After lots of repair, (seemingly) no spark or starter functionality

[Guest]

Hey everyone, I haven't posted in a while because I had to put the bike on the backburner for a bit. Back in December(?) I got a 79' GS850 that had been sitting for four years. In the past few weeks I've rebuilt the carbs, cleaned the airbox, changed the motor and gear oil. I've also replaced all of the o-rings and gaskets on the carb, boots, and head. I also have a brand new battery.

Mechanically, this was fine with the help of this forum and my manual. Electrical stuff is not my jam.

When I turn the bike on, the lights and everything turns on with it but I am unable to get the start button to do anything and I can really figure out if I'm getting spark. When I manually move the points they spark for a split second, and they move very slightly when I turn the engine over, but its really hard to tell if they're doing anything when I'm trying to kick it. Additionally, my plugs and heads are bone dry after trying to start it and I can't really tell if they're getting any spark.

Any help would be greatly appreciated, and even better if you're in Portland, OR and can come take a look at it.

Thanks in advance.

[giganticflying]

I guess my main questions are:

How exactly would you describe how you test to see if the plugs are getting spark?

How do you test to see if the engine is getting gas? (I slightly unscrewed one of the float bowl drain plugs and a little gas came out so its at least getting that far)

I once came across a guide on stuff I should do with the points/condensers but I can't find it again, anyone know where that is? Should I just go ahead and spend the twenty bucks to replace them?

Why would my start button not be working? Is there any way that my kill switch might be stuck to off? All wires look fine inside, nothing is loose or touching the handlebars.

[giganticflying]

I have a somewhat educated feeling that if the tops of the pistons and the plugs are still bone dry there is no gas/air mixture getting to the engine, is that just another carb do over?

[giganticflying]

Not to just process my thoughts to myself but I've done some jostling and found that after a couple of cranks on the throttle, and leaving the choke cable up, I can get a kind of kick back everyone three to four kicks on the kickstarter. After feeling that I checked all the spark plugs and all but the #1 are bone dry. #1 is blackened and has beads of some kind of fluid and the top of the piston appears to be a little moist! Also, I got the electric start to work (didn't know I had Hopefully someone can chime in with some advice to speed up this process, I'm done for the night.

[tom203]

So your starter is working now,it cranks, but does not seem to be much fuel passing thru carbs. Maybe your "choke" circuits aren't clean enough. You did put petcock on "PR" to refill bowls,right?
look for spark as in steps 1 thru 10 of this link (ignore signal generator stuff)

http://members.dslextreme.com/users/storagecliff/images/electrical_odd-n-ends.html#A17

[giganticflying]

I did set the petcock to prime. I'll run through those steps to check out the spark today. I'm still worrieed that the all the plugs and the tops of the pistons except for #1 appear to be dry, though.

[Steve]

... and found that after a couple of cranks on the throttle, ...

If you are "cranking on the throttle" while the engine is stopped, the only thing you are doing is exercising your wrist.

There is no accelerator pump on those carbs, so you are not adding any fuel to the mix when "cranking on the throttle".

Usually, the recommended procedure is:
- ensure the float bowls have fuel, use PRIme, if necessary
- apply full "choke"
- turn key ON
- pull clutch lever
- push starter button or use kick starter
- modulate engine speed with "choke" control

Did you notice that NOWHERE was the instruction to move the throttle, or even to touch it.
If you are using the "choke", do NOT touch the throttle.

.

[giganticflying]

Is cranking the throttle detrimental to the bike?

[tom203]

No, but it doesn't let " choke" do what it's designed to do- enrich things during cold start.

[Steve]

Is cranking the throttle detrimental to the bike?

If the engine is not running, cranking the throttle does nothing but exercise your wrist, as mentioned before.

If the engine is cranking and you are using the "choke", you are defeating the "choke".
That will make it harder to start and will just drain the battery and wear out the starter.
If you are using your kick starter, you will wear out your leg.

If the engine is already running and will accept some throttle cranking without bogging out, it's ready to go have some fun.

.

[giganticflying]

Ok, so no cranking the throttle. Regardless, I still am getting some kind of firing in in the first piston, but nothing in the other pistons. I'm also getting some kind of kick back when kicking the kick starter, about every three to four kicks. I guess it seems more like a fuel issue at this point, but you have any other suggestions I'd appreciate it. Diving into timing and back in the carbs soon.

[giganticflying]

By firing I mean when I pull the plugs after kicking for a while the #1 plug top is black with a little fluid on it but the others are still clean.

[tom203]

First check for spark at plugs (that link I posted before). Got spark ? Then assuming timing is right. (since you didn't take engine apart), then you need fuel at plugs. With "choke on", after some cranking or leg work, you should see signs of fuel at spark plugs which apparently you are not. Remove air filter element and block air intake with something that carbs can't swallow, like a fat hand, cover, etc..Idea here is to restrict air intake, so when you crank it more suction is put on "choke" passages so more fuel is pulled up into carb throats and onward to pistons. Try this and see if you see signs of fuel on most of spark plugs after a little cranking/kicking.
Also,sometimes after carb work, the throttle plates are left too open interfering with "choke" operation. Try backing off idle stop screw (between 2 and 3 carbs)- this closes plates across carb bores.

[81GS850]

Try starting fluid. See if it fires off. If it does keep spraying a little bit to make sure it's running half decent. If you can't get it started of starter fluid then somethings going on with the electronics. Check for a strong spark. I would cut half an inch off the plug wires and screw the plug boots back on to make sure you have a good connection there. First I'd make sure your ignition system is good then move to the carbs.

[giganticflying]

I will check for spark per those steps. If I do use starter fluid, should I spray it into the airbox or should I take the airbox off and spray directly into the carbs?