GT550 coils, Kokusan vs ND

debby · Post by **debby** » Tue Nov 18, 2008 9:13 pm

One of my GT550s has a Kokusan ignition, the other has Nippon Denso. It turns out there are different part numbers for the coils:

ND coil pack: 33410-31010
Kokusan: 33410-33020

Supposedly the two are NOT interchangeable. Does anyone know what the differences are?

Debby

tz375 · Post by **tz375** » Wed Nov 19, 2008 10:56 am

Debby,

I don't know the answer, but it seems to me that as long as the primary and secondary resistances are similar they should be fine to swap out.

Typically you you can use any coil as long as the resistances are appropriate. I think they'll be in the 5 to 10 ohm range on the primary side.

Arne · Post by **Arne** » Wed Nov 19, 2008 12:53 pm

I think the coils screw on to the mounting plate differently, so it wouldn't be a direct replacement.

BUT as long as you could fit them in there I imagine they would work alright.

Personally I'd switch out the whole works or just get the part that fit the one I was working on.

Good luck - Arne

Post by **Suzsmokeyallan** » Wed Nov 19, 2008 1:30 pm

This is very much a situation on cars where two suppliers are sourced for a similair set of parts.
For example on Honda automobiles out of Japan there are two suppliers of radiator and the fan related parts, one being Toyo and the other being ND.
Both items are doing the same job but are designed differently enough so the parts are not interchangable between each other.
Soooooooooo having said all of that blah blah, as long as the Kokusan coils have the same internal resistance as the ND ones you could replace them as a set, bracketry and all. The only thing that may be different is the connection itself to the harness but i doubt it as the sockets of that period were pretty much all the same style.
Kokusan items are weaker in output of their charging units anyways, so if you can upgrade to the complete ND set, coils, alternator etc, by all means do so.

GT Tim · Post by **GT Tim** » Wed Nov 19, 2008 2:03 pm

Yes guys, that's all well and good, they are different, and you all took longer answers to say that you think that it would work anyway...

She wants to know if anyone KNOWS what the differences are you knuckleheads! Arne started to get there..

I don't know, don't ask me, I just got a kick out of you guys not answering the question!

I know, I'm an asshole!

Coyote · Post by **Coyote** » Wed Nov 19, 2008 3:10 pm

The coils should interchange just fine. The reason I say this is because I had some electrical issues when I was getting the Buffalo going. I suspected it might be the coils so I swaped out the ND's for a Kokusan set off my 550. The bike ran just fine with them. It turned out to be a carb problem. After I got that straightened out, the bike ran fine with the Kokusan coils. I put the ND's back on because the were the originals.
This experience leads me to believe there's not much difference in the coils. They even mount the same.

Post by **Suzsmokeyallan** » Wed Nov 19, 2008 3:18 pm

Thanks for that Tim, i can see you are feeling much better now, things are really back to normal for you.

GT Tim · Post by **GT Tim** » Wed Nov 19, 2008 4:06 pm

Suzsmokeyallan wrote:Thanks for that Tim, i can see you are feeling much better now, things are really back to normal for you.

Don't try to change the subject....

advant63 · Post by **advant63** » Wed Nov 19, 2008 6:02 pm

debby,
i thought the secondary ignition were alll similar. only the primary (points, condensors ) and the associated rotating bits were different.
you have one of each setup. you should check your kokusan bike to see if it has nd coils.
yet another non answer.

debby · Post by **debby** » Wed Nov 19, 2008 10:13 pm

You guessed it! The first bike has a Kokusan ignition and ND coils. After cleaning and adjusting the points I have a nice fat blue spark on all three cylinders.

The other bike has an ND ignition and an ND coil pack. And I have a spare coil pack - also ND. So, no way to compare coils.

It's hard to imagine that there would be any functional difference between the ND and Kokusan coils...

Debby

jeff g · Post by **jeff g** » Mon Nov 24, 2008 6:16 pm

Functionally, they are the same. Mounting and appearance might be different, though. Change them as an assembly and you'll be OK.