I have a 97 XX with 2 Bros slip-ons and K&N filter. I rejetted with a Dynojet kit during the winter. Set up per the dynojet recommendations. The bike seemed to run great at first. The last two weeks the weather has been mild and I have put a few hundred miles on it. Now it seems to sputter a bit at low rpms, it also seems to hesitate a bit when I crank it wide open at about 5000rpm. I didn't do any of this when I first did the installation. Any thoughts? It also seems to run better when the engine is cold.