- Joined
- Oct 7, 2005
- Messages
- 1,170
Re: Engineering compromises leading to exhaust threads strip
Of course it was a design problem, but it was one that afflicted virtually every British bike in the post-WW2 period. I had trouble with exhaust rings on my 1953 BSA A7. In the case of the Commando, it inherited the Atlas engine, which was derived from the Dominator 600 and the 650SS. and they all had the same exhaust pipe rings.
Where the Commando suffered was from the impact of the Isolastics. The allowed the engine "pod" to move relative to frame-mounted components like the exhaust system. I think the freedom of movement was plus or minus 3/16". Since the exhaust is tied to the frame, the exhaust nuts had to absorb that movement. A good fix (but ugly) is to put a short length of flexible SS exhaust hose between the first couple of inches of the pipes out of the head and the downstream, frame-mounted components.
Of course it was a design problem, but it was one that afflicted virtually every British bike in the post-WW2 period. I had trouble with exhaust rings on my 1953 BSA A7. In the case of the Commando, it inherited the Atlas engine, which was derived from the Dominator 600 and the 650SS. and they all had the same exhaust pipe rings.
Where the Commando suffered was from the impact of the Isolastics. The allowed the engine "pod" to move relative to frame-mounted components like the exhaust system. I think the freedom of movement was plus or minus 3/16". Since the exhaust is tied to the frame, the exhaust nuts had to absorb that movement. A good fix (but ugly) is to put a short length of flexible SS exhaust hose between the first couple of inches of the pipes out of the head and the downstream, frame-mounted components.