+1.25 swing arm on 04 450r

[gibson450r]

i need help got a 1.25 swing arm from houser for my 04 450r so this makes it 06 07 length but when i go to measure the chain if the carrier is all the way loose the chain basicly fall of it so loose if i measure with the carrier all the way tight its still to loose to attempt to ride what am i doing wrong the gearing for the 04 05 is diffrent from the 06 is this the problem thanks anyone who could help

[250rmike]

go buy a chain cutter or pin popper and shorten the chain most dirt bike/atv stores should have them