I have a 1987 trx250x and it's an awesome bike, it's a true survivor. I got it off an older farmer and he took very good care of it. I am however looking for something faster like a 400ex or a 450r, but I don't want to sell my bike because of it's high quality for it's age. I've looked at getting some different front and rear sprockets to speed me up but I'm not sure what sizes would be best. I'm also looking for possible engine and exhaust upgrades that'll help too. Thank you.