I have made 5 sites, all about the same thing. There is 1 site specifically I want to outrank all the others, I built the other 4 just to link to the main site so it ranks well. However for some reason the others are ranking better than the main site. I only have incoming links from the 4 going to the main site and I have the other 4 backlinking to each other, do the backlinks carry more weight than the incoming links?

This is a common "technique" used by people to try to manipulate the SERPs. Needless to say Google is good at filtering this kind of stuff out. Your best bet is to scrap the four unnecessary sites and put all of your content on one website. Then redirect the other four domain to the main site using a 301 redirect. Then promote that one site and that one site only. You'll be surprised to see how much better it ranks when you're not trying to play games and make a serious effort for it to be successful.

I redirected 2 urls, thanks. The sites are all about Temecula Wineries, one targets that keyphrase, one is about wine tasting tours and the other is more of a city guide. Sound ok?

Also I have another city guide for a city close by that I link to all 3 of the wine sites on different pages, is this a bad idea too? I worked the links into the content so it looks natural and I only link to each one time. This guide is a pr2 so I thought it would help.

The links seem to help, the sites rank well on msn, and do come up on google just seemed to go down a little with the latest site. Should I buy some links? Make some unrelated sites for backlinking? Not really sure what to do. Thanks!

Try to get links from other winery sites and related sites such from wineyards sites, wine manufacturer, grapes farms, wine producing machinery sites etc..... dont play just within your sites, go and get more links from other relevant sites this will increase traffic for your site and improve your SERP.

Don't buy links if you got caught then you have to face Google better get links naturally.
Directory submission along with forum posting will help you.

Don't ever do that..... this will not help you, build links naturally from relevant sites

Yeah guess I just need some more time to get more backlinks. I left 2 of them just backlinking to my City of San Marcos site and see what that does, hopefully I made them good enough people will link to them.

Stymee - I removed most of the backlinks between the 4 sites and just backlinked the two main ones with another unrelated site I have. Anyways they got recrawled and both jumped in ranking and my conversion for adsense is hovering between 20 and 40%...so thanks!

Awesome.

There are 2 absolute advantages you are getting in this way:
1. You can use 3 way link exchange
2. If your other websites have different IP adresses - you will benefit from you scheme sooner or later!

Um, did you read the thread? Those "advantages" obviously didn't work out. They only saw improvements after they got rid of the extra sites.