'83 XL600 very weak spark

[SnS]

So weak I almost have to turn the lights off to see it.

Is there a usual guilty culprit that I should look for before I get in too far?

[patuca]

How it looks with the bike not running and cranking it over might not be a weak spark at all.  The question has to be...how does it run?

 

patuca

[SnS]

How it looks with the bike not running and cranking it over might not be a weak spark at all.  The question has to be...how does it run?

 

patuca

Once it's running, fine.

But to start it cold, I can kick till I'm blue in the face and I'm lucky to get a sputter out of it.

It used to start in 2 kicks, now it's more like 200

[patuca]

But if a CDI bike runs normally after it's started it's a real good indication the CDI is working fine and some other factor is keeping it from starting.  I would spend some time on the carbs, check the valves, put a new plug in etc.  

 

patuca

[Qqqqqqqqqqqq]

Yeah .. The fuelling is where I would start .

[BruceD_500]

I'll bet someone has replaced the stock soft silicone plug cap with a hard black plastic NGK resistor plug cap ???  Mine used to eat these resistor caps.  Mine also used to need the crank pick up changed occasionally.  

[SnS]

I went and got another new spark plug and it starts fine now...

I had tried used and a couple of new spark plugs before and just bum luck they were all bad.