I just got a 07 yfz 450 se and it has extended A-arms which makes it lower and I was wondering if trx450 A-arms would fit or what site to go to to get stock ones for pretty cheap!

 

Check out ebay for probably the cheapest for stock.

Will the Honda's fit on the Yamaha? Easy answer is no. Truthful answer is yes, with modifications, and no guarantees. And money. I'd just go get the stock off ebay. http://www.ebay.com/itm/Yamaha-YFZ450-front-a-arms-setup-brakes-hubs-spindles-2004-2009-YFZ-450-RAPTOR-/141024042695?hash=item20d5b01ec7&vxp=mtr, but you can always resell the parts you take off.

 

Hold on, what set of arms do you have that make it lower? Does it have a lowering kit or modified shock mounts? I wouldn't mess with honda arms. Just way to many areas to get snagged trying to convert them. Even aftermarket yamaha arms should be easy to snag used. It is the most popular 450.