Hi Everyone,


I'm just starting to use the SERPT to tune my bike after a cam upgrade and I have a question about the values reported in the working VE tables. After a brief ride to record data and allowing the "Smart Tune" function to recommend changes, I have what I perceive to be a large difference between the front and rear cylinders. Is this normal? I expected the values to be much closer because theoretically, the Volumetric Displacement of both heads are the same. Should I be concerned? Please see data attached.
Thanks,
Mike
2008 FLHRC, Andrews 48H cam, Stage 1 Intake, V&N Propipe.

 

Not an expert, but the numbers reflect changes that the system has made. The object is to get the changes down to 5% or less, run to run. As for the balance between the cylinders, the exhaust system can play a large role. I wouldn't worry about it right now, concentrate on hitting the as many cells as you can for each data collection, then note the % of change. As you go thru different rpm ranges, different loads on the engine you will see the ve changes. It just takes time and effort and a little understanding on how things work. Patience is a virtue, lol!

 

Thanks Wmitz,
So I keep reading that the goal is to get the VE values to within 5%. Here's another newbie question, does this mean that the "Smart Tune" table values are to be within 5% of the "Working" table values?

 

Different readings between front and rear cylinders are normal. This take into account the different temps between the 2 as the rear runs hotter than the front. Timing and VEs are adjusted for each cylinder to compensate for the difference in temps.