the 650 has a fuel pump because the big 4.2 gallon gas tank bottom is below the carbs, so to get all the fuel out of the tank it uses a low pressure fuel pump.
I dont know what the pressure should be, if you pull the line off the carbs and just turn the key on, it will run for about 3 seconds (if you dont start the bike). If fuel is flowing out when you turn the key on, it should be ok.
Since your problem appears to be intermittent, that will only tell you if the fuel pump is dead, or you happened to catch it at a good moment.
You have cleaned the carbs, when you had them off did you have the air filter assembly all apart? if it was sitting with the carbs off its possible a mouse or something got into the air filter and built a nest in the intake box. I have seen this happen many times on cars.
Also check your air filter, if its not clean like white paper it should be replaced, but with only 2400 miles on the bike I doubt its dirty. If it is dirty that would not cause an intermittent issue.
Its still possible there are some passages in the carb that got missed when it was cleaned - some need to be poked out with a hi-E guitar string or a similar very thin piece of wire. There are a couple paths the gas takes thru the carbs depending on the throttle position, and they all need to be cleaned.
Its also possible you have an ignition problem, but normally if a bike has been sitting for years, its ethanol fuel that has turned into jello somewhere in the fuel system.
I dont see any mention of the fuel filter. I thinks its alum on the stock 650, so you cant see if its full of ethanol jello. If it was not replaced when the carbs were cleaned then it will dump more goop into your clean carbs.
It worries me that you have run a few bottles of BG 44K thru the bike. I would think one bottle would be enough for 20 gallons of gas or more. If you poured a whole 11 ounce can into your 4 gallon tank, Im not sure what that would do, if it would cause any harm. I use SeaFoam on my bike, and its 1 ounce per gallon of gas. I know of people that have poured a whole 16 ounce bottle of seafoam into one 4 gallon tank, and the results were not good.
Last edited by KCW; 08-31-2018 at 03:08 PM.