[J3H]

Good evening Friends!
I'm having a problem with my 1969 CB450 and I need your advice. I spent the weekend getting the carbs running perfectly. I adjusted the floats as well as the air mixture so the plugs are burning lean and clean. Road the bike for 10 miles or so, it ran great. I parked it overnight and now it wont start. At first I thought it must be related to my work on the carbs, so I tore tore those apart again, but everything looks good. Then I realized that I was getting a weak spark on the left plug and no spark on the right plug. The points seem to be opening and closing smoothly, but no spark there either. I guess I need to move on to the coli and condenser, but I'm stumped as to why any of those components would go bad just sitting in the garage overnight?
Any suggestions would be appreciated, before I just go buy one of everything!
Thanks!
JH

 

[JAYinNY]

What's the state of the battery and charging system? Need full battery power for strong spark.

 

[J3H]

The battery is about 2 months old and the charging system seems to have kept it up until this episode. Of course, I ran the battery down trying to get it started since last weekend, so it's been on the charger when I'm not working on it to keep it fully charged.
One source suggested that I check to make sure that I have a full 12V at the points and if so, the condenser and coil are probably OK, but he did suggest that the one or both of the points may have cracked or pitted. He suggested looking at those. I'll look after work tonight.
Any suggestions are appreciated!
JH

 

[Lefty]

I'd check the timing and put a voltmeter on the battery while its cranking.

 

[ancientdad]

The battery is about 2 months old... ...I ran the battery down trying to get it started since last weekend, so it's been on the charger when I'm not working on it to keep it fully charged

A thought occurred to me - how many amps is your charger and what setting is it on when charging your battery? these are 12 amp batteries IIRC, and if you charge them long-term with even a 2 amp level it can do damage. You can start out at 2 amps but for overnight it should be around a trickle level to avoid ruining a new battery

 

[JAYinNY]

What's the state of the battery and charging system? Need full battery power for strong spark.

TEST the battery. TEST the charging system. DO THIS FIRST. If OK move on to other things.

 

[J3H]

Update:
Thanks for all of your suggestions. The battery seems to be holding a strong charge and can turn the engine over without any problems.
I re-set the timing today and I have a question. My left spark plug is connected to the left coil which is the yellow lead connected to the left (front) set of points. I have power at both sets of points, but when I rotated the LF mark (counter-clockwise on the compression stroke) to the index mark on my flywheel (@ apx 10 o'clock), the points cam is preparing to close the right set of points. Is it possible that my left cylinder is controlled by the right set of points or am I doing something wrong?
Thanks!

 

[Lefty]

I think you're fine. The spark occurs when the points open and the closed portion when the coils are charging seems relatively short.

 

[mike in idaho]

The coil fires when the points open, not when they close. Open circuit voltage, measured at the open points, doesn't necessarily tell you everything's ok. Measure the voltage at the black wire connection on the coil, with the points closed, that will tell you if the wiring, fuse and battery are up to snuff.

 

[J3H]

Now I'm really confused!
I set the points to close at the top of the compression stroke assuming that is when you want the spark plug to fire. Is that not correct?
No wonder the bike won't start!
What position should the points be in when my indicator marks LF and F align with the index notch on the rotor?

 

[FrankyV]

Now I'm really confused!
I set the points to close at the top of the compression stroke assuming that is when you want the spark plug to fire. Is that not correct?
No wonder the bike won't start!
What position should the points be in when my indicator marks LF and F align with the index notch on the rotor?

That is not correct. Review the service manual or the procedures posted elsewhere in this forum for setting the points gaps and timing the motorcycle.