Whizzing through Niddrie Mill, they sped down the street with hands off the handlebars.
"We were just doing the stupid things that boys that age do," recalls Steve McKenzie. "Next thing, I hit a kerb, went flying and smacked into a brick wall."
It's the kind of accident that countless youngsters get up from, dust themselves down and head on their way. For Steve, however, it resulted in a couple of days in hospital – and a lifetime of epilepsy.
"I was OK at first. Then I had my first seizure.
"There followed weeks of test after test, before the hospital confirmed I had scarring to one side of my brain. It had to be the trauma of the accident that caused it."
Today, father-of-one Steve is among 40,000 Scots who rely on daily medication to control their condition and live with the ever-present threat of a seizure.
As Epilepsy Scotland prepares to highlight the challenges faced by young Scots with the condition, he is acutely aware of how seizures – frightening for witnesses and potentially dangerous for the sufferer – can impact on their lives.
For him, finding out he was epileptic at 13 – he's classed as having "grand mal" seizures which make the body jerk and cause unconsciousness – meant his teenage years were dominated by the ignorant reactions of some and his mother's well-intentioned fear that even the mildest activity could be harmful.
It was only when he was much older that he finally felt able to try the sports and activities he'd always been warned were simply too dangerous.
And when he did, he realised what he'd been missing.
Today he's a fourth dan Karate black belt, one-time martial arts instructor and, having completed the recent Chris Hoy Half Marathon, now planning his first full marathon.
They are the exactly the sports which would have worried his late mother sick.
"It's understandable, but she was incredibly protective," he recalls. "I was 18 when I said I wanted to try karate. She was against it in case I got a kick to my head. It was only when my dad told her that the whole point of karate was that I'd learn how not to get a kick that she accepted it.
"I grew up being told that because of epilepsy I couldn't do this or that. I was wrapped up in cotton wool.
"My friends would go swimming but I couldn't in case I had a seizure. Or pals would plan trips and I'd have to stay at home because mum was worried.
"At school I was 'different'," adds Steve, 42, who works as an accountant and lives in Gilmerton with wife Brenda, 37, and their daughter Stephanie, three.
"Kids pick up on that and things are said. I learned to deal with it by laughing it all off, but there were times where it was hard."
It's a common reaction, according to Epilepsy Scotland, which is focusing its awareness week on the issues faced by people under the age of 25 with the condition.
To combat it, the charity is issuing two new booklets specifically aimed at children, one for under-sevens and another for parents to read with their youngsters.
Epilepsy Scotland youth worker Paul Scott is acutely aware of the issues facing young people with the condition. He was just 16 and, like Steve, enjoying an activity he loved when his life was altered forever.
"I was out surfing with a pal. He lost control of his board and the pointed end hit my left temple. I went to hospital, was stitched up and went home. That evening I had a tonic seizure," he recalls.
He was rushed back to hospital, where he slipped into a coma. Brain scans were clear, however, and Paul went years before his next seizure – and news he had epilepsy.
"I was working for an advertising agency in London," he recalls. "It was glamorous and exciting. We worked hard, there was a lot of stress and a lot of drinking.
"I was in Switzerland to do ads. Someone found me one morning walking about covered in vomit and blood. It turned out I'd had a seizure and hit my head on the side of a table, splitting it open."
He was 22, and scans showed scarring to his brain. "I was taking complex partial seizures," explains Paul, now 33 and living in Edinburgh. "I'm not unconscious when they happen, but I'm not fully aware either. When I come out of them, I'm confused."
Like Steve, the temptation was to avoid any strenuous activity. But Paul had already had to cope with changing his job, reassessing his life and moving to Edinburgh to be with friends who could support him – he wasn't about to cut himself off from his love of outdoor sports.
These days he continues to enjoy the thrills of rock climbing, snowboarding and kayaking. And having successfully tackled his first 10k race, he's planning to step up to running half marathons.
"I tell young people "your epilepsy doesn't stop you doing things". I can see why parents are protective, it's a lot to ask of them to let their kids do things.
"Young people quite often haven't developed the confidence to deal with things. If you make a lot of epilepsy it ends up defining you."
Today Paul works as a sexual health education worker, has just completed an Open University course and volunteers with Crew, the Cockburn Street-based drugs awareness and sexual health promotions service.
He also helps run two groups for young people with epilepsy, encouraging them to embrace life rather than allow their condition to get the better of them.
"There's so much ignorance around epilepsy," he says. "My life has changed as a result of it, but I'm not going to let it stop me."
Epilepsy Awareness Week runs from 13-19 June. For information, visit www.epilepsyscotland.org.uk