If so, there's a product calle Blue-Job which is supposed to be very good at cleaning them. Only trouble is, it's very expensive, £14.75 on Amazon for 14g, enough to do your pipes once. Well, do you know what it's made of? A mixture of 20lbs Aluminium oxide powder and 8oz of walnut shells. The walnuts probably don't do anything in that amount. So, if you want to get the blue off your pipes, just buy the aluminium oxide for £5.49 for 500g! on Ebay. The equivalent Blue Job price is a staggering £527 !                                                                                                                                                                             

that sounds pretty abrasive to me. i don't think yer chrome would like it much.
                                                                                                                                                                             

Way back in the day, when my BMW was new (to me), the chrome 2-1 Piper started to blue at the cylinder head end; a friend of mine told me to use vinegar on the pipes, and claimed it had worked treat on his Norton.  I never did get around to trying it, but it is a helluva sight cheaper than either of the options given above...don't think it would do much harm to your zorsts if it didn't work.

Hope this helps

Ride safe 

DM ;)

                                                                                                                                                                             

I quite like the blue pipes on my Bonny.....                                                                                                                                                                             

I quite liked the blued header pipes on my G/S too, which is why I didn't try the remedy offered by my mate lol