked all the stupid stuff, is there enough petrol etc... all good

ran test mode on sachse (again) left plug not firing.

hmmmm

changed plugs for new, started on the button.

strange the old plugs gave no problems on the shakedown run, will monitor situation

glad she's running again though

[Old Jock]

Good Stuff and many thanks for taking the trouble to report and close out the thread (I hate when people just take the advice and cannot even be bothered........... ...what sort of upbringing have these people had?)

Funnily enough had the LM1000 engined bike out today.

Going through the town and the first 20 miles or so of the run out, I was thinking, has it always been so gutless?

I just didn't seem to be making much headway at all.

She idled fine and was running on both cylinders (sort of)

Once out on the open road and shown her the stick a few of times, I heard a series of muffled backfires followed by a roar and the old girl lifted her skirts and started sprinting, the grin factor was 11.

Still in love after all these years

John

[lazlokovacs]

Oh it's a blimmin fun engine that big valve lemans 1000

shame my one turned out to be outrageously unreliable, it's languishing in a shed, becoming a parts donor for other projects, maybe just maybe she'll be back one day

thanks for your help