[SFCB350]

Hey,

I'm going through a tune up of a used 1970 CB350 that I bought and when I got to adjusting the points the test light I have doesn't turn on when the point gap exists. I've attached the light to the terminal of the left point and no matter where on the bike (engine, frame...) the light doesn't illuminate. I then switched it to the right point turned the engine to create the gap and still no light. The ignition is turned on so power should be running through it. Am I doing something wrong?

I tested the light on the battery and the light does work. *It could be important to note that the person I bought the bike from had installed Dyna Coils.

Thanks,

Rob

 

[tbpmusic]

See if you have current at the black/white wire under the tank - it feeds the points, etc.
I don't think you have a kill switch, do you?

 

[bilbikek411]

SFCB350,
I think a self powered test light w/ it's own batteries is also better than using the ignition power to light the test light too;when the ignition is on w/ each set of points sitting closed for more than a minute it does get the coils warm/hot.I say this because I cooked a coil once doing it w/o a self powered light or buzz box.

 

[SFCB350]

Well....Kill switch was on so I'm going to check the light and report back.

Good point about the self powered light though

 

[fxray]

Well....Kill switch was on so I'm going to check the light and report back.

Good point about the self powered light though

I agree with bilbike411. Use the self-powered test light for sure. Remember that you will be looking for the light to shut OFF at the instant that the points break open.

 

[JamesPal]

All you need is a 12v light bulb. Connect it across the points, one side to GRD and the other to the positive side of the points. Electricity will follow the path of least resistance. When the points are open power flows through the lamp, when the points close it flows directly to ground.

It is much better to dynamically time the bile with a strobe light. If you are serious about old Hondas, your tool kit needs one.

 

[fxray]

James, of course that will work, but there's no reason to take a chance on melting the coils. You know not to leave the switch turned on too long, but someone new to this procedure may take longer. Plus it is easy to get sidetracked, only to discover the coil case melting. We have read about melted coils on here a number of times. Using a battery powered test light just makes much more sense, and is every bit as easy. I agree about the strobe light, but you need to set things statically first and then check with the strobe.

I don't have XS650 coils on my CL350, I still use the ones it was born with, and they work just fine.

In the end, it's not a big deal -- just personal choice, I guess. I'm slowly working on my old BMW project. Since batteries and tires start to age out as soon as you get them, I don't buy them until right at the end of the build. Consequently there's no battery in the bike yet. However, by using a battery powered test light, my new points are installed and static timed -- ready for the first startup.

Ray

 

[SFCB350]

So if I get a self powered light I'm going to plug it in then attach the red to the points terminal then the black to somewhere on the engine for the ground then also place the test light on the engine somewhere to see if it lights up or will it just light up anyways since I have the black attached to ground?

 

[dtsmjr8dan]

Old school method I used as a kid was a cigarette rolling paper between the points. When the points opened, the paper would slide out. No electricity required. It's not as exact as the test light method, but close.

 

[SFCB350]

Old school method I used as a kid was a cigarette rolling paper between the points. When the points opened, the paper would slide out. No electricity required. It's not as exact as the test light method, but close.

Haha! I like that

 

[bilbikek411]

So if I get a self powered light I'm going to plug it in then attach the red to the points terminal then the black to somewhere on the engine for the ground then also place the test light on the engine somewhere to see if it lights up or will it just light up anyways since I have the black attached to ground?

Yes,you want it to just have the light go out and at that instant is where your timing is to static time it;when you get it running you can use a stroboscopic timing light to get it exact while also testing your advance w/ their respective timing marks.

 

[JamesPal]

When static timing with a test light, a power source, light bulb and the points are in series. When the points close, the circuit is completed and the lamp illuminates. The power source can either be the bike's battery or an external source.

 

[Malarcy]

Haha! I like that

Here is part of an article in motor cycle mechanics from the 70s on CB200 engine rebuilding.

"*** paper"


Sent from my iPhone using Tapatalk

 

[dtsmjr8dan]

Haha! I like that

We didin't have internet or any fancy tools back in the 50's and 60's.

 

[SFCB350]

I ended up tuning it with the test light that I had and I was careful to turn the bike off after 30 seconds or less and not let the coils over heat. Idles high but I'm going to dig into the carbs next. Sounds like the valves might be a little loose and making a bit of a tapping noise but I'm not sure...

 

[mike in idaho]

Put a piece of paper between the opposite set of points, that way you will only be heating up one coil at a time.

 

[JamesPal]

Power will only flow through the coils when the points are closed. You are always moving the crank in the direction of turning the light on. A *** paper in the opposite side points will keep the points from closed. There should be no concern with the coils overheating.

 

[fxray]

That's right, there should be no concern:

housing was melted

coil very warm

cooked a coil

coils got awfully hot

 

[JamesPal]

Is there something else wrong? If the coils get hot when it is sitting there, it may do the same when running.

 

[bilbikek411]

When the contacts close and it charges the ign. coil during running the plug fires and that stored energy inside the coil quickly discharges,when you let that stored high voltage just sit there w/o discharging it and firing the plug it does get hot.