Controlling Grids and axes in dual axis plots

This is a continuation of the question I asked earlier: http://www.mathworks.com/matlabcentral/answers/68730-controlling-dual-axis-plots

In the accepted solution for this problem, Kelly Kearney proposed a method to plot the dual axis using plotyy. Using the answer I was able to indeed plot the figures. However, there has been some issues involving the axes and legend that I might need help on.

Below is the code I used, modified from last suggestion, and abbreviated.

[ax,ln1,ln2]=plotyy(straininst,stressinst.*1e-6,e_piezo,cap);
set(get(ax(1),'Ylabel'),'String','Stress(MPa)');
grid on
set(ln1,'Color','b');
set(ln2,'Color','r');
hold(ax(1),'on');
handle=plot(ax(1),strainamp,stressamp.*1e-6,'c',strainamp(n1:n2),...
    stressamp(n1:n2).*1e-6,'y',e_amp14,-s_amp14.*1e-6...'--rs');
hold(ax(2),'on');
plot(ax(2),e_cap14,cap14,'Color','m');
legend([handle;ln1;ln2],{'E_{sg12}','E_{sg12slope}',...
    ,'piezo12','piezo14'});
set(get(ax(2),'Ylabel'),'String','cap');

As it is shown, the axis, for some reason, depends on the axis on the right, and also the grid. In addition, if I plot more data values to this graph, I notice that data parts are being cut off because of some "hard axis settings" that gets applied for some reason.

Attached in the picture where I put a lot more data points, and it is causing cutoffs in data as well as missing legend entries.

any help will be appreciated. Thanks!

[Samuel]

bp

[Samuel]

any help or suggestion will be appreciated. thanks!