TT Pro 50 H issues.

[Dox_21]

Hi all.

Been flying my second hand raptor for about a month now, and all has seemed well so far. But there are a few issues that concern me.

Raptor technique states that I should be able to turn the starter coupling with little to no resistance from the engine. Well I can only turn it about half a turn before it gets extremely stiff. Another 8th of a turn and it goes back to being lose, another half turn later and its tight again. I assumed this was normal and down to the engine compressing, but it even does it with the plug out.
The clutch is fine, as are the starter shaft bearings.

Also, I was flying today, just hovering, and I noticed strange things happening. Every couple of seconds the rpm would drop very slightly, for a breif moment, and then return to normal for a few seconds. This drop of rpm wasn't enough to make the heli drop noticably in the air, but it was enough to kick the tail slightly. eventually the rpm dropped more consistantly instead of 'pulsing', so I landed and packed up.

I understand that the second issue may be a tuning problem, or a bad clunk, but the first issue has me baffled.

[Dox_21]

Ok, I just took out the tank and had a look at the clunk.

By all accounts, the clunk line is completely ruined! It doesn't appear to be split, but it has shrunk to about half the diameter of the normal tube, and it feels like jelly! I'll replace and report back. I'll also remove the engine and check that the fan is tightened down against the engine.

Also, to add to the first post, the heli doesn't idle very well.
Clutch clearence shouldn't be a problem as I used 3 wraps of tape instead of the recommended 2, but in order to stop the engine cutting out I have to turn the bottem throttle position up so far that the blades are trying to spin.

From what I have read, this could be caused by the low speed needle being too rich. I'll try leaning slightly and see if the situation improves.

BTW, I've never tried to tune an engine before.

[Rickenbacker]

So your starter shaft is catching when you turn it (backwards, not the way that pulls the engine round)? Make sure you removed the washer from the front of the engine, the fan assembly should be snug against the front bearing with nothing in between.