Mountain Biking - CHain Keeps stikkking~!~~~

HI, guys, my chain broke last week, i got a new a stronger one but the teeth of the crankset were not good so we replaced the crankset, i try it today but in the 6 and 5 gears when i apply some pressure the chain skips.... What could be the problem?>>
thanks

It could be that the cassette is worn and may need replacing. Inspect the teeth for wear.

Have a look here (http://sheldonbrown.com/chains.html), particularly the section on chain and sprocket wear.

derailluer adjustment?

derailluer adjustment?
Possible. http://www.parktool.com/repair_help/FAQrindx.shtml

Given the problem appeared after a new chain was installed, I'd check the cassette for wear first.

Look, i checked the cassette, and there is a teeth missing, well i put the other wheel of my other bike which have the same cassette and it keeps doing the same thing

Look, i checked the cassette, and there is a teeth missing, well i put the other wheel of my other bike which have the same cassette and it keeps doing the same thing
The cassette from your other bike might be the same, but it's position on the hub may be slightly different which will mean your derailleur does not exactly line up with the cogs. You'll need to adjust the derailleur, possibly both limit screws and cable, if you want to use this wheel.

If there are teeth missing on the cassette, get a new cassette installed and then adjust your derailleur.

Could also be your front cogs, my last bike wore them out and threw me to the ground regularly before I fixed it.

Could also be your front cogs, my last bike wore them out and threw me to the ground regularly before I fixed it.
I think he said he's already replaced the crankset...

New chain + old cassette often = skipping in certain cogs. So both of your cassettes are worn. Hmmmmmm...

ok, i adjust the derailleur, and still doing the same thing, i look at the teeth and they look ok, Could it have been the the new chain does not match with the derailleur..

ok, i adjust the derailleur, and still doing the same thing, i look at the teeth and they look ok, Could it have been the the new chain does not match with the derailleur..
How many cogs on your cassette? What chain did you buy?

I think he said he's already replaced the crankset...
Oops. Busted not reading them through! :o

Yes, look what i did, (the Old chain IG51 shimano) the one that brokes, and the local shop said to put the HG (i cant remenber the model but it was the lx, ) he says it was stronger than the IG, One of the mechanics says it was not going to fit and the other two said yes. they put it in anyways and when i try it at the trail its happens,... What i did is I put the old chain the IG51, and guess what nothing happens, so its defenely the chain.. I will take it to the bike shop tomorrow, to explain the chain they installed is not the right one....