550 Igniter interchange success!!!!!!!!

[spyug]

It was the 750 plate that was modified so the pickups fit back in their own holes. It was necessary to take the pick-ups off to modify the plate. Basically to line things up I had to move the upper attaching screw hole inboard a bit and notch the outer edge of the plate there and at the bottom left and right to fit on the locating pegs. The upper right side peg had to be removed. The important thing was to insure the center hole in the plate doesn't rub on the rotor when it is installed.

I didn't find it difficult other than trying to remove the pick-up screws and getting the original rotor off.

[spyug]

Post #7 from Jeeprusty gives the factory figures. They look close at the initial setting but full advance comes on at lower revs on the 750 box. I am really not sure what effect that will have and I'd appreciate any insight.

I'm not in a gigantic hurry to ride this bike and I've done this as an "intellectual" exercise so I won't be riding if it isn't right.

If I can round up a coil tomorrow I'll know soon if this is really going to work.

Stayed tuned. Please keep your thoughts coming folks. every little bit helps.

cheers,
Spyug

[blowerbike]

ok then.
your individual cyl. pair timing should still be the same.

it will work and run fine..maybe after the fact..slot your plate to case mounting holes so you can advance/retard you timing if possible.
a degree wheel would be the best case scenario to know where your at for sure.

[Ranger]

Congrats and no problem, glad I could help by sending the needed organs. I have most of the electrical if needed, tossed the coils though.

Weird seeing pictures of the parts taken from another country instead of in my garage!

Hope there's not too much more you need to do to get riding.

[spyug]

Somewhere along the way I was told the 700 igniter's ignition timing would be slightly off from that of the 750 and likely more suited to the 550 engine. Research now shows that this is not the case and the 700 and 750 igniters are identical at:

13 degrees BTDC below 1500 RPM
35 Degrees BTDC above 2350 RPM

So one from either bike will be suitable. I just wanted to clarify that.

Spyug

[Nessism]

Great work on this Spyug!! Are you going to slot the plate so the timing is adjustable? Might not have to adjust at all but it also might be fun to play with. Use as much advance as the engine will tolerate without detonation.

[spyug]

I hadn't thought about that Ed until Chef brought it up. I had always thought these ignitions were fixed. I'll need to read the write ups on it. While I remember seeing a post or 2 on the subject I pretty much glossed over them since they didn't have any relevance for me at the time. Is there a spcific post you can refer me to?

Thanks for mentioning it.

cheers,
spyug

[Nessism]

I hadn't thought about that Ed until Chef brought it up. I had always thought these ignitions were fixed. I'll need to read the write ups on it. While I remember seeing a post or 2 on the subject I pretty much glossed over them since they didn't have any relevance for me at the time. Is there a spcific post you can refer me to?

Thanks for mentioning it.

cheers,
spyug

Just slot the plate hold down screw holes allowing the plate to rotate a few degrees. Rotate the plate to move the pickups. You can easily turn it 2 degrees which will make your initial advance match that of the regular 550 set up.

[chef1366]

Is this a sixteen valve 550?

[spyug]

Is this a sixteen valve 550?

Yes it is.

[spyug]

Well I trotted down to my pro-wrench this afternoon in search of a replacement coil. Imagine my surprise when he pronounced mine fine but in need of new plug caps. I had checked myself of course and it was definitely showing way over spec on the secondary windings.....or so I thought and it didn't spark. Brian's multimeter showed it to be in spec and he suggested I try it again without the plug caps ( I had done it that way I thought...must be losing it).

So I took some new caps and tried it again after supper and low and behold it sparks fine. There is a voltage drop at the coils of only about 1/10 of a volt so I'm not going to do the coil mod just yet.

With the long weekend coming up I'm now in good position to fire it up. Once I hear it running I'll chalk it up as fixed.

Stay tuned and I'll report in when I get her fired up.

Cheers all,
Spyug

[Nessism]

Hate to say this...but could the problem have been the plug caps all along and not the ignitor?

[chef1366]

The old crank triggers were melted.

[spyug]

Hate to say this...but could the problem have been the plug caps all along and not the ignitor?

No, I'm certain about the igniter being toast. There is a test for the resistance of the pinouts in the manual which I followed to a "T" and when I opened it up there was some evidence of burning too. It was junk.

The old crank triggers were melted

Well they weren't until I put the torch to them . Before I got smart and took the pick-ups off the plate. I was being lazy and figured I could heat up the rotor ( to free up the locktite) get it off and get the plate out in one piece. Kinda forgot about the conductivity of metal

I think what may have originally happened is that the PO had taken the bike apart to clean, repaint and refurb it and when he started to put it together again he miss wired it as I mentioned before. There was no main ground wire fitted and the positive from the battery had been wired to an engine bolt and the negative line from the battery was attached to the power terminal on the starter motor, effectively reversing polarity. I suspect he tried to turn it over at one point with the igniter in place and that was the end of it.

Possibly I did it myself when I first attempted to turn it over but whenever or however it happened it got toasted. As I've been told a few times, these igniters were not very robust and I guess it didn't take much to ruin them.

I hope the 750 kit works better and lasts longer

Spyug

[JEEPRUSTY]

that old unit had a rather lazy rewire.
It looks like only one side failed and yet they could not solder the damned thing back on right.