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Please watch this. https://youtu.be/rDZ4OfUR8EE

I recently bought that cappuccino. It developed this horribile ticking noise, like hammering on metal. Its not the IAC valve, it was stuck when i got it but its teplaced now, every other valve is functioning correct. As CO resistor it had L4, with that and the fixed IAC it could not idle correct, A/F Duty around 1V. At the moment I run it without a resitor giving me the wanted A/F Duty. Idle is around 1000. I tested the compression, the result was 10,9.8,10 bar using a weak battery. After that I took the camshafts out to check the lifters, 4 of them were broken, I replaced those (very hard to find) and put it back together. I also checked the timing, its perfect. It has new sparkplugs and oil, the spark wires are fine(Resistance).

I have really no idea what to do next other that removing the camshafts again and check the lifters again. Other than that the car runs and drives fine.

Does anyone has an idea?

Thank you

That does sound too loud and crisp for the IAC valve. I would concentrate on the valve lifters. It sounds like one of them is not "pumping up". They used to give me trouble, but I added some treatment to the oil, and thereafter always used fully-synthetic oil, and the problem has not come back. I expect the deposits which were blocking the oil flow were dissolved.

The other thing you can try, if the above has not worked, is an "Italian tune-up". Wait till the engine is warmed up, and then drive with the rpm between 4000 and 5000 for 3 or 4 miles. That may shift the muck. It did with my Peugeot.

Thank you for your replay.
I also thought it would be the lifters, now I have half Honda CBX 750 lifters and half original installed, all dont compress(tested it with my hand) but this made absolutly zero change. The four from cylinder 1 were really bad. Do you know any other lifters that may fit? I live in Germany so the original ones are not an option.

You can buy them direct from Japan, but they are not cheap.

e.g. https://www.megazip.net/zapchasti-dlya/suzuki/adjuster-hydr-valve-lash-1286053A02000

But I do think a blocked oilway is a possibility, and my above suggestions are worth a try.

Totally forgot to mentiom that the car was not moved for about four years until I got it two weeks ago. I dont know anything about the privous life of the car, so the perfect car you should not buy Already found those super expesive lifters, i will try that method you told me tomorrow, hopfully that works out.

Good luck, and let us know how you get on.

Sadly I still havent found a solution. Driving a while with high rmps didnt change anything. What I can defently say is that my lifters are fine, but if you ask me it sounds like lifter ticking on more than just one lifter. So the next thing I check where the oil passages to the lifters, there was no blockage. After that i took the head of to inspect the valves, maybe some of them were bend and wont close right so that there could be to much play, but no all seal proberly, but i saw that some of the exhaust valves where changed. Intresstingly the pistons were surprisingly clean especially piston 1, really shiny on the outside. The oil feed hole for the head also does not seem to have any blockage.
At the moment Im really clueless what causes that problem.
The next thing I do is to remove every valve and clean it and checking the oil pressure when everything is reassamled.
I hope you have any ideas

Back to the IAC valve, and perhaps I was too hasty to rule it out. Listening again, it sounds like the ticking speed is independent of rpm, which it is what you'd expect from the IAC valve, as it controls by varying the open/closed ratio, not the frequency. Also, it stops when the revs rise, which is logical, as the valve does not need to operate when the engine runs faster than idle.

Sticky IAC valves can be unstuck by spraying carburettor cleaner into the inlet port with the engine idling. Spray sparingly and repeatedly, avoiding stalling the engine. See http://www.suzuki-cappuccino.com/phpbb3/viewtopic.php?f=29&t=1307