Oil System Purge Push Gauge

I think you will find that,  for owner/maintainers, this test is done using the good old tongue in cheek (estimate) method ie no calibrated tools

The test pressure and how to do it correctly has been removed in the latest manuals.  Rotax does (or did have ..as I am not sure it is still available any longer) a tool for this to use with a calibrated scale.  (same scale we use for checking friction torque on the gearboxes fitted with a 30 degree freeplay) 

The engine is run up and when ready remove a valve cover and rotate it to TDC with the inlet and exhaust closed (compression stroke TDC)  At this point place the tool into the rocker arm pin end with the outermost pin and the other pin rests on the top of the rocker arm itself opposite the valve end.  Place the spring gauge on the tool end opening and pull down with the 16 lb force called out.  Measure the gap of the rocker arm contact to the top of the valve stem.  If under 0.5 MM (.020 thousand ") and you are good.  

A few years ago Rotax changed lifter suppliers and we now use fast bleed lifters.  These fill faster and pump up quicker than the old versions.  With these this test is rather difficult because if you delay in checking the gap it will simply bleed out too fast and the reading is inaccurate.  Because of this most technicians no longer try to get an exact measurement and use a soft blow hammer handle and just give it a ballpark push to check.  If the lifter feels solid you are good.  You can pretty much tell by the feel if it has air or is full of oil.

Cheers

I found this and used it today, it works. A bit slippery and had to push in using my belt while keeping the rubber tip on the inconveniently domed lifter with one hand and measuring with the feeler gauge using the other hand but it worked. 
https://www.mcmaster.com/product/6160K12

Hi Jim

Good find, I have seen them before but never remember who sold them.  Might be a good idea to simply make a nylon end for it, should be easy to do, could shape it to fit the lifter arm. 

Cheers

I have been successfully using that McMaster-Carr tension gauge for 11 years. I just cut the rubber tip to more or less fit the rocker arm.