Bike jump out of 1st gear do you have any veiw of the gearbox setup?

Hi,it sounds from what you are saying that you have got a inturnal falt with the gearbox,im affried the only way to make a propper diagnoses is to take it apart and look at the gear sincros there has to be worn bearings,or teeth on the gears,or the sellector,or something has just manidged to come loose.
I wish you all thhe best.

its not the clutch or chain its the gearbox by the sounds of it I would say the drive dogs on the gears in the box are worn away especially if it only does it in certain gears,what bike are we talking about here /???????????

first i would try changing the gearbox oil but it sounds like internal gearbox failure

Replace or recondition the gearbox, there is wear in the first gear lay shaft.

if this is a manual gearbox then its the indent springs in the selector rod movement inside the gearbox and this will involve removing the gearbox if i have correctly located the fault ,but without the make and model of vehicle i cannot say for certain as it could be the gearchange mechanism movement inside the cars cab and if tis cable then a outer sheaf on a cable could be loose and come out of its crimped holder

as with all bikes of this nature, check for runout in wheels, loose spokes, lighting working, suspension not leaking, brake discs for exsess wear, check coolant level , check engine oil for evedence of water, leaking water pump, radiator cap leaking past overflow pipe this could be pressure in system due to head gasket failure, fuel leaking, also check area around eng oil plug for evidence of repaire with cemical metal or similar, slightly noisy tappets is not uncommon,, normaly prety good bike, avoid bikes that smoke exsessive, check all gears are working correctly. dont jump out of gear ride in every gear and check for mechanical noise from gearbox, good gearbox normaly easy to select, doesnt jump out of gear, if u are looking at buying a bike of this nature they are fairly high maintenance, like to be cleaned , oiled and addjusted frequent oil changes, these are basic things i would check when buying a machine of this type, not nessasary a ktm, and these coments are not meant to harm your decision only help you chose the rite one.

that's a bad neutral safety switch...it's a shop repair...now, the reason it goes bad:

the 1st gear is for getting the bike moving, period...you "never" wind out in 1st gear...ever...high rpm and going from 1st to 2nd is very bad for a transmission...think about how much movement is happening to go from the bottom, past neutral, to 2nd gear...that's where most trans damage occurs...once you start moving, go to 2nd, then rev it out... remember...1st gear is for getting moving only...

Hello, wheelies mm not good for your gearbox or clutch, 1st off is the gearbox working OK, does it jump out of 2nd gear under hard acceleration? then we can move on from this point,
Ian

i suspect the modulator might be faulty and mayby
trans. filter would need replacement

it sounds like you have a broken dog on 1st gear. (on sprocket inside gear box) gearbox needs stripping down and investigating.