ARFs are manufactured with the hope, just the hope no guarantees, that the woods and components used will all weigh the same. They usually don't. Because of that, the retailer includes the suggested CG in the instructions. He wouldn't have to do that if all wood weighed the same, and your installed components matched his.

It's always worthwhile to check the CG. How you adjust it when it's not where it should be can be done a number of ways. The absolute best way is to move your installed components.

I just did the deed to an AirWorks Yak. Now, AirWorks is one of the premier retailers of ARFs we have in the US. Yet my Yak was noseheavy. What did I do?

Since the YAK came out just under the advertised weight and I plan to fly the stuffings out of the sucker, I really didn't want to add dead weight. Sliding the battery along the underside of the sucker while it was upside down on the balancer showed the plane level with the batter just aft of the wing's trailing edge.

I built a balsa box that almost exactly fit the battery and braced it back in the aft part of the fuselage. Bracing went to the bulkheads and supported the box really well. Some scrap balsa was all it took. OK, I also used some tongue depressors to brace and position the box. I'm guessing there was an ounce in the materials I used. It's neat and trim. And moved the balance where I wanted it. I'm guessing it took about an hour of very pleasantly spent time. [8D] Truth is, I was quite happy to do it. That's what the hobby is for, isn't it.