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Scale RCM 1/3 Scale Champ Build

TonyHallo

TonyHallo

150cc
Keep in mind that the engine is lubricated via blow by. Oil from the gas lubricates the bottom end. The new plugs corrected the miss, flew five flights today without a cruising speed miss.
I noticed the ring around the fouled plug was clean, I looked at the plug under the microscope and it looked like it may have a small section that was cleaning up but too hard to tell. I did switch to 40 to 1 oil from 30 to 1 fuel recently, the Roto web site recommends 50 to1 Stihl Ultra, I sent Aeroscale an email today to get him thoughts. Yesterday the engine missed more on each successive flight.
As a side note I have about 15 flights on the plane and haven't cleaned the landing gear, the gear is just starting to show some oil from the crankcase vent. I didn't take the complete cowl off so I could not see how much oil is collected in the catch can but it is working.

IMG_2762.jpg
 
Snoopy1

Snoopy1

640cc Uber Pimp
Doe both pistons fir at the same time. Or is it timed in such a way that one fires and the other cylinder is exhausting.
 
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TonyHallo

TonyHallo

150cc
The later, one side fires, the second fires 1 rev later. Not sure how the original ignition worked, the pickup was on the cam gear. I assume there are two magnets. When I sent it to CH Ignition for conversion, a magnet and hall sensor were installed on the crank nose. So it is working in a wasted spark mode. On another site I ask Adrian why it was done this way and his reply is the timing is set different with the stock pickup.
 
TonyHallo

TonyHallo

150cc
As I think of it maybe the problem is the left cylinder is sealing better than the right and keeping the oil on the combustion side. Now that I have the plane trimmed, I'm flying it much longer so we shall see before the end of the season. The problem isn't too severe and the engine provides plenty of warning. The first sign of problem was about 12 flights ago when it missed only once during the flight..
 
Snoopy1

Snoopy1

640cc Uber Pimp
You could do a compression test to see if your thoughts are correct. If it is you can check the ring gap. But if it is flying good and just have to change a spark plug now and again it’s not worth stripping the motor down, unless you have nothing to do this winter
 
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