XJ11/XJ650 interchangeable coils?

[Brendtron5000]

Okay, this is a bit convoluted...

I'm looking for replacement coils for my XJ650 J. Stock is 2.5 ohm primary, 11K ohm secondary. In my search I come across a coil for an XS 650, which looks promising... for later model 80-84 XS 650s with TCI, just like my bike. It's the high output replacement ignition coil on this page:

http://www.mikesxs.net/mikesxs-elect...ategory_id=2.1

I searched and searched for the what the resistance of the primary is (early models were 1.5 ohms, I think), because to little resistance will fry the TCI unit.

So, I come across this post:

http://www.xs11.com/forum/showthread.php?threadid=7092

Which says "And, if the bike has a ballast resistor....then yes it would need to be bypassed, these coils are rated at 2.5 ohms and are designed for 12 volt system. "

So it seems like they're 2.5 ohm primaries. Can anyone confirm that this has actually worked on one of your 11's, and that the primary is 2.5?

I could go with some Dynas, for $120 a pair, or go to dealer and spend 100's on an OEM set... Problem with they Dynas is that I'll have to fabricate a mounting bracket since the mounting holes are 90 degrees off the stock version.

It'd be awesome to pick up a couple of bolt on replacement coils for $64. Too good to be true?

Thanks everybody!

[mro]

If you don't get a responce PM Randy or TopCat.
Both know the 11's electrical pretty good.
Coils from MikesXS can work on the 11, but don't remember the spec's.


mro

[TopCatGr58]

Hey Brendtron,

Those are great coils, several of us have them on our XS11's and have NOT fried the TCI's! The actual primary resistance has been measured around 2.3 ohms, but that's not a problem. The problem you'll get is IF you were to get coils for the later CDI ignitions systems that use only 0.7 ohms....THEN it would draw too much thru the TCI and possibly fry it!

Also, the MikesXS coils are 35K volts power....you will notice a definite difference in ease of starting and running!
T.C.

BTW, there's a tech tip about them in the IIRC repairs section, but might be in MODs, can't remember exactly!

[Brendtron5000]

Awesome, thanks for the info!

Ordered them... hoping to get them soon, because the bike ain't running so hot with the current coils, wires and plug caps.

Now let's just hope the mounting holes are the same!

[fredintoon]

Collateral damage

Hi Brendtron,
Be careful mounting those coils. My XS11 came with hi-powered aftermarket coils that didn't fit so they were held on by a single bolt to sheet of rusty 22ga sheet-metal that was held to the frame with self-tapping screws. Alas that when I built a properly designed adapter for the coils Mr Stupid trapped one of the alternator wires behind it on installation. Amazing how the charging system quits once the insulation on the trapped wire pressure-extruded off to ground it out.
Also amazing is how much cost & effort was wasted in fitting replacement rotor, stator & reg/rect before finding the trapped wire. And fixing the PO's opened-up wiring with lotsa electrical tape.