xs1100 coils

[650mark]

when, and if, the ignition coil(s) fail do they just die suddenly or do they slowly fail? other than the bike not running, what other symptoms show up?

[DGXSER]

A few weeks back, a fellow XSive had bad miss in the low RPM range. Worse when you gave it more throttle. Turned out to be bad coils. Spark was weak at the lower output of the alternator in low RPM range.

[James England]

I used to have an annoying splutter which disappeared forever when I put the green Dyna coils on. I'd always assumed it was fuel but it definitely wasn't!

[TomB]

A few weeks back, a fellow XSive had bad miss in the low RPM range. Worse when you gave it more throttle. Turned out to be bad coils. Spark was weak at the lower output of the alternator in low RPM range.

I've just had exactly the same, below 3K rpm cylinders 1 + 4 would cut out, above 3K rpm they chimed in and ran great, I assumed it was 1 + 4 pick-up coil wires but they checked out Ok, changed the coil and back to normal running.

I also came to the conclusion it was worse at lower revs because of lower voltage output from the alternator, it was a pig to start only going if jumped with leads from a mates bike that was running.



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[Diskman01]

My stock coils seem to develop a misfire when very hot (+95Degrees) in city. Since it's been 60s and 70s lately it seems to run GREAT. And when the bike sits for a while after running (heat soak) they will develop a weak spark again.

I really need to replace my coils. No $ right now.

[DGXSER]

A less expensive option on the coils is the Honda VF1000 or Magna coils. They are a direct bolt in replacement for the 3 ohm coils (or just remove your ballast resistor like you would using the Dyna coils). You can spot them on evilbay for less than $40 often. The UK website list them as an upgrade for the bike, and I have been running them for about a year, it is also what I put on another members bike. So far he loves them.

They are still used coils, but they are much cheaper than the Accel or Dyna coils and they have replacable plug wires. So for the budget minded, they can make good sense.

[TomB]

I used Honda Fireblade coils to replace my bust one, they're the same as the VF1000 coils as far as working goes, just the fitment is slightly different as they have smaller hole centres, I just use one bolt instead of two. If you are happy to make little brackets bolt them up with two.

I've been running these type coils for a few years on one of my other XS11's without any hassles, the good thing about them is they have separate leads so they can be replaced.

Most modern coils (dunno about the plug top ones) I've come across are 3 ohm coils so will fit the XS11 with the ballast resistor removed.

[skids]

My stock coils seem to develop a misfire when very hot (+95Degrees) in city. Since it's been 60s and 70s lately it seems to run GREAT. And when the bike sits for a while after running (heat soak) they will develop a weak spark again.

I really need to replace my coils. No $ right now.

Bad plug connectors also get worse when hot. Make sure it is the coils 'cause the plug connectors are WAY cheaper.

[TopCatGr58]

Hey Diskman,

Your profile says your bike is a 78E, would be nice to have that info in your signature so it would show with every post instead of just in your Profile!

You may also want to check your ballast resistor, it gets quite hot when working, may be having increased resistance than normal with the heat which could drop the coil voltage even more! But like has been said, check the plug caps, they come apart where the plug goes in, inscrews, internal resistor there also, should only be ~5k ohm.

T.C.

[Mashermoto]

Diskman,

I had a similar issue with my 78E this summer that turned out to be a bad pulser coil. The test to check it is very easy to perform.

Unplug the 4 prong connector from the TCI unit and check resistance. White/red to White/green is for pick up coil number 1. Yellow/green to yellow/red are for number 2 pick up coil. Both should be 720 ohms, plus/minus 20%.

If that's not it and you are sure it's an ignition problem, then coils, plug wires or plug caps are a good bet.

[Rick Cwalina]

1980 yamaha ex 1100
no spark

Replaced coils and ignition unit .
Have voltage where I should still mo spark.
I hot wire white wire on stator and get spark on 1 and 4.

[Radioguylogs]

1980 yamaha ex 1100
no spark

Replaced coils and ignition unit .
Have voltage where I should still mo spark.
I hot wire white wire on stator and get spark on 1 and 4.

Measure the resistance of the ignition pick-up coils (aka pulsar coils) per the instructions in the service manual. Let us know what you find.