Bluex5 Posted May 2, 2021 Share Posted May 2, 2021 Hi all, long term lurker but first time poster. Took my standard GSXR1100L out today, the nature of the bike and the fact it’s my every day road bike means it rarely gets revved hard however I went for an overtake in second earlier on a slow moving car and it misfired but it felt really rough, not like hitting the limiter. Did some experiments and found that it’s misfiring at about 9 to 9.5k, which is accompanied by the tacho bouncing around like its signal is also braking down. I’m thinking CDI failure. Below this the bike rides perfectly, wiring harness was new last year, bike runs dyna mini coils. Tested the charging rate and it’s hard capped at 14.68V regardless of revs so I don’t think that’s an issue. Any input would be appreciated, I know the black boxes are 30+ years old now so failure wouldn’t be entirely surprising, however the couple of failures I’ve seen previously gave total loss of spark or loss of spark on one output (I.e. 1-3 or 2-4 dead). The tacho going mad leaves me pretty sure it’s electrical. Quote Link to comment
Gixer1460 Posted May 2, 2021 Share Posted May 2, 2021 (edited) 1 hour ago, dupersunc said: Coil breaking down. Dyna Mini's don't have much of a reputation for dying! Is the misfire repeatable when engine is cold, warm and hot? A CDI swap would be useful if you have one - I have one somewhere off a K/L 1127 engine, not been used for at least 20yrs. PM me if you want to try with some details . . . . have to find it first though LOL! PS. UK for location isn't a great deal of help when looking for help! Edited May 2, 2021 by Gixer1460 Quote Link to comment
Bluex5 Posted May 2, 2021 Author Share Posted May 2, 2021 Apologies, location added The fact the Rev counter signal appears to be breaking down along with the misfire is leading me to suspect the CDI as prime candidate. Will PM you shortly. Quote Link to comment
MeanBean49 Posted May 2, 2021 Share Posted May 2, 2021 2 hours ago, Bluex5 said: Hi all, long term lurker but first time poster. Took my standard GSXR1100L out today, the nature of the bike and the fact it’s my every day road bike means it rarely gets revved hard however I went for an overtake in second earlier on a slow moving car and it misfired but it felt really rough, not like hitting the limiter. Did some experiments and found that it’s misfiring at about 9 to 9.5k, which is accompanied by the tacho bouncing around like its signal is also braking down. I’m thinking CDI failure. Below this the bike rides perfectly, wiring harness was new last year, bike runs dyna mini coils. Tested the charging rate and it’s hard capped at 14.68V regardless of revs so I don’t think that’s an issue. Any input would be appreciated, I know the black boxes are 30+ years old now so failure wouldn’t be entirely surprising, however the couple of failures I’ve seen previously gave total loss of spark or loss of spark on one output (I.e. 1-3 or 2-4 dead). The tacho going mad leaves me pretty sure it’s electrical. Had pretty much same thing with my race bike once, dropped off 2 cylinders at about 9k. Was the cdi. If its at exactly same rpm its likely to be cdi, if it varies a bit then could be coil or pickup breaking down Quote Link to comment
Dezza Posted May 2, 2021 Share Posted May 2, 2021 Check the wiring for the ignition first, especially the block connectors to and from the CDI unit as the terminals often corrode. Quote Link to comment
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