Topic: 'Normal' idle rpm for a CX-7 cam or Megacycle 125-75 ?

[PeWe]

I have tested various jet combos for my Mikuni VM29 on my CB750 with 836, ported head and CX-7 cam.
I've noticed that a stable idle is around 1500rpm.
- Is this the normal idle or do I have improvements to be done with my VM29 carbs + ignition?

Maybe not that many other running CX-7 cam, Megacycle 125-75 might be very similar.

[MRieck]

1,500 RPM on a mechanical tach sounds about right to me.

[PeWe]

OK, good to know. I guess you have heard some with these cams.....
The engine sounds more tuned now than before with my old cam  that had lift .360  dur  270.  Last session yesterday I noticed stable idle at 1600rpm on the CB750 tach. I have not fine tuned the air jets yet so 1500 is what I can make and aim for.
Too low idle will end up in need of revving up the engine to "clear the throat" with a little bit black smoke visible. I guess that this is normal for this kind of cams....

[Doctor_D]

Sounds about right.  Mine gets a little erratic below 1400, especially with the reduced flywheel mass of a lightened crank and starter hardware.

[PeWe]

Sounds about right.  Mine gets a little erratic below 1400, especially with the reduced flywheel mass of a lightened crank and starter hardware.

Aha! Forgot that old mod. My alternator is lightened, crank standard. The idle is OK then. I'll let the engine run smooth, rpm comes next. Good to read about other engines with similar cam.