Scooterotica

..................the slot in the air intake scoop on S3's? Why did Innocenti bother with it, and why do the old 1960's tuning books state that you should increase its depth but not its width?

Also, the internal bits to the standard air-box- we tend to just dremmel them out, but again Innocenti designed them like that for a reason.

Any ideas Gents?

Chris

bristolmod wrote:..................the slot in the air intake scoop on S3's? Why did Innocenti bother with it, and why do the old 1960's tuning books state that you should increase its depth but not its width?

Also, the internal bits to the standard air-box- we tend to just dremmel them out, but again Innocenti designed them like that for a reason.

Any ideas Gents?

Chris

Just a guess but would imagine that the slot is there to smooth airflow to a motor that didn't need much since it had a small carb and didn't rev very high. The airbox internals are probably there to slow down the air. The bike will run more predictably if the air available to the carb is constant.

Someone who actually knows what they're talking about will soon be along to agree with me or call me an idiot.

crude "plenum" chamber possibly?

Chris (doesn't know what he's on about)

SO since then what was drilling out the back of the airbox all about?

i guess when innocenti designed and did the R&D on the engines the intake system was tuned to work in harmony with the carb, engine tuning and exhaust..

i would imagine they were looking for the best compromise between economy, performance, cold/hot starting, and quietness.. as well as effective filtering of the air for logevity of the engine.

thus there is some science behind the design of the intake system to achieve this.

now we all know that lambretta engines can be made to go a lot quicker, and so did innocenti, but the performance they came with as standard was designed in carefully.

so once we start fannying round with exhausts, carbs and anything else, the airbox and its design doesn't do what we want it to do on the modified engine and hence we reach for the dremel..

Alot of it has to do with reducing induction noise.

CPH Lambretta wrote:Alot of it has to do with reducing induction noise.

But that's the best bit

Agreed