Coil swap 650 to 850?

[Missile99]

Okay. I didn't see your reply before my last post. So far so good. The test light should have flickered on and off while you bumped the starter. Did it?

Are you checking for spark by laying the plugs on the head? If the plugs are blackened at all they might be insulated by the buildup and not grounding on the head when testing. You should have at least a faint spark. You can hear it even if you're not able to see it well.

Have you pulled the plug caps off to see if there's any corrosion on the wire? Snip off a bit to expose fresh wire if so. I'm wondering if when you tested the coil resistance with the meter that the leads reached to a clean spot. Make sure there's no corrosion in the plug cap or on the spark plug.

[GSNewbie]

Gonna try a new set of plugs...

Today I put the GS650 coils on the GS850.
I just put a plug for another bike in the cap and got some spark. I think I'll go get a full set of plugs and try again.

I couldn't get any spark through the old plugs.


I did see the lights go on and off when testing wires coming from the points (white and black) with the test light.
They are getting 10.09vdc on each cycle on the wires coming from the points.

Are you checking for spark by laying the plugs on the head?
Yes. Also tried the spark indicator light I have for checking spark through the wires.

If the plugs are blackened at all they might be insulated by the buildup and not grounding on the head when testing. You should have at least a faint spark. You can hear it even if you're not able to see it well. Could be an issue but doesn't seem to be

Have you pulled the plug caps off to see if there's any corrosion on the wire? Snip off a bit to expose fresh wire if so. I'm wondering if when you tested the coil resistance with the meter that the leads reached to a clean spot. Make sure there's no corrosion in the plug cap or on the spark plug.

This was in my last post. I removed 1/2 inch of wire and re installed the caps.

[Missile99]

Today I put the GS650 coils on the GS850.
I just put a plug for another bike in the cap and got some spark.

Sweet. Let's hope new plugs solve the problem. It is still unlikely that both coils have died.

This was in my last post. I removed 1/2 inch of wire and re installed the caps.

Oops. missed that. Okay. At least it's narrowed down to the coils/plugs/wires. What's nice about the points ignition is it's direct to coils instead of through ignitor. One less thing to have fail.

Keep us posted and good luck.

[GSNewbie]

WooHoo!

THANKS!!

It was the plugs!!!
(or at least that was the last straw)!
I ran the bike tonight and am surprised at how smooth it is running... I am running techron through the fuel and we'll see if I rebuild the carbs or just look for the head and cv carbs.

If I can find carbs, head, airbox boots for the right price, they sound like the way to go...


Gonna ride it tomorrow and see if I can shake some bugs loose. It was last plated in 2009 but I'm betting these carbs haven't been rebuilt proper...

I'd rather get the hp and only mess with fixing carbs and buying one set of airbox boots etc.

[Missile99]

That's great news!!
Did you leave the 650 coils on? Are the ones from the 850 shot?

A nice ride on a Monday sounds good. If this Tropical Storm would give me a couple of hours without rain/wind I'd burn off some petrol too.