I’ve had a nice Honda Shadow ACE (RC44) from 1999 since last year.

Unfortunately, I have a very strange problem when the engine is still cold. Maybe someone here recognizes the issue:

When the engine is cold, my bike starts without any problems with the choke pulled, provided it has been running the last time before. But if I don’t pull the choke when the engine is still cold and try to start it, the engine quickly dies (thats nromal/ expected...).

But here’s the strange part: if I then pull the choke and try to start it again, it gets stuck in a kind of “cranking mode.” No matter how long I keep cranking, it simply won’t start.

It doesn’t matter whether I fully open the throttle or what position the choke is in. The only thing that helps at that point is starting spray/brake cleaner sprayed into the airbox. When I use that, the engine immediately runs smoothly again.

The spark plugs are wet while cranking, so fuel is getting through (possibly too rich?). The mixture screw is set to 2.5 turns out, according to the manual. Idle speed is around 1000–1300 rpm. The carburetor has been rebuilt and cleaned (maybe the float level is too high?). Battery is new.

Are there any vacuum lines or similar systems on the Honda VT750 Shadow that could significantly affect the starting process?

Or could it be the choke itself? Has anyone experienced something like this before?

Endless cranking after one failed start (VT750 / RC44)