My friend bought a new Raleigh Mt bike with a 9 speed cassette. When the bike is under load, or even without, in the 2nd cog from the largest cog, the chain does not stay in place. It keeps popping out of place like what happens when you buy a new chain and don't replace the cassette. The bike only has maybe 40 - 50 miles on it. So, everything looks new.
I have tried the following:
1) Adjusting the cable tension on the barrel of the dereailurer.
2) Reinstall the derailurer cable.
3) Checking the chain for wear. (It was a new bike, so I thought I would eliminate this possibility.)
The only thing that I could possibly think of is if the hagar is misalligned. I don't have a tool for that, but this seems unlikely, as the only gear that is affected is the 2nd cog from the largest gear. (I dont know the # of teeth).
I've tried micro adjsting the tension on the deraurer, but not effect. The shifter does not have an tension adjuster. Any help would be appreciated.