Electronic Ignition & Static Timing?

[mbopp]

I recently replaced the electronic ignition plate on my bike with another one from a similar model (82 850 G, I have an 81). The plate installed fine, but am wondering if there is any configuring that needs to be done with the static timing? These electronic ones don't seem like the points ones (hopefully much easier). There is a little room for adjustment at the screw slots of the plate if need be, and didn't know if or how something should be done with that.

I can't get the bike started right now. Not sure if this is the reason or not. But would like to find out. Could this be the reason the bike isn't firing up?

Thanks In advance.

[earlfor]

As far as I know, the stock electronic ignitions on GS's did not have any provision for timing adjustment. All I have seen will only install one way and cannot be changed. None I have seen had a timing mark.
Do you have timing marks?

Earl

I recently replaced the electronic ignition plate on my bike with another one from a similar model (82 850 G, I have an 81). The plate installed fine, but am wondering if there is any configuring that needs to be done with the static timing? These electronic ones don't seem like the points ones (hopefully much easier). There is a little room for adjustment at the screw slots of the plate if need be, and didn't know if or how something should be done with that.

I can't get the bike started right now. Not sure if this is the reason or not. But would like to find out. Could this be the reason the bike isn't firing up?

Thanks In advance.

[mbopp]

No. I don't believe there are any timing marks.

[earlfor]

Then I would think it is non adjustable. Have you grounded the spark plugs (one at a time of course :-) ) to see if you are getting a spark on all four?

No. I don't believe there are any timing marks.

[SPARKSS]

I recently replaced the electronic ignition plate on my bike with another one from a similar model (82 850 G, I have an 81).. ......
I can't get the bike started right now. Not sure if this is the reason or not. But would like to find out. Could this be the reason the bike isn't firing up?

My first question asks whether it ran correctly (or at all) before you changed the ignition plate? If it did not run, then I'd move back a step and rerun your diagnosis. If it did run (and there was a valid reason for replacing it), then I'd want to see whether you have any spark at all (which might be happening even if way out of time due to incompatibility or other issues).

What say?

[mbopp]

Well, it did run before, but only on two cylinders. The plate came unscrewed before I owned the bike, and really damaged the plate and rotor, which I believe to by why it's only firing on two. So I've replaced it, and appear to be getting good spark on all plugs. Whether or not the timing is correct I don't know, but is what I hope find out with this post. It seems that with compression, and spark, that I have a fuel problem. But there is fuel in the carbs, and I assume it's getting to the engine itself.

If the timing is off on the ignition plate, would that prevent starting all together? It seems like I would get something.

[SPARKSS]

You're obviously on the right track by checking basics first.......Ignition timing might be what is incorrect. Do you get any firing noise as you crank it over....either attempts to start....or popping into the intake or exhaust? Are the plugs wet? You can always seperate a fuel problem from the equation by opening an UNLIT propane torch into the airbox and trying to start. This provides a VERY good combustible mixture which won't foul plugs......easiest if you have an airbox of course.

If there's no timing marks, you can always find TDC with either #1 or 4 (doesn't matter.....easiest on those outboard cylinders) and scribe a mark on whatever you can see rotating.....with a corresponding mark on an adjacent stationary piece......and use a n advance timing light to find it as you crank.........Alternatively, with almost no equipment, you can probably rotate the crank manually with a socket and bar back and forth across the point where #1/4 fires (open grounded GOOD plug or spark tester), noting with a scribed mark where that occurs and then, finding TDC through the plug hole, estimating (or measuring!) where that spark occurs...hopefully somewhere from say 15 degrees BTDC to near TDC (piston rising in the bore). If it's as the piston falls away, AND/OR is otherwise a long way from this window, then it'll be near impossible to get it running. With a timing plate that, for example, has it's pickup(s) mounted in a different area this will happen......it may be possible to either remount them or redrill/slot mounting holes to effect the change needed.

Hope this doesn't hinder your efforts!

[mbopp]

I get an occasional pop from the what sounds like the exhaust. I think I ought to tinker with the ignition plate a bit and see how that goes. The plugs don't appear to be too wet. Maybe just a little residue on them. I have to believe it has something to do with the way the ignition plate is mounted.

How do I determine TDC through the plug hole. I've not done that before. Just using some feeler device to find out when the piston is highest?

Another thing that just occured to me is how I put the rotor on. It will lock on to the advance unit one of two ways exactly opposite of each other. I wonder if I have it backwards. I guess I figured that wouldn't matter at all, but I wonder if it does. What you you think?

Not sure if it helps to have a point of reference, but this is the schematic of what I'm looking at...

http://houseofmotorcycles.bikebandit.com/partsbandit/ShowSchematic.aspx?deptId=1002168&machineId=6123

[chef1366]

Right before the F 1&4 there is a timing mark "T" Line this up with the timing mark through the hole. The crank trigger T should be a 1/4 inch or so above the crank trigger on the left side 1&4. Rotate the crank until the F 1&4 is lined up with the timing mark and the crank trigger T should be exactly pointing at the crank trigger 1&4.
If this is off you should pull the valve cover and check your timing.

Did you prime your float bowls before trying to start?

[mbopp]

I'm sorry, you'll have explain what the F 1&4 and "T" is. As well as the crank trigger. I'm assuming it has something to do with the position of pistons 1 and 4. I guess I'm not understanding what I'm lining up with the timing mark through the 'hole'. The spark plug 'hole' ?

Thanks in advance!

[SPARKSS]

Measuring TDC is done through the spark plug hole........it can be accomplished in various ways.....a dial indicator rigged to read the piston as it nears top is one precise way. Another is to use a mechanical stop (this usually takes the form of a special timing tool) screwed into the plug hole.......you bring the piston to an arbitrary point below top and screw down the stop pin (or bolt) until it just touches; make a scribed mark on a convenient crankshaft rotating member (could be either end of the crank)....BACK the crank almost 1 turn until the piston once again contacts and make a second scribed mark......the distance exactly between your scribed marks is TDC - quite precise.
Having said that......for what you're doing, you'd come pretty close with a carefully held rod in the hole.....scribing a mark (or finding your timing marks!) at this point.

That rotor being able to be mounted 180 degrees opposite is suspicious.....if it's not exactly symetrical as to the relationship between the pieces that align with your trigger coils and it's own keyway, then the timing WILL be off.......try it the other way.

[chef1366]

I was referring to the timing marks under the ignition cover. This is the round cover on the right side of the motor. The crank trigger T is referring to the metal T that comes out of the end of the crank and passes by the crank trigger. The crank trigger is the two magnetic pieces the crank trigger passes by. The left crank trigger is for the 1&4 cylinder and the right is 3&4.
Take a flashlight and shine the light through a little site hole at the top of the ignition plate. The crank has three lines. One is T for top dead center for #1 cylinder. Then there is F 1&4 and F 3&4.
When the T is lined up it is either the compression stroke for the #1 cylinder or the Exhaust stroke. During the compression stroke the #1 cylinder cams will not be compressing the valves and the piston is at the top of the cylinder.

[mbopp]

I see what your saying. I checked things out. And come to find out the rotor was on reverse of how it should have been. It was sparking 2&3 when it should have been sparking 1&4. Now.. Starts right up. We're in business! The rotor piece goes on to the advance one of two ways, I just assembled it wrong.

Thanks!

[chef1366]

Right on!.............:-D

[bwringer]

This might help you find TDC...

http://bwringer.com/gs/tdc.html