Scooterotica

So I take that Graham Bell is correct when he explains that there are so many factors to take into account when using a standard or manufactured product as they never match... Ideally, would we want to check and measure the CR on all these ali kits (Intending.. "ali kits out of the box" of course...) if we expect manufacturer specs? How would you correct the CR on such a recessed head? Would you use a program for this or would you do it the old school way?

Cheers for your help,

J.

as you say there are many factors in a build and most of the available kits have undergone lots of development to reach there end design so a little trust can be put into them and there assembly i nstructions as well as testing carried out prior to release ,but theres always room to fine tune and improve.
Correcting compression is quite easy removing material from the dome or as easy as running an extra head gasket to lower compression
or running a thinner head gasket to skimming the head and recutting the squish band or welding up even machining and pressing in an insert to reduce the dome volume increasing the compression
There are a few head design programs out there but all have a a big problem in that msv calculations are based on fixed squish clearances which in reality never happens but are useful for a baseline
ive formulated my own designs from many years of testing on a vast range of engine sizes with vastly different cr figures for small to large cc motors as well as air to lc motors but i might be doing things differently in another 12 years as thats progress and everyone has there own different take on things which is often seen between big engine manufacturers yet can have very similar results

Darrell Taylor wrote:why not test lower compression with an extra head gasket ,i think the casa has a recess but a gasket could be trimmed to fit for evaluation purposes....


.....on a road going low output motor the squish clearance is not the be all and can be used as a method to obtain lower or higher compression 1mm to 2mm can be used without problem

Dan, try this..