Police say they stopped a rider for going the wrong way on the Mountain Road today.
This was followed by a positive drug wipe test for cocaine and cannabis.
It comes after seven riders were stopped for speeding on the route over a period of two hours yesterday evening, Sunday, May 31.
Officers are reminding people to check the 30mph speed signs as they approach Ramsey Hairpin.
More childcare support available for next school year
Superstock race to be rescheduled to tomorrow
Former infrastructure minister to defend seat
Fundraiser launched for paralysed TT star
Keep jet skis out of swimming areas, says Coastguard
Peel's first live beach gig called off
40 arrests over Mad Sunday weekend
Anti-vax campaigner back in court