Wanted CB 400 4 coils for an F2 1977

[Oddjob]

Oh dear, what have I started. 😀😀

As for being up early, in fact I hadn’t even gone to sleep yet, my body clock is all messed up since I got ill last year.

[Ken4004]

That’s the same stuff I used to encapsulate new lead join, then reshape to original profile with milliput 2 part putty. Can be sanded and painted too. Yellow leads? Why not, I’ve just ordered blue but don’t even know what colour the bikes going to be yet!😳

Blue sounds nice as well again matches the stripe on the tank, well I need to make a decision, where did you get your leads from ?

[Oddjob]

A slight mod I made to the Ash fix on coils was to fit a 1m circle of lead instead of fitting 2 separate leads. That means you can fix the coil in place, I fit mine backwards so that water can’t be forced down the lead opening by wind pressure, this tends to mean you need slightly longer leads but even standard lengths fit. However you can now route the leads over the top of the engine using clips on the camcover bolts to secure them and get the leads to approach the plugs from the rear instead of the front. Looks much neater, no chance of melting them on the exhaust pipes, especially if the lead is disconnected for servicing etc. Use a long straight HT cap for the inner cylinders and long right angled for the outers.

You cut the lead when your satisfied with the routing.

[Ken4004]

A slight mod I made to the Ash fix on coils was to fit a 1m circle of lead instead of fitting 2 separate leads. That means you can fix the coil in place, I fit mine backwards so that water can’t be forced down the lead opening by wind pressure, this tends to mean you need slightly longer leads but even standard lengths fit. However you can now route the leads over the top of the engine using clips on the camcover bolts to secure them and get the leads to approach the plugs from the rear instead of the front. Looks much neater, no chance of melting them on the exhaust pipes, especially if the lead is disconnected for servicing etc. Use a long straight HT cap for the inner cylinders and long right angled for the outers.

You cut the lead when your satisfied with the routing.

Sorry not quite sure what you mean by 1M circle of lead , are you saying you get a loop of lead 1 metre long and solder the middle of the lead at one point at the coil as per picture attached ?  I managed to find a wiring diagram of the coil, do is this what’s inside the original coil a piece of wire the length of the coil connected in one place to the middle of this wire the the two ends connected to one of the ignition coil ht leads ( I hope you understand what I am saying)

[Oddjob]

There are 2 ht leads coming out of each coil. 1-4 and 2-3 usually. Now you get a 1m length of ht lead. Do the first connection to say the number 1 lead. You’d normally measure how much of the length you’d need and cut the lead to this length with maybe a bit extra, just in case. Now you’d do the other one, number 4. Again after attaching it you’d measure and cut. The problem being if you get it wrong and you cut it too short you’re going to have to redo that lead. My idea was to do the first connection and then go right to the other end of the 1m lead and use that to connect to number 4. So you’re left with a lead going from number 1 port to number 4 port. Only after you have fitted the coil in place and routed the wires as you want them do you do the cut. One lead is always longer than the other so there is no chance of getting it wrong. Leave each lead a few inches long so you can cut and trim a little as time goes by. It wastes a little of the lead but that’s better than risking cutting too short.

[Ken4004]

There are 2 ht leads coming out of each coil. 1-4 and 2-3 usually. Now you get a 1m length of ht lead. Do the first connection to say the number 1 lead. You’d normally measure how much of the length you’d need and cut the lead to this length with maybe a bit extra, just in case. Now you’d do the other one, number 4. Again after attaching it you’d measure and cut. The problem being if you get it wrong and you cut it too short you’re going to have to redo that lead. My idea was to do the first connection and then go right to the other end of the 1m lead and use that to connect to number 4. So you’re left with a lead going from number 1 port to number 4 port. Only after you have fitted the coil in place and routed the wires as you want them do you do the cut. One lead is always longer than the other so there is no chance of getting it wrong. Leave each lead a few inches long so you can cut and trim a little as time goes by. It wastes a little of the lead but that’s better than risking cutting too short.

Hi Odd Job thanks for the clarification I now know exactly what your getting st regards Ken

[Oddjob]

Like you, my name is also Ken, just for future reference.

Glad you understand now. Before you cut the leads try a test fit with the leads coming out towards the back of the bike instead of pointing towards the front. I found it cured the arcing problem these leads had due to water ingress, the wind used to force water down the lead and into the coil entrance and also down the rubber collar on the top of the ht cap as this was also facing forward. Never had a misfire in the rain after doing this mod. It did mean though that number 1 lead went to number 4 cylinder but with the wasted spark system Honda used this isn’t a problem.

[Ken4004]

Hi Ken

Thanks for your advice can’t wait to get stuck in after my holiday.

Regards Ken

[Johnny4428]

That’s the same stuff I used to encapsulate new lead join, then reshape to original profile with milliput 2 part putty. Can be sanded and painted too. Yellow leads? Why not, I’ve just ordered blue but don’t even know what colour the bikes going to be yet!😳

Blue sounds nice as well again matches the stripe on the tank, well I need to make a decision, where did you get your leads from ?

Hi Ken, ordered ht cable from these guys.
https://www.pedparts.co.uk

[AshimotoK0]

I wouldn't use silicone HT lead on the coil fix as I don't think you would get decent bond with the epoxy.

I only quoted the RS components epoxy as we use it where I work  it has a quoted high dielectric strength ...but you could use another liquid epoxy if it has a decent electrical spec. It's a great general purpose adhesive though and it can be filled with aluminium powder, silica etc for a whole variety of uses.

[Ken4004]

Hi Ash thanks for the advice, from what I can see the descriptions of some of these HT leads don’t give a great deal of detail, do you think the bright coloured cables are predominately silicon coated ?

I’ll check the specs on the epoxy resins to ensure good electrical properties, just trying to find a small quantity as I don’t think I would ever use a litre can of it.
I have seen the sachets where once you open it you need to use it unless I can find a small tin of epoxy + hardener.

[Oddjob]

I wouldn't use silicone HT lead on the coil fix as I don't think you would get decent bond with the epoxy.

Sorry Ash but explain that a little please.

AFAIK the main supply of HT leads these days is silicone sheathed. Not 100% sure what Honda used back then but it seems silicone is the stuff most commonly used these days.
I can understand your concern regarding the adhesive quality or lack thereof in this case. But I’m a little confused as to why you think this is a cause for concern. The new lead is soldered to the stump of the old lead, so I’d imagine just that would mean it can’t be pulled out easily. The epoxy I understood was just there to fill the hole you need to make to gain access to the old core of the old lead. If it also grips the outer sheath of the new lead that’s a bonus I suppose. I always smeared silicone sealant on the outer sheath where it enters the coil body in order to prevent water ingress. You’d imagine silicone would grip silicone wouldn’t you? Or am I wrong?
My set of coils is still only half done as my illness last year just stopped everything so I’m fortunate in some respects that I can alter mine without too much trouble. I was intending to fill the hole with the epoxy you sent me so it was almost flush with the body of the coil, then overfill a little with something like Araldite and then dress this down until flush and then spray Matt black in order to blend the repair in.

Have I got something wrong? Or just misunderstood your concerns here.

[exvalvesetdabbler]

Nothing much bonds to silicone apart from silicone. Silicone doesn't have much structural strength  either.

The original ht leads look like pvc or similar thermoplastic with a rubber jacket.

Getting resins to bond with other materials is shrouded in mystery.  A lot of the primers used in industry are obviously proprietary.  In critical applications we sometimes had no option but to buy the molding kits with all the needed resins and primers.  Without the right resin and compatible primers the bond would usually fail, usually when in deep water.  We were bonding polyester and polyeurothane sheathed cables to stainless using a rubber compound. For less critical applications ie
Prototyping cable harnesses epoxy seemed to bond with most stuff.  Low energy plastics were the worst, polythene or polypropylene.


Regards
Dave

[AshimotoK0]

I think Dave has pretty much answered you there Ken.

I usually use 7mm PVC cable or Hypalon and abrade/degrease the surface. Hypalon isn't supposed to good for bonding to rigid epoxy but I have abraded it and found it to be OK with the RS adhesive. I don't think the original PVC cable 'bonded' well to the plastic Honda used anyway.

[Ken4004]

Ok thanks Ash I will therefore get some pvc ht leads instead.