The return of the GP and Goldie mythology
Rick lets style take precedent over practicality – but argues it’s also going to make him happier
‘I’D PREFER THAT IT’S THE ONE I WANT ON THERE’
Now hear me out... I know I said it was foolish to try and do two things, and it made sense to set up my newly-invigorated Gold Star on the easily-tuned MKI Concentric carb and think about reverting to the GP later but I’ve weakened and the GP is back on.
I’ll be honest, it just looks better and if that means a bit of hardship, well, that’s style for you. No pain, no gain – and besides, if I’m going to have to spend ages setting up the carb, I’d prefer that it’s the one I want on there, not a compromise.
The Amal GP is a track carb, only fitted to Goldies for racing homologation purposes – well, that and because it was the only Amal made that could accommodate the massive 1½in inlet port at the time. The big Concentric came later and offered improved starting and a tickover with only a modest loss of top speed. Or at least, so they say; but Goldies are responsible for more myth and legend than the catacombs of Transylvania and I don’t fully believe it. If anything, a race carb should be more tuneable than a road bike – and racing bikes that don’t start are useless. Anyway, since getting the power back after sorting the squish, I observed two things with the Concentric fitted previously. First, it was an easy starter. I always assumed difficult Goldie starting was either due to wetting the plug or the low-speed unfriendly valve overlap, but the float height is a bit low on the Concentric and it won’t start unless you flood it very liberally, so maybe it needs more (not less) fuel to start. Secondly it no longer seems to smoke. Before, you’d get the odd waft at traffic lights. Since the carburation was always a bit rich on the GP, I did wonder if this was ‘bore wash’ – excess fuel diluting the oil. I read an interesting booklet by 1920s carb manufacturer and expert Charles Binks in the VMCC library recently. Binks said that, within reason, a low float height was no problem but high was disastrous. Supposing my GP height – although set correctly – was still too high, wetting the plug on starting and over-richening the mixture enough to wash the bore at low speeds... more clues, more experiment to do…