Forum

[another Allan]

Wide Open Throttle, perhaps?

[John L]

Fuel flow meter/economy gauge, etc. = vac. gauge, which won't work satisfactorily on a single cylinder engine.

[simon]

A vacuum gauge will work fine on a single you just have to run it via a manifold insert with a small hole of around .5mm which will smooth out the pulses. I've used one very successfully for balancing the carbs on the Ducati which is to all intents and purposes two independent singles on a common crank.

[John L]

.....and a four-cylinder engine with 4 carbs. is effectively 4 singles on a common crank, and a six-cylinder... well, you get the picture. I've balanced carbs. on 2-,3-, and 4-cyl. bikes (including more Ducatis than I care to remember) using vacuum gauges, and so am quite familiar with their use for that purpose - what I MEANT to say is that a fuel economy (vac.) gauge on a single would be somewgat superfluous. Incidentally, I have a diesel car with an analogue (vac. type) economy gauge and a petrol car with computerised digital readout - I'm unconvinced that either is much more than a gimmick.......

[Phil Ashbrook]

I presume this is all about STD mid 90's Bullet 500 , as soon as I started to mod the engine my fuel consumption has got higher and higher , my ultimate goal is 612 cc on a big port Fury cyl head running on E85 fuel or pure Ethonal as a test . I can go up or down on compresion with my barrel spacers and I have the full Amal MK2 alcohol conversion kit including the high flow fuel tap .
So far I have never had a problem with flow on the standard 1995 export fuel tap even with a 40 horse engine that has far more torque than standard so I can plod around in 3rd or 4th and use it for overtaking double B trucks ( 2 trailers )there are electronic kits that can be used to work out averages but generaly I can feel it's sweet spot .
My question is can our hosts high flow fuel tap be used for petrol and Ethonal , will petrol melt the filter part and what type of fuel cap is the best breather and has the Ethonal proof gasket .
I know you need almost twice as much fuel so I would have to get the 18 litre fuel tank to make it viable .
I'm intrested to know my MPG with my ported small fin head with 535 piston and high lift cams is before going to the Fury head with a 612 crank , it's something our hosts could do as the only graph of engine speed and BHP seems avalible .
As a race team they might not want to give away to too much info to their rivals but a full blown Enfield race engine might be 20 MPG or less , I would love to find out .

[Norm]

Phil,
I put a 612 together a few months back and fuel consumption hasn't increased dramaticly, probably because the motor is just loping along and not revving it's heart out with a 22 tooth sprocket, 120,130 easy stuff, hardly breaking into a sweat

[Phil Ashbrook]

Hey Norm , your 22 front sprocket idea would be a must for city to city riding in Australia , I'm slowley gathering hands on data of the 612 set up , it's the logical way forward for more grunt at lower RPM's and a safe and strong big end and con rod and belt drive would go very well with it .
I just blew a bolt on my clutch , it stretched first leading to a harsh grinding sound on the clutch cover , the Indian clutch is at it's limit with my tuned 535 engine and lube does not really penetrate the clutch roller ball race bearing as mine crapped it's self , I'm kinda glad the bolt blew alerting me of the situation.
From what I gather the 612 needs the alloy barrel with the improved steel liner and engine breathing would be best done with the Fury head and Titanium valves and the copper beryllium seats .
It would be good if our hosts made a mini generator so I could use the crank ignition and remove the gears for the distributer shaft , this is all big bucks stuff ...but I'm sure it's worth it for power and peace of mind , it might even be able to cope with a few laps of the isle of man .