Forum

[Les H]

Copper tube= 15mm

[simon]

No surprises at 11.5:1 my old beast is only around 9:1 although I've got it a set of nice new 87mm pistons that are likely to notch it up a bit. Being a GT860 it isn't a paticulary sporty machine but more of a torquey cruising machine without the bling of the modern variety. With regard to cleaning the plugs the one way I did get one clean was to connect it up to a megger with a 240 volt power source rather that a wound handle. It was quite entertaining watching it arc inside the plug burning off the carbon. It cleaned the plug a treat but the owner of the tool was unwilling to do it to the bag of plugs I had at home as he thought it would fritz the megger.

[Les H]

For a more effective cleaning punch...maybe a few 1/4" steel ball bearings....they will ram the grit down harder....check that plug electrode has not bent...don't think this will happen though.

[simon]

I do remember the old bench top plug sandblasting machines but as you say Norm it was forty odd years ago that I saw the last one. Maybe a Van de Graaff generator or a Tesla coil would be the tool to clean them although as my friend with the megger pointed out they aren't that expensive especially on a single. The impressive thing about using the megger was the very bight light that was produced by the carbon like a tiny carbon arc lamp.

[Presto]

One possible reason why a Bullet engine favours higher octane fuel maybe due to the notoriously inefficient combustion chamber shape - a shape that does nothing to aid clean burning of the fuel and consequently produces a range of other 'issues' - (as they say nowadays!).

[simon]

That is true the is no squish band on the RE head whereas there is on the Duc. It would be interesting to redesign a head to a modern two valve profile.

[Alex.]

Always thought different grade fuels was bull, but decided to finish off my tank of supermarket petrol on my Saturday trip to Triumph dealers open day, and filled up with Esso Premium for today's West Coast Rally - the difference seemed really clear to me, smoother, quieter and better pick up especially from low revs when I would normally change down. I am converted!

[Presto]

I get the point Simon, and agree with you, but the problem is that there is no 'modern' two valve head on a 500 single!

[Midge]

Some may remember that I had used Tippex to mark the throttle positions. I have known for a while to maintain my 'cruising speed' of about 55mph on the motorway it takes roughly 1/2 throttle,(above that speed the handling suffers due to the windshield).

Now the last time I filled up for some unknown reason I filled up with Sainsburys super unleaded instead of the standard stuff. Since then, the same journey and speed only requires 1/4 throttle. I am convinced that it appears to have a bit more grunt as well, It's got a gas-flowed head and less restrictive inlet / exhaust, but the piston is standard compression. I'm a convert to racing dinosaur juice!

[ed.lazda]

I did a reasonably long trial of 95 vs 97-98 octane in my Bullet 350. The high grade stuff consistently gives me somewhere near 10% better fuel economy. This makes it worth paying the extra, even if it has no other effect.