An update for anyone interested.
After removing, wire probing, and thoroughly cleaning out the cold start and pilot jets, I've been able to start the bike several times without needing any starter fluid. Many thanks to all for sharing your experience.
As a follow up, I do find that it takes about a dozen attempts to kick start the bike in order to get it started from cold. (about 3-4 with chokes on until I smell gas, then another 9-10 with chokes closed before it finally fires up). I can't help but assume I should be able to do better than that, though I'm not sure where I adjust from here. Any thoughts? Perhaps it will get better after getting some runtime after 36 years in hibernation?
In addition, I've noted that kicking over the bike with the chokes on eventually starts dumping gas out of the air vent pipes on either side of the carb body. Is this normal if you keep the chokes open too long or do I need to go back through the carbs again and adjust further?
We are always interested
Triumph motorcycles are not known for being hard or fussy starters, if I ever have to use more than two kicks with the ignition on then I suspect something else is wrong.
The enrichment device is not like a normal choke, if you open the throttle the venturi effect is lost that pulls the extra fuel in, but if you donít open the throttle the engine does not catch and start.
I am not sure I have much more to add to the starting technique that I have found with the mk2 carb, this seems to have been covered by others who seem to start them in a similar fashion to me-it is good that there is a consensus of opinion.
Like Trident 150 I use 2-3 kicks with ignition off, but only to build 40-50psi oil pressure before firing the engine.
Bring the pistons close to tdc switch the ignition on and give a good kick, extra fuel will be drawn in through the enrichment device, about 2/3 of the way down crack the throttle 1/4 to1/2 open-fires up just about every time.
One thing I noticed with mk2 carbs is you need choke with a cold engine and do not need it with a hot engine, but if your engine is warm, maybe stopped for 20 minutes, you will need choke to get a first kick start.
I believe the mk1 carb requires a different starting regime.
The only mk2 carbed bike that I had and was a pig to start, broke down with a coil failure, once I replaced the coils it instantly became a one kick wonder. I had already rebuilt the carbs 3-4 times trying to fix it. Iím not saying your coils are bad, but everything has to be right, not just the carbs.
What method did you use to balance the carbs?
For the pilot mixture screws, start at 2 1/2 turns out, when the engine is hot, screw them in until the engine starts to fail on tickover, then screw them out until the engine starts to fail, note the number of turns between these two points, and set the screw half way between the two.
Take a ride, if there is a hesitation or flat spot just as you start to accelerate, adjust the screws, until it is minimised - this can make the tickover lumpy due to the mixture being rich, you just have to make a compromise.
I believe I have seen a post by either gpz or johntioc where they drill the side of the needle jet to fine tune this phenomenon.