hi dave,
not really problems only things that have broken over time,
I would keep a spare lower wishbone in your toolbox, after doing 20 feet jumps for nearly an hour, a small glancig blow by a 2 inch stone wiped out my lower arm ( the lower arms are the same for the front or rear about £8 for a set)
also , if you haven`t done so already i would purchase a cordless drill for starting, in bith mine and a friends mta4 after a few runs the fuel soaks the pull cord and teh knowt slips , then the cord comes right out, starting with a drill is fasster and easier anyway.
Do NOT !! strip the gear box unless essential, the drive cups for the front to rear propshats are VERY TIGHT and have loctite on them , making them impossible to remove with cutting.
other wise keep it clean and a drop of oil on the bearings after cleaning .and it should be very reliable and give no probs,.
the brake is not very good, but the fuel line tip i gave you earlier will make a difference.
LASTLY !!!!1 after every run , go round and check teh security of ALL nuts and bolts, add thread lock to the ones that go into metal.
also check wheel nuts are tight regularly when running, they DO come slack afetr a short period.
Adz..
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