If you're not interested in getting oil under your fingernails, you may want to ignore this posting! But if you want to know how rugged an old BMW can be and how important it is to be lucky as well as good.......We have just fixed a problem with the engine on our bike. I caused the problem 1 year and 35,000kms ago.

Just before we set off on our "ride to the end of the earth and back" I serviced the bike - I always do it myself, mainly because I'm tight with money and don't want to spend money on labour charges, but also partly because I don't trust the ham-fisted kids who pose as mechanics in most bike shops.

Part of the service routine is to "re-torque” (loosen and retighten) the studs (big bolts) that hold each cylinder onto the crankcase. The idea is to stop oil and gas leaks from the cylinders. Unfortunately the torque specified by BMW is right on the edge of what the studs can take - if you sneeze during the procedure the studs start to tear out of the aluminium crankcases, and then you have to take the cylinder off, and repair the damage.

So 2 days before the off, guess what I did? Yes, I over-torqued one of the studs and I felt the metal starting to give way. SHIT!! What to do? Two choices quickly boiled down to one as I considered all the million and 3 things we had to do in the next couple of days. I could strip the bike and get it repaired, or just ease the tension on that stud a bit and see if I'd get away with it. So this ham-fisted kid took the easy way out and loosened off the nut a bit ;-).

And the bodge worked. The stud held all the way to Kyrgyzstan where we filled the engine with water and wrecked the starter motor, ignition unit, piston rings and cam-chain. I fitted my spare ignition unit on the spot, which got us going again, and used the internet to order a second-hand starter motor from Motorworks in the UK. It was delivered in 4 days by DHL to Almaty in Kazakhstan. Once fitted the now rattling and smoking bike survived right across Kazakhstan, half of Russia, around really arduous Mongolian deserts and valleys and into Japan.

In Mongolia we stayed at a guesthouse in Ulaan Baataar where an internet friend (Vincent Danna from France) had also stayed with his BMW R100GS (the same bike as ours). He had had a terrible time with his bike when a serious rattling noise started in his transmission. These old GSs are infamous for drive-shaft bearing failure at about 35,000kms and he of course diagnosed the problem immediately and ordered a new drive-shaft from BMW in Germany. It took over a month for BMW to find and deliver the part to Vincent in UB – he was stuck there without his bike. He was seriously pissed off when he found out that our starter motor had only taken 4 days to come from the UK and even more annoyed when the rattle turned out to be a gearbox bearing that had gone, rather than the shaft!! So he had to source a new gearbox bearing. The incredibly helpful Mongolians did lots of things for him – they found him a decent mechanic and a bearing supplier, and they also had a word with a local policeman who just happened to have an old BMW engine lying around in his lock-up. Vincent got his bike fixed and rode it all the way down to Pakistan and then shipped it home. AND the point of all this to OUR story is… that the old BMW engine was still lying around in the guesthouse’s garage when we arrived in UB.

Something that had also worried me about my engine was one of the adjusters on the valve gear, which seemed to have a dodgy thread (something to do with a ham-fisted home mechanic again!!). And there was a scrap engine begging to be cannibalised – so I asked the guesthouse owners if I could take the part I needed. “No – it’s not ours to give” came the answer, so I turned from the ham-fisted kid turned into the swift thief, opened the rocker cover and stole the part I needed. But it would have been a pain to get the adjuster out of the rocker gear and then replace the rocker, so I undid the 2 large stud-nuts and stole the whole rocker arm, adjuster, shaft, supports and nuts. The assembly was a bit heavy but it got secreted in with my tools and spare parts and promptly forgotten.

We rattled and smoked into Japan where the terribly nice, not-at-all-ham-fisted men at BMW took the bike apart to replace the rattly cam chain and the leaky piston rings. Wonderful - all fixed - or so we thought!

Then an easy month in Thailand followed by some serious riding in Cambodia hit the bike hard. All of a sudden we had a terrible rattle from the top of the right hand cylinder and the engine balance went to hell. Inspection showed that the valve clearances had increased, and repeated adjustment didn't stop the problem. A further check of the cylinder stud torques showed the problem was that damned stud I’d strained back in the UK. The Japanese mechanic had re-torqued the dodgy stud back up to the correct (very high) torque, and then a bit of hard treatment had pulled the stud out. The chickens had come home to roost. Now the right hand cylinder was only held on by 3 studs rather than 4, and the exhaust valve rocker shaft was only attached at one end rather than at both. As I revved the engine, the forces on the rocker shaft increased and bent the shaft – I had a bizarre form of variable valve timing. The standard fix for the problem is to do what I should have done in the UK – take the cylinder off and repair the stud hole in the crankcase using a clever little screw thread called a helicoil; but where to buy one in Southeast Asia? We knew of suppliers in Bangkok, but that would have added a 5 days detour to our trip.

We crawled out of Cambodia and into Thailand where we spent a week on the beach (it’s not all motorcycle mayhem!!) and as the bike seemed to be doing sort of OK we decided to ignore the obvious need to repair it and head up to the Laos border. On the way we spent a couple of nights in a big town (Ubon) and I took the opportunity to see if the local bike shops could supply helicoils. The first one I came to said, “Yes, what size do you need?” Whoo!! Excellent!! So I took the rocker cover off and pulled out the stud (a loose rattly fit by now) and showed the shop proprietor. No problem, he could helicoil the crankcase for me.

The stud with stripped aluminium still attached

So I took the cylinder off the bike – not a difficult job as those cunning Germans leave the cylinder sticking out from the side of the bike. But it was a procedure I’d not done on a BMW – the things so damned reliable that there’s usually no reason to dive into the engine. An hour to take it all apart and “there you go mate, helicoil that”. But rather than getting out a box of delicate precision made helicoils and cutters, he gets out a power drill, a box of huge great brass inserts (threaded tubes) and tatty cutters. He thinks I’m going to let him play Dr Frankenstein with my bike, but he’s wrong and ‘politely’ I tell him so. Then I remind him what helicoils are by showing him pictures of helicoils that I’ve downloaded from the web and tell him to get his arse in gear to call his tool suppliers. An hour of calling and he says he’s found a supplier and he sends his son off on a bike to get the parts we need. The promised hour’s delay turns into 3 and his son returns with another machined insert – this time made from steel – and I loose my temper. To hell with the ethic of “to loose one’s temper is to loose face in South East Asia” – the guy gets the rough edge of my tongue, but he keeps coming towards the bike with that power drill. Eventually I got loud enough to make him realise that I was dissatisfied with his service, about the time that I changed my approach to “why did you lie to me?” – from the embarrassment approach rather than decibels; I’ll remember that next time.

Open and ready for the Driller Killer

The bike went back together and we were back to Plan A – ride through Laos, fix the bike when we got back to Bangkok (in a few thousand kilometre’s time).

The next day we rattled off to Laos. To limit the stresses on the engine and the noise it made we decided to ride at 70kph (about 45mph), horribly slow by European standards but not usually a problem in undeveloped countries where the roads are often so poor that higher speeds are dangerous. Anyway, the point of the trip is to observe stuff as we pass through rather than shoot through so quickly that we can’t see things, smile at people and chat to each other on the bike. And all went well through Laos until we got to the hilly jungle tracks in the far north. There we were confronted by dozens of small streams to cross, each one requiring a muddy descent down one bank and then a steep ascent the other side. During one such ascent, using a fist-full of revs, the engine started to rattle really loudly and the balance when to hell again. I’d taken the rocker cover off dozens of times before, but this time it was scary, in the jungle, miles from anywhere with a seriously sick engine. Somehow the valve clearance had opened up to a massive 6mm, and would not adjust down – the rocker shaft had bent a lot and wasn’t keen to sit back where it should have been. What I didn’t realise was that the rocker shaft had actually broken at the end where it was bolted down, and it was now only wedged in place.

Rumble in the jungle

Drastic circumstances need drastic measures, so I dived into my bag of spares and dug out a spare nut, added it to the end of the stripped stud and reattached the rocker cover. Now the thin aluminium rocker cover would press down on the sheared stud and its stack of nuts, and so hold the rocker gear in place. But we’d have to keep the speeds right down as thin alloy is not supposed to bear massive loads. And hey presto, the bodge worked and after a night in a village brothel we limped out of the jungle and across the Mekong into Thailand.

Then we got really cocky and nearly blew things completely. The engine was running well (the valve timing seemed to be pretty near perfect), a clean bed and a hot shower beckoned and I opened the bike up to a heady 90kph. Bad idea! The stresses on the valve gear are governed by a “square law” – if you double the engine speed the stresses on the gear quadruple – and the increase in engine speed was enough to erupt bodged stud right out through the weak rocker case. Luckily the engine balance went to hell when this happened, as I didn’t notice oil spraying furiously out of the hole in the engine. It looked like I’d blown it big-time.

A detailed inspection (helped by a local drunken mad-man from the village in which we’d stopped) was a real shock. I discovered the broken rocker shaft – it looked like we’d be hiring a truck to move the bike. But wait a minute – what about the rocker I’d nicked in Ulaan Baataar? Would the shaft be the same size as in my engine? Of course it’s the same size – BMW don’t change anything unless there’s a very good reason. A few minutes more bodging and we were back on the road again.

A couple of days later in Chiang Mai we found a shop which sold helicoils and I did the few hours work which I should have done a year before. Finally the bike was whole again, and it had survived through a combination of bullet proof design, gentle treatment, severe thrashing, luck, grand theft, pure luck, careful repairing and inspired bodging.

I guess nobody who reads this will want to buy a used bike from me?!!