Odd queaking sound coming from gearbox?!

[Quibble]

Ok this is an odd one...

Over the last few days I have cleaned and reassembled a V2 gearbox that needed new bushings and a re-shim. There was a problem with the bevel gear having too much play and being shimmed too low. That is now sorted. There was also a problem with the sector gear not quite clearing the cut-off lever, again sorted.

The connectors, cables and battery don’t get hot at all when firing (unlike my previous effort with another gearbox) so I’m 99.9% confident that the shim job is good! The gearbox sounds healthy each cycle (smoother than before, motor whine has reduced) and the ROF is great.

However, after 4 or 5 bursts of full auto, a strange hi-pitched noise occurs every cycle but it doesn’t sound like a gear grinding / stress kind of noise. It’s more like a hi-pitched squeak… I’ve never heard anything like it before in a gearbox.

Has anyone come across something similar to this before? I was thinking it might be caused by excessive lubrication, the piston rubbing against the cylinder or the piston sliding along the guide rails in the gearbox? Maybe it’s worth mentioning that the cylinder is not ported?

Thoughts, opinions all appreciated as always. Cheers

[BALBOSA]

Re: Odd queaking sound coming from gearbox?!

if it has a motor in the hand grip that can be adjusted either screw it in a bit fire and if it persists let it down a bit and try again, to me it sounds like the motor is the one screaming

[Quibble]

Re: Odd queaking sound coming from gearbox?!

Hi thanks for the reply. It's definitely not the motor alignment / bevel gear. I spent hours shimming that to perfection and the motor height / meshing is just right. As I mentioned before, the gearbox sounds great when cycled and the motor whine has in fact reduced. It's not a motor screaming / struggling noise. Believe me I know what that sounds like lol. It's hard to describe problems and sounds using text alone.... I'll see if I can upload a video later after work.

[Quibble]

Re: Odd queaking sound coming from gearbox?!

For those who might be interested it turned out to be dry motor bearings... it's a very old motor! A bit of 3 in 1 oil left to set in over a few days did the trick.

Thanks!

[BALBOSA]

Re: Odd queaking sound coming from gearbox?!

no way, interesting will have to keep an ear out for that in future nice one!