Thanks again, Menno. Strange as it may seem, so far I did not have to replace my 43 year old rubber boots, by the new ones that I have bought decades ago and that are still in their packages. I've tested a couple of times by spraying brake fluid, but never detected a leak.* When revved, rpm drops to idle immediately and from 6000 rpm, bike pulls like a rocket. I presume I must be an exception. Nevertheless it's good to know where good clamps can be obtained because the OEM clamps do stretch eventually.
* I did detect a leak caused by a defect O-ring between manifold and head however.
