I too thought that with an alloy head, the car would have had hard enough valve seats to cope. The car has now done 2,500km in my hands, 2,000 of which was coming back from Italy - all with an additive. So I have done only a few hunded km with no additive since we got here.
There was a reason for my question, of course!
After three days to do those 2,000km with no problems, all the issues have started since we got home! First it wouldn't idle, so I stripped the carb and freed up a partially seized throttle spindle.
Then it came home on flatbed after refusing to start, having driven perfectly to the destination. I think the dizzy had moved.
Then it started spluttering and I thought a good run would sort that as all it had done in recent weeks was short starts and stops. One minute it runs sweetly, then misfires, then stops firing, then picks up and back to normal, then repeats the process. Its like driving a baby kangaroo! Anyway, it came back on the end of a rope last time as it wouldn't make it up the hill home! It seems to be getting worse.
I decided it might be fuel, so stripped the fuel pump. Couldn't get the right overhaul kit, so we now have a new pump and inline filter. I took the pickup out of the tank to make sure that was OK and blew down the fuel line (quite hard work!!). I am now at a loss. I have perfect ignition, points gap, timimg, plugs, leads etc I am sure.
I have clean fuel arriving at the carb, I have checked the float movement, cleaned the main jet again and again, but the problem remains.
When it runs perfectly, it sounds really sweet, crisp exhaust note etc - spot on. Do I buy a new carb? It's not the original carb as it is an IMB 10, whereas it should be a 2 or something, but a new one is really expensive and no guarantee of a fix.
I am completely stumped!! I thought these cars were so simple and reliable - right now we have lost faith and we daren't go anywhere!
Help!
Ian