So who wants to know about the green Mikes Coils?

[TopCatGr58]

Hey Folks,

No reply from MikesXS but didn't expect one!

Question for the folks with the Black ones that died..did you check them with an ohmmeter, and what readings did you see on the fried ones???

I just got mine taken off, and they are measuring ~2.4 ohms on Primary, and ~14.5K ohms on Secondary...non-resistor plug caps! IIRC, these were the readings before I put them in.....thinking that ~2.4 ohms was close enough to the 3.0 for the TCI?? I just did a search both on MikesXS as well as the old thread, and I can't find any actual SPEC of resistance for primary side, just that they were recommended for the later TCI controlled 650 ignitions, not points type.

Anyways, they are already OFF, I already have the new Dyna's and will be putting them on soon. Then I can test to see if I'm getting power to all 4 plugs again, instead of just 2!

But if anyone has their Failed coils resistance specs, I would be interested in seeing/hearing about them! Thanks.

T.C.

[dbeardslee]

T.C. - IIRC when I was diagnosing the problem it came down to the coils being the only thing left that could be causing the problem I was having. Electrical tests came back normal, but I don't think I ever took a reading when the bike was fully warmed up. It seemed to be related to heat somewhat as it would run OK for the first 5 minutes or so, and then it would start stumbling really bad in low rpms. Once I got it above 3.5k or so it would run better, but the low rpm stumble on a warm motor was my main symptom. And when I say stumble I mean STUMBLE - it was pretty bad.

It kind of acted like a carb problem, and you know XS's and carbs. I 'fixed' the carbs 15 times and still had the problem. Funny how working on the wrong part doesn't get the job done . It's the best reason I can think of to keep your old coils if they work - you can always use them as a diagnostic tool in a pinch.

[fredintoon]

Hi Guys,
my son installed a Mikes green coil on his 1980 XS650 as part of his spring tune-up. He sez it ran the bike just great for a month or so then it started idling funny on the left cylinder. So he swapped the plug leads over and it started to idle funny on the right cylinder instead. So he swapped his original coil back in and now it runs like a clock.
BTW, same deal with Mikes carb boots, the set my son swapped in started to break up after a month and he's back to running on the 31 year old stockers.
Consensus on the XS650 list these days is that you only buy from Mikes if you can't find the part anywhere else.

[petejw]

ive been running the black coils for a few years now,
probably put over 10,000k's on them,
the spark i get is orange in colour tho, far from
a nice thick blue spark, might have to invest in a set
of dyna coils.

[MrOzz]

Hey Folks,

No reply from MikesXS but didn't expect one!

Question for the folks with the Black ones that died..did you check them with an ohmmeter, and what readings did you see on the fried ones???

I just got mine taken off, and they are measuring ~2.4 ohms on Primary, and ~14.5K ohms on Secondary...non-resistor plug caps! IIRC, these were the readings before I put them in.....thinking that ~2.4 ohms was close enough to the 3.0 for the TCI?? I just did a search both on MikesXS as well as the old thread, and I can't find any actual SPEC of resistance for primary side, just that they were recommended for the later TCI controlled 650 ignitions, not points type.

Anyways, they are already OFF, I already have the new Dyna's and will be putting them on soon. Then I can test to see if I'm getting power to all 4 plugs again, instead of just 2!

But if anyone has their Failed coils resistance specs, I would be interested in seeing/hearing about them! Thanks.

T.C.

I am getting 1.6 Ohms on the primary side, Showing a complete open on the secondary side.

Question to myself. Why did I keep them after installing the Dynas? LOL

[TopCatGr58]

Update

Well, I finally got around to finishing the install of the Dyna's, and Godzilla is running as strong as it was when the Black ones were NEW! SO...that proves that the Mikes ones were bad even though I had good test readings!

Well, the Mikes Green ones are essentially the same SHAPE and such as Dynas, but since they Don't provide a warranty, I wouldn't trust them. So I hope they last for the folks that got them, but would suggest folks look to the Dyna's instead....1 year warranty for 1 thing, as well as a very good reputation for quality!

T.C.

[jetmechmarty]

would suggest folks look to the Dyna's instead....1 year warranty for 1 thing, as well as a very good reputation for quality!

Z1 Enterprises has the Dyna coil for less money than Mike's green.

Marty (in Seattle)