Topic: Issues with a Dyna S electronic ignition

[dotslashsandwich]

Hello SOHC4 forums, first time poster here (though I've used the archives for the better part of a year)!

My SOHC4 is a 1975 CB550K (sunburst orange, very sexy), and it's my first motorcycle, so I'm learning as I'm going. It came with a Dyna S installed by the previous owner. It ran fine for ~1k miles until the cylinders started periodically cutting out when running at speed. Quite a mysterious gremlin to a newbie like me. Well I finally figured out how set a timing plate, and found that the plate was rotated fully counter-clockwise, so about as advanced a spark as could be. Burning real hot.

I set the timing correctly using a strobe timing light (rotated the plate to set the 1-4cyl coil, and moved the 2-3cyl pickup to set the coil for cylinders 2-3). As I was adjusting the 2-3 pickup, I noticed that cylinders 2-3 weren't firing any more. I gave the pickup a tap and they would kick in for a second. A harder tap kept them running. There's my issue! When I was adjusting this pickup it slipped off and I noticed there was some sort of grease (conducive grease?) beneath it. Could it be that I should re-apply that grease so the pickup makes a better connection with the plate?

Upon further inspection, the ignition is actually wired wrong, as the left pickup controls the 2-3 coil, and in the instructions the right pickup should control the 2-3 coil! It has run quite nicely for ~1k miles, but maybe the error built over time?

Do I need a new ignition?

THANKS!@!!@!@!

[Xnavylfr]

With the DYNA and points you can actually hook them up either way ,but you have to remember which coil fires which plugs. The big difference is when looking for timing marks, if you have a strobe timing light hooked to #1 wire, when it fires you'll see #2/3 mark and opposite if the light is on #2 wire.
DYNA has had a run of BAD systems lately because the pickup modules were getting too hot.
Are you sure what you think is grease is NOT the backside of the module melting??
Before you say positively it is the DYNA,(if you have parts) replace the DYNA with a set of original points/backing plate/condensers. If the problem still appears ,it could possibly be a coil going out!
On the very last page of this installation guide is a SHORT T/S for the DYNA! This link may just be the last page!
http://www.hondachopper.com/garage/dyna_s_installation/dyna_s_installation.pdf

Xnavylfr(CHUCK)

[dotslashsandwich]

Hmm interesting point about the meltage, I'll go check right now. In the meantime, I must stress how when whacked, the pickup will turn on/off. If off (or just not receiving the signal from the cam), the pickup can be pressed with great force and it will turn on again.

Do the pickups need to make a good connection to the timing plate? A sort of grounding?

[dotslashsandwich]

I just removed both pickups from the plate and inspected the backsides. It's just brushed metal, no melting at all. There was a splotchy (at best) amount of a greasy substance on the backside of each. Since there was areas of metal-metal contact (not entirely metal-grease-metal), I'm going to assume that it's OK for the pickup to touch metal. I'm going to try removing the grease and re-timing the engine. Then try spreading electrical contact grease evenly over the backside of the pickup.

Lets see what happens!

[Xnavylfr]

I don't think so!! But I could be wrong. To check this theory , put a piece of rubber or plastic behind the module and bolt it down, then check if you get the same reaction from it!!!


Xnavylfr(CHUCK)

[Spanner 1]

I don't mess with Dyna stuff... but I know the pickup coils do not need to ground against the plate and that the 'grease' your talking about is there to conduct heat away from the pickups and is very necessary and does not need to be wiped away... basically it fills any tiny voids between the p/u and plate for even heat dissipation.... common on electronics that generate heat when working... 

[dotslashsandwich]

Darn it, I read your reply too late, Spanner! Tried silicone conductive grease to no avail. It is in fact thermal grease, confirmed a second time by the guys at the local cycle shop. I have extra thermal grease so that's not a huge issue. The bike shop suggested that I mess with the 'air gap,' or the distance between the cam and pickup. I moved it radially out as far as it goes, as well as in as far as it goes with no change.

After working on it some more I found that I can get it to the point where I can grab the left pickup (securely allen'd) and push/pull it to make the coil turn on/off. I feel like I could almost rig up a clamping device to keep the pressure on...but that would be gross (ew).

I think it might be busted...