I've had 3k mile of trouble free riding. But on my last ride up to San Simion to see the elephant seals. Hearst Castle. As I affectionately refer to her as "Hawg". She left me stranded. Has to call a friend to load it up. Only to have to call AAA for a flat tire on the rescue truck.
I rode about 45 trouble free miles to stop and get gas . No issues. Then rode the final 5 miles to my destination. Pulled in and the bike immediately died. Wouldn't start , nothing. So I go check out seals for 45 minutes. Come back and the bike starts right up. Comes to a high idle. Thought great. I'm on my way. Nope. It idles. But as soon as you give it gas. It bogs, and sounds terrible.
I get it home and remove the seat , and air intake. Noticed the bottom of the carb looked wet. And below it. I removed the carb. And took it over to my buddy Alex @ Perfomance Marine. Hes the one who worked on it last. Pulled the bowl. Still absolutely spotless inside. Removed the vacuum piston diagram. Soft and pliable. No apparent holes. Inspected the needle and seat. Then applied a pressure pump to the fuel inlet. And the needle and seat was holding 10psi no problems. Fuel level was about half way up the bowl. Alex said that was about right.
The starting enrichment valve was replaced 2k miles ago. Should be good. Page 4-4 The air cut off valve. I applied vacuum to it on the hose feeding the valve off the manifold. Applied 20hg of vacuum. And it would slowly bleed down over time. I then blew back threw the air vent tube that feed to the side of the carb. No vacuum, I could blow back threw the thermal valve. I then slowly watched the vacuum guage as blew. Then at 16hg it closed off. And I could no longer blow threw it. You could very slight suck backwards. Held pressure, but would slowly drop off.
My seam to think it's the air cut off valve from reading other threads. I did notice also when it was it was bugging. It I was to manually open slide. It would clean up and rev to the moon. Release, back to the same problem at hand.
What am I missing, and what is your diagnosis? Thank you. Sincerely Phil. Opps 1987 Helix. Just shy of 9k original miles.