Coils for my Xj 600 84

Coils

I'm am about replacing the coils on my 1984 xj 600 as one of them seems to be breaking down after about 20-30 minutes of running, the specs say from 2.43 - 2.96 ohms resistance on the primary coil, but the coil above is a 3 ohm part, will the bike run okay with that resistance? or do any of you know a better solution then the coils above.

i phoned yamaha for replacement coils and they quoted me $300 for a single coil which is rediculous and i will not pay that.

thanks for your assistance.

 

One thing to verify is what resistance you read when you connect the probes of your meter directly together. Subtract that value from the value you got when checking the primary resistance of the coils to get a more accurate value for the primary resistance.

 

i have checked coils as above and the primary resistance is right, but not so sure on how to check the secondary, the bike runs great for about 20 minutes and then dies in the ass, its not battery related, so im thinking coils.

plus it cant hurt to have nice strong coils on the bike.

 

If you want to replace coils anyway, and don't mind that you might still have this "dies after 20 minutes" problem to solve, then Dyna's would probably be a good improvement.

What else have you checked as far as the dying issue, though? Do you have a fuel filter that might be clogged and restricting fuel too much for long running periods? Does that bike have a fuel pump? Is the fuel tank cap maybe not breathing well?

 

tried running it with the fuel cap off, just had fuel filters/jets re-done, carbies tuned as well. had the shims done and the electrical system checked but the guy told me it needs new coils..

so thats my plan.

are those dynacoils good for an xj600 84 model? do you have a link.

its definately not fuel starvation, as it is a miss that starts on one or two cylinders then gets heavier and heavier untill its totally gutless.

 

I'm pretty sure Chacal (XJ4Ever ink at top of page) will have them and appropriate mounting hardware.

 

left coil secondary through the plug leads is 22.5k-ohms
primary is 2.6-2.7

right coil seconday is 27.8k-ohms
primary is 2.8 ohms

both measured without sparkplugs and straight into the plug boots/caps.

which one is broken! i think the spark cap resistance if supposedly 10,000ohms then both are no good? i really just want to replace both with new ones but it'd be nice to know which one is fubar'd.

 

I've heard that some bikes have 10K caps, but mine has 5K ones, and the other XJ's I've seen also had 5K.

I tried to check for your bike, but I was not able to find any information on a 1984 XJ600. Was it made for a non-US market?

Anyway, if they're 5Km, then the left coil sounds good, and the right coil sounds questionable... but I'd still remove the caps and measure the coil and caps separately. The caps screw off of the wires.

 

thanks for your patience and help sqlguy, yes my particular xj is made for non-us markets, i believe it has 5k caps as well based purely on the resistance im getting via the coils, i will check that when my mate brings his multimeter back over this weekend, in the meantime i will order a set of those dynacoils, is there a particular model i require or are the all suitable for my bike?

also, how in the world do i go about ordering some! all i really see is a list. haha

 

Easiest thing is to email:

info (AT) xj4ever (dot) com

Len doesn't seem to sleep, always knows the answers, and has the fastest shipping I've ever seen. You'll probably have new coils before I'm done posting this....

Cheers,
Paul

 

Are you really sure it is the coils? Although the specs are sightly different, they are not very different.
How about sourcing a used coil just to try, or swapping the two you have.
Does the problem swap over?

 

after 15 minutes of running it starts to cough and splutter and slowly lose power.

if you rev it hard it makes the problem even worse. causing it to miss and lose power very quicky and almost completely.

i believe its one of the coils breaking down after it gets hot. what does it sound like to you?

I've had carbs tuned/valves checked/shims/brushes done in alternator and cant really imagine it could be anything else.

 

The TCI unit itself is the other thing it could be. Cracked solder joints and dried out capacitors will often have temperature-related misbehaviors.

 

doesnt really get that warm back there, the tci box after running is cold to the touch, also when i pulled the coils off the bike after running it, two spark leads were warmish and the other two were dead cold.

 

It's not the environmental warmth I'm thinking of with respect to the TCI, but rather the internal warmth of components like the coil driver transistors. These will heat up while running and will also heat the components near them.

 

dont really have one on hand to just pop in and test. which is a shame

 

If you have a decent electronics shop you can work with, you might be able to have them open it up, resolder any cracked joints, and swap in some new, high-temp (105C or better), capacitors. That should not be very expensive, as it's an easy job for any real component-level repair shop.