The brief story of a 1960 Triumph 6T “Thunderbird” – So far.
Mid-September 2021, a good friend of mine decided to venture into the world of classic British motorcycles. Following advice from myself, he managed to bag a bargain. A quite rare and beautiful un-molested example of a Triumph pre-unit 650 twin in the later duplex frame. She fired first kick and sounded really nice, but as we had no idea of the history, I suggested doing a few fairly straight forward jobs before we took on any great adventures.
First and foremost was to do the sludge trap. This is located in the middle of the crankshaft, so it’s engine out to dismantle, refurbish and chuck back in. A job which sounds far more daunting than it actually is.
The disassembly was going well and concerns of a full sludge trap were confirmed upon removing the plug. Off to the parts washer to clean it out and prepare for a new catch tube, plug, big-end shell bearings and bolts. However, upon measuring the journals we found that one side had worn enough to warrant a regrind. So off to Coventry Classic Engines it went.
Crank back. The re-build can begin. But oh no no no… It’s not going to go as well as planned. When tightening the bolts to the specified torque settings (some like to use the “stretch method”, but this picture indicates why I don’t trust it) one of them let go. We put this down to an inferior quality pattern part. Something many classic bike mechanics are more than overly familiar with.
New bolts obtained thanks to a friend and former classic bike parts supplier Mike Ellis who was super quick digging through his boxes old stock. The bolts in question are quite expensive, so in a quest to keep costs down, he was more than happy to help. So, cheers, dude!
While the bike is sprawled out across the workshop and going by the worrying amounts of silicone sealant used by the previous builder, we decided to delve into the gearbox to make sure everything is as it should be. Thankfully nothing more than a couple of tab washers and kick-start ratchet return spring to hold us back, so we gave it a good clean out, changed the oil seal and reassembled it. We could then FINALLY start putting the larger lumps back into the frame.
On the home straight… Or so you’d think…
To be continued…
