Main Motorcycle: 2005 Bonneville Blue 790
Join Date: Sep 2006
Location: Central Maryland, USA
Other Motorcycle: 1973 CB450, long gone
Try a 115 main jet. Your original might be a 110. See which needle you have and install NBZT if they're not there already. Then adjust the pilot screws and synch the carbs if you can.
And as already mentioned, do not apply any throttle while trying to start, it absolutely will not start if you do.
My 2005 was notoriously reluctant to start in cooler weather until I made these changes. It still doesn't idle easily off-choke when cold, but I don't care because I can control that with the throttle until the motor thoroughly warms up, usually 15-20 minutes of riding.
If you're not sure how to go about doing this, download a copy of the "Jenks Manual" for much more information.
2005 Bonneville Blue 790cc, AI removed, Staintunes RC, no snorkel, inlet enlarged, 118/40/NBZT needles/1 shim/3 turns, Ikon 7610s, Ricor Intiminators, Barnett green clutch springs, Michelin Pilot Activs, D9 gauge panel, tachometer.
Last edited by Baltobonneville; 06-14-2019 at 08:13 PM.