Power to the Coil

[Paul75]

Guys

Would anyone know if there is a way of testing if I am getting power to the coil? I have a spark to the right plug but not to the left. If I am getting power to the left coil then I will know if the coil is dead or not.........

Many thanks in advance!

 

[MaxPete]

I think you just need to test for 12V on the double red-white connector that is located under the fuel tank Paul.

I suspect that you ARE getting power to the coil - but your high voltage connections may be dirty/burned/corroded or simply weak - and so I'd be checking there.

I wrote a note on how to service those HT (high voltage) terminals and I've clipped it from the other thread because, my guess is that your actual coil is OK. It likely just needs to have the terminals cleaned and a new plug wire installed.
-----------------------------
The high voltage (aka high tension or HT) terminals in the coil and the spark plug cap are tapered screw-on terminals with a rubber grommet and a threaded cap to keep it all together.

On my bike, one of those connections was bad, which caused a cylinder to drop-out. Here's how to fix it:

1. Unscrew the cap over the bad cylinder HT lead on the coil;
2. Remove the HT lead from the coil (you may find that it simply falls out);
3. Trim off a few mm (say 1/4 inch) of the end of the lead to get a fresh connection;
4. Remove about 1/4" of the HT lead installation - and spread the conductors out radially on the end of the lead (see the photo below - courtesy of 5Twins);
5. Reach down into the shrouded terminal on the coil with a smal wire brush and remove any rust/crap on the terminal screw;
6. Put a little dab of silicone ignition system sealing grease on the lead;
7. Insert the lead until it touches the terminal screw;
8. Now rotate the lead while pushing it in to screw it onto the terminal;
9. Turn it....maybe...4-5 revolutions until you gently feel it bottom out (the terminal end is tapered - it looks a lot like the end of a wood screw);
10. Now simply thread the cap back onto the coil and tighten the cap BY HAND - making sure that the grommet is back in place along with some of that dielectric ignition system grease to keep water out of the connection;
11. Repeat the entire process on the spark plug cap - it uses the same type of tapered screw connector - and don't forget the dielectric grease.

Here is 5Twins photo of how to prep the end of the HT lead prior to screwing it onto the coil terminal.

Here is a photo of a screw-type HT terminal on one of an ignition coil. I got this image off the web.

I did this operation on my '76 XS650 Standard and it worked like a charm at preventing cylinder drop-outs.

Cheers,

Pete

 

[Paul75]

MaxPete thanks so much for your detailed reply...... I'm going to take the coil off tomorrow and take another look at it, I remember when I fitted it there was slight corrosion on the terminal screw thread which I thought I'd cleaned up pretty well but maybe not enough.....I also remember testing the coil with a volt metre at the time to see if it was ok, it was but I cannot for the life of me remember how I did it!!

Do these screw threads act as earth?

 

[TwoManyXS1Bs]

...Do these screw threads act as earth?

No. But they do act as a thermal sink...

 

[MaxPete]

No they don't but as noted above, you need to ensure that there is no rust, paint, salad dressing etc. on those coil mounting pads.

The earth (ground) portion of the high voltage circuit is the spark plug screwed into the cylinder head itself.

Let us know how this works!

Cheers,

Pete

 

[5twins]

When you screw the cap back on against that rubber ring or "doughnut", that's what does most of the wire holding job. The rubber ring compresses and pinches against the wire, holding it into the coil. So, slide the rubber ring up snug to the coil after you're done "threading" the wire in, then tighten the screw cap against it.

 

[Paul75]

Thanks all, I've just taken the coil off the bike and cleaned up the terminal screw again, this time with the Dremmel and a very small wire brush attachment. I then cut off the old connectors and put on fresh ones. I'm now getting a nice strong spark so thanks again! My next issue is when I hit the starter button the bike will turn over but only intermittently. For example it will turn over on the 1st press of the button then on the 2nd and 3rd press of the button it will sound like the starter motor is just spinning up and not catching........I'm learning all the time so any help is appreciated as always guys,

Paul

 

[XSLeo]

Could be a weak or poorly charged battery, the starter needs everything the battery has to offer. The starter push button may be dirty, poor grounds on the handle bars. Low voltage on the red/white wire at the starter relay, some call it a solenoid, poor/dirty connections on the battery to the starter relay, same for cable from relay to starter.
Time for some cleaning and voltage testing.
Leo

 

[5twins]

..... or it could be the notorious #4 starter gear .....

 

[Paul75]

I've just done a little reading up on this #4 starter gear fix before I head off to work, it sounds exactly what it is.... :-(

There is a fantastic thread called '#4starter gear fix' with images but the images are not viewable (something to do with photo bucket), is there any way of making them appear?

 

[MaxPete]

If you check my recent thread "'Build Thread 81 Special to Cafe" I did the #4 starter gear repair, complete with photos. I think it will get you though the task.

It isn't a tough job really - just a couple of a little tidbits to know about AND for goodness sake - DO NOT install a starter gear with a hairpin / wishbone slip force of less than 7-8 lb and more is better (this simple measurement is fully explained in the thread).

Like everything else on MamaYama's 650, this job can be done by mere mortals without mortgaging your house for special tools etc.

Pete

 

[Paul75]

Thanks Pete, I did read your excellent thread on this before I started it. I only managed a force of 7.5 pounds, I'm going to try it. Question, I have the cover and clutch removed, if I take the plug caps off can I hit the starter to test it at this point?

 

[TwoManyXS1Bs]

Have a look thru this:

http://www.xs650.com/threads/testing-my-starter-gear.43623/

 

[Paul75]

Can I still ask the question, I have the cover and clutch removed, if I take the plug caps off can I hit the starter to test it at this point or should I screw the clutch back on?

 

[5twins]

Yes, you can test it, but if you have an electronic ignition, you need to ground the plug caps or you could damage it.

 

[Paul75]

Just running points 5T.....

 

[xjwmx]

not viewable (something to do with photo bucket), is there any way of making them appear?

There is a fix for Chrome and a couple of posts lower for Firefox too. I think it ought to be stickied with a big headline
http://www.xs650.com/threads/photobucket-big-changes.49818/page-4#post-518240

 

[Paul75]

Just hit the starter....perfect result!!! No slipage!

 

[MaxPete]

Whiz bang Paul!!!

 

[mrtwowheel]

I'm going in there for the same fix soon, will be interesting to see what shape that gear is in. I see now that the upgrade clip on wishbone is heavier grade, but if this fix needs to be repeated after a while anyway, I don't see a big difference in which one is used.

There is some difference of thought as to if it should be pinched on, or off, of the gear. I would think that OFF of the gear would give it a more permanent and easier set.

Scott