koppel Posted December 4, 2018 Share Posted December 4, 2018 As above, if anyone knows the stock gear ratio on G&G CM's off hand you'd save me a teardown. 😁 Cheers Link to comment Share on other sites More sharing options...
Supporters Prisce Posted December 4, 2018 Supporters Share Posted December 4, 2018 Don’t quote me. But I’m pretty sure 13:1... wait for confirmation from someone who can confirm first! @Sitting Duck @Iceni should be able to concour. Link to comment Share on other sites More sharing options...
Iceni Posted December 5, 2018 Share Posted December 5, 2018 I think it depends on model. The early models were certainly on 18:1, You were lucky to push <15rps on a 7.4 lipo with them. But they were sold with the intention of pulling an M130 on the USA market. On 11.1 you were looking at <20rps when set for 350fps. The newer models I have less idea about. I've actively avoided them.What's your rounds per second and what batteries do you run? Less than 15 rps on 7.4v it's 18:1 on an 18K motor. Less than 20 rps on 11.1 it's 18:1 on a 18K motor. The safe level of RPS I would use is 25rps. Any more than that requires a gearbox rebuild, with modifications made to stop the gearbox eating itself, Short stroking ect. 25rps on 7.4 and 18:1 is a 35K motor. 25rps on 11.1 and 18:1 is a 25K motor.The other important question is why do you need to do the teardown in the first place? Is the gearbox non functional? Because if the gearbox is functional I would almost certainly do the motor rather than the gears. A motor is easier to change, and doesn't require the time or the effort that is involved with a gearbox rebuild. And in pretty much all instances when you do open a gearbox up there is more cost than just the component you originally intended to replace. It's normally prudent to do a full service, Shims, Bushings, Airseal nozzle, Grease at the most basic level, but it adds a layer of cost. You may also run into issues like the COL getting jammed up on the sector cam, loosing parts, inability to get the box closed. It is never a simple job. Link to comment Share on other sites More sharing options...
koppel Posted December 5, 2018 Author Share Posted December 5, 2018 Cheers chaps, i know it has the grey can 18k motor in it and rof is not all that high, i'll run the rof on the chrono tomorrow & see. The missus doesn't appreciate gunfire at mignight😭 Link to comment Share on other sites More sharing options...
Iceni Posted December 5, 2018 Share Posted December 5, 2018 1 hour ago, koppel said: grey can 18k motor in it and rof is not all that high Sounds like 18:1 then. Those 18K motors are pretty poor performers. A motor upgrade would probably be the way forwards for you. It's a 10 minute job, and only requires the bottom of the pistol grip removing. Your batteries might also be suspect. If you are running the older NiMh type I would use this as an opportunity to upgrade. If you are running lipo's make sure to take a note of them and post it with the chrono results. We will need to see: Voltage Capacity mAh Discharge C rating. It's 2 values normally written like 30/60c or something similar. Link to comment Share on other sites More sharing options...
koppel Posted December 10, 2018 Author Share Posted December 10, 2018 Well i got round to measuring it and the ROF is 845rpm on a 3s 1300 mah Lipo with a 33amp continuous and 65 amp burst rating. That's just over 14 a second so im guessing that confirms an 18:1 Link to comment Share on other sites More sharing options...
Iceni Posted December 10, 2018 Share Posted December 10, 2018 Just over 14rps on a 3s battery? That's an 11.1v isn't it? Those numbers seem off if it is 11.1v. Either your motor is totally shot or you meant it's a 2s battery (7.4v). Link to comment Share on other sites More sharing options...
koppel Posted December 10, 2018 Author Share Posted December 10, 2018 Yeah defo a 11.1v, also have 9.6v nimh and it does 13 on that! Link to comment Share on other sites More sharing options...
Iceni Posted December 10, 2018 Share Posted December 10, 2018 Make it harder to pick a motor for you then. Because either the gearbox is restive or the motor is absolutely pants. You may end up having to do more than just a motor change, It may need a service as well. Same rules apply however, 11.1v your looking at about 25K rpm for 18:1 gears. I would however wait for a second opinion. The motor been so weak has put me in the mind that there might be something I've missed. So @Sitting Duck have a look at this one as well please. Link to comment Share on other sites More sharing options...
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