No spark issue 1980 XS650 Special

[Mike197]

Hello all, recently acquired a 1980 650 Special to add to my collection.
Previous owner says they replaced some gaskets and then could not get bike to start.
They then put the bike on the "back burner" so to speak and I bought it complete for $200 a few days ago. They think the timing is off and that's why it won't start... Maybe the timing is off, who knows.

I should still get spark even if the timing is off?... Right?.
I have good compression, so if timing is off it is not off enough to damage pistons/valves.

Before checking timing I figured I would check for spark.. No spark.
However I notice with my inline spark tester installed I get a nice blue spark when I switch the kill switch from off to on.. Anyone ever notice this with their bikes?.

As for checking things, I've tested the coil, checked grounds, checked continuity from orange and red white wires from TCI to coil, checked pick up coil resistance all seem ok.

Is the spark when moving kill switch a sign the that TCI is no good?.
I have power and ground at the TCI.

Any suggestions?.

Thanks!

 

[Grinder]

Try the post.http://www.xs650.com/forum/showthread.php?t=38788&highlight=Spark+turning+key

 

[Grinder]

Try the post.http://www.xs650.com/forum/showthread.php?t=38788&highlight=Spark+turning+key
Leo has some good info here.

 

[Hawkeye]

Do not use a battery charger! Use a fully charged battery! Always leave your plugs hooked! If you have powered your bike without the coil connected to plugs, it could fry your coil. Just some of the stuff I found out the hard way.

 

[XSLeo]

Ok, With a fully charged battery, turn the key on, check battery voltage. Use this voltage as a baseline. Now check voltage at both the TCI box and coil red/white wires. Both should be the same or within about .2 or .3 volts of battery voltage. If one or the other doesn't then trace back along the red/white wires to find where it gets lost.
Most likely at the engine stop switch or main switch. These can both be disassembled and cleaned.
A weak or bad connection where wires plug together is a problem area.
Leo

 

[XSLeo]

Almost forgot. On the cam timing, it can be easy to misread the repair manual and install the cam wrong.
Easy to check. Set the timing marks to TDC. Now look under the round chrome cover on the upper right side of the head. With the TCI it should be empty. just the end of the cam \. Look closely at the end of the cam, it will be threaded and have a hole in by the seal. This hole is for the earlier points advance unit. They didn't stop making the cams this way.
Now with the timing marks at TDC this hole should point straight up or down. If off by about ten degrees the cam is of by one tooth on the chain. If off by about 90 degrees the cam was installed very wrong.
When installing the cam there is a notch in the boss by the sprocket, at TDC this notch should point up. On the sprocket out by the teeth is a dot or dimple, at TDC this dot should be even with the head to rocker box sealing surface. It's not hard to misinterpret these marks and put the dot up. This puts the cam 90 degrees out of time.
Leo

 

[Mike197]

Thanks Leo,
I'll check that suff out when I get the time.
But should I still have spark even if the timing is off?.
I figured I would try to get spark first then worry about timing.

Have a great holiday!.
I'll keep you posted.

 

[retiredgentleman]

Thanks Leo,
I'll check that suff out when I get the time.
But should I still have spark even if the timing is off?.
I figured I would try to get spark first then worry about timing.

Have a great holiday!.
I'll keep you posted.

Are you still using the stock fuse panel with glass fuses? If so, it should be replaced with modern automotive blade type fuse holders.

Its also a good idea to open up the TCI black box and have a look inside. Some lads have found water inside! Look for any burnt components.

 

[Mike197]

Well the bike does not have the original fuse box, someone had replaced the fuses with individual inline fuse holders and glass fuses .
I'm getting the proper voltage where I should be getting it according to the service manual.
But once I get the bike running and I know what I'm dealing with I will replace those fuse holders with something better.

As for the TCI, I did remove it and took a peek inside, it looks good to me.
I'm going to have a friend of mine who does electronic repair have a look and get his opinion.

Like I said in my original message I'm getting no spark when the engine is cranked, but I get a nice blue spark when the ignition is on and you turn the kill switch off and on.
I've swapped the kill switch with a known good one and same thing.
The TCI does get warm after cranking.
I appear to be getting power to the TCI and power to the coil.
The coil tests good as do the pickup coils.
My next step I figure is to test for a pulse from the pick up could using a LED.

Thanks all for your help so far!.

 

[XSLeo]

On the TCI, Power gets sent to both the coil and TCI box. The TCI box uses signals from the pickups on the stator. It uses these signals to turn the main power transistor on/off.
When the main power transistor is on, it grounds the green wire from the coil. This allows power to flow through the coil primary side, building a strong magnetic feild in the coil.
At the right time the main power transistor gets shut off, this stops the power through the coil, collapsing the magnetic field, this creates the current in the coil secondary side, creating the spark.
Now in your case, the transistor isn't getting turned on/off as it should. When you turn on the power the TCI is grounding the coil, but it doesn't unground it. When you turn off the power it works just like ungrounding the coil, it causes a spark.
Now this can be caused by several things. A bad TCI box, Bad pickups, or maybe bad wiring. between the TCI box and pickups.
Find where the pick ups plug into the harness. Unplug it. In the pickup side of the plug there are three wires.
With an multi meter on the 2000 ohm scale, test from the black or black /white wire to the two colored wires. On the 81 you should get a 550-850 ohm reading on both colored wires.
If they test out good, it's time to test the wires between the pickups and TCI box, Open the TCI box, Locate the black/white, the green/white and the red/white wires that go to the pick up. Use your meter on the 200 ohm scale and touch each of these wires at the TCI box and at the plug for the pick up. There should be a very low reading.
If a high reading or no reading you have wiring issues between the TCI box and pick ups.
Another thing. Find the big plug for the reg/rec and unplug the reg/rec, now check for spark.
In the rotor there is a magnet, it gets weak, so weak the strength of the magnetic field of the rotor hides the magnet. The pick ups need to "SEE" the magnet. A weak magnet can't be seen.
Good news on that. Radio Shack sells a rare earth magnet that fixes this. 3/16 inch-4mm is the size, can't recall the item number, comes two to a pack for around $3. "glue" a new magnet right on top of the old magnet, use your favorite epoxy glue. I like JB Weld.
That should get you started. Do these checks and report back.
Leo

 

[Mike197]

Hello and Happy New Year!.

Leo,
So I've gone through the entire wire harness and completed all the checks and tested the pickup coils and fly wheel, everything checked out good.

So the only thing left to do was to try another TCI unit.
I bought a used TCI locally at a motorcycle junkyard and low and behold when I got home and plugged it in SPARK! When I cranked the engine.
I have to admit that I had a feeling all along that the TCI was my problem... But I didn't want to throw parts at the bike and spend money on it without making sure everything else was good on the bike... Thanks again for the help.

So the next thing is to put the exhaust on and add some fuel and get it running.

Thanks to everyone that replied to my thread.
I'm sure I'll be counting on some more help as I get further into this project.

Mike.

 

[XSLeo]

If the bike sat for very long you might want to read www.amckayltd/com/carbguide.pdf
It will help you get the carbs clean and tuned.
Leo

 

[5twins]

Yes, if the carbs are dirty, don't even attempt to start the bike. You'll suck the gunk in the float bowl deeper into the carbs and make matters worse. Remove a float bowl and have a look inside. This can be done with the carbs still in place using a stubby screwdriver. If it's all gunked up in there, pull the carbs and do a complete cleaning.

 

[Mike197]

Hey, got the bike running. The guy I bought from told be the carbs were clean so I took his with for it.
Originally when I bought this bike the previous owner said it wasn't running because the timing was off. I never had spark so I didn't worry about the timing until I got spark.
I got the bike for a couple hundred bucks with the title.
I bought this bike for parts, I just wanted it to run so I could hear what the engine sounded like.
Bike ran good, no smoke sounds like a tight little engine.
I may use this engine for my build.
Thanks again for your help.

 

[shiftybobber87]

Hey mike197 i was reading through your feed and im having similar issues i had spark last season and my bike ran great,all year long but when i pulled it out to go for one last ride last summer it fired right up i let it run for a couple mins then shut it off then when i went to start it again smoke rolled from my electrical i tested my coil and thats good and my regulator is good too i have power to everything but no spark??? Just wondering what you did to finally get spark thanks

 

[Mike197]

Hello,
The problem I had was that I had a faulty TCI box.
You mentioned that smoke came from you're wiring, I would check for any wires that might have shorted to ground and check all fuses.Where did the smoke come from exactly?. If you had smoke there is something burned/damaged somewhere. Don't replace anything until you are 100% sure the wiring is good because you could damage the new parts you try/replace.
Use the helpful advice on this thread given to me by others about how to check the system.
Good luck and let us know what you find.

 

[shiftybobber87]

Thank you for your info i went through all my wiring last night and i didnt see anything burnt so i test everything again and i noticed i had power going into my coil but nothing coming out so maybe my coil went bad?? But im not sure if i tested my coil correctly i took my digital olhm reader and put the red on one side and the black on the otherside with the key on and got nothing... am i testing it correctly?? Thanks for your help

 

[XSLeo]

shiftybobber87, You don't mention your bikes year but I assume it's close to an 80. If an 80 up, then it uses a TCI. The coil the TCI uses is a dual out put coil. The primary side has two small wires, a red/white and an orange.
The secondary has two plug wires.
To test, first set your meter to it's lowest ohms scale, digital this is usually 200 ohms. Now touch the test probes together. This gives you the ohms of just the leads. Remember this reading.
Now touch a probe to each of the two small wires. Now subtract the leads ohms from the test reading. One of my meters has a .7 ohm leads reading. Lets say I test the primary of a coil and get 3 ohms. I then subtract the leads ohms to get the actual ohms. As in 3 - .7 = 2.3 ohms well within the 2.5 or - 10% ohms needed.
You also need to test from the primary leads to ground, this is done by setting the meter to a higher ohms scale, like 20K. Now touch a probe to one of the primary wires, the other to the steel were it mounts. You should get an infinity reading.
On the secondary side set the meter to a higher scale as the 20K or 200K. With the caps on the plug wires touch one probe into each cap so the probe touches the metal parts. you should get a reading around 15-25000ohms. Also test to ground. infinity here too.
With the coil installed and bike powered up, you should get battery voltage at the red/white wire on the coil. The orange wire depending on what the TCI box is doing then it should read close to battery voltage or near zero volts.
The TCI box controls the spark by turning the power flow through the coil on or off. When turned on the orange wire is grounded, so you will get a zero or near zero volt reading. When off the orange wire is not grounded and you will get a near battery voltage reading.
Leo

 

[shiftybobber87]

Thanks alot leo i will try that and see if it works sorry for the late response i have been pretty busy lately but i appreciate all the help i can get

 

[chizler62]

Be certain to disconnect the primary side coil wires while measuring resistance. You want to isolate the coil but leave it mounted/grounded.

Another check I do when diagnosing in addition to XSLeo's advice is a voltage drop at ignition side of the switched hot wire R/W.

Key off. All wires hooked up. Volt meter in DCV negative lead to positive post of the battery and positive lead to R/W wire. Turn key on.
Depending on the amount of voltage drop you'll be able to detect what to look for. A little is normal, age, dirty connectors, corroded wires will all add up. Basically if you don't get near battery voltage then work backwards towards the battery.

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