Matt Polanski, 30, was killed following an accident at the Knockhill race circuit in Fife just over two months ago.
Today, his wife Jill told how deciding to donate his organs was one of the toughest decisions she had made, but it had meant some positive came out of her husband's death.
Mr Polanski's heart saved the life of a woman, his liver went to a man, his kidney and pancreas went to another woman and a teenage boy received a kidney.
His wife said: "It was one of the hardest things we've ever had to do but I'm so grateful that something positive has come out of Matt's death."
She and her 13-year-old daughter Bethany are now urging other families to talk about organ donation and their wishes.
Almost two-thirds of organs that have been donated in Scotland over the last five years came from people who were not on the organ donor register.
With 62% of donors not on the NHS Organ Donation Register, a new campaign has just been launched urging people to speak out about their wishes, with TV and radio adverts urging people to have a "wee chat" with their loved ones about it.
The Evening Times is currently running an Opt For Life campaign calling for a change to a system of presumed consent with all the necessary safeguards built in to protect those who do not wish to take part.
Mrs Polanski recalled how she and her husband had discussed the issue three years before his death, when he was renewing the photograph on his driving licence.
She had been in the pit lane at Knockhill with Bethany, who was preparing to race that day, when her husband suffered serious head injuries in the crash.
"As soon as I heard they'd sent for an air ambulance, I knew how serious it was," she said.
The motorcyclist was treated by medics at Knockhill before being rushed to Ninewells Hospital in Dundee, but his wife said she knew "that was it" when she saw the condition his helmet was in after the accident.
Mrs Polanski added: "The neuro-surgeon then broke the news that the bleeding and trauma to Matt's head was so massive, that he'd gone."
She was then asked if she would consider donating his organs, recalling: "I remember feeling very numb as the accident had only happened about three hours beforehand.
"But I knew Matt's wishes and agreed instantly to donate all his organs, apart from his eyes. His family just looked at me but I was able to tell them that I knew that's what he wanted."
She added: "I trained as a dispensing optician and have a medical science background, so I knew how important organ donation was.
"A close family member of Matt's has one kidney, so my view was very much that if anything happened to that kidney, he would rely on someone else giving one up.
"I clearly remember the discussion and Matt saying he would have no objections for that very reason. He'd made the decision, all I had to do was honour it."
She said their daughter was "struggling" to cope but added: "When I went outside to explain that recipients and their families would be making their way to hospital, Bethany hit me with the incredibly grown-up statement that even though her daddy was gone, because of his decision, some other little girl could still have her daddy tomorrow.
"The way she handled things helped me find peace and cope with those last few difficult hours."
Mrs Polanski said she was planning to write to the people who received her husband's organs "to let them know the comfort it has brought us as a family".
Public health minister Michael Matheson met the mother and daughter at the launch of the latest organ donation drive and said: "I am incredibly thankful to Jill and Bethany for sharing their story, and for helping to highlight how important it is for you to share your wishes with your loved ones.
"In Matt's case, this discussion meant that Jill was able to make the decision to donate his organs, and this meant that he was able to save four lives.
"Matt and Jill's story is a very real example of how important organ donation is and how joining the register could save lives."
He added: "The reality is that more than 600 people in Scotland are waiting for a life-saving transplant and across the UK three people die every day because they don't get the organ they need in time.
"That 41% of Scots are now on the register - higher than the UK average of 31% - shows we are on the right track."