Forum

[Norm]

Now I think about it my Inter has also done that to me over the last few monts, not that I get out on it that often, but it has 2 taps, one is set up as reserve, and sometimes I can't get fuel to flow from the tickler, turn to reserve and it will tickle up then I turn the reserve tap off and no problems

[Tzen]

Sofia, as the carb is supplied by our host as a direct replacement for the Electra I was kind of assuming the main jet would be ok...however, I will raise the needle as suggested because this does sound symptomatic of the problem. I guess if the needle needs to be fully raised and the problem still exists then maybe a larger main jet would be needed? On a bit of a leaning curve here so more than happy to take advice.

[Thack]

I'm not at all convinced this is caused by the wrong jet or needle position. If that were so, I would expect the hesitance to be consistent when running at high power, rather than occasional. And switching to reserve and back again doesn't fix a weak jet or needle.



No, this to me sounds a lot more like fuel starvation. I would investigate the tank breather and the fuel tap/filter before messing about changing jets. As the others said, if it came from Hitchcock's you can be very confident it is correctly jetted.



There is one other possibility: sometimes a weak spark can seem very much like fuel starvation; that is, the bike runs OK most of the time but hesitates at large throttle openings. The wider the throttle, the higher the spark voltage needed at the plug. So, although I doubt this is the case, just bear in mind that possibility if you get no joy with the fuel system.



As you know, it is almost impossible to diagnose a fault via writing, so I'm sure we are all feeling frustrated that we can't get our hands on the bike and start fiddling!

[Tzen]

Ok, on checking the needle I noticed there was only one notch left to raise (i.e. it was already on the second from bottom notch), I have lifted the needle by this remaining amount so any more adjustment may mean a larger main jet. Can't get out to check it as the weather is 'orrible at the moment...will have to wait and see!

[Gwilly]

A large carb at full tilt uses a surprising amount of fuel per minute, witness twin supplies on some race engines..

Remember the float chamber extensions on the monoblocks. Was it just a gimmick?
At best the flow through the enfield tap is not designed to pass vast quantities under gravity feed..

So a damaged filter on assembly plus varnish/crude build up will soon restrict the supply when most needed..

Note the reserve filter much shorter and more robust looking, wonder why that is..

So i think don't fiddle with the carb too much until your certain enough go go juice is actually being delivered.. Simple first...

[sofiaspin]

Remember that our hosts provide a carb set for what will be anticipated normal use by the average punter looking for a bit more poke, not to really crack on - for which there are big bore kits etc. I think they also jet the carbs for use with an air filter. As I said, I have been here/there. So, I rang our hosts, and after explaining the cut out worries, was encouraged to purchase a larger main jet - cant remember now, a 230? (Bike is sold). This improved matters slightly but the impact is minimal - read Gwilly's note - so I should have gone to a much bigger size. As a comparison, my Venom was running at 280. It was a 500cc running to a 30mm Amal mk 1, and open pipe and near open mega. Not dissimilar to the bullet set up. The key point is the much larger main jet of the Venom - which ran faultlessly and fuelled perfectly throughout the rev range. My bullet was running lean, which is why I suggested raising the needle on yours in my earlier post. I did not mean to suggest it is linked with high speed running. After a few more near cut outs at around 70mph on the bullet- I simply rolled off on the throttle and stopped trying to turn the bullet into a cheap venom carbon copy. Perhaps that offers you more insight! I have to say, however, I loved hammering that bike! It was light, with alloys and stripped down, so it was crying out to be hammered, so I know where you are coming from.

[Tzen]

Hi all, some really interesting responses, very much appreciated. I will check out if the raised needle makes a difference, though as mentioned the problem did appear to be intermittent. I will also remove the fuel tap assembly and give everything a good clean. I do give it some welly I must admit, indeed (changing the subject slightly) i'm also thinking of installing the hosts shrouded push rod adjusters as I understand the pushrods can jump off the standard adjuster at high revs - with obvious mayhem ensuing! All good fun...he said through gritted teeth....oh, if I change the spark plug what is the best option, and might it be worth changing the plug cap? Well, I did pick a RE so I could tinker!!!!

[Mark M]

Another possibility, I seem to remember that someone had a problem similar to yours and discovered that the fuel pipe itself had a very small bore, much smaller than the exterior size suggested. Whether this was due to ethanol degradation (or maybe just poor material quality) making the pipe swell is not clear but replacement is cheap and easy.
REgards, Mark

[Frank]

I don't like the sound of ON not being straight down but slightly forward. It should be straight down and there is something iffy there if it isn't. Perhaps there is restricted flow through it. You could try running it permanently on Reserve position to prove the tap. Trouble is with a new carb, new TCI,unrestricted down pipe and different silecer and now the carb needle adjusted you won't know where you are soon, there are too many variables now! As for plug I found a big improvement with an Iridium, others will disagree with their worth. The original metal shrouded plug cap type had a bad reputation years ago for shorting and arcing and were ditched in favour of the plastic type but I've had no problems with mine, but then I never go out in the wet.

[Tzen]

yes Frank, know what you mean about so many variables...hey ho, too late now!! Mark, the fuel pipe diameter is a good point as I changed the pipe when I fitted the carb. I have some left so will measure the internal diameter; anyone have the measurement from the standard item? When I said ON is not fully down I was referring to the diamond shape of the tap base plate and its slightly offset position, with the ON being at the bottom point of the diamond. If the tap is switched to a vertical position it doesn't quite line up; hope this makes sense? Just need it to stop bl**dy raining now...