Stepping Down From Idle

[Vintage Engine Repairs]

Curious to learn more. In OPE, we want a quick return to idle and a nice lumpy burble at idle for good off idle acceleration.

On the other hand, dirt bikes are often tuned with a leaner idle and have a slower return to idle.

My guess is, the ope doesn’t have a mid circuit, so the engine needs more fuel at idle that what is ideal, to cope with the flat spots in the mid range, where as a dirtbike has a mid range (needle height & taper) so they can be run leaner at idle and thus crisper?

Have a listen to this car, you’ll hear how it sounds lean on return to idle and at idle, but is that better, if you have a mid circuit?

Any advice would be much appreciated:



Here is what I’m referring to re dirt bikes too

 

[rogue60]

It's a two stroke who needs idle... Run em wide open throttle!

 

[Chevboy0167]

 

[Vintage Engine Repairs]

It's a two stroke who needs idle... Run em wide open throttle!

That’s insane

 

[rogue60]

That’s insane

Not wrong 494 kilometres per hour! (307 mph)

 

[Chevboy0167]

This guy.......is cool!

 

[singinwoodwackr]

It's a two stroke who needs idle... Run em wide open throttle!

Ok…when do they do a chainsaw?

 

[Chevboy0167]

How does 55,000 rpm idle sound to ya? LOL



It's neato, but not practical....

 

[rogue60]

Ok…when do they do a chainsaw?

Think I'd run genuine Stihl chain if one them guys tweaked my saws lol

 

[bwalker]

Curious to learn more. In ***, we want a quick return to idle and a nice lumpy burble at idle for good off idle acceleration.

On the other hand, dirt bikes are often tuned with a leaner idle and have a slower return to idle.

My guess is, the *** doesn’t have a mid circuit, so the engine needs more fuel at idle that what is ideal, to cope with the flat spots in the mid range, where as a dirtbike has a mid range (needle height & taper) so they can be run leaner at idle and thus crisper?

Have a listen to this car, you’ll hear how it sounds lean on return to idle and at idle, but is that better, if you have a mid circuit?

Any advice would be much appreciated:



Here is what I’m referring to re dirt bikes too

A dirt bike or sled commonly have 6 tuning circuits, vs 2 for a saw. No properly tuned dirt bike returns to idle slow. OP3 tuning is always a compromise due to limited low and mid circuits.