Electronic ignition not advancing

[Guest]

Hello--

I recently got my '84 gs110gk back on the road after changing the intake boots and O-rings. After a few initial rides, I noticed that the bike won't go past ~6k RPM (guesstimate since tach cable broke). It almost feels like it is hitting a limiter as opposed to fuel starvation. I did some brief searches through the two manuals on bike cliffs site and did not see the method to check timing.

My questions are:

How do you check the timing of the ignition w/ electronic advance with a timing light?

Assuming my advancing pick up is good, is it possible that my cdi, which I replaced once, is going bad?

What are my options if the previous question is true?

[tom203]

If it's making it 6k, the timing is likely advancing- full advance is in 4k range. But check... Does your signal plate have a hole in it to allow you to see the TDC mark on crankcase? Can you post a pic ?

Before you changed intake boots was it reving better?

[bwringer]

Hook up the timing light the same way you would on any other vehicle. Usually there are two clips you hook up to the battery to power the light, then a clamp that goes around a spark plug wire. Start with the #4 (right side of the bike), since it's the closest.

Here's a diagram of the rotor and pickups on a GS with electronic advance:

From this page: http://bwringer.com/gs/tdc.html

Basically, at idle or just above, you'll see the rear of the tab on the rotor (where you see the "F") pass the 1-4 pickup when the light triggers. At some higher RPM, you'll see it trigger at the front of this tab.

Switch the clamp on the timing light to the #3 wire and you'll see the same thing, only at the 2-3 pickup.

Do the same for #2 and #1, and see if there's anything weak or intermittent going on with the ignition on any of the cylinders.

I doubt that there's an issue with your electronic ignition module (it's not a CDI), that would still allow the bike to run but not allow it to advance the timing. Problems with the spark plug wires or boots, or with the coils, are far more common.

And of course it could still be the carbs, or maybe airbox isn't sealed correctly. Hard to tell from just a written description!

Tach cables are pretty cheap -- might as well replace that as soon as you can.

[WilliamGLX81]

I have the same issue with my 81 gs650gl. New carb boots/rings, carbs rebuilt, all new o-rings, valves adjusted, new plugs/wires/wiring, etc. etc.

It hits about 6200rpm and it's like the spark is shut off until it drops down to a little lower. It's just like hitting a wall, and I have no idea why.

Did you get anywhere with it?

[habsdoc]

Sounds like fuel starvation to me.

[SirFoxx]

I have the same issue with my 81 gs650gl. New carb boots/rings, carbs rebuilt, all new o-rings, valves adjusted, new plugs/wires/wiring, etc. etc.

It hits about 6200rpm and it's like the spark is shut off until it drops down to a little lower. It's just like hitting a wall, and I have no idea why.

Did you get anywhere with it?

I agree with habsdoc, sounds like you have a fuel issue. Mine would stumble, but it wouldn't die out. My issue was mainly my air filter. It looked like someone replaced it 15 years ago, and when I changed it, it was literally disintegrating and getting sucked into the engine. If you want to check your timing, hook up the timing light to the #1 plug, and you should see the timing mark move when you rev the motor.

[tom203]

"hits about 6200rpm and it's like the spark is shut off until it drops down to a little lower. It's just like hitting a wall, and I have no idea "

I'd also be suspicious of fuel level dropping in bowls. Lots of new stuff, new petcock? maybe it ain't delivering enough fuel

[JTGS850GL]

Could be a kinked fuel line.

[salty_monk]

I spent ages chasing a "fuel starvation" on my 1000G - Turned out to be a fired CDI. It failed the clymer tests for it. Put in a Dyna S to fix the problem. If yours has electronic advance you might need a Dyna 2000 instead...

[WilliamGLX81]

I thought I'd already replied to the first round of posts to this.

I took apart my mechanical advance last night to check it out and found massive corrosion. It appears that there was some kind of flimsy paper "gasket" that leaked and let LOADS of water into the casing over time. I'm surprised the pickups worked at all. The arms of the advance mechanism were rusted in place fully retracted, which hopefully explains the issue with the RPM limit.

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I soaked the bejezus out of it with WD-40 and it freed up in a minute. I wonder if that's been the problem the whole time. I'll have to clean the carbs to find out for sure though.

[Steve]

If you want to check your timing, hook up the timing light to the #1 plug, and you should see the timing mark move when you rev the motor.

It's actually easier if you connect it to #4, as bwringer mentioned in post #3.

#1 and #4 fire at the same time. The only time you would see any difference is if you have a bad plug wire that is not providing enough of a trigger signal to the timing light.

.

[WilliamGLX81]

One of my friends mentioned that I may need to replace the springs because of the rust. Does anyone know more about this? Specifically if it's necessary and where to find them?

Cheers!

[tom203]

One of my friends mentioned that I may need to replace the springs because of the rust. Does anyone know more about this? Specifically if it's necessary and where to find them?

Cheers!

I got a bunch of these for the 650 shafties, both advancers and signal coils setups on plates. PM me and maybe send a pic of your current setup.

Edit: I just saw your current setup, pitiful... you should stop riding in salt water!