BMW's Marco Melandri has once again been beset by chatter problems in today's Brno World Superbike sessions and is mystified by its cause.

The little Italian suffered with the vibration problem at the start of the season but thought it had been cured. He is losing time on corner entry because it is upsetting the front of his S1000RR

“We worked on the set-up of the bike and found some good solutions. In general, the bike is working well but we are struggling again with chattering. It is not easy, because we don’t know exactly what is causing the issue but we are going to work on it tomorrow. We will try to improve it and also work with the tyres and then we will see," he said.