Right, im a bit stuck. The last few weeks i've been having fuel related issues (i think), one thing after another, most of the time its been at the roadside rather than being driven. The engine refuses to tick over at times, and when it does it then wont rev without fluffing, banging and popping. i managed to get it to run beautifully this afternoon (although soaked by the rain) but when i took it round the block it felt strangled, as if id left the handbreak on, but would suddenly pick up, and pull like a train, before playing up again. ive tried going back to basics (points, standard filter, exhaust etc) ive changed from a big jetted carb back to a standard solex, and even tried different combos of jets, changed the diaphragm but to no avail.
As it stands its got 123, Harley coil, 2>1 exhaust, standard carb, its timed up perfect, and this is the set up its had for the last three years.. so whats different now?

any help will be greatly recieved, as i actually dont trust it to go anywhere anymore without playing up

have you got a spare coil to hand? My old harley coil died and it gave the same symptoms, might be worth ruling out.

thats something i havnt tried..

Nope, just tried.. no difference

kind of have to be systematic about things as its easy to go round in circles creating as many problems as you are solving.

are the fuel lines ok no kinks good rubbery bits?

fuel pump ok? take the lid off the carb as soon as it falters and dies - there is a shelf in the float bowl the fuel should be at that. Back flush or replace the needle jet the floats work

Blow through each carb jet including the idle on the front - blow down each of the drillings at the top of the carb with the jets out

when the lid is off make sure the carb lid gasket is complete and not covering any of the holes in the carb - some of the repair gaskets cover one of the drillings

carb base leak? inlet manifold leak?

if you just peg the hole you cant see if there is problems with the advance ( points) strobe will show the advance moving slowly no jerks or jumps. it will also show where the 123 is advancing to.

all low tension side of the ignition ok?
HT side ok no wires touching and shorting coil not shorting ?

perhaps simply fitting a 2 into 1 exhaust isn't that simple after all eh? tho clever people designed that one.

and its BRAKE

Forgot to mention pumps been replaced, and yes i did pull it apart and make sure its fine first, ht leads have an extra plastic sleeve and are not touching, had the top of the carb off and checked, also blown through all jets and drillings, gasket is fine, again already checked before replacing. Ignition is all fine, got my pop to check advance while timing it, plus i've just re-wired everything under the bonnet from scratch so its all tried and tested and all is fine, and before you ask i had this issue before re-wiring!

Try new HT leads....clean idle jet....spray wd40 or brake cleaner around the gaskets and inlet manifold into engine for leaks

new pumps are shite due to having hard plastic valves Team Stinky found that out the hard way last years race 2 new pumps then stuck an old one in and it went like a well polished turd off a gold plated shovel

tried leads, carbs been cleaned and sprayed, and the pump was a spare, hence it was checked first :/

I recon its carb related rather than ignition

Whats the primary main jet/ and where did you get it?
is it a twin choke?
if so try this at a fast idle dribble some petrol down the 2nd barrel if the engine remains the same then alls well if it increases in rate then the butterfly is open when it should be closed, there is a small adjusting screw somewhere on the spindle ( depends on model of carb) adjust so its closed for most of the acceleration but as soon as the cam starts to operate it it opens.

if its open it makes the car behave as if it has an induction leak