82 GS300L - Right-Side Drop Outs, Bogs, Stalls

[philmotion]

Ok thanks Grimly!

Condensation in a vacuum line is just the moisture vapour present in the air being dropped out of suspension because of the vacuum.
In other words, it's normally part of your engine's daily diet and nothing to worry about - indeed, your engine runs a bit better when there's a bit of humidity.
Only start to worry if it condenses out in the tank and settles along the bottom, rusting the seam out.

[Gorminrider]

Could this condensation, or in other words these water droplets be finding their way into the float bowls and cause the erractic behaviour?

...Any fluids in the petcock vacuum tube have no direct way to get into the floatbowl...the vacuum function is walled off from fuel by the diaphragm ....it'd somehow have to go all the way back via the carb throats, then down through the carb jets...and all that is against the engine's suction t'wards the pistons!

Must be cold in Ottawa to cause this. It should go away on a warm engine.

[philmotion]

NEW DEVELOPMENT:

After thoroughly cleaning the carbs one more time and putting everything back together again, I report still no change = erratic idle in neutral and at low speeds.

I pulled the sidecover of the regulator and ignitor unit side and when pushing and pulling on that entire assembly, i.e. where the starter solenoid is I noticed a considerable change in behaviour and idle!

I tried wiggling individual wires around the RR, battery and igniter. RR seems fine, battery does not cut electrical i.e visibly killing the lights, but in particular when moving wires from the igniter unit the idle changes sporadically and bike even dies occasionally.

This definitely now feels electrical and I would suspect that this is no normal.. My question now is where do I start?

...Any fluids in the petcock vacuum tube have no direct way to get into the floatbowl...the vacuum function is walled off from fuel by the diaphragm ....it'd somehow have to go all the way back via the carb throats, then down through the carb jets...and all that is against the engine's suction t'wards the pistons!

Must be cold in Ottawa to cause this. It should go away on a warm engine.

[roeme]

Called it.

Start by doing a visual inspection: Any wires rubbed through? Charring? Corrosion?

And while doing so, clean connections.

Also you could get a cheapo multimeter and watch the resistance while wiggling. Or generally check if resistances are fine.

Edit: However, if it's only occasional, I wouldn't trust it too much...

[philmotion]

Sure did! Will have a look today. Nothing seems visibly charred, burnt or corroded but maybe there are some loose contact points in some of the connectors. Will have a look and get back to you.

Called it.

Start by doing a visual inspection: Any wires rubbed through? Charring? Corrosion?

And while doing so, clean connections.

Also you could get a cheapo multimeter and watch the resistance while wiggling. Or generally check if resistances are fine.

Edit: However, if it's only occasional, I wouldn't trust it too much...

[fbody_mike]

Great news! The weakest signal in the area will be the one from the pickup coils, follow that wire from the right side of the crank case back to the ignitor module and look for any breaks, especially near where you press and get a response.

[philmotion]

Hey everyone,

Ok, so I started poking around at the igniter unit and the connector where I believe the problem is originating, namely in that it appears to be immediately and obviously more sensitive, meaning any fiddling about in that area provokes a response in idle.

I did clean the connections on both the igniter and the connector, even removing the tabs to ensure they are mating nice and snug. This did help a little, i.e. less sporadic with drop-outs however I mostly noticed that when I

1) lightly put pressure on the entire connector I seem to get more of a response and than fiddling with the individual leads
2) when I depress on a particular section of the gelatin-like back of the igniter, I get a real bog and drop-out

Could it possibly be that the igniter unit is defective? As the igniter is not a box I can easily open to see the components (waterproof gelatin-like backing), I am assuming there is no way to get to it to either fix it or reverse-engineer it and I would simply need to find a replacement?

[fbody_mike]

Unfortunately you've got an ignitor box that is only used on the gs300l. Makes it harder to find second hand and no longer available new. But it sounds like you have a short or broken joint in the box. People have dissolved the potting material with solvents like Xylene. It's an easy choice to make that attempt when the box is completely failed because there is nothing to lose. So for your situation I don't know what to recommend because trying to dissolve the potting may ruin it or may reveal an easy to fix solder joint.
Maybe what I'd do is to find a way to secure the wire harness so that it doesn't move or vibrate when riding so you can stop the bogging. Find a replacement ignitor, make sure it works, then try to dissolve the potting on your current box so you can fix this box for a spare.

[Grimly]

It's not like the ignitor boxes are made of unicorn snot.
For example, the GN250 ignitor box is currently being investigated as a drop-in replacement on the XS650 forum.
It's also a parallel twin.
Depending on the triggering of the GS300, it might be a drop-in for that, too. It would be the cheapest known way of replacing an ignitor I've ever come across, given that aftermarket GN250 boxes are selling on ebay for $25 or so.

The next step up is an ignitor from www.ignitech.cz, which is guaranteed to work.

[philmotion]

Thanks Any danger of dropping in a GN250 ignitor box and seeing what happens?

Also curious if the GS250's ignitor box is the same?

[fbody_mike]

The gs250 has a mechanical advance, and the gs300 has electronic advance. So no, it won't work unless you get the entire signal generator from the gs250 and who knows if the crankshaft shaft ends and covers are the same.

[philmotion]

Damn, thanks Mike. Tempted to open that sucker up and see but I agree with your cautionary advice below. Will hunt around and see if I can find another first, possibly hit up that Czech site that Grimly suggested.

[fbody_mike]

I wonder if the gs500 like the early 90s one might work too. It looks close and they made zillions of those things.

[Grimly]

The gs250 has a mechanical advance, and the gs300 has electronic advance. So no, it won't work unless you get the entire signal generator from the gs250 and who knows if the crankshaft shaft ends and covers are the same.

GN250 box is electronic advance, too.
Further to my mention, there are a few XS650s running well on these boxes with no problems at all.
One or two owners have remarked how nicely they run compared to even their old TCI unit, which was probably showing its age.
As far as the older points-equipped XS650s go, the work being done at the moment is to modify the older generator rotor with a magnetic trigger and make a pick-up mount that can easily be replicated at home (or someone will probably make a batch of them).

So, as it stands right now, the GN box is a simple swap on to a TCI-equipped bike, with nothing else needing done. That got my interest going, as I have a couple of bikes that might well benefit from a cheap easy solution to elderly ignitors failing at some point. Unfortunately, the prospect of simply using two GN boxes on a four-cylinder engine is likely doomed to failure as the built-in advance curves won't be identical.
You can be sure though, that if I had a twin-cylinder bike from Zuk I'd be looking seriously at these.

[philmotion]

Sounds like this might be worth giving it a go. My igniter has 7 pins whereas the GN250 has 6. Any idea on how I would need to adapt the wiring to go 7 to 6 on the GN box?

GN250 box is electronic advance, too.
Further to my mention, there are a few XS650s running well on these boxes with no problems at all.
One or two owners have remarked how nicely they run compared to even their old TCI unit, which was probably showing its age.
As far as the older points-equipped XS650s go, the work being done at the moment is to modify the older generator rotor with a magnetic trigger and make a pick-up mount that can easily be replicated at home (or someone will probably make a batch of them).

So, as it stands right now, the GN box is a simple swap on to a TCI-equipped bike, with nothing else needing done. That got my interest going, as I have a couple of bikes that might well benefit from a cheap easy solution to elderly ignitors failing at some point. Unfortunately, the prospect of simply using two GN boxes on a four-cylinder engine is likely doomed to failure as the built-in advance curves won't be identical.
You can be sure though, that if I had a twin-cylinder bike from Zuk I'd be looking seriously at these.