The motor often fires up and tickover sounds good but it dies after a couple of seconds. If this is a typical sign of a particular problem - let me know.
I know it needs sparks, petrol, and compression. It (seems it) has all 3 ... until it doesn't.
The bike has been running in the past so valve timing, compression etc were ok then. It has been stripped for shipping since so everything is now suspect..
The oil system was primed before I did anything else, the tell-tale shows pressure as soon as the bike starts.
Ignition is a distributor with 12v twin coils (wasted spark), power is from a fully charged 12v car battery
hotwired direct to the coils.
Timing has been checked & rechecked, Sparkplugs were fitted new before it went into storage (so are unused but not new).
Plugs have been removed & cleaned, they soon go black / sooty - no surprise given the amount of petrol I've fed it.
3 monoblock carbs give similar results which makes me think the problem isn't the carbs. Pilot jets & floats were checked on all carbs before use. I have a spare needle but not sure if it will work with the 375 or 376 - what length do they need? Carbs available are :
375 (ok but undersized? Missing needle?),
376 (snapped airbleed & tickover screws - but should work if they are set somewhere near? Carbtop ring has snapped and is held with a jubilee clip, missing needle?)
389 (looks most complete & usable, bike has been running with this in the past)
Fresh fuel was bought last week, I've been using a lawnmower petrol tank as a supply (also an open funnel) so I can see any movement. All seems ok.
Pouring neat petrol down the carbs / into the cylinders doesn't really help.
There's no other wiring fitted yet, the petroltank / fueltap hits the rocker covers so I'm using a temporary tank for now,
I have a basic toolkit here (inc timing light & multimeter) but assume if I don't have it I can't get it.
Getting spare parts here is near impossible, I don't have a compression tester but it feels like it has compression.
Hopefully the problem is something obvious but I'm missing it...