I acquired a 1971 Norton 750 a couple of months ago that hadn’t run since 2003. I got it running in a couple of days and it sounded pretty good on the lift. Since then I have been getting it road worthy. Rear brakes, chain, cleaned the oil tank and replaced all the oil lines. Then moved to replacing fork seals and checking front brake. I went to take it on its maiden voyage today and no spark. Battery is good, all lights and horn work. I’ve been all over this bike and don’t know what I might have done to cause this but I obviously did something. I am hoping that someone can give me some troubleshooting tips to locate the problem. I am still running points. Thanks in advance for some guidance.
No spark
- Thread starter FL54
- Start date
Let's sort this out.
Have you tested all the buttons on the left and right sides and verified what each should do.
On my 1973, the left lower is the horn, the left upper is the flash high beam, the right lower is kill switch and right upper is
not used. (On my bike, I wired the right upper to control the electric starter). Yours may be different but have you identified what each should do?
1) After you had the bike running, and before you tried to start it and it wouldn't start, did you take apart any of the handlebar controls??
2) When you try start the bike now (but before you kick it), is the ignition light on, do headlights work and do stop lights etc work?
Obviously a connection somewhere is bad, the question is where. Do you have a voltmeter?
If not, we will look for a connection problem or a frayed wire problem.
Dennis
Have you tested all the buttons on the left and right sides and verified what each should do.
On my 1973, the left lower is the horn, the left upper is the flash high beam, the right lower is kill switch and right upper is
not used. (On my bike, I wired the right upper to control the electric starter). Yours may be different but have you identified what each should do?
1) After you had the bike running, and before you tried to start it and it wouldn't start, did you take apart any of the handlebar controls??
2) When you try start the bike now (but before you kick it), is the ignition light on, do headlights work and do stop lights etc work?
Obviously a connection somewhere is bad, the question is where. Do you have a voltmeter?
If not, we will look for a connection problem or a frayed wire problem.
Dennis
Here is the diagram with blue arrows showing the switch and blue arrows showing the wire going from the switch to the coil.
I don't know where your switch is positioned as I have a 1973 with the switch layout as mentioned earlier.
If you didn't touch the kill switch (wherever it is) between the time you started the bike and the time you tried again and no start, I think the problem may be elsewhere.
In the meantime, I suggest it an idea to do a check for spark at the spark plug to be sure the problem is electrical, not fuel.
Dennis
I don't know where your switch is positioned as I have a 1973 with the switch layout as mentioned earlier.
If you didn't touch the kill switch (wherever it is) between the time you started the bike and the time you tried again and no start, I think the problem may be elsewhere.
In the meantime, I suggest it an idea to do a check for spark at the spark plug to be sure the problem is electrical, not fuel.
Dennis
Thanks Dennis. Really appreciate the help. Lower left is horn,high beam switch is thumb toggle on right. Kick only so no starter. Yes I did take apart the handlebar controls. In fact I replaced the left one.
Ignition light comes on and all the lights work. Yes, I do have a voltmeter. I also removed the ignition switch to check for corrosion.
Ignition light comes on and all the lights work. Yes, I do have a voltmeter. I also removed the ignition switch to check for corrosion.
kommando
MEMBER
- Joined
- May 2005
- Messages
- 7,917
Note the brown/blue wire coming from the battery negative and through the fuse connecting to post 1 on the ignition switch. Note the white wires coming from post 2 on the ignition switch. Start here, with the ignition switch on is there 12V at post 2, if yes them move on to the next connection which is white wire into the multiblock under the tank where a further 4 white wires emerge, check for 12 V here, next then go to the yellow the other side of the kill switch. The multiblock is a favourite failure point, if you have had the petrol tank off it has to be top candidate.
trappnman
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- Joined
- Jun 2013
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- 135
lots of advice- but why not start with basic troubleshooting. You say lights and horn work- so ground can be eliminated. Make sure its not the kill switchI. If its not, then if you got a good battery, and with key in start position, do you have current to the points? If yes, then got to next step, current coming out to the coil, and so forth. Follow the trail. No spark at points makes it even simpler- connection to battery.
concours
FULL MEMBER
- Joined
- Dec 2011
- Messages
- 10,653
… And a DMM. Cheaper than a spark, plug,Some progress. Yellow/ white from left control is kill switch and found disconnected. According to the wiring diagram, it should connect to Blue/ White wire in main harness. Only B/W wire in main harness is connected to the white block that already has voltage. Hoping to find b/w female empty but not there.
