A minor update, seeking advice or just moral support really! Having re-installed the old-style plastic floats I now have decent fuel levels in both my carbs. All the jets and the needles are new, and I have new 3½ hard-anodised slides, which is the cutaway that the MK2A is supposed to have. And, I've given the pilot jets a good poke with a 0.4mm drill bit, that seems barely to have made any difference. I also have a new air filter in my black plastic box, well oiled and still clean. So, finally, I feel that my bike not only runs well but also has plenty of power for me. Along the way, I also now have a pretty reliable tick-over, albeit around 1,000 – 1,100 rpm, maybe faster than some. Trouble is, there's a very narrow but gaping flat spot between idle and trickling-in-traffic speed, that tends to make things jerky if my clutch control isn't spot-on, there's a fair bit of popping on the overrun if I have the throttle open a crack, and the bike and I are really not happy around town, at least until everything's warmed up. Even then I remain nervous. Out on the road the bike's very crisp and satisfying indeed, but I can't help but spend a lot of time in town ... So ... According to the Amal carburettor tuning guide, the thing that you print out and turn into a dial that tells you what to do, I think I need to go to a smaller cutaway, so 3 instead of the 3½ that's specified for the MK2A. I can imagine that's entirely possible – for example the MK2A's supposed to have bean cans but I've got peashooters, because of which I've 260 main jets; and, weirdly, whereas the carbs came with 2-ring needles, they now have 4-ring needles – none of that may be strictly relevant, I just mean that there've been considerable changes. Should I bite the bullet and spend in the region of £50 on size 3 hard anodised slides, just in case? Or is there something else I might try? I feel like I've done everything else I can think of. It's occurred to me that it can't hurt to try – except the bank, of course – but if anyone thinks that'd be silly ...?
One other thing while I'm here – at cliffa's prompting I did a buoyancy comparison the other day, between a StayUp float and a perfectly serviceable old-style plastic one, that I hope was fairly scientific. I placed one of each in a float bowl with spindles and fitted both with aluminium needles – that seemed the best way to compare their buoyancy alone. I filled both float bowls to the brim with fuel, and the photo shows the result – the StayUp is vastly more buoyant, and this must be the cause of my problems in getting a useable fuel level with them. I'm on the point of sending them back to Burlen with a detailed explanation and photographs – I sincerely hope something comes of this other than a straightforward refund. Cheers.
