2 STROKE WORLD .net

The 2-Stroke Garage => Turning Wrenches => Topic started by: m in sc on July 06, 2025, 02:03:07 PM

Title: 50+ year old electronics.. and why not to trust them
Post by: m in sc on July 06, 2025, 02:03:07 PM
off the ls2. perfect storage and low, low miles. still, time takes its toll.

original vs new ngk



Title: Re: 50+ year old electronics.. and why not to trust them
Post by: 1976RD400C on July 06, 2025, 04:27:50 PM
I just had to replace a coil on my YL1. The thing checked ok with a meter, same readings as the other one, but would not spark. Checked everything, cap, wire, voltage to it, points, it just wouldn't spark. Swapped it with the other side to prove something was wrong with it before spending $50. You need little hands to change them out being they are inside the frame.  :rolleyes: 
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: grcamna3 on July 06, 2025, 05:48:47 PM
Mark, the top one is original,but the bottom one(NOS)is correct at 5 ohm ?
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: m in sc on July 06, 2025, 05:56:35 PM
bottom one is a new ngk one and yes, 5 ohm is correct. 1st one is one i pulled off bike.
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: scully on July 06, 2025, 06:58:32 PM
I just picked up the 69 H1 with CDI ouch them plug wires bite hard adjusting the car carb Idle ! With it running.. orig mileage is 7200 ... electrics are 👍 going to buy an all in one ign box though... peace of mind commuting 👍
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: automan on July 06, 2025, 07:39:53 PM
5k not 5ohms
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: m in sc on July 06, 2025, 08:18:58 PM
we know. just easier to say
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: Striker1423 on July 06, 2025, 10:39:29 PM
I have a new set of coils for the GT. The big problem I have is the layout of the new set is backwards to the old and when mounted in the bracket the far left coil hits the frame.

I had to resort to cutting the old wires out and epoxying new ones into my
old coils for now.
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: axldk6 on July 09, 2025, 09:10:09 AM
I did the SV coil conversion with new plug ends. trying to get a better spark. when I save up enough $ I am doing the electronic conversion. The other rd I bought has the points conversion ( did not know till I got it home and inspected)and has a real good spark. In the meantime I think I will replace the brushes and clean the surface and see if that helps?
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: m in sc on July 09, 2025, 09:50:26 AM
good(battery/points) spark is def reliant on good supply voltage to coils,ie: charging system.
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: grcamna3 on July 09, 2025, 11:34:23 AM
Quote from: axldk6 on July 09, 2025, 09:10:09 AMI did the SV coil conversion with new plug ends. trying to get a better spark. when I save up enough $ I am doing the electronic conversion. The other rd I bought has the points conversion ( did not know till I got it home and inspected)and has a real good spark. In the meantime I think I will replace the brushes and clean the surface and see if that helps?

"the points conversion" on your other rd? What is that conversion ?
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: axldk6 on September 06, 2025, 05:36:05 PM
sorry I did not reply earlier, open heart surgery is a bitch, I ment to say my other rd had a Dyna ( vintage smoke?) system already installed.hope that clears that up.
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: SoCal250 on September 06, 2025, 08:43:41 PM
Quote from: axldk6 on September 06, 2025, 05:36:05 PMsorry I did not reply earlier, open heart surgery is a bitch, I ment to say my other rd had a Dyna ( vintage smoke?) system already installed.hope that clears that up.
:eek: Yikes, hope everything is good now and you're back to being you :cheers:
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: teazer on September 07, 2025, 12:51:55 PM
Quote from: Striker1423 on July 06, 2025, 10:39:29 PMI have a new set of coils for the GT. The big problem I have is the layout of the new set is backwards to the old and when mounted in the bracket the far left coil hits the frame.

I had to resort to cutting the old wires out and epoxying new ones into my
old coils for now.

Replacing the HT leads is often all that's required for the old GTs. What coils did you get as replacements?  I have used a few different coils over the years with differing fitment issues, but most are an easy fit.
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: Striker1423 on September 07, 2025, 02:20:44 PM
Quote from: teazer on September 07, 2025, 12:51:55 PM
Quote from: Striker1423 on July 06, 2025, 10:39:29 PMI have a new set of coils for the GT. The big problem I have is the layout of the new set is backwards to the old and when mounted in the bracket the far left coil hits the frame.

I had to resort to cutting the old wires out and epoxying new ones into my
old coils for now.

Replacing the HT leads is often all that's required for the old GTs. What coils did you get as replacements?  I have used a few different coils over the years with differing fitment issues, but most are an easy fit.


I got a set of Nippon Denso replacement coils from Japan that came with a numbered harness (1,2,3) and NGK caps off eBay. In their instructions, they basically have you razer knife off a small portion of the coil plastic near the center wire to clear the frame. I'll check that out when I work on the swap.
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: teazer on September 07, 2025, 04:45:15 PM
The only coils I had a major problem with were from a GS500 where I had to flip one coil and sand the smallest amount off two adjacent coils.  Most of the aftermarket coils have spade connections but fit without issues.

If yours are genuine N-D, they should be good +/- and minor trimming.

I inherited a pile of old OEM coils and probably half of them had one or two coils with breaks on the low side and most of them benefited from replacing the plug(HT) leads. SuzukiDave was the guy that taught me the replacement lead trick a few decades ago.
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: m in sc on September 07, 2025, 06:58:59 PM
yeah. they're good.. till they aren't.  I heard this about triple cdis for years,  thrn in like a 2 year span there was a rash of failures
Title: Re: 50+ year old electronics.. and why not to trust them
Post by: Striker1423 on September 07, 2025, 07:38:28 PM
Well, I should say, I was being rather lazy when I did it. I had the super cheap aftermarket coils from eBay and ran into fitment issues, so I used the plug wire from those coils and new NGK caps. The plug wires were all braided copper. I had a roll of solid core somewhere, but couldn't find it and figured the braided leads would work. Which, they do, but I just want the piece of mind on new coils.

https://www.ebay.com/itm/297441808911

Expensive, yeah, but seemed worth it.