Very bad running.

[K2-K6]

Definitely looks like the condenser is failing on 2&3 system.

Temporarily, it may improve if you open that points gap slightly to at least keep the cylinders running as a possible bodge, while waiting to get a new part.

Failing condenser stops the points switching load cleanly, with the energy wanting to spark out there rather than competently operating coil function.

They are pretty slow on two cylinder aren't they, and sound like a bag-o-spanners 

Very minor fault though, and when correct it'll be back to smooth again.

[Bradders]

Thanks K2-K6, I have some spare condenser’s that I can try, it certainly sounded like something terminal. Any gotchas to fitting condenser’s?

[K2-K6]

Thanks K2-K6, I have some spare condenser’s that I can try, it certainly sounded like something terminal. Any gotchas to fitting condenser’s?

Just watch where all the little insulated washers/components go on the electric terminal post.

The circuit passes through that junction without touching anything that could give a path to earth. If it earths unintentionally, that coil won't run at all as no switching will occur.

Just careful diligence as you disconnect and re-connect the new condenser. Low risk, but puzzling if you get them wrong.

[Bradders]

Thanks K2-K6, will try and fix them in the next couple of days.

[Oddjob]

Swap the condensers wires over to the other points, see if the sparking follows it.

If so, change the condenser.

[TrickyMicky]

I had exactly the same problem a few years ago. It was not long after I had replaced the complete points back plate with a nice new fully fitted out pattern one. First failure was miles from home, the very nice RAC man was familiar with these bikes and diagnosed a faulty coil, and we travelled back home on his lorry.  New coils fitted, problem re-occured about a month later, so like you I removed the points cover and ran the engine and it looked like firework night.  Still had the original 1976 backplate which was re-fitted along with two sets of genuine(expensive) points. No more problems!
  PS the condensers are the original factory fittings, 47 years ago, the other problem with the pattern plate was difficulty in trying to get the correct timing for both sets of points. Try  and stick with originals if at all possible. Have fun. Mike.

[Bradders]

I had exactly the same problem a few years ago. It was not long after I had replaced the complete points back plate with a nice new fully fitted out pattern one. First failure was miles from home, the very nice RAC man was familiar with these bikes and diagnosed a faulty coil, and we travelled back home on his lorry.  New coils fitted, problem re-occured about a month later, so like you I removed the points cover and ran the engine and it looked like firework night.  Still had the original 1976 backplate which was re-fitted along with two sets of genuine(expensive) points. No more problems!
  PS the condensers are the original factory fittings, 47 years ago, the other problem with the pattern plate was difficulty in trying to get the correct timing for both sets of points. Try  and stick with originals if at all possible. Have fun. Mike.

Hi Mike, My backplate is original but not sure about the originality of my points or condensers. If you think genuine points are expensive try original condensers, David Silver is charging over £50 each original condenser!

[Oddjob]

I have original points and condensers, all in genuine Honda packaging, however they ain’t cheap but cheaper than DS, let me know if you’re interested, try and problem solve it first though, I only want to sell if it fixes your problem not for them to sit in a drawer because it was something else.

[Bradders]

Thank you Oddjob. I’m sure I have my original ones stored somewhere so will try them first. Thanks for the offer. Chris.

[Bradders]

Evening all. Have finally changed my condensers , sadly with no improvement. Number 2 and 3 points are still arcing like mad. Any suggestions what I might try next?

[Bryanj]

Clean the contact faces with a diamong file DO NOT use sandpaperas the grains are actually glass and will act as an insulator

[Bradders]

Thank you Bryanj, I will try that next.

[Bradders]

Evening, have fitted my spare points to my bike after giving them a thorough clean with a file, also reset the points and re set the timing. The bike bike starts well and runs much better but sadly the points are still arcing. Any suggestions what I could try next?  Thanks.

[McCabe-Thiele (Ted)]

If you switch the coil for 1 & 4 with 2 & 3 does the arcing issue  move to 1 & 4?
 
Are the LT wires & connections  between points & coil all in good condition?

[Bryanj]

You will always get some arcing, depends on intensity and colour, if the condenser was bad the running would be off