Spark Problem, please help

Greetings:
ust got my first bike. Wife finally left me. It is a bit of a project bike. 1982 XJ 750J. It is turning over, getting gas, but only have spark on the left coil feeding Cyl 1 & 4. No spark at all on the right feeding 2 & 3. I have determined so far that it is not the coil. As I moved it to the other side and it worked fine. I got a new CDI/ignitor off ebay and it does the same. So I am thinking it might not be that. It appears that the wires are good because they show continuity when hooked up to the meter. What in the world could it be?

I really appreciate any help you can give. I am very excited to have it running and taking it out for my first ride.

If one is local, I live in Annville, PA near Lebanon Valley College.

Thanks, Jason

 

Jason, welcome to the forum. when you say you switched the coils, do you mean you put the coil for 2 & 3 on 1 & 4? Also, are the plugs new? Sometimes plugs can go bad & just won't spark.
Gregg

 

Thank you for the quick reply! Theay are not new. I will check I will move the ones sparking now over to see if anything changes. I think I might have done this already and they worked. My frustration right now is making things a blur. Will.let you know after dinner.

Thank you,
Jason

 

If you did switch your plugs around before & they worked, sounds like your problem will be solved with new plugs.

 

Hello. Switched the plugs around and they wrok fine. So I'm still at the mind boggeling issue of just coil not getting it's signal to fire. I did check the wires and they are receiving the 12 v.

Thank you,
Jason

 

Hello:
Strangest thing. I am now getting spark from the coil but only very intermittent. I might get 16 sparks from cyl 1 and then 1 spark to cyl 2. Any ideas?

 

I did and the ones that weren't firing now do. So I'm thinkg the plugs are working.

 

Check the pick-ups under the left motor cover. Do you have a manual of any kind for this bike?

 

I am waiting for the manual to arrive in the mail. Dumb question...what are the pick-ups and their function. Is there a way to test these pick-ups?

Thank you,

Jason

 

Remove the left side cover. You will see 2 coils - those are the pickups. The part on the end of the crank has a magnet. As it rotates the magnet causes a slight voltage in the coil This tells the TCI to fire the main coil when it detects this signal..

 

Thank you. I have a parts bike. (Got them as a pair.) I'll pull them apart in the AM and swap. I'll let yous know.

Thank you all for your help. It is very much appreciated.

Jason

 

Good Morning:
I just pulled the cover off and see the pick ups. I take it this is what works like the distrubtor, points and cap to a car. Anyway. Everything is very clean in there. I put my volt meter on the two feeds to my cdi from the pick ups to see what happens. The coil on the left that is working has the orange wire, and when I hit the start to crank over it makes my needle drop/pulse showing it is using the voltage. When I move it over to the grey wire which feeds the right coil that is not working, the needle does not drop at all, but it is showing full current. Does that mean the pick up is not working? Like it is not sending a signal to the CDI which would make the needle gradually drop/pulse showing the voltage usage? I can't wait for the mail for my book to arrive!

Thank you, all your help is very much appreciated. I am very excited to get out on this bike.
A buddy of mine has an '84, 1000. Awesome bike but he has no idea on how to work on them. I enjoy learning this. He just wants to ride. Don't blame him.

We are going to head out to the local bike shop around lunch. My wife's friend's family owns it and they are having an open house with a show and stunt riders. The kids will love it!

If you are local it is Lebanon Valley Cycles.

Again, thank you.

Jason

 

The pickups generate a signal like this when the reluctor passes them:



This is pretty hard to read with a meter; you more or less need a scope.

If the VR pickup is the problem, then swapping the orange and grey wires at the TCI unit should swap the "reliable" spark from one pair of plugs (one coil) to the other (of course, also resulting in timing that 180 degrees out of synch, but useful for testing purposes).

 

Probably not the best thing...but I put a jumper connecting the orange and the grey, and I got consistent spark from both. It looks like a bad/worn out pickup..?
Thanks!!!
Jason

 

These are a pain to take off! The lower screw on both bikes are on way to tight.

 

Frozen fasteners are the bane of all of us. Impact drivers and good penetrating oils work wonders.

Sounds like you located your issue not you have fun of making the repair. let us know how it works out.

 

Thank you. This my first bike and I think if I get it running and it sounds decent, I'm gonna attempt a full rebuild with powder coating and nice paint. I like the style of this bike. This is a great internet site with great memebers. Thanl you all for your help and hopefully I'll have soon news posted soon!

Jason

 

Penatrating oil ... heat ... impact driver

 

Good Evening my new Xj friends.

I hope all had a good weekend. Mine went from good to bad to good to confusing.

I removed the pick up that looked like was giving me a problem. I spliced one from my parts bike on to replace it. Now my all my wires show current but I have no spark to any plug. Do you think this could be the cause of a bad/weak ground? Was it wrong to cut and splice a different one on or do I need to replace the whole pick up unit/assembly? I have not tracked all the gorunds down to clean them up yet. I think that is my next task.


Have any of you experienced anything like this issue before?

Thank you,

Jason

 

Greetings:
So my grounds are clean and secure. Still I am now not getting spark at all. Is it wrong of me to splice a different pick up on? I don't see why that would cause a problem. Also, I am doing this with the kick stand down. When I put it up, same problem. So I have another problem with the kickstand safety relay. But, if I have read right on other posts, if the kickstand is down it shouldn't even crank over, like mine currently does.

So I am still stuck on this ignition/spark issue. After all the talk about the pickups and checking everything else I thought that has to be it. Especially with the voltage/pulse thing I found.

Any more suggestions/insight would be greatly appreciated?

Thanks,

Jason

 

I'm in the same boat basically. The last thing on my list is the pickups too, so I'm checking them wed. and hopefully thats my problem and not my tci.

 

Let me know how it works out for you. I'm kind of lost at this point.

I think I'm going to have to start at square 1 again and just trace and clean everything again.

 

will do. yeah me too, I might even take out the harness and use that barebones harness diagram on the forum to eliminate alot of BS parts.

 

Is this your first Yamaha Max?

 

Do you have an analog multimeter Jason? Use it on the dwell setting to look for an output pulse from the pickup coil. If that is confusing, try using a voltage reading and turn the engine by hand and watch for a voltage spike. If you find the pulse as the reluctor passes the pickups, your pickups aren't bad. Look for the pulse at the TCI box (orange and grey are your inputs, black is the return for both). If you are getting the pulses there, you need to look for pulsed 12VDC (or close to 12vdc) at the coil plugs. If no voltage at coils, the TCI is unhappy. Clean it up and try again. If you do have 12VDC, you need to ohm out the coils. If you swapped the coil plugs and the 2&3 set fired, your coils are good. If they didn't, you need to fix or replace the coils. There are quite a few threads on how to recondition/repair your coils, do some research. Let us know what you find out.

 

yeah Its my first. I've only had dirtbikes.

 

Yes. First bike period. Wife finally gave in. Kids can't wait to hear it run. Me too.

 

Good Evening,

Thank you all for your help. It's got to still be the pick ups. I got the pulse on one side but not the other. Even with splicing in pick ups from my parts bike (they must have also been bad, they were reall rusty) I only get one side.

So I have found some on ebay. Only issues is that they say they are from an '82 Seca XJ 750. Will these work fine one my XJ 750 Maxim? Didn't know if they were pretty much the same or not. My repair manual doesn't state a difference.

Can I use them?

If so, I will try to get them for the weekend to give it another try.

Thank you all!

Jason

 

Before you close the book on the ones you got.
Check:

Folo the wire out the cover ... to the front ... remove the "Holder" and look to see that the wire isn't >>Pinched<< by the Side Cover ... grounding it.

If the Pick-up's wire got pinched when the PO did a gasket or deal ... the Pulse generated at the Pick-up Coil never gets to the Igniter.

 

Thank you Rick.

I will remove it and check it for any pinching. If I recall, one of the tests my buddy did over the weekend was tested each wire with a voltmeter to make sure the weren't shorting. He said all the wires appeared good.

Will splicing them in cause an issue?

Thank you.

Jason

 

Splicing is fine, make a good soldered joint & use heat shrink casing.
I had the same problem as you with the Kawasaki I am rebuilding, it turned out the auto advance had rusted & moved on the spline, I changed out the pick ups & the igniter, but wound up using the original igniter & spiced on pick up coils, with a replacement auto advance.
So if you have more than one problem / faulty part, you can chase your tail until you nail it down. Keep at it & good luck.

 

The Maxim and SECA pickups should be interchangable.

 

Not if you make a good solder splice and Heat Shrink it from grounding-out.

Put two Diameters of Shrink on the at the splice.
Shrink the Inside one to secure the splice.
Shrink the outside one to prevent damage.

 

Open up your TCI via the screwed on cover and check your circuit board for any bad/broken spots. thats what I found my problem was. put a drop of solder on it and it got spark now. heres a pic of my bad spot

 

Nice picture.
Very good illustration.

But, you're more likely to need a Magnifying Glass or a Jewelers Eye Piece to closely examine the Board for a hairline crack.

Use good light.

 

That is amazing, Blackout, I have never managed to see damage like that on a goosed PCB.

 

yeah it was hard to see at first. it was just a hairline crack in two places and when I touched it with a screwdriver it broke off like that.

 

So the wires that come from the pickups to the CDI should show 12V. Correct? Then when I would turn it over and the plate would pass each pick up it would cause a "disruption" and cause the 12V to pulse.

What gives the pick ups there 12V? Where should that be coming from? The CDI or does it have to do with being screwed to the plate that is attached to the alternator?

I'm not getting 12V to my pickups. Only like 1.5 - 2 V.

If I can figure out where they are to be getting their 12V. I might be on track to my problem (or just another one).

When I take off the cover to the CDI and touch a ground to the pick up side orange or grey, I get great blue spark from my plugs.

Oh Yeah, I just bought new plugs. So I can now rule them out from any issue.

THANKS!
Jason

 

Looking at my factory manual, the pick-ups get 12V from the TCI. 12V from battery goes through main 20A fuse to main switch. From there through 10A ignition fuse, then to engine stop switch, and on to safety relays, TCI, and ignition coils. Power to TCI is by the red/white wire, which should have 12V if main and engine stop switches are both on.

Pick-up coils should measure 700 ohms plus/minus 20%. I would make sure that you have 12V to the r/w wire to TCI with key on. Next check for 12V on orange and grey wires to pick-ups from TCI. If no or low voltage is noted, try unplugging connecter and measuring right at TCI. If 12V is found at that point, you have a poor connection somewhere down the line.

If still no 12V, bad TCI. If you can open it up, you may be able to find a poor solder joint or connection.

I really hope you can get this going! Mike

 

I'm following this thread too, same problem. I guess the reason nobody responded to my thread was they were over here. :cry:

 

No, there is no 12V to the pickups. The pickups are passive devices. They are coils wrapped around magnets. When the reluctor is dragged through their magnetic fields, it induces current flow in the coils. As I mentioned before, the signal looks somewhat like this:

 

SQLguy, you are correct, of course. It is the ignition coils that get 12V with the main switch on, and the TCI is triggered by the pulse induced by the reluctor passing by the pick-up coil.

Sorry for the confusion I've caused. I'll just go over here and shut-up now.

Mike

 

Ok. So all hot wires and grounds on the side that feed the box and ignition coils show good and 12v.
My ground is good over on the pick up harness side. No pulse when turning over. I do however show a little current on their o & g wires.I ordered the ebay pick ups last week and hope they arrive monday. They supposedly came off a running bike. Once I put those on I should know for sure if it is a pick up issue.
I just thought I was supposed to be getting 12v to the pickups via the cdi and then the maganetic pulses were to interupt it

 

So, does the left side represent the initiation, and the top of the wave the peak current flow?
Very scientific too, but I can't find a scope in my garage. 8)

 

Basically, the voltage spikes up when the leading edge of the reluctor "tooth" passes the pole piece of the pickup, and curves down when the tooth leaves the pole piece.

This shot is a bit deceptive, because it's one I took after installing my home-made 36-1 wheel in place of the original reluctor. The original waveform looks similar, but with the spikes much further apart and not evenly spaced.

My main points are that:

1. There's no 12V DC at the pickups and

2. You're not going to be able to recognize a "good" signal from the pickups with a multimeter set on DC. You may be able to tell good from bad with a meter set on AC.

In general, though, swapping pickups is going to be the best way to tell if one is bad; since it's very unlikely for both to fail at the same time.

 

The SPEED at which the Crankshaft Rotor passes before the Ignition Pickup is:
PULSE WIDTH

The Pulse Width is the Signal that the TCI uses to electronically Advance and Retard the Ignition Timing.

 

Good Evening:

Thank you to all for your help. It was the pick ups! I got ones off a seca and it fired up! Unfortunately she did not stay running. But, I already knew the carbs need rebuilt. So I have a veteran carb rebuilder on my side who will be taking care of them for me.

So this means I will pull them off this weekend. And start cleaning everything else up. I got everything for the oil changes and brake pad replacement. I will paint the tank and get the seat recovered.

Hopefully it will be on the road to inspection in a few weeks!

Again thanks to you all for your help.

With all I've gone through so far with this bike with my buddies helping and getting my son greasey with it, and the crap my wife gave me, and the new friends I've made here. It'll be a keeper. So it just may get the full rebuild with powder coating and custom paint this winter.

Pics to follow soon!
Jason

 

Do yourself a favor, go watch the verteran do his thing so you can do it next time.

 

Jason,
Did you use the 'Set' from the Secca? Page 146 in the Haynes manual says they can not be replaced individually.

It was killing me to read through those 4 pages waiting for someone to say it!

Anyway, good work.

The only reason I'm looking at this situation is because I have extremely low spark and the bike will barely stay running, maybe 5 seconds at at time If it starts, the compression is great accross the 4 and almost equal 120-125 psi.

I'm saying the spak is low looking at the arc from inside the plug boot to a screwdriver tip.

Any Ideas anyone?

A

 

Check the length of the Alternator Brushes.
They need to be 10mm minimum.

http://www.centechwire.com/Merchant2/me ... _Code=FB-6

Fuse Panel, too.