Wiseco offers 2 pistons for my DRZ. A 12.2 cr flat top and a 13.5 cr than is identical except for a .040 dome on top. It's my understanding that a dome is a band-aid and is poor for turbulence, flame travel, etc. Would it be better to use the flat top and mill the clyinder or am I splitting hairs? Also at what point does milling start to effect cam timing? Thanks
Any time you change the distance between the crank centerline and the camshaft centerline on these engines you'll impact the cam timing. Usually you'll retard the LCA on both intake and exhaust.
The small amount of additional piston crown height required to bump the compression to 13:1 will have a minimal effect on flame travel. The increase in charge density that comes with higher compression ratios tends to speed the combustion process and using a fast pressure rise fuel like the newer oxygenated race fuels will tend to improve combustion efficiency as well. The change in piston crown profile has been a non-issue in my experience.
On that DRZ if its a 400 motor youll also want to keep that head as high as possible as the t chains arent the greatest and tend to slacken quickly esp with HD springs and racier cams. Didnt we talk about this before Rich? Anybody come up with a stouter chain yet? Ive heard tell of a quad shop but not sure.