Poor Spark/No Spark

Hi all

I am doing up a 1982 XJ550 and I have been trying to make sure I even get spark when it turns over before I start pulling the Carbs apart so that I can get this thing firing.

Let me start by saying that electrics are not my speciality and I panic at the thought of using a multimeter/voltimeter.

I checked all the wiring and earths etc and they all look fairly good. But when I get it to turn over, I can see a slight spark when I take the plugs out and earth it to the engine.

I have been reading up and it says that I should pull the clutch in when testing this, but as with my other bikes, it won't even turn over if I don't pull the clutch. This DOES turn over, but the spark is either low, or I can't see it (Depends on the lighting in my back garden).

So here are my questions:

As it doesn't have a working clutch cable yet, should I jam the button in and see what happens?
Should I be looking to replace the CTI?
Should I be checking the coils (remember I am an electrics novice)?
Is there anything I could have missed?

All I am looking for at the moment is a nice strong spark because I think the carbs are so gummed up that there is no real fuel getting to the chambers (plugs are new, but remain VERY clean), preventing any firing at the moment. I will be putting kits through these as I think the float valves may be jammed.

Ok, so thank you in advance for any help and I look forward to helping you all in return one day.

 

Try doing a spark test without one of the plug caps. They unscrew from the wires. If you get a better spark then replace caps.

 

If you have even an inexpensive multimeter, you can check plug cap resistance (they unscrew off the end of the wire). Believe it should be 10Kohm on the XJ550 (at least on my '83 it is). I had one plug cap read infinite resistance, not passing any current on the multimeter. As a result, it had a real weak spark. You can get replacements caps from Chacal (Xj4ever).

I replaced all of mine for good measure.

 

Have already replaced all the caps and tried the uncapped thing. It was still weak.

Will try to find the meter but any other ideas are welcomed.

Any thoughts on the clutch button idea?

 

what kind of 550 do you have? does it have dual disc brake?
does your vin have this code in it?
550's:

1981-83 XJ550 Maxim USA: 5K5
1981-83 XJ550 Maxim Canada: 5K6

1981-83 XJ550 Seca USA: 4U8
1981-83 XJ550 Seca Canada: 4U9
euro MODEL ID CODE: 4V8
first do you have a repair manual if not start a conversation with me.
this link is where you need to start
How to Use a Multimeter and Read Schematics and Wiring Diagrams.
ohm out your ignition system
specs in this link
The Ultimate Relay, Switch, Sensor, and Diodes Guide
you need to test your charging system with bike running or confirm fully charged battery to start bike with specs in above link

clutch safety switch with bike in neutral if switch isfdisconnected bike will start or put a jumper wire across the connector inside the headlight bucketbe careful bike will start in gear if you jumper the connection

clean our carbs
IN THE CHURCH OF CLEAN

THE SECRET LIFE OF CARBURETORS

Something New, Something Naked

contact me I have a carb cleaning book I can send you for mikuni carbs

 

What's the age of the battery?

My guess is that the battery is too weak

 

only take out one plug at a time to look at the spark. the spark goes through two plugs, both plugs need a good ground.
even then the spark might not look as strong as you're used to seeing. my lawnmower has a bigger spark that my xj