Engine races on start up

[carlluvscorinne]

Hi All:
I have a 1964 CB77 carbs have been rebuilt, new floats (set to 22.5mm), new needle and seat, factory slow jet #42 , factory main jet #135, factory main jet needle on second notch from the top (second notch from the bottom was too rich), new points and condenser with everything set per emos tune up procedure. Everytime I start the bike cold I just hit the start button (no choke, but it is 70 degrees outside), and the bike instantly fires and races to 4000 rpm. It stays at 4000 rpm for about 1 1/2 mins. then the rpms drop down to about 2000 rpm. It does this every single time I start it cold. Is this normal or any ideas why it does this? I'm just worried it's going to damage something by racing that high on start up. When wam the bike idles at aound 1500 rpm, if I lower the rpm any more than 1500, when I close the throttle to come to a stop the bike dies, but then starts right back up with the starter button and idles at 1500 rpm. Any help greatly appreciated.
Thanks,
Carl

[LOUD MOUSE]

Do you have tubes on te bowl vent?. ........lm

Hi All:
I have a 1964 CB77 carbs have been rebuilt, new floats (set to 22.5mm), new needle and seat, factory slow jet #42 , factory main jet #135, factory main jet needle on second notch from the top (second notch from the bottom was too rich), new points and condenser with everything set per emos tune up procedure. Everytime I start the bike cold I just hit the start button (no choke, but it is 70 degrees outside), and the bike instantly fires and races to 4000 rpm. It stays at 4000 rpm for about 1 1/2 mins. then the rpms drop down to about 2000 rpm. It does this every single time I start it cold. Is this normal or any ideas why it does this? I'm just worried it's going to damage something by racing that high on start up. When wam the bike idles at aound 1500 rpm, if I lower the rpm any more than 1500, when I close the throttle to come to a stop the bike dies, but then starts right back up with the starter button and idles at 1500 rpm. Any help greatly appreciated.
Thanks,
Carl

[carlluvscorinne]

Hi LM: Yes, both bowl vents have tubes on them ...

[LOUD MOUSE]

Take the tubes off.
Those are not over flow vents.
They balance the air in the carb as gas goes in and through the carb. ................lm

Hi LM: Yes, both bowl vents have tubes on them ...

[carlluvscorinne]

Thanks LM I will give that a try...They sure looked like over flow tubes, and when one of the floats stuck gas poured out of it, so I just figured it was an over flow.
Thanks again, Carl