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Hi, Ive been reading your posts and my z13 is doing exactly the same, I've just rebuilt the engine using different head and cams. All valve seats recut and shimmed up to spec, checked gaps twice.
As with you, top right side and only when hot. It definitely sounds like a loose shim gap but can't imagine why. The engine has only been run for a few hours so will have to keep a close eye on it.

Petez13 wrote: Hi, Ive been reading your posts and my z13 is doing exactly the same, I've just rebuilt the engine using different head and cams. All valve seats recut and shimmed up to spec, checked gaps twice.
As with you, top right side and only when hot. It definitely sounds like a loose shim gap but can't imagine why. The engine has only been run for a few hours so will have to keep a close eye on it.

I just had a good listen to your bike running from your latest post on uneven exhaust pressures and I couldn't make out your ticking noise. Maybe it wasn't hot at the time?

I found that the number 5 cylinder is not firing until it gets up to some crazy revs (6000-7000) and then it starts to splutter a bit, heaps of spark as well. I was hoping that you guys might be able to tell me if a valve problem will cause this?

I have spent the last 2 days trying to discount all the other scenarios i.e. pulled the carbies and gave them a once over and all journals and jets seem to be ok. Tested the ignition coils, tried testing the ic igniter but the tests on that always fail. I did send the unit to Carmo Electronic in the Netherlands to have it tested october last year and it passed. That doesn't mean it's still ok now though. Checked the timing and it tested fine on No. 6 but didn't pass on No. 1 at 3000 revs. Checked the HT leads and spark plugs. My ignition coils measure 2.5 ohms on the primary and 13500 on the secondary and I still have the original resistor installed.

I just want to make sure that I'm not missing something. Thanks everyone for your help so far

Yaegunp wrote: I found that the number 5 cylinder is not firing until it gets up to some crazy revs (6000-7000) and then it starts to splutter a bit, heaps of spark as well. I was hoping that you guys might be able to tell me if a valve problem will cause this?

I have spent the last 2 days trying to discount all the other scenarios i.e. pulled the carbies and gave them a once over and all journals and jets seem to be ok. Tested the ignition coils, tried testing the ic igniter but the tests on that always fail. I did send the unit to Carmo Electronic in the Netherlands to have it tested october last year and it passed. That doesn't mean it's still ok now though. Checked the timing and it tested fine on No. 6 but didn't pass on No. 1 at 3000 revs. Checked the HT leads and spark plugs. My ignition coils measure 2.5 ohms on the primary and 13500 on the secondary and I still have the original resistor installed.

I just want to make sure that I'm not missing something. Thanks everyone for your help so far

Since they share coils with another cylinders I doubt that would be the case but you could try swapping the coils around to see if the non-firing cylinder moves as well. I'd also swap the plugs and wires to a different cylinder just to completely eliminate the possibility. I had a brand new dud plug which I discovered by moving it from cylinder 1 to 6. If your ignitor was bad I don't think the problem would be limited to one cylinder.

I'd still be inclined to say something is buggered with that carb if everything else checks out. They are finicky bastards. One tiny little piece of crap in the wrong place and it will run like shit.

The ticking noise isn't as noticeable as yours but it's definitely there. If you turn up the volume on the video clip you can hear a bit on the overrun. The video was more to show the uneven exhaust pressures, if held around 4000 rpm you can't miss it.