Can't finish off the extra-plates-in-clutch experiment with the GF because I'm waiting for nyloc nuts to arrive. Can't progress the M21V2 starter build for similar reason, so spent this afternoon wrestling with the Firestorm.
Last time out (my son riding) it lost a cylinder. Was back on both when arrived back at the workshop, so I took the tank off to have a look-see. Normal plug socket wouldn't fit, so had to order an 18mm long / thin socket to check the rear plug - it's about 6" down a small hole. That seemed OK so took the air cleaner off to get to the carbs. That's a nightmare in itself, you just can't get to the breather pipes underneath. Next started on the carbs - they're 2" Stromberg-type units with diaphragms. Another nightmare - the diaphragm springs are 1/2" OD and a foot long. Try getting that back in place. They're uncontrollable.
Checked the rear diaphragm and it seemed OK. Thought about replacing both, until I discovered they are non-detachable from the plastic slide. Now those diaphragm/slide combinations would cost under a pound to make (the plastic slide is quite crude). Well, apparently they are no longer available but, when they were, cost £206 each. No, that's not a typo.
And so this afternoon I re-fitted the rear diaphragm (can't get to the front one without taking the whole carburettor assembly off so not going there) and wrestled for a couple of hours getting the air filter base back on. Under the air filter itself there's a couple of tiny foam filters for the breathers - will need to find something for that as they've crumbled to dust. That'll be another day - had enough today of struggling with this beast. The bike is 20yrs old, but it's like a modern car insomuch as getting to anything verges on impossible.