I'm on the final stages of a rebuild. 69 TR6R. When installing the mufflers to the pipes on both sides there is sufficient play to cause an air leak; even when the clamps are nipped down tightly. Both pipes and mufflers are stock, original components. Any suggestions how to enlarge the pipe area to fit snugly into the muffler/s? One millimetre should do it.
You can buy pipe expanders, I have a set and very handy, much easier to do if you haven't had the pipes chromed as the chromed pipe is a harder than the steel alone. But slide it in, and big spanner to spread the jaws. When I used to make pipes as part of my job I had a pneumatic version. So much easier and quicker.
Glass bottles don't shim as well as cans. Also the labels tend to cook and smoke once the exhaust gets some heat into it.
Seriously though, I've used the beer can method, it works and can be made to look tidy. I also found there was quite a difference between equivalent sized modern chrome metric clamps and the imperial sized clamps the suppliers here sell. The metric equivalents should fit in theory but the imperial clamps are a better bet. It seems a lot rides on that smidgen of an inch lost or gained in the metric/imperial crossover.