It's tough to answer that question. It all depends on how it runs with the 152's. For all I know you could put 120's in there. (jk, don't do that).
What elevation do you ride?
So what does the wash or even the plugs look like with the 152's????
If they are dark, I would play on the safe side and drop a little at a time. 150, then 148, then 145, you know what I mean.
You can also fool around with the needle, but again that all depends on what it's at now.
Check this out.....
http://www.zenitram-inc.com/vmax.htm
Looks like the 152 is the stock jet.
Also see the clutch chart