Yeah, you should be able to get it pretty smooth.
It's an art, not a science. An iterative repetition of cycles, hopefully with less and less change each time. It's just tricky because airflow affects idle mixture, and the two of them affect idle speed, which in turn affects air flow, which affects mixture...
It's been a long while since I had SU's on my PV's motor, I've had the DCOE's for a long time. Which are even more subtle to tune, because you're doing one cylinder at a time, not two (although perhaps a bit clearer in response because the bores are completely isolated - no crossover pipe in the intake).
And everything else has to be in good shape as well:
- ignition set properly
- no spurious low compression issues
- no flat cam lobes
- valves properly set
The last time I had lumpy idle issues and tried to fix them by fiddling with the carbs - it turned out to be a mechanical issue (cracked piston leaking compression on one cylinder). So just quickly check all that other stuff first:
- set valves
- do a compression check
- set timing and look at plugs
It's an art, not a science. An iterative repetition of cycles, hopefully with less and less change each time. It's just tricky because airflow affects idle mixture, and the two of them affect idle speed, which in turn affects air flow, which affects mixture...
It's been a long while since I had SU's on my PV's motor, I've had the DCOE's for a long time. Which are even more subtle to tune, because you're doing one cylinder at a time, not two (although perhaps a bit clearer in response because the bores are completely isolated - no crossover pipe in the intake).
And everything else has to be in good shape as well:
- ignition set properly
- no spurious low compression issues
- no flat cam lobes
- valves properly set
The last time I had lumpy idle issues and tried to fix them by fiddling with the carbs - it turned out to be a mechanical issue (cracked piston leaking compression on one cylinder). So just quickly check all that other stuff first:
- set valves
- do a compression check
- set timing and look at plugs