Really I don't see the need to change a diaphragm on a yearly basis.

The only reason to change the diaphragm is if it gets deformed. This happens when the engine sits for a long period of time and doesn't get run. On the older 91' since it has the plastic like diaphragm-gasket combo...theis can happen quicker than the two piece diaphragm gasket combo of the earlier YS 120's and the 06'-later 110's

However there is no reason to change diaphragm and gaskets just because the engine is a year older.

When the engine sits for a long period time unused....then the diaphragm can become deformed...This is when to do it.

So a preventive little thing is to keep some diaphragms on hand and once a year replace it just to make sure I guess....But its not something that needs to be done on a regular basis just because....

If you fly on a grass or dirt field...you may consider new bearings more often that a guy that is flying on pavement all the time. That doesn't mean every year...I would say grass field a good number is 150-200 flights start to think about a replaced rear bearing. Pavement it can go about double that 300 -400 flights and then its likely time for a new bearing. It all depends on how much use you have on the engine.


Troy Newman
Team YS