Funny thing about the Diesel line is that one ball will look completely different from another in the same line, however the only one that even comes close to being "yellowish" is the Power Diesel and it's orange and blue. Mine is more blue than orange, but a buddy has one that is alot more orange than blue! Unless it's something new I don't think it's a Diesel. There are other Hammer's that sound like what you're describing- Saw Blade, Vicious Attack, but no Diesels.
Spike