I have just started flying a funtana. After about 10 flights the ys 63 up front has started to click quite loud. I have stopped running the engine immediately. When you turn the engine over by hand after 2 turns of the prob from the start of the stroke you get 2 clicks then it is ok for a turn then you get 2 clicks again. I have removed the rocker cover and had a look but the clicks seem to be coming from the bottom of the engine.

The engine is brand new and is being run on model technics yamada mix. Anyone out there had any problems like this or have any ideas what the problem is?

Most likely the clicks you hear are coming from the rockers. It is correct that the valves move only once each every two cycles and it sounds to me as though you have one valve far outside of adjustment. Once again, remove the valve cover and feel for excessive play. I normally set my rockers by feel going for just a tiny bit of clearance when cold. If you can really wiggle them then they are too loose. Use the instructions and a feeler gauge to be sure you are within tolerances. I shoot for the tight end of the specifications.

Mark

would the clicking come from the botom of the engine though? even with the cover off the clicking comes from underneath the engine

Pull the back off the engine and check the disk valve. It's the round disk on the backplate. This is sometimes loose and creates the clicking. Theres a set screw that holds the shaft. You want it to turn freely but not wobble. Pay attention when you put it back together. Theres a key on it that fits into the crank to make it turn.

The clicking may be coming from the cam gear hitting the bottom of the rods, The excessive play would leave a gap that is allowing the gear to loose contact and then make the sound when it makes contact on the next cycle.

OS makes a valve adjustment kit with feeler gauges and a little wrench or you can get the feeler gauge at an auto supply store. Check the instructions for adjusting the valve gap since you would not be able to tell just by looking.

Madfreestyler, the clicking you are hearing is more than likely the cam gear. Every YS I have and I do have a few of them, clicks exactly like your does. If the clicking gets very loud you will notice a loud clicking noise when the engine decelerates. It almost sounds like a buzzing sound. Make sure you are using at least 20% oil in your fuel. To get rid of the noise you will have to purchase a new cam. A friend of mine just replaced a cam in his YS120 this week that had the exact same noise you are talking about. The noise is now gone and the cam was $30.00. If the engine is still under warranty send it to YS for servicing and a free cam.

Good luck. Bob

cheers guys for all your advice, much appreciated!!!!!!!!