Alright guys i've been rebuilidng my 79 650 special for the past 2 months. I'm fairly certain i have all of the wiring correct as i am getting power to the points. However i'm not getting a spark at all. Did i incorrectly install the ignition advance unit's rod? There is a gap between the points at all times even when trying to start it. Is it supposed to be offset so that it hits the points upon rotation? Any help would be appreciated, thanks.
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Rebuild: No Spark
- Thread starter bbancsov
- Start date
There is supposed to be no gap most of the way around and it is supposed to open up when firing. The gap at the high point should only be the distance specified in your manual, somewhere between .010"-.014". There is plenty of information about setting the points online and in the repair manual. I just spent the last week or so reading it all since that's where I am in the process. 
Good luck.
Good luck.
Yes, the contacts should open to let the spark across. The gap should only be there when it's firing on either cylinder. (at least that's how I understand it).
Keep in mind, I only know what I've learned these last couple weeks and it may not be enough to explain what I'm trying to say accurately.
Keep in mind, I only know what I've learned these last couple weeks and it may not be enough to explain what I'm trying to say accurately.
Okay thanks, i'll do some more research as well. If anyone else would like to chime in or has a beginners guide on setting up/checking ignition timing i would greatly appreciate it. I just don't understand how i'm not getting a spark.
jchrisk1
XS650 Junkie
Thanks! Will give this a shot tomorrow after work and report on what happens!
So i gave it a shot today, i'm having a hard time understanding these instructions. Mainly what point to connect the timing light and at what state. I've been checking the grey wire contact point when the alternator timing mark is right at f, but then not knowing which way to adjust the plate via lock screw...
jchrisk1
XS650 Junkie
Try this method. It should get you close, provided your points gap is set correctly. There are different ways, but this worked for me.
Hooked up a meter, black to ground, red to wire on points right side. Key on, meter set to AC. Turn the rotor CCW until the mark is in the F zone. There is a keyway on the end of the advance rod that you can just see behind the nut that should be pointing upwards. If it is pointing down, turn rotor 360. Loosen right side points plate, hold red lead to points wire and slide it left to right until it just moves. Lock it down. Do the same thing for the left side, keyway down, moving left points plate and holding red lead to that wire.
You want to try and set both sides at the same point within the F marks. The right side plate is the big one in the back. It will turn both plates, so, do the right first, then the left. Then check with a timing light. Making sure that it doesn't go past full advance at 3000 rpm's.
Hooked up a meter, black to ground, red to wire on points right side. Key on, meter set to AC. Turn the rotor CCW until the mark is in the F zone. There is a keyway on the end of the advance rod that you can just see behind the nut that should be pointing upwards. If it is pointing down, turn rotor 360. Loosen right side points plate, hold red lead to points wire and slide it left to right until it just moves. Lock it down. Do the same thing for the left side, keyway down, moving left points plate and holding red lead to that wire.
You want to try and set both sides at the same point within the F marks. The right side plate is the big one in the back. It will turn both plates, so, do the right first, then the left. Then check with a timing light. Making sure that it doesn't go past full advance at 3000 rpm's.
hmusket
CBMMA Member
Here's another how-to link, with some illustrations: http://www.650motorcycles.com/points.html
I set my points using one of those cheap continuity testers, key off, alligator clip on the points half with the wire, and continuity probe point grounded on the engine.
I set my points using one of those cheap continuity testers, key off, alligator clip on the points half with the wire, and continuity probe point grounded on the engine.
The keyway is pointing to the right and left sides when the timing mark is on F...
jchrisk1
XS650 Junkie
When you say you've been rebuilding this for two months, do you mean the motor? Because that's not right. With your pistons at TDC, your cam marks should be at 12:00 or 6:00 depending on which side is on the compression stroke.
Has this thing ever ran?
Has this thing ever ran?
jchrisk1
XS650 Junkie
jchrisk1
XS650 Junkie
There's one on the left also. You may not see it on the points cam. But that's not important really. If it's close, it's probably good enough. We've kind of wandered from the real issue. Don't pull your motor.
Okay, first of all, have you adjusted your cam chain and set your valves, in that order, yet? If not, do that first. Then turn your rotor with a wrench to TDC. Don't worry about the keyway, just find which side both rockers will wiggle a bit. That will be the side that is on the compression stroke. You want to start with the right side when adjusting your timing. Once you find which side is at TDC, then start with the directions above, or follow the links.
You points cam is not perfectly round. It has a high spot on it that opens the points. When it is at its highest point you set your points gap to spec. Then adjust your timing.
Okay, first of all, have you adjusted your cam chain and set your valves, in that order, yet? If not, do that first. Then turn your rotor with a wrench to TDC. Don't worry about the keyway, just find which side both rockers will wiggle a bit. That will be the side that is on the compression stroke. You want to start with the right side when adjusting your timing. Once you find which side is at TDC, then start with the directions above, or follow the links.
You points cam is not perfectly round. It has a high spot on it that opens the points. When it is at its highest point you set your points gap to spec. Then adjust your timing.
jchrisk1
XS650 Junkie
Okay, I read some of your old threads and if you didn't install your cam correctly with the pistons at TDC then you do need to pull your motor and do it right. Hopefully you haven't damaged any valves and/or pistons. But now you will need to make sure of that as well. Follow the link above for setting your cam timing properly.
Pulled the motor, valves looked fine. Fixed the cam timing, was off by 3-4 teeth i don't remember exactly it took alot of adjustment to get it correct. Motor is back in and valves are set, will be working on the ignition timing this afternoon and we'll see if she fires.
jchrisk1
XS650 Junkie
Good on you for fixing the cam timing. Now you should have better luck with everything else. Keep us posted.
