A competitor in this year's Isle of Man TT has been fined over claims he "did not act appropriately" during a race.
The rider was fined £250 by race organisers the AutoCycle Union (ACU), who have not named the person involved.
The incident relates to some riders ignoring yellow flags, which were waved by marshals to signal an incident further round the course.
The flags signal to riders to slow down, but some have been seen to flout the rules.
A statement from ACU said: "During this year's TT Races, the ACU Events race direction received reports from the Marshals of incidents where they believed riders had ignored a yellow flag situation, requesting that they slow down as an incident had occurred further ahead on the course.
"The ACU events race direction reviewed these reports, including interviewing each of the riders reported individually, and decided that in one instance a rider did not act appropriately in a yellow flag situation. That rider has been fined £250."
The Isle of Man TT Marshals Association (TTMA) has called for the ACU investigations to be made public.
In a statement it said that concerned marshals, race officials and riders had raised the issue of a lack of attention being paid to flag signals.
It said: "The TTMA understands that certain riders have been warned and one rider fined for his transgression; this however has not been made public, therefore no one knows that anything has been done.
"Furthermore the TTMA would like to receive a response to this statement outlining any actions intended, so that they can report back to the marshals."
It added: "If the road races are to continue we must do everything we can to ensure we do not lose our valuable volunteers.
"The TTMA works hard and at some expense to recruit them and without them there will not be any races."