Topic: Just won a GEREX electronic ignition!

[amattel]

ok.  I have gone ahead and bought a set of CB900 coils.  My understanding form my reading is that they are somewhere around 2.2 ohm primaries.  From what I've read on this site, they work really well for CB750's and they are reasonably priced.

I will do some research now to see what I have to do, bracket-wise, to make them fit.

thanks for all your input.  I feel like I have a much better understanding of coils and how various ignition systems use them.

The Gerex should arrive before the coils so I may install that first with stock coils and get it working that way before the new coils ariive and I add that to the mix.

Thanks,

Adam

[amattel]

Here's the latest update.

Wednesday morning I installed the Gerex cdi.  Went pretty smoothly.  The cdi unit was smaller than I expected maybe 4" x 3"..  All the wiring was easy to figure out using some installation instructions I found on the dyna's site for the dyna III.

IT STARTED RIGHT UP!!!

This is sooo cool.  When something actually works for me first time it kinda startles me.  I did this?  wow.

Anyway using the stock coils it ran really really well.  so good that what was supposed to be an around the block test run turned into a 50 miles ride to ALice's restaurant!

It idles so steady like clockwork. and has lots of smooth power delivery.

Well, here come the clouds in the story.

On my way back from ALice's somehting went pop, and then I was running on 2 cylinders.  It sounded like a cross between a thumper and a Two stroke... really loud but very little power. 

I made it home the last 30 miles splitting traffic on two cylinders.

After it cooled down for half an hour it run great again.  I think perhaps the gerex multifire ignition overwhelmed my poor stcok 5 ohm coils and the 1-4 coil overheated and failed.  this is my guess, anyway.  I just tested the resistance of my stock coils 2/3 was 5ohm and 1/4 was 4.7 which happens to be the one that failed.  I could tell by the two center header being extremely hot anf the two outside only being very warm.

As soon as I get some plug wire I will finish installing my cb900 coils and see how that works.  I tested these and they are 2.5 ohm (primaries)  so hopefully they will do better with the gerex.

Adam

[oldfart]

[And still, I use points in my SOHC4s!

Me too!

You know, I think we should start a club for folks who still like points!  Just kidding...

[oldfart]

It's a CDI?  Pretty cool find there Adam!  Ought to work with just about any coil.

Didn't know anyone made a CDI for an SOHC4.  I'm envious.

Zap a 12 V coil with 300V instead of 12V, gives you a rip roarin spark.  You can probably open your spark gap up to .035 inch.

Cheers,

You can open your plug gap to 0.035" with just a change to GL1000 coils.  By definition, a multispark system is CDI.  The reason is that CDI systems by nature have very short duration sparks.  This made them not very useful in emissions spec machines, in which mixtures are so lean the short spark doesn't work well.  Hence CDIs were developed to have multiple sparks so as to effectively have longer spark duration.  Gerex used a hall-effect pulser system made of actual rotating magnets -- kind of unusual.  Very well made though.  Incidentally, I installed a number of Gerex systems on old Gold Wings, and on none of these did we use special ignition coils.         

[mrbreeze]

Hey Adam.....welcome to electronic ignition!!!!! I felt the same way as you when I first ran with my Dyna ignition.I'm not knockin' points but it is definetly noticable when you switch over.Hope to see ya' in Berkeley on the 16th.

[Dusthawk]

Adam, congrats on the great find. I've been folowing he thread soaking up the info and plan on getting a dyna here fairly soon.

Keep us posted on how the coils do when installed.

Ditto on the 16th

Peace and Long Rides,

Jeff

[oldfart]

Terry -- Check your private messages.

[Terry in Australia]

Well I just scored a complete Gerex ignition system from a guy on The GS Resources, from an original RC Engineering GS1170, for free! He said it was working fine, but he didn't know much about them, so replaced it with a Dyna S and Dyna 3 ohm coils.

Does anyone here know where I can find a wiring diagram or installation instructions, or both? I think I can work out which wire connects to what, all the original connectors are fine, and the Gerex 1.2 Ohm coils, CDI box, bracketry and ignition plate and rotor look to be in great condition (bike had only 9K miles on it and looks like new)

I'm going to set it up on one of my Suzuki GS bikes, and could probably nut out the installation, but after killing a Martek 440 ignition a few years ago (never feed power into a signal wire..............) I don't want to bugger this one up! Cheers, Terry.

[amattel]

hi Terry,

I just used the online wiring diagram for the dyna III on dyna's site.

the only issue was the purple and green wires going to the ignition coils instead of blue and yellow..  I took a shot at it and ran great on first start!

Adam

[Terry in Australia]

hi Terry,

I just used the online wiring diagram for the dyna III on dyna's site.

the only issue was the purple and green wires going to the ignition coils instead of blue and yellow..  I took a shot at it and ran great on first start!

Adam

Thanks for that Adam, did you have any problems working out which way the rotor was supposed to fit over the advance retard unit on assembly? Cheers, Terry.

[amattel]

hi Terry,

I just used the online wiring diagram for the dyna III on dyna's site.

the only issue was the purple and green wires going to the ignition coils instead of blue and yellow..  I took a shot at it and ran great on first start!

Adam

Thanks for that Adam, did you have any problems working out which way the rotor was supposed to fit over the advance retard unit on assembly? Cheers, Terry.

When I did it it seemed obvious... if yours is in more pieces than mine was it may not be.  I could iake pictures for you if you need me to.

Adam

[Terry in Australia]

G'Day Adam, hey thanks for that mate, one clear pic of the assembly with the points cover off would probably be enough mate, I really appreciate it! Cheers, Terry.

[amattel]

G'Day Adam, hey thanks for that mate, one clear pic of the assembly with the points cover off would probably be enough mate, I really appreciate it! Cheers, Terry.

Here you go!

Adam

[Terry in Australia]

Thanks Mate, that's just what I need! Cheers, Terry.

[scottly]

From the Gerex installation instructions: "The Series II GEREX is smaller and different in configuration. The cable no longer comes out the back, but exits at the end cap. The harness no longer goes thru a hole in the mounting plate."
Evidently, I have a series II, but there is no label stating this, nor any engraved marks anywhere. (I even used a magnifying glass.)
Also, the instructions say to re-gap the plugs to .063"-.065". I had always gapped my plugs at .028.

[754]

.63 - .65 mm would be very close to 28 thou..

[scottly]

.63 - .65 mm would be very close to 28 thou..

Thanks, the spec was in inches; I modified my post with the proper notation marks.

[Terry in Australia]

Geez, this thread both brought back old memories and also reminded me that I've still got that Gerex ignition, I wish I'd remembered it before, because I bought a new old stock Martek 440 for my second GS1000 a few months ago when the OEM ignitor box failed. D'UH!

I'm not surprised at the much wider spark plug gap, I think Hondaman spoke about setting the gap much wider with some electronic ignition installations.

[scottly]

Regarding coils, a few years ago I stumbled across a set of twin output canister type coils, so I swapped them in, not really expecting any increase in performance. On the first test ride, I snapped open the throttle at about 10 MPH in 1st gear. The bike felt VERY strong, but something felt "funny", like maybe the clutch was slipping. On my return back to the shop, I found a black strip on the pavement 40 or 50 feet long.
I measured the resistance of the coils today: 3.7 ohms. Labeled "K. V. Products". 

[scottly]

Were it in my possession, I would fit it to the bike and characterize the output pulses using an oscilloscope.  This would determine what coil type to use, and whether a stock or equivalent storage type is required or a special Gerex coil or similar.

Cheers,

TT, I will try to run these tests when I get my bike put back together. I checked my HP scope today, and it can handle an input of 350V. I also have an engine analyzer scope, which can measure up to 50KV secondary outputs, but I'll have to get creative and figure out a way to trigger it, as it triggers off the points, or the tach signal on cars with electronics.