Honda-SOHC

SOHC.co.uk Forums => CB750 => Topic started by: Alimacdee2 on November 24, 2014, 08:54:20 PM

Title: gunson's tachostrobe
Post by: Alimacdee2 on November 24, 2014, 08:54:20 PM
Hi all, thought I'd give the forum a try,  I'm trying to double check the timing on the Honda with my trusty old tachostrobe, I can get the Gunson's universal spring connector on no 1 or 4 spark plug no problem, without it shorting on the head, but now finding it impossible to get it on 2 or 3, this connector has always been a pain to use, I think its more suited to a distributer cap, anyone know a more reliable connector I could convert it so its sohc friendly? Ah the joys of points ignition, its all coming back!!

Ally
Title: Re: gunson's tachostrobe
Post by: Lynx on November 24, 2014, 08:59:18 PM
Hi Ally,

My version on the Gunson is a later design. I has a spring loaded clamp that just hooks on to the HT lead. Would it be possible for you to adapt your connector so it wraps around the lead instead of being in-line?
Title: Re: gunson's tachostrobe
Post by: Alimacdee2 on November 24, 2014, 09:16:04 PM
  that would do it, I wonder if that later style clamp is available, is it a special kind of inductor? could you post an image of it  please.

cheers
Ally
Title: Re: gunson's tachostrobe
Post by: K2-K6 on November 24, 2014, 09:16:16 PM
I vaguely remember something that was a plastic covered plug extension that screwed onto the plug and had the plug top replicated at the other end giving about 100mm extension, can't be really sure about it.

Could you modify a straight NGK plug cap by grinding off the insulation around the HT lead end so that you could fit it to your gun lead and then the supply HT onto that?
Title: Re: gunson's tachostrobe
Post by: Alimacdee2 on November 24, 2014, 09:51:40 PM
I've got a few spare plug caps, if I can figure out something like that, Its just getting the extension between the spark plug and the existing plug cap somehow, If i can get my head round it, could possibly do that.
Will look into these and update.

cheers
Ally
Title: Re: gunson's tachostrobe
Post by: Lynx on November 24, 2014, 10:15:47 PM
This is the HT detector on mine. Looks quite complicated but I'm sure something could be made to work simply. You push on the right side of the bottom piece to open the hole up in the middle. Slide it over your lead and close it up again.
Title: Re: gunson's tachostrobe
Post by: Lobo on November 24, 2014, 11:48:09 PM
Hi Ally,

I've got the same machine / same problem...

First up, great idea but I'm not sure if your fix will work Lynx as an induction type unit. But worth a try... use a common old clothes peg to clamp the two leads together as a starter for 10?

I 'solved' my problem by doing more-or-less what K2-K6 suggested; and made up an extension by destroying an old plug, and to its core attaching a flying lead to a suitably sized spring - which has  an insulating sleeve abouts it.

Yes... very Heath-Robisnon, but it works fine .

Simon
Title: Re: gunson's tachostrobe
Post by: Alimacdee2 on November 25, 2014, 01:06:06 AM
Hi Simon
Nice, I'm thinking the fly lead fitted to a plug cap could be the way to go, and could also use it on 1 or 4 cylinders.

cheers
Ally
Title: Re: gunson's tachostrobe
Post by: Bitsa (Ralph Wright - RIP) on November 25, 2014, 09:16:14 AM
Bought this a few years back from a car parts place ht connector is a spring loaded clamp easy to use
Cheers
Bitsa
Title: Re: gunson's tachostrobe
Post by: Alimacdee2 on November 26, 2014, 02:45:59 AM
+1 for an Inductive pick-up if I can just find one.. tho I think I've almost cracked it, ordered some copper cored HT lead.


Cheers
Ally
Title: Re: gunson's tachostrobe
Post by: Seamus on November 27, 2014, 09:25:43 AM
I ended up using the connector lead from a colortune to extend the connection from the plug. Had one kicking around.

Other option is to solder wire onto a spark plug ferrule and use shrink wrap to insulate.
Title: Re: gunson's tachostrobe
Post by: Alimacdee2 on November 28, 2014, 11:52:28 PM
Nice one again, just recently found my colourtune kit too, tho the adapter's thread is smaller than a standard spark plug's, if I find a spark plug ferrule may still be able to use it, will check this out over the weekend.

cheers
Ally
Title: Re: gunson's tachostrobe
Post by: Alimacdee2 on December 04, 2014, 11:56:15 PM
I Kept it simple and made a lead with a spare plug cap, copper cored ignition lead and bullet connector. It worksfine with the spring connected, easy on no4, 3 was a pain with the engine & pipes hot, have a couple of small blisters to prove..burned again, wont post the pics! now see the benefits of the clip on pickup! may still try that method,
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