1983 NH80 Starting issue

[Colincorb]

Hey guys,

I have a 1983 nh80 with a strange issue. After sitting for a day or more, it is very hard to start and I often need starting fluid and have to crank the throttle all the way open while holding the electric start to get it going. However, once it gets running, it starts up super easy for the rest of the day. No issues while it’s running also. I figured it was an issue with the auto choke so I referenced bears post and bypassed it. However it is still struggling on the first start. I figured if it was a dirty carb, then it would be struggling to start every time, not just the first start.

Would love some help. Thanks.

[motormike]

Indeed a strange scenario...
While I have never owned Aero 80, I have owned several Urban Express bikes which share that same auto-choke system.
I bypassed those Urbans with great success, never having any trouble after the bypass was done.
Because you say the only difficult start occurs when cold, after a day or two sitting, I see the possibility of two conditions.
1. Fuel is slow being delivered to carb
2. Fuel is overfilling the bowl and flooding the cylinder causing hard-start cold.
Also this: You can never clean the carb too many times...
Good luck and report your findings.

[Bear45-70]

If my Aero 80 did this I would open up the slow speed mixture screw about a 16th of a turn and see if it got better.

[Bear45-70]

On second thought it could be a leaking vacuum petcock and replacing it or adding a remote petcock would fix it for sure.