The story of my welded sprocket
This story started a couple of years ago when we were still living in Poland. It was time to replace my old chain. I went to a mechanic and paid for a new one, plus two shiny sprockets. The story should have finished here, but two days later, when riding in remote villages of southern Poland, one of my new sprockets came off while negotiating a turn. I was lucky enough to stop the motorcycle just before the chain jammed and blocked the wheel.
We were stranded in the middle of nowhere, scared about what had just happened and what could have happened. It was Saturday evening so chances of quick recovery weren’t high. There were no mechanics nearby, only one guy with a welding machine. The sprocket was brand new so I figured I would get another 20.000 km out of it with good care. At the same time I was pretty frightened about the sprocket falling off again. Emotions got the better of me and I agreed to have my sprocket welded to the drive shaft. At the time it seemed a reasonable idea.
In September 2013 we started our big motorcycle journey. We drove from Poland to Georgia. For about 8.000 km all was good, until I realised that the welded sprocket, which was not aligned properly, was causing the chain to vibrate excessively and wearing it down faster than it should. I had to do something about it quickly, but didn’t know what. The weld seemed to have been done well. I posted a question with some pictures on Horizons Unlimited and was told the following:
That is WELDED… Permanently… You’re not grinding that sprocket off without taking the end of the shaft with it. He’s turned the shaft molten from the very end.
Quite simply…. You need a new shaft.. It’s F**ked
In spite of this advice, I decided to try my chances at getting the old sprocket removed and somehow a new one attached. All I needed was a new set of sprockets and a chain. On my brief visit to Poland in February this year (2014), I picked up a set and packed it nicely in my hand luggage before catching a flight back to Georgia, where my motorcycle was waiting. Unfortunately the security personnel were not impresses with my motorcycle parts and refused to let me go through. Luckily some guy queuing to check in his suitcase agreed to take both sprockets for me. I picked them up a few hours later on the other side.
When we left the airport, we quickly boarded one of the tourist buses going to Batumi. Because there weren’t enough passengers, we were moved to another, smaller bus. Most long bus journeys in Georgia start with an obligatory petrol station stop. It was while the bus driver was filling the tank that I realised I’d left my sprockets on the first bus we’d been on. It took me some time to persuade the driver to go back and when we did finally get back to the airport it was too late; the bus with my sprockets had already gone. After a couple of phone calls I was told that the bus hadn’t got far and somebody would bring my things back to me within 10 minutes. As promised, they were returned to me.
After a few days of looking for a good welder or mechanic in Georgia, a friendly Canadian biker offered his help and gave me a list of contacts. Within a week I was making my way to Tbilisi where he introduced me to a welder. This guy knew what he was doing. With the right tools (bearing puller and grinder) he quickly removed the old sprocket. The drive shaft was in very good condition so we decided that welding a new sprocket should work. With the utmost caution, he took his time to make sure that the new sprocket was properly balanced on the shaft. After about 1h I had my motorcycle ready to ride.
Aftermath, with the welded sprocket
About 7000 km later the sprocket is doing really well. What will I do the next time I need a new chain? Probably the same thing, but it should be much easier as the current weld is pretty clean and hasn’t deeply penetrated the shaft. I am really happy I didn’t listen to advice on forums. If I had chosen to change the shaft, it would have been a major piece of work and a lot more costly.