Dirt Rider Magazine

I cant tell you whats wrong with your  bike from here but you can check it out yourself. is the cylinder off it? its easy enough to check the crank once the top end is apart.

the only other thing i'd be concerned about is the cylinder/head condition. when things come apart the cylinder is easily scored and bits can damage the head when they get sandwiched behind the piston.

if you want to do the rebuild on the cheap then getting a new conrod installed is generally ther money saver option over replacing the whole crank. an experienced motorcycle mechanic can assemble the new rod kit for you for about a half hours labour cost.

you have to check for any vertical play. any vertical play at all indicates a damaged bearing. there will be some axial play, maybe up to a millimetre. the last thing is to rotate the crank via the conrod. it should rotate smoothly with no notches or noises.

I cant recommend any machine shops sorry dude. all the ones i know will require you to ship internationally :-)

that depends on you and your dad.   You obviously need a repair manual for it.  If you are going to take it somewhere, I would tear it down to the bare bones on your own time and give only the part you can't handle.   If you want to tackle the work on your own we can offer a little help 

Sorry to come in late.

To begin, and using KTM bases pricing, a 2008 144SX piston assembly, rings and all but gaskets, will run you around $160 US on average. The connecting rod (conrod) repair kit will run you around $250 and the complete crank assembly is just over $400, all US prices. You might get lucky and it only needs bearings, which run about $40 each, but unless you have a press and truing stand, you will need a shop to do the repair for you. To be honest, unless you have a case splitter and possibly a crank puller, you are going to have to have a shop do the work anyway. In no way should you try and split cases without a splitter. I have seen people try and do it with other means and end up having to buy new cases, and those are not cheap by any means.

To get to the conrod, you will need to get the top end off, and to get to that you need to remove the tank, radiators (at times), and possibly a few other aspects outside of the radiator shrouds and such. Loosen the head bolts in a star pattern and do not take the nuts off all at once. Release the pressure slowly so you do not warp the head. The same goes with the cylinder (jug) as well. Though it will not warp as easily, if at all, you still need to release the pressure on each nut slowly so you do not damage any threads or the like. Do a good visual check of the cylinder and I suggest you also do a bore and taper check as well to see how it is and if it is in factory spec. or not.

Next, like NZ stated, check for play at the connecting rod. Vertical movement means you need to split the cases, but you need to measure the lateral movement and check it against factory specs to see if the cases need split then to get the conrod assembly repaired or replaced. Chances are that if you can move the kicker then you have not had any damage to the cylinder and such, but that means nothing for the crank. Slow movement by working the kicker with your hand is in no way the same as having that engine working at 4000 RPM and having issues of a bad crank.

Get the service manual and follow what it says and you will be fine. Good luck and keep us posted.