Ignition issue

[Sable]

Heya, I have a 1990 FZR1000A which has developed an odd problem. After about 50 minutes of riding the engine will die and refuse to start up again for about 15 minutes. After about 35 minutes the engine feels like it starts firing on 3 cylinders. When it starts playing up I get a lot of overrun noise, backfires etc until it dies. The motor when it's running sounds sweet, no odd noises or anything. My initial thought was the coils or the trigger wires thereof, although someone else suggested the fuel pump to me. Any ideas, or any common faults with this model? It's done 95,000k and allegedly had the engine rebuilt 15 thou ago although considering the bodywork, frame is in good order and cost ~$900US. Thanks muchly.

[McFizzer]

It could be running rich and flooding the carbs.. if it was an ignition problem with th coils I would say that you'd have problems on starting all the time. Have you taken the carbs apart for cleaning and to make sure that the jets are all clean and correct but I'd look more into what the float height may be.

[coreo19]

ignition coils can go bad with heat. the bike could run fine at start up ( ignition coils cold) but once the motor gets warmed up along with the coils, the coils could be shorting out or something with heat. but id think or atleast hope the motor would be warm before a thirty minute ride time or 50 minute ride time.....take both coils off heat them up and test resistance or ohms with a multimeter

[chefen2006]

hmmm...I the CDI can fail the when it heats up. I had a Suzuki looooooog time ago with the same problem. Went fine when cold and once it heated up it died. Had to wait till it cooled down to start again. I gues you could try to replace the CDI with a good one and see what happens??

[chefen2006]

...ahh and check for sparks when the problem is pressent,that way you will know if it is ignition or carb related.

[reelrazor]

Ehh, I am thinking this is compression related.

Specifically- tight valves.

Rebuilt 15k ago-prolly no valve lash check/adjustment at the 'break-in' interval after the rebuild....done another service interval since then....

Starts backfiring prior to no-run.

Like chefen said....make the problem occur, and check spark immediately. I am betting it is there. keep a long phillips head with you, and open a couple of the bowl drain screws..I am betting you have fuel.

Then, get it home and check valve lash. I surmise that you will find .000" lash on a number of valves.

Hot failure coils, and ignition modules usually don't start altering timing..they just drop cylinders or flat out drop all spark

[yamaha_george]

Ehh, I am thinking this is compression related.

Specifically- tight valves.

Rebuilt 15k ago-prolly no valve lash check/adjustment at the 'break-in' interval after the rebuild....done another service interval since then....

Starts backfiring prior to no-run.

Like chefen said....make the problem occur, and check spark immediately. I am betting it is there. keep a long phillips head with you, and open a couple of the bowl drain screws..I am betting you have fuel.

Then, get it home and check valve lash. I surmise that you will find .000" lash on a number of valves.

Hot failure coils, and ignition modules usually don't start altering timing..they just drop cylinders or flat out drop all spark

[sweekster]

Ehh, I am thinking this is compression related.

Specifically- tight valves.

Rebuilt 15k ago-prolly no valve lash check/adjustment at the 'break-in' interval after the rebuild....done another service interval since then....

Starts backfiring prior to no-run.

Like chefen said....make the problem occur, and check spark immediately. I am betting it is there. keep a long phillips head with you, and open a couple of the bowl drain screws..I am betting you have fuel.

Then, get it home and check valve lash. I surmise that you will find .000" lash on a number of valves.

Hot failure coils, and ignition modules usually don't start altering timing..they just drop cylinders or flat out drop all spark

[coreo19]

when i did my valve lash i had a 5 or 6 valves out of the 20 that was .000 and it ran fine but pretty much impposible to start. once started it ran fine. also ran a ton better after the valve lash. but like reelrazor said you could very possibly have some very tight valves

[erniefzr1000]

Bad coils or CDI related to heat. Also check your trigger wires, I worked on a biked that wasn;t getting spark to one of the cylinders, I figured it was the coil, but on further investigation the wire had a defect and was not making contact inside the coil.