Author Topic: 1965 Trail 90 Has No Spark  (Read 703 times)

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Offline stingray68

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1965 Trail 90 Has No Spark
« on: July 10, 2017, 11:36:03 AM »
Hey Guys,

   I have finally finished putting the engine back together and mounted on the bike. When I kick the engine over I do not get any spark....I did not replace the points, but did clean them.  I also have the battery hooked up (horn works) so I am reasonable sure the key is in the run position.  Is there any way to test the coil?  I figure I will start with the experts here since you have never let me down yet!  Thank you all in advance.....Mike

Offline Hop

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Re: 1965 Trail 90 Has No Spark
« Reply #1 on: July 10, 2017, 07:21:18 PM »
Mike , Do you have power at the points with the switch on? Have you checked the engine to bike frame wire plug for corrosion? Hop

Offline rwgibbon

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Re: 1965 Trail 90 Has No Spark
« Reply #2 on: July 10, 2017, 08:05:27 PM »
Mike,

I always check and double check the simple things.

Are your points opening and closing when you kick over the motor?
Also check the coil wire to the plug. Is it corroded at either end?
Are you sure the spark plug is good?

Good luck.

Randy

Online BS Mechanic

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Re: 1965 Trail 90 Has No Spark
« Reply #3 on: July 10, 2017, 10:30:38 PM »
If you haven't already, download the 90 shop manual from this site, in the "downloads" tab under "manuals".

As suggested, make sure your plug is good!  Try kicking it over with the plug out resting against the cylinder head fins.  You should see a spark in the gap.  If any doubt at all, use a new plug.  Trying to troubleshoot with a bad plug causes all sorts of headaches!  DAMHIK!

First thing I would check is to make doubly sure the points are really making contact.  It's extremely easy while trying to clean the points to get non conductive stuff in the small recesses on the surfaces of the points.  Just because you can't see it doesn't mean it won't prevent electrical contact!   I always check this with an ohm meter with the point wire disconnected.  Make sure the resistance is zero when the points close.

Next thing to check is the stator coil.  The coil that makes the current for the ignition. (There is no battery connection on the 90's.)  With one end disconnected, the resistance of this coil should be low, not more than a couple ohms.  Don't remember what the exact value is, and I couldn't find a value in the 90 shop manual.  Shouldn't be zero, but should be very low.

The ignition coil itself should measure a few ohms on the primary side, and high on the secondary side. (the one with the plug wire)  If it's infinite (open circuit) on either winding the coil is bad (open), if too low, it's probably shorted inside, also bad.  Again don't know exact values and don't see them in the manual.

Make sure the ignition switch is working correctly, and all the wire connections are good.  Probably should measure each of the wires to make sure they are connected and conducting current correctly.

Good luck!  Electrical trouble can be frustrating since you can't see it!
« Last Edit: July 12, 2017, 12:42:39 PM by BS Mechanic »

Offline stingray68

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Re: 1965 Trail 90 Has No Spark
« Reply #4 on: July 11, 2017, 08:10:40 AM »
Good Morning All,

   First of all thank you for all your comments!!  I started checking the continuity of the circuit and I will try to answer all of the items above.  I did download the manual (I could not have done this project without it (this is my first rebuild), and the help from you on the forum!  I do have power to the points, and I have power thru the coil.  But, when I check from the spark plug cap (clean inside) and the near side of the coil (which does have some corrosion) there is no continuity.  I am guessing this might be the problem....I would still like to check the continuity of the points like BS Mechanic posted.  Also, what is the best way to see of the points are opening and closing while kicking the engine over?  Thank you all very much!  Mike

Online BS Mechanic

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Re: 1965 Trail 90 Has No Spark
« Reply #5 on: July 11, 2017, 09:11:42 AM »
If the timing and point gap are correct, then the mark on the rotor will be on the engine case pointer (at the front) at the same time the points should be just opening.  The points will be visible through the slot on the rotor.

I can't figure out how to insert a picture, but see the attachments.

(well, it looks like I got the pictures after all!!)


Offline stingray68

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Re: 1965 Trail 90 Has No Spark
« Reply #6 on: July 11, 2017, 09:17:36 AM »
Thank you for the pics and explaination!  I will check this out after work....Mike

Offline stingray68

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Re: 1965 Trail 90 Has No Spark
« Reply #7 on: July 11, 2017, 05:41:47 PM »
Okay,  I can see the points open, but it does not align with the marks.  When the points open the mark is roughly 15 degrees past the mark.  I hope that makes sense.  Is there a way to bring this into alignment?  Did I snarf something up?  I made a mark on the stator and the crankcase housing before I removed it so I put the stator back in the same spot....Thanks again for the help!! Mike

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Re: 1965 Trail 90 Has No Spark
« Reply #8 on: July 11, 2017, 09:11:38 PM »
Are you measuring the point opening with a meter?  (It can't be done accurately by eyeball.)  If it's as you say, it's 15 degrees later than it should be, but even with the timing off, it should still spark.

Timing is very sensitive to point gap, so if the point gap isn't EXACTLY the same as before, the timing will be off, even if the stator plate is in the same place. 

To be honest, I usually adjust the timing by putting the stator plate in the "center" position, and adjusting the point gap to get the correct timing.  You still need to verify that the point gap is within the range listed in the manual when you're finished, but this has always worked for me.

Offline rwgibbon

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Re: 1965 Trail 90 Has No Spark
« Reply #9 on: July 12, 2017, 07:41:02 AM »
If you put the bike on its' center stand and put in gear you
can rotate the rear tire and watch to see if the points open
and close.

Clean the ends of the coil wire and make sure there is a good
connection to the coil and the spark plug cap.

Have you tried a different spark plug?

It sounds like your getting close.

Offline stingray68

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Re: 1965 Trail 90 Has No Spark
« Reply #10 on: July 14, 2017, 07:46:06 AM »
We have spark!!!  Thank you to everyone for chimming in for me on this topic!!  I have one last request (for now)!  Could someone please post a pic or explain how the chain guard attaches to the frame!  The one that has me puzzled is the rear mount!  I seems like it is tapped in both the chain guard and the frame?  I will post some pics when it's on the road!  Thank you all again....Mike

 


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