TOPIC:

I took my KZ1300 for a second ride yesterday with increased distance of 50km round trip..long enough to start to cook my boot. Speed between 80-90km/hr with odd steady burst to 100km/hr for maybe 1 minute every now and again.

My problem was that 5km from home she started to misfire badly,running on odd cylinders very rough. Apply throttle and response was negative or a bit of speed maintenance but difficult to increase revs.

My best guess is that there may be fuel vaporising but I think it was not indicative of fuel starvation as it was firing on some cylinders. My other guess is that the coils had a good chance to heat up and started to break down. The coils when I assembled them from original had cracks in them and I glued them up!!. Since then I am aware that if they have cracks then the internal insulation can break down....maybe this is the problem.

On the fuel I may also have the line too close to the block. Again I think it should be running above the valve casing ?

My question is : How to determine which is it...fuel or coils.

I left the bike over night and this morning started it up and it is running nicely ..fired first crank no choke and idled and revved in a few blips to 2500 revs. All good at that point but I did not go for a run in case I had to walk home.

Hence my thoughts it could be either problem or both??

Any suggestions before I jump in head first would be much appreciated
Thanks Bill
Aust

I had almost exactly the same thing happen to me. YMMV, but what it was in my case was a virtually invisible coating of dust inside the vacuum piston bores that caused them to stick. As you probably know, the ONLY thing that causes the CV carb pistons to return to idle is their weight. No springs. What happened to me was that the center carb's CV piston stuck wide open. This doesn't cause a runaway RPM, because the throttle valves still close as normal, but my engine would gag and refuse to accelerate above 3000 RPM. It was unrideable, and believe me, I have a very loose definition of that! I couldn't even get 1/4 mile home before I went and got my WD-40 to flush out the CV bores.

That is something else I that had not occurred to me. I will also look into that.Thanks.
Have you had any coil failures due to cracks in the out case?

No, but my bike has less than 6,000 miles on it, and was mostly kept under cover since its owner stopped riding it over 12 years ago, so probably not the best one to ask.

There are lots of people who recommend substituting Gold Wing coils for the stock ones (search the site) and there are MANY other variations of the GW-style coils out there, so don't feel like you have to spend top dollar for a specific part number just because that's what your bike came with. There are many other options that use exactly the same mounting and wiring setup, just pay attention to the primary resistance and use a ballast resistor if required.

If you suspect coils and fuel evaporation , do the easy one first , re-route the fuel line . Mine goes down , and up to the carbs , others may route theirs differently . If the Coils are original , they have many Years on them , and being split will not help , O.K fixing for a 'Get You Home ' , but Me , I would be looking to replace them .

Thanks Clive, I will do the fuel line . The coils that are cracked are the AW82-TRi which I will change as they must have a few miles on them if they are cracked . There are too many hills around here for me to push it home for the sake of changing out old coils.