Carb for Comet

[redbloke1956]

Hi, Chanky Bore,
I had Ernest Hegeler´s Comet for testing some months ago. I mesured wheel diameter and had a digital bicycle-speedo fitted, which gives a nice catalogue of information, especially top speed, when you are crumbling into the fuel tank and
cannot stare at the dial for minutes, as there might be other traffic around. It had a 30mm Concentric MK1 fitted and
Ernest´s homemade cams, which are more or less MKII timing figures, but with quietening ramps. Compression I did not take, it started first kick, every time. Ah well, it also had Ernest´s dyno with his own electronic ignition 32deg btdc.
I achieved 142 kph, which is some 90mph, in other words, works standard.
It was just to see, that it can do it, not to try it any time! 75mph upright seating, easily, anytime on the motorway, no
oiling, no seizing, safe running!
I think, a Comet, which cannot exceed 75, isn´t adjusted correctly. Remember, that was the topspeed of a 250cc NSU- Max of the early 1950s, so it wld b a shame for a Comet!
Good luck!

Thanks Little Honda, those are the figures I would have expected from a mildly tuned Comet, it puts my mind at ease.
Kevin

 

[chankly bore]

The Comet I mentioned has MK 3 cams and a good lucas magneto.I have not given it a hard time yet as I have not run in the piston. My old original Comet with a standard original silencer and MK 2 cams will sit on 70 or more if I want to, but I am growing old, like the 'bike and like minor roads and no traffic!On a country road last year I herded a flock of goats-a good memory. Yes, you can do more speed,but mechanical stress is a geometrical progression and increased speed of the whirring masses of inefficiency is a major factor.I would rather slow down and do less rebuilds.HOWEVER!! I am building a 650 c.c. special--so there! Cheers F5AB/2A/7945 since 1970

 

[redbloke1956]

The Comet I mentioned has MK 3 cams and a good lucas magneto.I have not given it a hard time yet as I have not run in the piston. My old original Comet with a standard original silencer and MK 2 cams will sit on 70 or more if I want to, but I am growing old, like the 'bike and like minor roads and no traffic!On a country road last year I herded a flock of goats-a good memory. Yes, you can do more speed,but mechanical stress is a geometrical progression and increased speed of the whirring masses of inefficiency is a major factor.I would rather slow down and do less rebuilds.HOWEVER!! I am building a 650 c.c. special--so there! Cheers F5AB/2A/7945 since 1970

Hi Chanklybore, You misunderstand my intentions, I don't want a bike to ride fast cos I have my Beemer for that, I want a bike that I can do 60mph on when I need to without flogging the poor old thing, I am quite happy to putt along at a leisurely pace...but it is downright dangerous to do that when you have no choice but to take the Highway. I no nothing about the history of this engine so am busily making it better than new before it raises a piston in anger, I figure while I am at it why not add a few extra ponies without sacrificing reliability.
How are you getting 650cc from a Comet?