Originally Posted by bjr_93tz

Hi J-P,
yes these engines seem very difficult to diagnose the cause as many different causes seem to produce the same running problems. Having the tools to test each part is working properly would have saved much time and money. Once it's running well again, I'll hopefully have some good spares..

That being said, this engine did go back to YS factory early in it's life for a warranty repair during the first "horror 9 months" I described in my opening post. The failed rear bearing was easy for YS to diagnose and replace, but the failing cdi sensor was missed and caused me much grief. I was on a steep learning curve with this engine and I had the impression YS didn't want to see it (under warranty) again.

1. On the subject of the cam timing dot, for some reason the English DZ170cdi manual isn't available on the YS Japan website, but the ones available elsewhere on the 'net (and which came in the engine box) says dot pointing down. Dot up/ Dot Down, it swaps position every complete rotation of the crank so it isn't too important which we chose.

However our Japanese friends must laugh at the confusion, because in the Japanese language manuals their position for the dot hasn't changed since the DZ140.