Burning fuel from the engine is very HOT at the first foot out the cylinder, the head pipe usually discolors to a blue then lower on pipe may turn to a gold... Normal under normal conditions of tuning.
There are Many products out there to address that problem.... Even Harley has them for sale.
Is the blue on the Head pipe (which is normal at the exhaust port) Or on farther on the pipe..... If it is on a double walled covered pipe, Muffler, you have a way too lean condition...
Pretty much all harleys turn blue and it doesn't take too long either. There's products that will lighten/remove it but they also dull the area down where it almost doesn't look like chrome any longer.
Another way to solve the problem is to get the outer chrome covers. The V&H Straighshots are made this way and you cant tell that they are covers, they look like the pipe. But, if you look behind them underneath you can see the blued pipes!
Not really sure why, but I have always actually liked the way the discolored pipes look....Not enough to remove my chrome covers, but I just think it looks cool. JMO.