This was going to be my longest day: 500km already done and only another 350km to go.

As I accelerated away from the petrol station I felt a slight vibration beneath me but I ignored it and continued up through the gears. I passed a Shell station as I clicked into top gear.

There was another click and the engine revs raced.

'Oh shit'.

I pulled the clutch in very quickly and coasted to halt.

The good news was that the engine was still idling. I looked down at my chain.

It wasn't there.

It had snapped and fallen off.

I could see it lying in the road some distance behind me. A bloke on a moped appeared from nowhere and went back to get it.

I was fairly sure the master link had broken. The circlip which holds it all together eventually wears too much and falls off. It's only a short matter of time after that before it breaks.

The same thing had happened in Ecuador a four or five months ago. I had had a spare link but the circlip wouldn't fit as it was for a different chain. I got a local fixer to put two small blobs of weld on each pin to stop the side plate falling off. That had got me back to Quito for a replacement chain.

I now remembered that I didn't get a new chain but used Armando's old (and free) one.

Luckily I still had another spare link and got it out. Unfortunately it was the same problem - I couldn't fit the circlip. The Shell manager directed me to a local welder a few hundred metres away..

Jorge was really kind and stopped his engine rebuild to help me. Very soon afterwards he'd welded the pins and I was back on the road.

He wouldn't let me give him any money at all. Not even ten pesos for a beer.

I got back to speed and settled into my normal rhythm. Even though the road was dead straight I was really happy to be riding through green scenery instead of the stark, barren Bolivian altiplano.

There was only an hour of daylight left so I wouldn't be able to get to Resistencia before dark.

Just as dusk was falling, I felt another slight vibration but, being really sensible I just carried on at my normal speed.

One minute later the chain broke again.

I was in the middle of nowhere.

The road was busy but no one would stop to help me.

I was standing by the side of the road with my thumb out holding my broken chain in my hand. In hindsight that probably wasn't a very good idea.

As I tried to persuade some one to stop I was glad that I still had my tent and warm sleeping bag. I'd used neither since I left the USA several months ago and kept on thinking about about sending them home. I was now really glad I hadn't.

Once it got dark I was sure no one would stop at all. I'd pitch my tent as far way from the road as possible and just wait for the morning.

A pick up truck went past and started to slow down. He looped back and stopped besides me. I was elated.

He said he'd go back to his farm, get a trailer and return in an hour.

Ten minutes later it was pitch dark.

I sat on the ground further way from the road remembering that sitting in your car on the hard shoulder of any motorway is the most dangerous place to be.

As I was thinking about my good fortune a breakdown truck stopped and put on it's flashing orange lights.

He was a free breakdown service that is paid for by the road tolls. I was so happy to be in Argentina .

I showed him my chain.

He suggested shortening it and then joining it again without a master link by just hammering the pin flat. A brilliant idea.

He drove off with my chain to find a tool to remove two links.

'How far was it?'

'Ten minutes' he replied.

As he drove off my anxiety increased enormously.

He had my chain. If he didn't return I was really buggered.

In the dark things are always much worse. At least I wasn't in Transylvania .

True to his word he reappeared a short while later. We fitted the chain but it was too short. There was no free play at all. It would completely bugger my engine if I used it.

The next plan was to tow me the ten or so kilometres back to the last town.

I'd never been towed by a vehicle before so was slightly nervous. However, he only went slowly and we soon made it back to civilisation.

We met the local police, two up on a Honda 125, the pillion carry a repeating shotgun. It was now half past ten.

They rode off to find a bike mechanic.

A few minutes later we set off again. Juan's shop was still open. The situation was explained and he started looking for the right sized chain to add the few links I needed. It took a while but he eventually found the right size.

Twenty minutes later it was spliced and refitted.

'Would I be able to make it to Resistencia 120km away?'

'Yes if you don't stress the chain and only go slowly, no more than one hundred kilometres an hour'.

I rode at eighty kilometres an hour. I did not want it to break again.

I limped into the outskirts of Resistencia . As I rode round a roundabout I felt another click and the bike started to vibrate a little more.

'Oh shit' not again'.

I needed an hotel. As I approached another Shell station I saw a 'Hotel' sign on the opposite side of the road.

I turned into it and immediately, pulled into my bay in front of my room and had a look at the chain.

One of the side plates had come loose. Lady luck had shined on me again.