Topic: Has anyone ever tried this coil job from the FAQ's?

[Kinch]

This post is somewhere in the FAQ's for stock CB750 coils that have fixed plug wires:

Early Honda coils had fixed spark plug cables yes? Well they're still inductive, and the cables will be the first to go with age, corrosion and cracking.  I could literally HEAR my 1 and 2 cylinder cables shorting out on the engine when the bike got to operating temperature, and the bike ran terribly.  So, I deduced that if I were to simply CUT OFF the cables at the coils flush, and drill them with approximately a slightly undersize 7.5mm bit (approximately .218") nice and square, I could SHOVE brand new 8.5mm Accel graphite-impregnated core cables in them and reuse the spark plug connections since they have a stud center, and simply screw them on.
I knew the connectors weren't the culprit since they're so heavily constructed, but the cables themselves looked like junk so they had to go.
Now I have beautiful NEW Accel cables and original coils and connectors, and the bike runs great.  If you think about how much new dual-post Accel brand coils and cables cost, I saved about $140.00 x 2, and it works.
By the way you can only drill about half an inch into the coils and still get a connection, so you'll have to epoxy the cables into the coils once they're shoved in, which works fine and is an invisible fix.

The beautiful part of this is that an Accel $40.00 UNIVERSAL set of cables for an American V8 car has enough cable length to do this fix to about six SOHC fours.  HUGE man, that's HUGE!


I got this idea from my mechanic friend Dr. John, who specializes in Honda SOHC fours.


(Thanks to polishbeer)

My plug wires were shot and too short to fix so I'm going through this process but I've got to the point where I've drilled into each plug hole a little under 1/2" and still don't see much other than a few mangled strands of copper to connect to. Have I not drilled far enough in? I don't want to completely ruin my coils if I already haven't.

Has anyone ever tried this who could offer advice?

Thanks in advance

[mystic_1]

I think the idea with this particular mod is to just shove the wires into the holes and rely on the spark jumping from the old wire to the new wire.  I don't think that doing it this way actually fastens the wire cores together, you're just relying on the epoxy to hold the ends together.

Have a look at this site, it's a different technique that takes a bit more work but should turn out much better.  At the stage you're at you can still switch to this method:

http://www.xs11.com/tips/repair/repair24.shtml

cheers
mystic_1

[Kinch]

Nice one, thanks.

[Clyde]

The article mentioned deals with Yamaha coils.
The only Honda coil I have attempted to fix, just had copper wires no pin.
I have seen Suzuki Gt750 coils and they can be repaired much in the same way as the Yamaha article, but without having to damage the outer cover. The new HT leads are pushed in over a screw/pin and epoxed in place to prevent them being pulled out and water leaking in.

[SteveD CB500F]

There's a thread here somewhere (with pictures) describing how to cut into your coils to fix new leads and then epoxy them back up.

I'll try to find it and post a link.

[SteveD CB500F]

Here it is:

http://forums.sohc4.net/index.php?topic=10429.msg98088#msg98088

Maybe I should put it in the FAQs.

[Terry in Australia]

I had the same problem Clyde describes, but have replaced the wires on plenty of Suzuki coils, basically it's just a case of getting the old ones out and shoving new ones in. I've only used copper cored wire though, but I guess graphite/silicon wires would work ok too. Cheers, Terry.

[jreich]

Here it is:

http://forums.sohc4.net/index.php?topic=10429.msg98088#msg98088

Maybe I should put it in the FAQs.

I used this method about a year ago, and it worked great....I prefer this method simply because I know that I am getting good contact with the coil wires because I soldered it together with each of the plug wires.

[Kinch]

Here it is:

http://forums.sohc4.net/index.php?topic=10429.msg98088#msg98088

Maybe I should put it in the FAQs.

Brilliant, thanks everyone.