Author Topic: No Spark  (Read 959 times)

Offline Saesneg Shaun

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Re: No Spark
« Reply #15 on: May 05, 2022, 07:18:19 PM »
Wondering if the rod is backing out of the crank which will release the advance mech ?

If that's happening, then the securing nut may be reaching thread end before tightening mech properly.

The rod seems to be in rock solid. What is very worn is the large nut with the slot in the middle. Years of cranking the engine over on it has turned the centre oval. I don't know if you can just buy the nut?

Actually just looking at the cost of the advance unit/points/condensors on DSS I might as well do an electronic conversion!

Any recommendations? DSS unit or Boyer seem reasonable choices.

Offline K2-K6

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Re: No Spark
« Reply #16 on: May 05, 2022, 08:27:31 PM »
Likely you'd get someone with a nut on here to help you out if you put request out for one.

Electronic, many use the advance mech to then run various levels of electronic switching.

Boyer is fully electronic, triggering, advance the lot and has very good reputation for performance and reliability also. Probably the most proficient if you're changing.

Unsure if Boyer needs that nut too, or has alternative. 

Offline Oddjob

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Re: No Spark
« Reply #17 on: May 05, 2022, 09:55:29 PM »
Sure I've got one somewhere, just need to find it.

CMS have them at 18 euros or so. DS don't stock them.
Don't play stupid with me, I'm better at it

Offline Saesneg Shaun

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Re: No Spark
« Reply #18 on: May 06, 2022, 07:10:03 PM »
Thanks for the help guys.

I'm totally fed up with messing about with the points so have ordered a Boyer Electronic Ignition kit.
I went for that one as it doesn't use the stock advance unit compared to the DSS unit and they have been around for donkies years.


Offline Saesneg Shaun

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Re: No Spark
« Reply #19 on: May 10, 2022, 08:18:08 PM »
Just to update this I fitted the boyer electronic ignition today and she's running on all four again.

Its looks like my problem was the large nut had been used to crank the engine over and had gone oval in the middle. Even with the 10mm nut done up the big nut was still moving around. Fortunately the Boyer kit does away with the large nut and the points cam.

I have a bit of popping through the exhaust but i'm waiting for a strobe to be delivered then I can time it properly.

Offline K2-K6

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Re: No Spark
« Reply #20 on: May 10, 2022, 09:36:55 PM »
Good you've got to the bottom of it.

Those are timed at full advance as you can't set them like a mechanical system that advances the trigger point. They effectively run at full advance with a rpm register internal that allows them to retard only from set point for start and low rpm.

Seems a bit odd if used to conventional mechanical system, but logical once you think it through. 

Should be easier to start now  :)

Offline PHILIP2908

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Re: No Spark
« Reply #21 on: May 11, 2022, 08:12:17 PM »
I've got the same problem; the spindle and nut scribes an oval as the crank is spinning. You can set the timing OK but it plays havoc with the points gap.
As you say its caused by monkeys turning over the engine with the plugs still in: the compression proves too much at tdc and the spindle bends.
I had a look at a replacement but none seem to be available. From the parts diagram it looks as it just screws into the end of the crank.
I also thought about removing it and getting it straightened by an engineering shop but then had nightmares about it snapping off on removal which would probably necessitate a full strip down to get at the crank.
Consequently I will probably go for the Boyer system too. Can you please give some feedback on ease of fitment and what effect it has on the running?
Best regards
Phil
1974 Honda XL250 K0 - Silver - owned for 32 years. Not running at the moment
1972 Honda CB750 K2 - Now candy apple red - Ex USA, a DK special - needs a lot more work than I thought - very quickly becoming a DS special...

Offline Bryanj

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Re: No Spark
« Reply #22 on: May 11, 2022, 10:01:06 PM »
The 750 spindle is available as a spare and has an O ring on it where it screws in

Offline Lobo

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Re: No Spark
« Reply #23 on: May 12, 2022, 01:25:55 AM »
I removed my spindle recently - not easy. Heat, molegrips, rattle gun (on low) all to no avail. What worked in the end was a roller cam stud extractor, obviously down near the base. But still nail biting…

Offline Saesneg Shaun

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Re: No Spark
« Reply #24 on: May 20, 2022, 04:06:24 PM »
Well dang, its still not sorted.
Got the ignition timed with a strobe lamp to full advance at 4500rpm.
Also did a carb balance whilst I had the bike partly disasembled (I know, I know, should have tackled one issue at a time)

Road tested today and she won't accelerate over 4000rpm in any gear. Tried with the fuel tap on and in res and with the cap open but with the same result.
Starts and ticks over fine.

Any ideas?

*edit, just pulled the plugs, No's 1,3&4 very black and sooty, No 2 tan/clean?
« Last Edit: May 20, 2022, 05:37:15 PM by Saesneg Shaun »

Offline Saesneg Shaun

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Re: No Spark
« Reply #25 on: May 24, 2022, 05:16:52 PM »
Found the cause.
I just popped the float bowls off to find 1,3 & 4 main jets in the bottom of them  :-[
I didn't tighten them up and they rattled loose. No wonder the plugs were were black lol.

Offline K2-K6

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Re: No Spark
« Reply #26 on: May 24, 2022, 06:44:01 PM »
 ;D  ;D  ;D oops!

At least you found them quickly.

 

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