ESE's works engine tuner

[ApolloMotoMoto]

ApolloMotoMoto,
The reason why I thought not to go too small with the squish is the following:


A 125RSA has a squish gap of 0.7mm

Jan

You super sure about that?

It was a MotoGP engine, and the squish gap IS a "tunable feature" of the engine. Are you super confident that everytime the RSA125's rolled off the paddock they did so set to 0.7mm squish gap???

I will repeat that Wayne shared a rather large clue, and if you do the deep dive (husaberg where are you!) this has been discussed probably 10-20 times over the course of this thread; what squish gaps WERE actually used in racing, what was tested on the track but never really "raced" and what was tested on the dyno. I can assure you it was not a static single numer over the entire racing pedigree of the engine.

I can absolutely assure you that no matter how "inadequate" your crankshafts are, they PALE in comparison to what I am playing with.

I build and tune "80cc Motorized Bicycle Engine Kit" engines from such fine makers as Jilin-Zeda Technology Corporation, Runtime Products, and Zong Dong Freight Corportation (not joking).

It is made with Chinese "cough" equivalent to something like SCM440, called CR40.

The videos you see on facebook of the fine manufacturing conditions that you will find in a shop with dirt floors, you can start to understand what I am working with.

I am certainly not running them as they come "out of the box" , and with correct preperation, mostly a good press fit and well trued, I am running my 42mm stroke at 0.30mm squish gap without clipping at 15k RPM's.


I totally understand your hesitation in theory, but in practice your concern is actually unfounded (especially if your piston speed is significantly lower than the RSA), and you are leaving a key piece of the Rosetta Stone un-leveraged because of it.

[Jan Van Hamme]

You super sure about that?
.

No, I'm not sure about that at all. That's just what I read and found in a datasheet.
I also have no idea how a racing engine is tuned when it goes on the track or on the test bench.
There are people with tons of experience and knowledge that far exceed mine, and there are also probably a lot of falsehoods to be found here and there on forums.
It's not easy to always make the right synthesis that would then be the correct one.
At the end of the day, I really value the practical experience and approach of those who have already proven themselves.
After all, the world doesn't revolve around just pressing the run button on a 5-axis CNC machine.