2007 WR 250 R Athena big bore kit problems?

I have a 2007 WR 250 R and recently had a athena big bore kit installed. I was relativley happy with the power of the stock engine, however my crank shaft recently siezed and was persuaded to upgrade to the athena big bore 290. The upgrade included:

-Athena 290cc kit WR 250F
-IN HOT Cam YZ/WR250F STG 1 YAM
-EX HOT Cam YZ/WR250F STG 1 YAM
-Athena WR 250 290cc top end kit
-Crank shaft assembly

After getting the bike back from the shop (took 2 months, because they had never done this upgrade for this model before) I noticed that the bike runs like garbage in low RPM. I thought that the big bore kit was going to increase the power at all RPMs?. I don't think that the carburetor was tuned after the install which seemed strange to me, so this could be the culprit.

If anyone have any experience with this problem or suggestions your help would be greatley appreciated.

Spangler.

2007?

Do you have a fuel injected dual sport?
Or a carbed non street legal wr250?

This forum is mainly info on the 2008 and up wr250x and wr250r's.

Not trying to be rude, and you are more than welcome to stay if you have the other bike.
Just trying to clarify what we are talking about

Sorry, it is a carbed non street legal wr250r motocross bike
thanks

You mean a WR-250F?
The bike that's basically like a YZ-250F with a headlight and taillight?

yes it has stock headlight and taillight, no signals no horn no mirrors. I always thought it was a yz250f but the shop is calling it a WR 250 R, it is a four stroke it blew it up now it has the athena big bore kit and some cams and anew crank but its running bad. I bought it used l8 months ago and rode it on the road and in the bush

If it's got a carburetor, it ain't no WR-250R, which is fuel injected.
If it's a 2003 WR-250F, by chance, then it would be called a WR-250FR on the cover of the Owner's Service Manual and on the parts catalogue.

I've only read positive things from guys riding WR-250Fs with the 290cc big bore kit, so, especially if it took a place 2 months to install the parts (that's an afternoon project in somebody's garage), I think it ain't right somewhere, as you suspect.