New member from Scotland

[bigiain]

Hello I've just joined
I've just bought a 1985 55w tenere to replace the one I wish I never sold 25 years ago!
I'll try and put photos on later but it's the red and white one on spotted on eBay with the chair on the front.
It's a non runner with no spark,the plan is to strip it down over winter and put it back to standard.
I've taken the seat and tank off ,and the wiring is all there and looks not bad.
I know it's probably been asked before but here are some daft questions.
The battery is a bit flat (the horn is weak) would this stop it sparking?
The neutral light switch isn't connected
Can anyone give me an idiots guide of what to check
I have a multimeter a test lamp and a kettle!

[Mezo]

Welcome

Its late here for me (aussie) and im half asleep.

Mezo.

[ActionManMelb]

First up, a battery is not required for spark on your model.

Quick first test is to remove the tank and locate the cdi box under there.
Unplug the B/W (black with white stripe) wire. This wire is used for the IGN on and kill switch functions.
When it is unplugged and not grounded the CDI is active.

Remove plug from cylinder head and kick the motor over with the plug in the HT lead and touching the head.

If you have spark.....
If not.... report back for more tests.

[bigiain]

Thanks
Unplugged black and white wire.
Still no spark

[steveloomis]

Does your bike have a side stand switch? If so, trace the wires up till you find the 2 plugs. Are they still plugged into the wiring harness? If the Side stand switch is missing, did it have one? Look above towards the wiring harness and see if two wires are plugged into each other bypassing the function. If so, then that is correct, cdi thinks side stand is always up. If your cdi an OEM unit, yamaha part number etc. Probably original and faulty.

Are you handy with a volt meter? If you have one, put it on the AC volt setting and select 20 volt or what ever scale is close to it.

With plug out for easy kicking, unplug wires going into the stator on left side of engine. There are 3 sets of wires, the two white wires are the charge wires for the voltage regulator, we don't need these, there are two wires with bullet connectors. They should be red and brown or will have a small sleeve on each wire that is red on one and brown on the other. These wires are the charge wires for the CDI and are what power it. Unplug the wires and insert the ac voltmeter into each wire from the stator, no matter which. You are going to measure AC voltage across the two wires, not each wire to ground. When you have the volt meter attached, kick or have someone kick over the engine briskly. You should see a good voltage kick on the meter. An analog meter is easiest to see this, but a digital will show it too. It is not important how much voltage you see, just that it is a good up swing. If this is ok, we move on to the trigger coils.

Trigger coils are connected to the plastic plug and wire colors are white/green white/red and green. Connect AC voltmeter between the white/green and the green wire coming out of the stator. Same drill, kick briskly and you should see a kick in voltage but probably not as much as the charge coil. Then check the other side of the trigger coil the white/red to green. If you get good ac voltage kicks out of all three coil sources then your stator is most likely OK and the CDI is dead.

If you are not getting any AC kick out of any coil but others are then it time to check with an ohm meter and check for broken wires. Let me know if you need additional assistance. Additionally, look at the stator coils to see if any are discolored, usually very dark if they are burned. The last person I assisted with this had a bad stator coil and a neighbor had a rebuilt one, solved his problem.

Steve

[bigiain]

Thanks Steve
My bike doesn't have a side stand cut out switch or the wiring for it.
I've put my multimeter on the red and brown wires but there are only 2 ac volt settings 600 and 200
I tried 200 it's a digital meter and doesn't register when I kick the engine over
Will I try and get a meter with a 20 setting ?

[steveloomis]

Yeah, a 200 volt scale is a bit high. None of the kill functions will affect your readings from the stator as the kill is just a ground to the CDI unit. How many wires does you CDI unit have. I think there are 8, 10 and 11 wire versions. The USA model uses the 11 wire. No side stand versions is 8 wire I believe.

[ActionManMelb]

From here on you need a fairly high level of electrical knowledge.

You need to study the wiring diagram for this engine and do basic resistance tests on the two pickup/firing coils and then the stator windings.

If these check out OK, then it is very likely the CDI has failed. (common problem).

See if you can find a mate or someone more local on the forum to loan you a substitute CDI to test.

[bigiain]

Thanks guys , I appreciate the help.
Sorry for boring the arse off you but here goes.
The cdi has 8 wires
Orange
Black
Black/white
White/red
White/green
Green
Red
Brown
My mate is coming round tonight with his multimeter and a few beers. We will try the tests Steve.
What I did notice when poking about was the coil has a big split in it,looks like it has burst open and melted slightly.
I've ordered a new one. What would cause this,just age?
When my 16 year old son comes home I'll get him to put up photos as I've not got a clue!
It wouldn't know a photo bucket from a flying saucer.

[Mezo]

When my 16 year old son comes home I'll get him to put up photos as I've not got a clue!
It wouldn't know a photo bucket from a flying saucer.

Your funny

Yep you need to open a Photobucket account (or similar) we do not host pics on the forum (even me) you load them up on PB & then you can share then anywhere.

Melted CDI sounds like your problem, but before you spend any money just go through the suggestions the lads are pointing you at.

Invest in a decent meter.

Mezo.