Nostalgia. The ease of working on the engines or simply to learn a new skill. Brian Baillie has another reason.
His bike, a parakeet-yellow Honda 4/400 from the era of Donna Summer and footballers with curly perms, was registered in 1977, the year he married Anne.
He says: "That's one of reasons I've kept it. I've been married 37 years and my bike is 37 years old. There's a connection and a sentimental value."
Baillie is the secretary of the Ayr Classic Motorcycle Club, which is hosting its 25th annual show tomorrow (sat June 7) at Ayr Racecourse. There will be 125 classic and custom motorcycles, from the heyday of the British scene through to the domination of the Japanese, with examples from France, Germany, Italy and the USA. The oldest bike will be a 1914 Victoria, made in Glasgow.
There will be displays from Triumph's stunt-rider, Kevin Carmichael, from Kilmarnock, and there will be a band, autojumble, trade and clothing stalls.
Baillie, who says his parents would not let him have a bike when he was growing up, is almost umbilically connected to the show. He first saw the classic four-cylinder, air-cooled Honda in 1988 at the classic show on the Sunday. On the Thursday, he passed his test. The next day, he bought the bike.
He says: "It's a good wee bike to work on, though balancing four carbs can be tricky. The braking is rubbish. It's a single disk on the front, a drum on the back."
Baillie served his time as a car mechanic before retraining as a techy teacher - he works at Carrick Academy, in Maybole - and didn't pass his bike test until he was 42. Before the bike, he had a classic car, a Morris Minor. He said: "When I had the Morris, there was lots more to go wrong, especially if the car is not used much. Its brakes may seize, you might have to touch up the sills. A bike does not suffer the same."
Baillie bought the bike for £1500, and over the years has spent a further £800 on it. His voice fills with pride when he talks about it. "Any motorcyclist, if you mention the 4/400, will say 'Oh, they were lovely bikes.'
"It was in a fair condition when I bought it. It was a bit tacky. There were various things wrong - the cam chain adjuster wouldn't adjust, so in order to repair that, you need to strip the engine."
The Top Gear presenter James May has a 4/400 in blue, and the bikes are a favourite with restorers. "You can get any part - there are various companies doing copies of parts because they are highly sought after."
I'm surprised how small the bike looks in the metal and I'm even more surprised when he tells me the 400/4 was only imported for two years, as to this day it's not an uncommon bike to see, more than three and a half decades after imports stopped. Baillie, a youthful 59 years old, says the profit margins on it were tiny. "It cost the same as the Honda 750 to build."
The bike was almost 20 years old when he bought it, and had a dozen previous owners. Although he has restored it, he has left, in the name of authenticity, a small dent in the tank, which happened when something fell on it in his garage. He has also chromed the engine covers, despite the bike coming out of the factory with matt cases.
"I thought it suited it. If you were a true enthusiast you'd say 'that's not right.'"
How does he keep the 32,000-mile bike so shiny? "It's easy. You bring it home, get your duster out and the chrome cleaner. I would do that for 10 minutes before I came into the house. And I would do that every time I took it out."
He says a classic bike is fairly easy to keep, compared to a car. "In the winter I put it into a sealed vacuum bag and suck the air out of it, with a vacuum cleaner. It keeps the moisture away. I can put my bike away shiny and it comes out shiny."
His enthusiasm for classics is palpable, so I ask what he thinks of the new(ish) Glasgow transport museum at Riverside, which has bikes displayed high on the walls. He's not impressed. "It's shocking. You get a crick in your neck. Great for looking at the underside of cars. I don't see the purpose in that."
Baillie says putting the show on is a huge undertaking for the club, which has 120 members from across Scotland, and will have 30 members helping on the day. Former TT racer Ewen Haldane, from Perth, a contemporary of the late great Bob McIntyre in the 1950s, will open the show. Money raised will go to the Click Sargent charity for children with cancer.
25th Scottish Classic Mortorshow, Sunday, Ayr Racecourse. See www.ayrclassicmc.com. Entry £7, under 14s free. 10am-4pm
You could win a Honda at Victor Devine's open weekend. Go to www.honda.co.uk and register for an entry code and take it to the Finnieston showroom on Saturday or Sunday. The top prize is a Honda CB650F and other prizes include race school days at Donington with Ron Haslam and a Shoei X- Sprint helmet signed by TT legend John McGuinness. The full Honda range will be on display including the new VFR800 and test rides can be arranged. There will also be advice for those who are thinking about getting into motorcycling.
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