Some of you will recall my problem of serioussmoking on my newly restored '61 Bonneville. After much head scratching and cursing the problem looks like a rogue rebore. I took the calipers and micrometer out and found it to be plus 24 thou, not the promised 20 thou!! I suspect someone went way over the top with the honer. I bought the barrels and pistons from a supposed Triumph expert in the trade, but that was over two years ago when I started the restoration and was keen with the wallet. We will be having words.
I have now sourced new parts and guess what, the pistons fit nicely in the bores. So anyone want some as new plus 20 pistons (7:1) and a plus 24 barrel that needs boring out to plus 40?
I hear you thinking why was he using 7:1. well the head is well skimmed and the most I wanted was 7.5:1 with a old 8 stud head. So the 7:1 with about 30 thou skiimed off seemed about right. That said, going forward I am using 7.5:1 with a thick head gasket.
So watch this space, when its all back together, I'll report back.
Will
