id just toss the old batteries and get fresh ones.
The analog meter TS depended upon batteries being good or you could have erroneous readings….
Be careful to put both screws opr all screws back in, forgetting one you are likely to l;one if if you think Ikll put it in later…at least I have.
You have a nice unit. The plastic screw in the face of the meter is used to adjust the meter so the meter pointer is pointed to zero. You use a plastic screwdriver on these so no magnetic interference or magnetism from the tool is affecting your adjustment or you don’t put any magnetism into the device’s coil. Even regular metal screwdrivers can have a little magnetic residue. Most stainless steels are not magnetic but they are not Strong steels like tool steels that are properly hardened.
The usually jeweled meter will not or should nit require adjustment very often, like very rarely to never ideally.
Replace both batteries with fresh ones.
They unscrew from the spark plug leads. Trim off about 1/4 inch of the end of your spark plug wire when you remove it from the lead. This ensures it screws into the spark plug lead wire and it accesses good copper or fresh copper when you attach or reattach the spark plug cap. Our spark plug wires a copper core wire, a non-resistance wire. This is as opposed to all modern cars and bikes which use a resistance core wire, a carbon impregnated core that has resistive wire properties. It is stranded abd moist cannot be reterminated or do not have replaceable caps but you replace the entire wire when the insulation breaks down and you have leakage through the insulation. If you are dry and the ground is bands it hasn’t been raining if you get shocked by brushing against or momentarily touching the insulation of your coil wires the wires a need changed or in case of permanently attached wires you either have to do some surgery on your coils to replace the wires, or you replace the coil and wires completely.
So. Sometimes good to figure out if the coil wire is good first. Trying to crank and touching the wire during cranking, you get lit up and your arm hurts from elbow down usually, it is time to replace the wires or the coils plus the caps…
After you pull the caps puff isf the boots are good then you keep going…
As you found. The black that causes meter movement to red probe/clip after you change the right knob to the R x 1000 as has been said…
Remove your spark plug caps.
You cannot measure them in circuit, attached to the coils.
Put the negative or black lead inside the cap to make a connection to the tree in Al inside the cap. Since you have alligator clips you can take a piece of copper wire your sand the copper that is being clipped to to make sure there is no oxidation or stuff that is making the connection have a little resistance. You can give it a light scrape with a blade edge to ensure you have bright clean copper. The other end of I presume solid wire that you are using and a probe extension or spin your own problem is going to get the same light sanding or scrape to give bright copper too. House wiring or heavier can make a decent extension to your resistance measurement abd being stiff like house wiring allows you to porters firmly on what’s you are probing with that end.
Once your touch the black and red probes together you adjust using the left hand dial to be zero on your ohm scale.
Once the meter has warmed up or been in use for a bit your ohm meter zero might drift slightly;up, this is characteristic of analog meters but openly after a few minutes should you see that drift. After taking readings if you see a steady movement of the zero then your batteries might be suspect or your meter could have a problem.
It usually is a slight movement. Anything significant is telling you the meter has a problem.
So red lead on one side and black on the other connection, be it the end that screws into the wire or the end that is attaching itself to the electrode on the end of the spark plug.
Then you read the meter scale and multiply your reading time 1000 to give you the reading.
The resistance scale goes to an infinity a very high value. In measuring with resistances and voltages you always start your measurements on higher than you expect scales and then lower the scale or setting on the meter so you don’t damage the meter pegging it hard against the stop or upper end of the scale. Resistance range has a zero adjustment and you normally wont hurt the meter following that approach. Pegging the meter can damage the meter as it can slam the needle very very hard and that can damage the coil or bend the needle.
The 550 and 500 came with 10k ohm caps basically you cannot find some of the NGK caps now, as NGK quit making the bent ones I think. The long straight ones you can still get.
The bent ones were for the cylinder 2 & 3 on the CB fours
The XD05F NGK as Bill said.
Stu’s advice to pull the batteries is very good, these old analog devices can be ruined by leaky batteries.
The capacitors if anty go bad and some resistors breakdown with age or go out of range. These old meters can be repaired if people want to take the time and effort to disassemble, test components, replacer components which aged poorly after 50 to 75 years, or longer…
The voltage readings can get you in serious hot water…
Never try measuring the current of a MC or Auto battery as your meter is in line with the power feed and these meters are only capable of handling usually 10A unless it states different AND YOU HAVE to use the correct leads to measure the current, even on a VOM meter you often have a different black wire or often ground/negative wire probe for the voltage than the resistance.
NEVER try to read powered OR operating circuits when measuring resistance or capacitance.
Components in a circuit often must be removed from that circuit or you can be measuring other paths in the circuit.
This is why troubleshooting bad component is difficult, And will often rely upon visual inspection clues when looking at electronics that are not working.
Without the schematics of a device you are often unable to troubleshoot it if t you do not know or have guidelines/troubleshooting from the maker of the product. The amount of effort to remove a component it is normally replaced rather than reinstalled. Capacitors often fail in old units, if the maker did not remove the markings from the capacitor, yes that sometimes was done, or the markings were removed from the transistors or IC chips or it was a custom chip.
So, some stuff could be reverse engineered, but many custom or other means were used to make it difficult to impossible to service.
That’s the beauty of non electronics in old bikes, simple techniques and methods and why electronics are often disposed or go to special shops who have the equipment and knowledge to start walking through a circuit. You quickly hit a wall in what you can do.
