Topic: CB350F gremlins (...incompetence)

[ChuffChuff]

Hey everyone,

I recently bought a CB350F that's had a 400F head put on, it's the first bike I've had since I was about 16 (not that long ago), and I'm fairly inexperienced with them (previous was a CB250K4). Bloke I bought it from had it hot when I arrived, took it for a little test ride, decided to take it (although it did have a suspicious rattle just above idle in a narrow rpm band). He told me it was about due for a service, and to have valves etc. done. Took it home, did the valves and got a new battery and points plus replaced all the old fuel.

Then my issues started - when I first tried to start it after all these various switches one cylinder would fire and the others wouldn't. Just re-did the valves, hoping it was my mistake there, and then tried to start her again - now not firing on any cylinders. So, I went back to double check the electricals, and one set of points is now not working (but both were before, after I replaced them), the other is but gives very weak spark on cylinder 4, and none on cylinder 1.
I also pulled the carbys off a while back to check them, gave them a bit of a clean but they were all in pretty good nick. I'm now a little lost - why the second set of points now isn't working baffles me, as does the very very weak spark (and how the other guy got it running in the first place!).

Any advice or tips would be much appreciated!
Cheers, Finn.

[calj737]

It is not uncommon to have the points ground out against the ignition plate. Look very carefully at the small wire coming from the points, and insure there's not a contact spot for that exposure.

Of course, it is possible that you have bad plug caps (too high of resistance), cracked plug wires (HT leads), etc. But start at the points plate. It has caught many a veteran with the same anomaly.

[HondaMan]

This may go unnoticed, but...the battery is small on this bike, and if the key is ON with the engine off for more than about 7 minutes, it will very quickly die. If, for instance, you tried setting points timing with a static timing lamp and it took more than about 2 minutes, the battery is likely very low. Less than 9 volts at the coils, and there will be almost no spark.