85 gs550 mechanical advance question

[Doug B.]

My 1985 gs550 has electronic advance and no mechanical advance. I am wondering if anyone has retrofit a mechanical advance from a prior model 550 in order to use a dyna ignition. I'm gonna be in trouble if my stock igniter ever bites the dust.

 

[Nessism]

There is a thread in the archives where someone did the swap. Not sure if the ignition curve is the same but bike ran.

 

[earlfor]

There is a thread in the archives where someone did the swap. Not sure if the ignition curve is the same but bike ran.

My best guess is the ignition curves are the same or very close. I retrofitted a Dyna S ignition to my 85 GS1150E which was manufactured with a electronic advance ignitor. I installed a mechanical advance from a 79 GS850G. A 850G is probably as far away from a 1150E as you can get.
The bike ran flawlessly for years.

 

[earlfor]

There is a thread in the archives where someone did the swap. Not sure if the ignition curve is the same but bike ran.

My best guess is the ignition curves are the same or very close. I retrofitted a Dyna S ignition to my 85 GS1150E which was manufactured with a electronic advance ignitor. I installed a mechanical advance from a 79 GS850G. A 850G is probably as far away from a 1150E as you can get.
The bike ran flawlessly for years. I did have to change the crank cover to one from a 83 1100 though. The stock 1150 cover wasn't tall enough to clear the rotor. The 83 cover is deeper.

 

[Doug B.]

My best guess is the ignition curves are the same or very close.

I'd agree with that. The engine's needs will be very similar between one model and another as long as most of the variables are similar (carbs, air-cooled, comparable cam profiles)

I'm off on another tangent now, looking at the Dyna 2000 DDK3-2 ignition, which allows program my own advance curve anyway. While it doesn't say it will fit my bike, I'd imagine with some light modification it should work, it is listed to fit nearly every other GS 4 cylinder made..

It seems like overkill on my little 550, but I'm planning on keeping and riding this bike for a long time.

I'm chasing a gremlin where once in a while the bikes feels like it develops an ignition skip under acceleration, and I've eliminated most of the more common suspects already. I want to check voltage at the coils under load first but my gut tells me that won't be an issue..

This bike was ridden for a bit with a faulty regulator, and it overcharged enough to boil the battery dry (by the PO) and I'm thinking that the igniter was damaged..

I wasn't able to find the article in the archives, I did look first.. probably don't know the magic search term to bring it up..

 

[Doug B.]

I contacted Dyna regarding the installation of the 2000 ignition on my bike and got this reply:
The issue in fitting the Dyna 2000 comes with the crank trigger. The 1985
motor was different than the earlier motors in that the OEM ignition plate
uses two (2) hold down screws instead of the three (3) used on the earlier
motors. Also, the rotor we use will not index onto the crankshaft end
therefore the timing cannot be properly set.
Given that this is a very limited application, we have never made a system for
this model.

My concern is the crank rotor and in what way it is different than the older bikes (aside from no mechanical advance)

I did find most of the info on using older / different ignitions on these bikes but didn't see a direct comparison of the rotor styles and their differences. Making a custom backing plate should be pretty straightforward, but its possible the rotor could be the deal killer.