King Arms 6mm bushings too tight?

[Chuuchuu]

Did some searching and googling, but haven't found any answers I was looking for.

I bought some new King Arms 6mm oilless bushings, and they fit nice and tight into my mechbox. However, when placing the gears into the bushing it was a bit tight, and the gears didn't spin as smoothly as my nylon bushings. But they moved, so I figured it was good enough.

After assembling the bushings I installed my Bushings, Guarder SP 120 spring and Guarder spring guide (the awesomely heavy one), I gave my gun a test run. Nothing spun at all.

I figured the spring was too strong for the motor, so I downgraded it back to my stock spring. It shot a few times, and then it got stuck on the last tooth on the piston. Thats when I started to worry about the new bushings I bought

So I went back to my stock bushings and stock spring, and it started shooting flawlessly again.

So now I'm thinking, maybe the new bushings were too tight, and yes, I've greased them properly. I've read some advice where people told me to drill the bushings, but before I do that is there a better approach?

[stokes]

Buy new ones...

[TokyoSeven]

Maybe it was a fluke shim related incident?
If you have the time you can put them in again and keep your fingers crossed.
Im no gun doc sir, but best of luck.

[CDN_Stalker]

Whenever you install new bushings and/or gears, you should check the shimming to make sure it's good. Not all bushings are made equal, some can easily use the stock shim types and locations, others might need one shim less or one shim more to make it work right. I'd say that the bushings you installed are not quite the same as the stock bushings, therefore too tight of a shim job, causing the problems you have.

Reinstall the metal bushings, take out the cylinder and tappet plate, then put your mechbox together and snug down two screws (middle and back works best), then use a small screwdriver to spin the gears. If they don't move much at all or takes a lot of effort, you found your problem and are on your way to the first (of many) shimming experience of your life. Good luck!

BTW, it's easy and straight forward, just time consuming. Ideally you want to check each gear's shimming individually, start with only the spur gear, make sure it spins and doesn't have any side to side movement. Then the sector gear alone, then the bevel gear alone. Then all three, and you are done. They should spin maybe a 1/4 to a 1/2 turn after you give them a shove.

[Omi-san]

Originally Posted by CDN_Stalker

Reinstall the metal bushings, take out the cylinder and tappet plate, then put your mechbox together and snug down two screws (middle and back works best), then use a small screwdriver to spin the gears. If they don't move much at all or takes a lot of effort, you found your problem and are on your way to the first (of many) shimming experience of your life. Good luck!

I wonder why mechbox.com and other tutorial sites omit that detail. Makes a hell of a difference when your mechbox is held by the screws instead of just your hand.

[Chuuchuu]

Originally Posted by CDN_Stalker

Whenever you install new bushings and/or gears, you should check the shimming to make sure it's good. Not all bushings are made equal, some can easily use the stock shim types and locations, others might need one shim less or one shim more to make it work right. I'd say that the bushings you installed are not quite the same as the stock bushings, therefore too tight of a shim job, causing the problems you have.

Reinstall the metal bushings, take out the cylinder and tappet plate, then put your mechbox together and snug down two screws (middle and back works best), then use a small screwdriver to spin the gears. If they don't move much at all or takes a lot of effort, you found your problem and are on your way to the first (of many) shimming experience of your life. Good luck!

BTW, it's easy and straight forward, just time consuming. Ideally you want to check each gear's shimming individually, start with only the spur gear, make sure it spins and doesn't have any side to side movement. Then the sector gear alone, then the bevel gear alone. Then all three, and you are done. They should spin maybe a 1/4 to a 1/2 turn after you give them a shove.

Actually I didn't even try doing that yet, and closing the mechbox while spinning the shims sounds a lot more feasible than what mechbox.com suggests. I shall try out your advice, many thanks