What is the HT engine typical idle speed?

[AussieSteve]

I don't have a tacho yet, (that's possibly on the drawing board in the future), so can anyone reading this that has measured their idle speed, not guessed, tell me what their engine idles at? Both 48cc and 66cc.

This is relevant to the 6-12V, 5-7Ah generator/battery charge system I'm putting together for shift-kits. I want to try to get full voltage at near-idle, so that any lights don't dim, (too much).
Not sure if I'm making one for me, or a number to sell. We'll see.

... Steve

 

[MikeJ]

Hi Steve -

According to my SenDEC digital tach, my 66 cc idles around 2200 rpm after the engine is thoroughly warmed up. That is just enough fuel flow to overcome internal friction losses plus a little more. While the engine is cold and is warming up, I have to keep the speed (and fuel flow) around 3000 rpm, else the engine dies and requires a restart.

MikeJ

 

[AussieSteve]

That's higher than I was expecting to hear. I'd guessed that mine was idling at about 1500, when warmed up. 2200 is even better, from my point of view.

... Steve

 

[swifty]

I have a kartech digital tacho with max rpm recall on my bike.most of the time it idles around 1850-2000 rpm. If it gets down to under 1600 rpm it sounds like its going to stall & usually does after a couple of minutes if you dont blip the throttle.My engine is ported,raised comp,ceramic coated head, ceramic coated & dfl piston pz19 carby(mikuni copy)& a few other mods I did.

 

[AussieSteve]

Thanks, Swifty. Your's is modded, which probably makes a difference, but I want to cater to a low idle as much as I can.
I'll aim for usable output at a minimum of 1850 to 2000 RPM, if at all possible.

... Steve