What to make of the Honda CB500T that lay in the back of the garage? The clock read a reasonable 18000 miles but the chassis was blurred by surface corrosion.
The thing laid up for over four years. Of course, it would not start. The owner reckoned that one winter morning it had refused to fire and he'd given up after buying a new battery. The vertical twin had such a bad reputation that I wasn't too keen. He wanted a hundred notes for the wreck, I thought it would be a kindness to take it away for free. Reluctantly, I agreed to thirty quid if he would deliver the sod.
I told the wife it had cost a tenner! I knew she would be despondent to find yet another tatty motorcycle taking up space in the garage. She would often go into a rant about all the time I wasted messing about in the workshop. Her idea of an evening's fun and games, Coronation Street followed by a good drama. Once a week was about all I could stand of an evening's TV.
So I wasn't unhappy to find myself fighting the engine's sump bolt into submission. Its rounded off comers meant the only way of extracting it was with a chisel and hammer. As in its complete destruction. Did my knees no good at all, on the damp garage ground. A huge collection of spares from past misdeeds (my own and various friends) meant I had a replacement to hand with a bit of digging. The sludge that fell out of the engine didn't look too good but it was free of any actual engine debris.
Fresh oil added, the engine kicked over several times to get it circulating nicely. The 'new' battery had decomposed over the years, its acid weakening the bracketry. A working battery was attached with some jump-leads. No spark. The points were all gummed up. Disassembled them, cleaned everything up and then spent a pleasant hour figuring out how to set the ignition timing. Right, we have a spark.
I told the wife it had cost a tenner! I knew she would be despondent to find yet another tatty motorcycle taking up space in the garage. She would often go into a rant about all the time I wasted messing about in the workshop. Her idea of an evening's fun and games, Coronation Street followed by a good drama. Once a week was about all I could stand of an evening's TV.
So I wasn't unhappy to find myself fighting the engine's sump bolt into submission. Its rounded off comers meant the only way of extracting it was with a chisel and hammer. As in its complete destruction. Did my knees no good at all, on the damp garage ground. A huge collection of spares from past misdeeds (my own and various friends) meant I had a replacement to hand with a bit of digging. The sludge that fell out of the engine didn't look too good but it was free of any actual engine debris.
Fresh oil added, the engine kicked over several times to get it circulating nicely. The 'new' battery had decomposed over the years, its acid weakening the bracketry. A working battery was attached with some jump-leads. No spark. The points were all gummed up. Disassembled them, cleaned everything up and then spent a pleasant hour figuring out how to set the ignition timing. Right, we have a spark.
But no running engine. Two possible problems came to mind - decayed rubber manifolds between carbs and inlet ports or the carb diaphragms gone west. The latter were much easier to check, both cracked. There are various solutions to this, ranging from cutting down items meant for autos to fixing with Superglue. No-one in their right mind would bother asking a Honda dealer about the cost of replacements. Decided to go the Superglue route, see if it worked OK.
Now we were in business. Nope, the engine didn't burst into glorious life but it did make some promising noises. New spark plugs - very odd grade and size, too - finally did the trick. I hadn't a clue what to expect from the DOHC vertical twin motor but guessed that the loud tapping noise coming from the top end wasn't a design feature. Carefully tweaked the camchain tensioner but no difference.
That just left the valve clearances, for which I would need a manual. Damn, more expense. In one of those cosmic coincidences, John Menzies was having a sale of bargain books which included an Haynes manual for the CB450/500T. I snapped that.up for a fiver and set to work on the curious top end. Conventional valve springs replaced with torsion bars, the clearances set by rotating an eccentric shaft on which sat the rockers. This would've been easy enough hadn't the clearances been really tiny - the existing ones were huge in comparison giving me the hope of an easy cure.
After about six hours of swearing I'd finally set everything up perfectly. At this point the engine was very reluctant to catch. I'd somehow snagged the one-into-two throttle cable, the motor not wanting to fire with the carbs half open. The plugs were oiled up and I had to fit a second set - I was quite pleased that I'd bought two sets in a fit of pessimism. Finally, the engine caught and quickly settled down to a 700rpm tickover. I was amazed at how quiet the motor sounded (not the non-standard 2-1 exhaust). Once warmed up it revved away with no hesitation. Only the minor fact that the battery was sitting on the workbench stopped me leaping aboard for a test ride.
Now we were in business. Nope, the engine didn't burst into glorious life but it did make some promising noises. New spark plugs - very odd grade and size, too - finally did the trick. I hadn't a clue what to expect from the DOHC vertical twin motor but guessed that the loud tapping noise coming from the top end wasn't a design feature. Carefully tweaked the camchain tensioner but no difference.
That just left the valve clearances, for which I would need a manual. Damn, more expense. In one of those cosmic coincidences, John Menzies was having a sale of bargain books which included an Haynes manual for the CB450/500T. I snapped that.up for a fiver and set to work on the curious top end. Conventional valve springs replaced with torsion bars, the clearances set by rotating an eccentric shaft on which sat the rockers. This would've been easy enough hadn't the clearances been really tiny - the existing ones were huge in comparison giving me the hope of an easy cure.
After about six hours of swearing I'd finally set everything up perfectly. At this point the engine was very reluctant to catch. I'd somehow snagged the one-into-two throttle cable, the motor not wanting to fire with the carbs half open. The plugs were oiled up and I had to fit a second set - I was quite pleased that I'd bought two sets in a fit of pessimism. Finally, the engine caught and quickly settled down to a 700rpm tickover. I was amazed at how quiet the motor sounded (not the non-standard 2-1 exhaust). Once warmed up it revved away with no hesitation. Only the minor fact that the battery was sitting on the workbench stopped me leaping aboard for a test ride.
Not that the chassis was in any state to withstand the Honda's forty-odd horses. My stash of spares was raided for newish tyres, a silencer with some semblance of baffling, chain and new brake fluid for the front disc.
After a bit of heavy work with the hammer I managed to fit the battery into the minimal space provided (I hit the brackets not the battery!). No lights, no horn, no tax disc, no insurance... the test ride was a very brief blast around the housing estate. The wife went into a tirade about annoying the neighbours with the unholy racket. Ten minutes later, a plod Metro took a turn of the area, obviously hoping to catch some juvenile delinquent.
About a week later I was all legal. I'd even found a proper silencer. I'd also cleared off all the corrosion, touched up the paint where necessary and had an ardent polishing session - didn't look half bad. Now for a proper test ride. No problems below 6000rpm, rumbled along just like a Triumph 500 Tiger, but try to whack open the throttle, left the motor gasping for breath. In second it would finally catch at about 7500rpm and scream around to 10000 revs but the big flat spot was extremely annoying.
I reverted to the 2-1 exhaust that accompanied the bike - a real ear basher! The bike spluttered below 6000 revs, caught and accelerated off up the road at a pace that had me seeing double. Leaving a trail of destruction - sonic boom didn't come into it! Reverting to the previous set-up, I cleaned out the air-filter at the local garage, though god knows what the attendant thought I was doing with his air-hose. Better, but not perfect, the flat spot reduced to 6200-7000rpm. A couple of holes in the air filter, the bike only had a slight hesitation at 6500rpm, made the power punch appear all the more violent.
Given its reputation, I wasn't expecting much but the 500T had more urge between 75 and 100mph than most of the old British 650's I'd owned. Even managed to smooth out, almost magically. The pistons move up and down alternatively, reducing the vibration to mostly low rev rumbling. The bike topped out at the ton-ten and was a happy cruiser at 85mph. Not bad going for an old relic that originally looked like it was corroded to death. If you weren't used to old Jap gearboxes, mind, then death might also be conjured - if not of the rider, at least of the engine spitting fire at exorbitant revs due to the false neutral. An acquired art!
None of these speeds were tried until some much needed suspension and braking mods were done. Basically, the suspension and front disc were totally worn out. I just happened to have an old BSA A65 front end to hand, complete with excellent TLS drum brake. A used pair of Girling shocks went on as if made for the job. The front yokes were reluctant to mate with the steering head but I managed to use the old yokes, plus some washers, with the BSA’s forks.
In all probability, the steering geometry was subtly altered but compared with the loose mush of the worn stuff I thought I was on a brand new bike. The TLS drum needed much effort to pull the 420lbs up but at least worked in a predictable manner. It wasn't as good as an old Triumph or BSA twin, didn't really have that stuck on rails feel. But it wasn't anywhere near dangerous. With its Velocette inspired tank and saddle, the bike looked every inch a classic motorcycle from the fifties or sixties.
I kept the bike a mere three weeks. But only because some gent had the kindness to offer me 1500 notes! He wanted a British bike but couldn't take all the hassle. He obviously didn't know about the CB500T's mechanical history but we were both happy. Even wifey managed a smirk!
About a week later I was all legal. I'd even found a proper silencer. I'd also cleared off all the corrosion, touched up the paint where necessary and had an ardent polishing session - didn't look half bad. Now for a proper test ride. No problems below 6000rpm, rumbled along just like a Triumph 500 Tiger, but try to whack open the throttle, left the motor gasping for breath. In second it would finally catch at about 7500rpm and scream around to 10000 revs but the big flat spot was extremely annoying.
I reverted to the 2-1 exhaust that accompanied the bike - a real ear basher! The bike spluttered below 6000 revs, caught and accelerated off up the road at a pace that had me seeing double. Leaving a trail of destruction - sonic boom didn't come into it! Reverting to the previous set-up, I cleaned out the air-filter at the local garage, though god knows what the attendant thought I was doing with his air-hose. Better, but not perfect, the flat spot reduced to 6200-7000rpm. A couple of holes in the air filter, the bike only had a slight hesitation at 6500rpm, made the power punch appear all the more violent.
Given its reputation, I wasn't expecting much but the 500T had more urge between 75 and 100mph than most of the old British 650's I'd owned. Even managed to smooth out, almost magically. The pistons move up and down alternatively, reducing the vibration to mostly low rev rumbling. The bike topped out at the ton-ten and was a happy cruiser at 85mph. Not bad going for an old relic that originally looked like it was corroded to death. If you weren't used to old Jap gearboxes, mind, then death might also be conjured - if not of the rider, at least of the engine spitting fire at exorbitant revs due to the false neutral. An acquired art!
None of these speeds were tried until some much needed suspension and braking mods were done. Basically, the suspension and front disc were totally worn out. I just happened to have an old BSA A65 front end to hand, complete with excellent TLS drum brake. A used pair of Girling shocks went on as if made for the job. The front yokes were reluctant to mate with the steering head but I managed to use the old yokes, plus some washers, with the BSA’s forks.
In all probability, the steering geometry was subtly altered but compared with the loose mush of the worn stuff I thought I was on a brand new bike. The TLS drum needed much effort to pull the 420lbs up but at least worked in a predictable manner. It wasn't as good as an old Triumph or BSA twin, didn't really have that stuck on rails feel. But it wasn't anywhere near dangerous. With its Velocette inspired tank and saddle, the bike looked every inch a classic motorcycle from the fifties or sixties.
I kept the bike a mere three weeks. But only because some gent had the kindness to offer me 1500 notes! He wanted a British bike but couldn't take all the hassle. He obviously didn't know about the CB500T's mechanical history but we were both happy. Even wifey managed a smirk!
Charles Delroy