Symptoms of a failed ignition coil on early R1100S

oyster · Post by **oyster** » Wed Jun 20, 2012 6:50 pm

Help needed, misfiring on one side. Has anyone had a single spark coil fail on them? What are the symptoms? Is it a mild loss of power? Miss firing on one side? Just no spark? Or starts with a mild issue that progresses into failure? I would have thought that if the problem on mine was a coil, the problem would be apparent on both sides.

timbox2 · Post by **timbox2** » Wed Jun 20, 2012 8:04 pm

Never heard of a coil going on a single spark, leads though, I'd be swapping the leads round and seeing if it follows it, dont cost nothing cept time.

Oh, and PM me if it is the lead, Ive got a spare you can have, they are stupid money from BM

oyster · Post by **oyster** » Thu Jun 21, 2012 2:11 pm

Thanks Tim. I had the coil out and checked all connections, no joy, still misfiring.

slparry · Post by **slparry** » Thu Jun 21, 2012 3:40 pm

many years ago I did the shims on my Z650 and took the cams out as required to do them.

When all reassebled it ran like a bucket of spanners, fearing I'd mistimed it and bent a valve I stripped it and checked ..... many times over the course of two days .... before finding a crack in the ceramic of one of the spark plugs! Have you popped in new plugs (and caps and leads while your at it) ... or at least swap them to see if the problem migrates over?

oyster · Post by **oyster** » Thu Jun 21, 2012 4:38 pm

I tried an old set of Brisk plugs. It ran better! But still misfired.

Steptoe · Post by **Steptoe** » Thu Jun 21, 2012 6:28 pm

Check the resistance across the injectors terminals - you're looking for a reading around 16 - if one is well down or higher it'll cause a misfire, and usually high fuel consumption.

oyster · Post by **oyster** » Thu Jun 21, 2012 6:37 pm

Thanks Steptoe. I just checked, both at exactly 16.