Because the bike was still running roughly, cutting out, revving, misfiring and generally not a happy camper, I've been looking into its issues to try to get it to run much nicer.
The carb has already had lots of attention, so this time it was the electrics...
The bike has a low tension circuit and a high tension circuit. It also runs on a 12v negative live system, which apparently means the live wires earth to the frame etc. The low tension is where the common faults generally are and the Technical Handbook, (page 108) lists a bunch of tests to identify potential problems there. I'll start there and see where I end up.
Symptoms include; The Zener diode had blown again, this was first thing, the main headlight wasn't working and the rear brake light has decided to have a holiday too. The bike is running rough, misfiring and when warm, very hard to start.
I checked all the earth connections and couldn't see much wrong with them, but scrubbed them with wire wool anyway. The battery had 12.7v, which was good enough for this load of checks.
Further investigations online, found that a lot of people replace the Zener and regulator with a modern Regulator/Rectifier. I bought one to try. At £6, its a cheap test to see if the bike runs better. Once I'd figured out the wiring, which is:
I mounted this under the saddle and in the same place as the older version. I also added some sticky back foam to help with vibration on the metal mudguard. It does help, the bike feels a bit more crisp when it starts. However, the first one blew and so I was back to square one. Something is shorting somewhere is the thought.
I've now not got a spark at all at the spark plug. So I've replaced the condenser, the coil, the HT lead, the spark plug and I still have no spark. mmm...
Next up is the gap for the points, which should be .015 inches and the spark pug gap is .020 inches. The gap was way out, so I've reset that back to the correct setting. I have no idea how old these points are so I might just buy some new ones and learn how to fit them.
I'm almost at the end of my knowledge here and may have to resort to outside help again, which is unfortunate. Time to walk away for a bit and do some more research and mull things over a bit.
