I have a website with PR2 and over thousand indexed pages. I created a new website and finished all the on-site SEO. My site was on Google's 4th page within a week for target keyword. I added a link of the new website to the old website. Now back link checkers show over 50 back links from old website (this is growing). I observed that Google started pushing my website on 5th and 6th page now. Why is this? Shall I remove the link from old website? Does Google doubt that its link spamming?