So I was doing a search to get clarification on an issue I was having with my 58' pre unit triumph. Since I needed to pull off the belt drive(dry clutch) to replace the transmission seal, I wanted to replace the engine drive side as well and I found something I have never seen before. I cannot find any info whatsoever. Looked up all the available part numbers and there is no such part or number for what I found. I also found the the belt pulley on the crank was not fitting tight and was loose. I bought this off a guy who said he was a mechanic but... the belt drive was so tight, it caused a seal leak. Check out the pics. Have you seen this part before? Its splined/tapered and has an o ring.