Ave got a ktm 125sx 02 just done a top end rebuild piston air filter and plug but the bike still wont start with a kick only with bump any ideas thanks

Lots of engines make characteristic noises and air-cooled 2-strokes have lots of characteristic noises even when new and even when there is nothing wrong.

If you have just spent a parcel of money on it your first port of call should be to the person or dealer who carried out the work. Having a top and bottom overhaul means a world of different things to different people. If you don't know what has been done and what needed to be done you will be somewhat in the dark and at a disadvantage with perhaps unrealistic expectations.

Perhaps the engine hasn't had as much of an overhaul as you thought. A full bottom end overhaul is a good deal of cash and lots of work that would make it as good as a new engine again. Maybe the dealer decided for reasons of economy to refit some of the old parts instead of replacing everything.
I suggest you read your invoice and then go and ask some leading questions.

unfortunately the most cmmn cause for a bike not starting ff the kick start but starting with a bump is being too low on compression,although to you foot it may feel like enough it does need to be nearly 100% as high as it should be to kickstart.the easiest way to check the condition of the piston is to take the exhaust off and look up the port in the barrel ,it is usually the exhaust side of the piston that gets damaged as it gets hotter.good luck.Adam

check the carb float level and mixture settings

hi
If you have run the engine with too little oil then there is probably damage to the piston / rings & / or bore
Remove the exhaust to have a look

Ride Safe
Bike-Doc

Could be low compression due to head gasket leak, worn piston rings. Or bad spark due to dirty plug, wrong gap, plug breaking down, lead or cap breaking down, ignition fault. Choked air filter, fuel filter.
Try these in easiest order I.E. remove air filter and see if it starts easier, do a compression test, cahnge plug, lead cap. Check the fuel filter.
I am sure it's a simple solution.(high milage engines tend to be difficult to start so take this into account)

timing could be slightly take the magneto casing off then remove the cylinder head when the piston is at the top of cylinder head a metal lump on the magneto should line up with the first or second marking on the casing behind the magneto, carb might need cleaning,if its been rebuilt because of piston ring blowing then maybe they didnt skim your head properly your best off takin the bike apart which really aint that differcult go up to the main engine lump and you wont have that many problems

gearbox oil-20w/40 0.73 qts. cooling system-1.26 qts. 50/50 mix 2-stroke oil-shell racing x/40 fuel grade-98 spark plug-ngk r 6918-b8 spark plug gap--.024" main jet-190 idle jet-48 needle position-3 pilot screw # of turns out-1.5 rear tire pressure-14 lbs front tire pressure-14 lbs keep air filter element well cleaned & oiled w/ air filter oil.there are service manuals available for this model.