CB350 1971 Restoration Project

[McCabe-Thiele (Ted)]

If you cut a single  wire out of a wire brush you can poke out the crud - also if you have a long wire you can twist it down from the top so it acts like a drill - once the crud is loose a squirt of WD 40 should work in the absence of an Ultrasound cleaner.

[K2-K6]

Similar experience recently with 400 four idle jet, size 40 with radials clear but bore partially obstructed such that it was difficult to get a stainless cleaner through the bore. Soaked in Acetone and eventually cleared with then more clear slighted view through it when held up to light.

It brought tthat cylinder into play as it hadn't seemed to be running at low rpm before.

Really stubborn deposit inside there though, believe they'd already been cleaned ultrasonic method prior to this.

[philward]

Reference my similar issues similar to Ben's with my 350, I have posted on my 'New Money pit' thread as I don't want to appear to take over Ben's thread.

[BenPowell]

Hi everyone,

More updates on the bike,

My V5 arrived last week only a few days after the inspection which was a nice surprise. So it’s now insured and ready for the road.

I took the bike out on Saturday for its first ride out, got a few miles down the road and started getting issues with misfiring and bogging down, which got worse the further I went.

I few things I have found is the charging system was a bit weak, but I’m getting good power from the stator, I’ve replaced the rectifier for a modern one which improved it slightly, but the thing that made the most difference was permanently wiring in the ‘night time coil, by connecting the wires in the headlight bucket, yellow wire into the white with yellow stripe. Thanks to Ash for that suggestion.
I now get a steady 13V at idle which is good.

But the bike was still running rough and misfiring on one cylinder (left side) so tonight I removed the point cover and ran the bike and the left side point contact is sparking continuously while the righ side had no sparking at all, so I think it’s time for a new condenser. Fingers crossed that sorts out the last of the running problems,

I checked the point the other day for sparking and could see nothing, got in the shed tonight where it’s darker and it was obvious straight away.

[Trigger]

Hi everyone,

More updates on the bike,

My V5 arrived last week only a few days after the inspection which was a nice surprise. So it’s now insured and ready for the road.

I took the bike out on Saturday for its first ride out, got a few miles down the road and started getting issues with misfiring and bogging down, which got worse the further I went.

I few things I have found is the charging system was a bit weak, but I’m getting good power from the stator, I’ve replaced the rectifier for a modern one which improved it slightly, but the thing that made the most difference was permanently wiring in the ‘night time coil, by connecting the wires in the headlight bucket, yellow wire into the white with yellow stripe. Thanks to Ash for that suggestion.
I now get a steady 13V at idle which is good.

But the bike was still running rough and misfiring on one cylinder (left side) so tonight I removed the point cover and ran the bike and the left side point contact is sparking continuously while the righ side had no sparking at all, so I think it’s time for a new condenser. Fingers crossed that sorts out the last of the running problems,

I checked the point the other day for sparking and could see nothing, got in the shed tonight where it’s darker and it was obvious straight away.

Had the same problem with my 750K6 at the weekend Ben. Misfiring and bogging down and it was a condenser. It is the first time i have had a condenser go down on me so, i was stumped what the problem was at first. The K6 is 46000 miles plus and it still has the same old points and condensers from when it left the factory.
The bike would run and rev up to on the bench but, out on the road under load it would bog straight away. 

[AshimotoK0]

I bought an insulation tester specifically to test out the collection of condensers I have. It's no use just  measuring their capacitance with a low voltage standard multimeter as you also need to measure the leakage at high voltage. I got surprising results .. a lot of 1970's condensers, mainly from CB250/350K's, looked fine but were leaky at the high voltage. The best results I got (including so NOS genuine ones) was a sed condenser from a a 1961 CB92 

The Honda Service testers always had a function to do this but I suspect it was used more for shocking the apprentices by throwing them a charged up condenser to catch, than use on customers bikes. 

I will test your condensers when we meet up again Ben. Beware Daiichi ones not made in Japan, there are some nasty, rubbish Chinese copies on the market.

[Trigger]

On a condenser Ash, is it earthed out on the mounting point or can it be tested on the bike with out being screwed to the points plate ?

[K2-K6]

Interesting Ash, my understanding is that they can get up to approx 400v pinged back toward them as spark ionisation effect hits the circuit through coils etc.

[AshimotoK0]

On a condenser Ash, is it earthed out on the mounting point or can it be tested on the bike with out being screwed to the points plate ?

You should be OK with it screwed to points plate but with the other terminal disconnected.