Was out testing my Translogic flatshift system last night and managed to hit a false-neutral. Slotted it back into gear and noticed power was way down and thought the worst - however, it sounded like it was just misfiring (maybe running on 1-2 cylinders) and I nursed it home at 4,000 RPM (sounded terrible).

Back in the garage, I noticed that exhaust pipes 2 & 3 were a lot cooler than 1 & 4 and upon removal of the spark plugs, I noticed the pistons of 2 & 3 looked wet (unburned fuel I guess), whereas 1 & 4 were dry. I then tested the spark plugs by turning the engine over with the plugs out and yes 2 & 3 were not working, 1 & 4 fine.

This suggests that the coil serving 2 & 3 is knackered - is it reasonable to presume that the false-neutral sent the revs sky-high and consequently blew the coil? I don't know how many revs it was doing when I was periodically in neutral but I'm guessing it was high!

If anyone has any spare carbed R1 ignition coils then please let me know!

Thanks

Try swapping the coils over before spending any money.

Hi - i took the trigger wire from the 'good' coil (which fires 1 & 4) and transferred it to the 'bad' coil to see if it would fire 2 & 3 - it did not, so I assume the problem lies with the 'bad' coil and nothing 'upstream' (I can take the trigger wire from the 'bad' coil, transfer it to the 'good' coil, and it fires 1 & 4 fine).

Check the compression too but hope it's justs a coil !

Don't want to sound negative, but there is no reason I can think of why hi revs should blow a coil.
Hopefully it is, but more coincidance than cause.

Also rev limiter should protect the engine from any damage.

John

When you sawpped coils, did you swap plugs too? A wet plug will not fire....

Did the Yamaha tests on the coils and they were both fine! The only wires I did not test were the +12V feeds to the coils - one of them was dead! It is the +12V feed to each coil that is cut by the ignition-interrupt box and it seems that on the upshift, the power to both coils was cut, as normal, but one regained power and the other didn't, hence the misfire. I don't think I actually hit a false neutral at all, it probably just seemed so from the lack of power from the misfire. Have now removed interrupt box.

CHEERS!

One more thing - do you think I should replace the spark plugs on the non-firing cylinders? I had to drive about 6 miles with only 1 & 4 firing, to nurse the car home. ta.

Yes. Unless you bung them in the oven on gas mark 5 for an hour they'll be stuffed...

Just don't let Mrs Ferrino know if you do!