Gearbox lock up

Discussion in 'Gun Building, Modifications & Repairs' started by kwasr10, Sep 28, 2012.

  1. kwasr10

    kwasr10 New Member

    Hi, i have a tactical force Mp5 and i was looking to upgrade it. I also have a kwa sr10 and recently upgraded it. i put the old kwa parts into the mp5. It has 100% air compression and seal. Its original spring is an m100 and it chrono's in at 300 fps. i want it at least to get to be a 435fps gun. i tried installing an m130 spring and what happens is the motor pulls the piston all the way back and then locks up. Once the piston is in the furthest back position it just wont fire. I am almost 100% sure i put everything together right. This has happened twice already. i tried 2 different batteries and i use a 9.6v 1600mah
  2. alex

    alex New Member

    i will tell you what you need to do, but i doubt very much that you will follow it. but here it is anyways (not in any particular order):

    adjust AOE
    properly check shimming starting with the bevel to pinion
    describe what kwa parts you used
    use a JG gearset with an m130 main spring
    replace motor with a neodymium torque
    replace piston with a partial teeth or full metal rack (your choice).
    if there is a piston head bearing, remove it
    use a spring guide with bearings
    replace your wires with 16awg
    install a mosfet + deans or xt60
    use a 7.4v LiPo (mAH size that will fit your battery compartment)
    don't forget a balance charger
    replace bucking with your choice of quality buckings, i prefer madbull blue
    i recommend an o-ring nozzle, but if it's not leaking, then it's a keeper
    perform a full system compression test (hopup installed, plug the barrel end and push down on the piston).
    use teflon tape to seal the cylinder head, #14 o-ring from home depot for the piston o-ring (you may need to heat stretch it).
    if you have nylon bushings, replace it with metal bushings (don't forget to re-shim).

    learn to do all this and you will have a reliable gun.

  3. kwasr10

    kwasr10 New Member

    At what angle should the AOE be? How do i properly shim and check it? BTW thankyou very much for the reply