Joe Screen has stepped down as Belle Vue captain to concentrate on sorting out his mechanical problems.
The Aces veteran has been suffering engine problems in recent meetings and has decided to step aside to try and solve the issues.
"I have not been able to give the captaincy the kind of attention I have wanted to because I have been too busy trying to sort out my own problems," Screen said.
"Hopefully, it will be a short-lived problem because I've got a brand new engine coming shortly from top Danish tuner Brian Karger."
Aces team boss Chris Morton added: "Joe feels he can't give the job the attention he wants at the moment. We felt it was a reasonable request in the circumstances and we reacted to it."
Belle Vue have yet to decide on their new skipper with the choice seemingly between Jason Crump and Charlie Gjedde.
Meanwhile, Belle Vue star Steve Boxall is to decide whether to ride again or not this season.
"His arm and shoulder are stronger than they were when he returned for the British Under 21 final and scored ten points," said Morton.
"The surgeon has said he can ride if he has intensive physio and leave the operation until the end of the season.
"He will need three months recuperation after the operation so it would put him out for most, if not the rest of the season, if he has it now.
"Steve's first reaction was to have the physio and carry on but we'll be having further talks with him this week."

Pedersen reigns in Poland
Grand Final 2nd Leg - Heat 14
Grand Final 2nd Leg - Highlights
Swindon v Wolves - Woffinden
Woffinden hopes to clinch title
Ward wins U21 title
Wolves 54-38 Swindon - Heat 15
Wolves 54-38 Swindon - Highlights
We give you the chance to see Australian star Darcy Ward claim the World Under-21 world title in Croatia.
Speedway's furry friend answers more of your questions ahead of the Elite League Grand Final.
Sky Sports' Nigel Pearson cannot wait for the play-offs to begin with the Elite League title on the line.