Tuesday 15 February 2011

A Mechanic's Tale

We had an old Honda CB750 four in the workshop at the beginning of the month. Made a godawful racket. 1969's a long time ago and the tell-tale signs of going around the clock were there for all to see. The paint on the sidecovers and tank was down to the metal whilst the footrest rubbers were also worn out. It's little things that give high mileage bikes away and I didn't believe the 37000 miles on the clock.

The owner did, he bought it only two months before. He actually believed all the classic nonsense you read in some magazines. The first Honda four was a radical machine in its day but no match for even eighties' 550s. All kinds of things can go wrong with high mileage CB's, usually from the top end but on this occasion it was the primary chain. Shades of old British twins, there. Put it this way, I've never come across gear primary drive that's failed, even in machines with over a 100,000 miles on the clock.

With its horizontally split crankcases it was simple enough to get at the primary chain, even if it couldn't be extracted easily. I phoned the owner up with the bad news, warned him that I suspected that the bore and small-ends were also likely to be trashed. He had a screaming fit when I estimated how much it'd cost to rebuild. He wanted the machine back without paying for my labour but we eventually agreed on a reasonable sum (for cash).

A week later the guy returned, having shoe-horned a CB750F motor into the chassis. His major complaint was a rumbling final drive chain. Easily explained by the misalignment of its sprockets. In fact, the sprockets were completely mismatched. I cut and welded two sprockets to get them to line up, but there was still some grumbling, especially on the overrun. I suspected that there were some teeth missing from the gears, a thought which caused the owner to break out in a cold sweat...

Two weeks later the proverbial callow youth brought the bike in on a trailer. The erstwhile owner had sold the CB on, not even mentioning the engine swap; classic prices are so silly that greed rules. The engine was locked up solid; the gearbox had broken up. The damage was so extensive that the only solution was to fit a used engine. Finally, the bike was in decent shape but it'd cost the same kind of money as a good used 750 Zephyr Kawasaki!

A much easier job was on a Yam XS650 twin. Remember them? There are still lots of them growling around the streets. This one had totally unpredictable starting. Sometimes it'd go first kick, others it'd take an hour to start. Anyone who's had experience of seventies' Yamahas will guess the cause - the killswitch shorting out. Other bikes experience a similar malady when the sidestand cut-out switch goes awry.

In much the same manner, old GS Suzuki's are infamous for the way they burn out their electrics. We had an early GS750 in the shop with a motor that kept cutting out. I favoured some kind of electrical demise as it was typically elusive, running well whenever I tested it but cutting out on the owner. Could've just been a loose or bare wire shorting out under certain circumstances. In fact, it was crud in the petrol tank messing up the floats in the carbs. The crud came from the petrol tank rusting through. The owner was unwilling to believe this simple sign of fatigue until I put a screwdriver through the bottom of the tank. He only calmed down (a bit) when I pointed out I'd saved him from riding off on a potential fireball.

He was further mollified by the offer of a good tank off a bike that we'd confiscated after the owner refused to pay up when we stripped down his engine - very rare for a GS, the main bearings were shot; it was only later we found out he'd used the bike for drag racing. Some people! Anyone on a bike over ten years old should check out their tank to see if it's rusting through - I've seen a couple of bikes that've ended up blackened wrecks after a couple of gallons of fuel has fallen over a hot engine. Better safe than sorry. Agreed?

Occasionally, the chance to purchase a crashed bike turns up. There's something a bit odd about the availability of write-offs, a hint that some back-handers are involved. Nevertheless, the odd bargain comes my way. Two weeks ago it was a low mileage CBR600 with all the plastic shattered and a wrecked exhaust system. The wheels, forks and swinging arm were all scored rather than bent or broken; nothing a little artistry with a grinding wheel couldn't hide. Pattern plastic, some welding on the brackets and a half day's work with the spray gun had the Honda looking like the manufacturer intended. When you can make a couple of grand profit for half a week's work, the business begins to make some sense. Regrettably, such good deals are very, very rare.

From the sublime to the ridiculous. A little RXS100 turned up with enough piston slap for a bike twice its size and mileage. The Yam's usually a reliable warhorse but the vagaries of the learner market mean many end up well thrashed. The rings were stuck in the piston, black gunge everywhere and lots of score marks in the bore. The small-end had somehow survived, a testament to the basic toughness of the engine. I mentioned to the owner that he should use stroker oil and not coal-tar, the old codger almost bursting into tears. Turned out he was running the bike on such a shoe-string that he used old engine oil, donated by the local car garage. Luckily, none of the cylinder studs stripped their threads so I did a quick rebuild using bits we had hanging around the garage. Flush from the CBR deal, I only charged him thirty notes. The ungrateful bugger spent fifteen minutes whining that he wouldn't be able to eat that week!

Word must've got around because a couple of old guys turned up with ancient specimens that they expected me to revive for a similar amount. There was even a Raleigh Wisp; at least that's what I think it was under the rust. I had to spend valuable time explaining that there was no way I was going to become involved in these lost causes; not unless they put a few hundred notes up front. I did take on a CD175, but only on the understanding that it'd only receive attention when there was no other work available.

Working on old bikes that ain't worth much can turn out to be a lost cause as there's no way I can charge more for the work than the machine's worth. A few stripped threads, a couple of ruined gaskets or stubborn bolts causes the whole budget to go out of the window. I do try to help where I can; with some common problems I just point the owner in the right direction and tell him to fix it himself. However, I draw the line at lending out tools, they become too personal when you do this kind of thing for a living.

The most recent disaster area I've come across was an allegedly 60,000 mile 400 Superdream. I don't think these machines are aptly named at all. The engine was rattling and knocking away like the end was nigh but it still seemed to run okay. Tearing the top end off gave pause for thought. All the studs stripped their threads, the gaskets were baked black and the pistons almost flopped out of their ruined small-end bearings. Further disaster was revealed when the cranks were split; all the bearings gone and the balancer chain had almost worn a hole in the sump! There was no way the engine would run again if I tried to reassemble it but the owner insisted that it was just a shot balancer chain, which could anyway be thrown away.

After an argument and extracting two hundred notes up front, I did what I could for the motor, ignoring the way everything flopped about on shot bearings. It took me nearly a whole week to get the engine back together; collecting quite a few bruised knuckles along the way. As I suspected, the motor didn't run at all well and I ended up in a shouting match with the owner who reckoned it was my incompetence rather than the worn out components that were at fault. In the end, I found him a CB250N motor at trade price and helped him fit it. If I let him go off in a rage I could've lost serious business as he would've told all his mates how I'd supposedly ripped him off.

I do like working on bikes. It helps other people and pays the mortgage. There are a lot worse ways of earning a crust and every day brings a new challenge.

All kinds of rolling wrecks turn up for MOT tests. Time was when the examination was rather cursory. It was just a case of checking the bearings, brakes and lights. These days, it's much tougher. Noisy, leaking exhausts on bikes of older than five years are the most common cause of failure. Bodging is still allowed. If the silencers are patched and reasonably quiet then they'll pass. Welding is the only long term solution but I've passed bikes with an exhaust bandage that I knew would probably fall off the next day!

MOTs are only concerned with the condition of the machine on the day of the test. Although it's a tedious business, I've seen bikes that have passed the test and a week later they're fitted with bald tyres, rotted exhausts and a generally ratty appearance. As a means of telling the condition of a machine on the day of sale the MOT isn't worth the paper it's written on.

It's surprising the number of people who'll turn up on bikes with illegal tyres. They come out with the old, old story about replacing them the next day. As if I'd only been in the game for five minutes. It's not just a question of tread depth but also the state of the sidewalls. They often crack up on cheaper tyres before the tread goes. There's no way I'd pass a bike in that state. There's always the chance that the tyre would blow up the next day and I'd be in deep shit. Besides, it's really stupid to ride on worn out tyres, a quick way to check out the state of the National Health Service.

Because there's a lot of competition in the MOT business I'm always happy to do a little bit of work for free. Tightening up steering head bearings or putting the back wheel in proper alignment. One guy wanted me to strip down his seized rear caliper for gratis. No chance of that, they can seize up so solidly that they can take hours of work to tear apart. As with the tyres, any slight malady in the braking gets a fail. Even spongy brakes down to old hose will merit a failure, as it'd be just my luck to have the hose fail five minutes after he'd left the garage clutching the MOT certificate.

I do a lot of work sorting out clients' brakes. Drum brakes, unless really high mileage, don't need much attention, although I do a nice line in replacement cables. Especially for the old Jap bikes, as dealers are reluctant to stock spares. I make up my own cables, once you know what you're doing it's only five to ten minutes a throw. Very old drums tend to go oval and I've even seen a few castings with hairline cracks, but on 30 year old bikes what can you expect? No, it's the disc brakes that cause the real worries. Calipers seizing, discs cracking up and hose or master cylinders leaking (especially after an accident).

Luckily, I have an apprentice who has to learn the hard way. I let him loose on the more recalcitrant bits, it keeps him amused and my heart rate within sensible bounds. It's possible to modify some of the calipers so that they can be forced apart easily. That makes the next service easier and cheaper You'd be amazed at some of the bodges I find inside calipers from some of the suicide merchants. Washers behind pistons, hydraulic fittings Araldited in place after the thread's stripped and Plastic Metal filling cracks in calipers. I had one caliper hung on to the forks with a couple of bent nails!

It's interesting, I've been at the game so long that after a cursory inspection of a bike I have a pretty good idea of whether it's going to fail or not, even before I've really checked anything over. A feel for the overall condition of a machine and a clear eye for the more obvious bodges. I'd say 95 times out of a 100 I'd be proved right in my initial assessment.

Motorcycle suspension is another dubious area. I've become a dab hand at taking forks and shocks apart for refurbishment. The Japanese stuff barely lasts out the guarantee. Stronger springs, new seals and bushes sorts most of the troubles, but it helps to have an hydraulic press! Hard chroming the forks is usually necessary unless the owner's had the sense to fit gaiters. They don't like to bother until they've gone to the expense and hassle of having the forks rebuilt. After that they are usually more amenable to common sense.

Once the Jap bikes get over ten years old rust on the frame eats into the rear shocks' stud. They often snap off with interesting results to the handling. I know one chap who fell off as a result and ended up in hospital. I'm not bad with the welding gun, but I usually build in a bit more reinforcement than standard. It's such an important area that it doesn't pay to cut corners. Old step-thrus are even worse as the whole pressed steel back end will disintegrate.

For some reason, old Kawasakis are prone to rusting petrol tanks. The first symptoms are poor running when the rust gets into the petrol tap's filter. The next thing you know is a lap full of fuel. I once tried to weld in some plate into the rotten underside of a tank. Never again. A whoosh, as a small fireball formed from the old petrol, singed my hair. To add insult to injury, the tank burnt away as the torch was waved in its direction. The metal was so thin there was no way any welding could be done.

Another common Kawasaki fault was the sidestand cut-out switch malfunctioning, causing the engine to run intermittently or cut out altogether. It's a five minute job to wire it out of the system. Most customers are overjoyed at such a simple and cheap remedy, fearing it was one of the notorious ignition units on the way out! A similar effect on engine running was also common on the older Yamahas (XS400, XS650, SR500, etc) but this time from the ignition cut-out switch on the handlebar cluster.

I know some poor sod who'd stripped his SR500's engine down to the crankcases in search of the solution. He'd given up in disgust and for the first time in his life gone to seek professional help. It's dead easy to rip people off under such circumstances, but I've always stuck to being honest. After we wired out the switch, the SR ran fine. I only charged him a fiver, but he was so grateful that I ended up with both his regular servicing and a recommendation to all his friends. Over the years he alone must've sent me over a dozen customers. In fact, with the recession making people hang on to their bikes for longer, I've been overwhelmed with work in past year or so. It helps that my rates are between a third and a half of what the big motorcycle shops charge.

There's always someone who thinks that even that is too much. One Z900 owner was affronted by the suggestion that a camchain swap would cost £35 plus parts. I tried to explain to him that even though it didn't need a full engine strip there was a bit of skill involved. He walked out in a huff, only to come back a week later with an engine that had mangled its valves on the piston tops. He'd put the valve timing a couple of teeth out. I reluctantly agreed to sort the mess out. There was even more bad news, when I drained the sump there were lots of bits of metal in the syrupy oil. Only after a lot of denials did the owner admit there was a very slight possibility that he might've dropped a bit of the old chain link into the motor. In the end I found him an engine out of a crashed bike, it just wasn't worth the cost and time to renovate the old one. God knows how deep the damage had gone.

Twice, customers have tried to get one over on me by turning up with a bike or motor, demanding a straightforward repair and then trying to insist that the massive damage I found in the engine was nothing to do with them, was caused by my own ineptitude. All sorts of threats were uttered unless I sorted it out at my own cost but I remained steadfast; if I'd given in, once word had got about the local area, there would've been a long line of hopefuls turning up with similar sob stories. In both cases I decided the best thing to do was dump the stripped down bits in front of the houses of their owners. I had to write off my own time but luckily I hadn't got far into the jobs before the disputes arose, so my losses were small.

That kind of thing is all part of the hustle and bustle of the job. One of my favourite parts is doing complete engine rebuilds. It's not something that's as easy as the manuals make it look. With Japanese engines, once they are disturbed it's very easy to dent their durability by doing a poor rebuild. The golden rule is not to use pattern parts. Even something as simple as a gasket can be cut wrongly so that an important oilway is blocked off, ruining an otherwise perfect engine. Just a few bits of grit in the assembly, or a few nicks on something like the con-rod, can drastically reduce engine longevity. I revel, though, in a job done well, when all the new bits are put back together.

It's a pity that some of the owners aren't a bit more sympathetic to their engine's needs. They will spend a small fortune on new engine parts, pay my labour, then rev the motor like crazy from cold and roar off up the road without a moment's thought for running in. Six months later they are wondering why the motor's in urgent need of attention. Still, it keeps me in work.

T.L.