Pipe Blueing

The bluing happens due to excessive heat from the exhaust gases. You don’t have to live with it. Try Autosol Bluing Remover or any good liquid polish to remove the bluing.

 

Some factory pipes are twin wall construction to minimize discolouration.

 

Malcolm Woods.
Eldon has it in one. The w650 is double skinned like the later Bonnies. You can get stainless pipes I think from toga or Norman Hyde easier to clean.
Regards
Joe.

 

I quite like the bluing I wish the pipes on my speed twin would turn blue.

 

I don’t mind blueing although if they were stainless then still no better as they usually turn brown and lose the silver finish immediately from the word go in my experience.

 

You could do it with a blowtorch

The tempering colour would be around 260C if memory serves me right. A light cooking at the head end would make it straw/yellow. Go steady then and creep the colours along the pipe to where you want them to end

 

You could try disabling the sai unit depending on which bonnie you have

 

Most of the 2016+ Bonnie’s have twin skins that stay shiny. I whipped them straight off for straight through to lose the cat and just polish them once a month.
Blue Job works ok and should be used when they are new.

 

I like the blueing - gives the bike character

 

I thought because they we're stainless they won't go blue

 

Crispey nailed it.

The bluing is a direct result of emissions legislation and air injection into the exhaust which turns the first 12” into something of a blow torch. Cleaner exhaust but blue chrome.....just like leaving the racks in your oven if it has a pyrolytic cleaning function.

 

Have a read on "tempering colours of steels" or something similar.
When stainless is welded the colours appear due to oxidation of the metals surface. It is this oxide layer that protects stainless from further degradation and due to the chromium content prevents/reduces rusting depending on the grade and operating conditions .

 

Hi Malcolm, if yours is a 2015 bike then I think it's the older 865 cc version which means things can be done.

Confirm please before I continue.......

 

My Street Twin headers have 'bronzed' rather than 'blued'. I quite like it.

 

Hi Mally, OK, first of all a little explanation: the sai system (secondary air injection) is part of the emissions control devices; it permits, under specific conditions, fresh air to enter the cylinder head, after the exhaust valve and into the exhaust gasses stream. This fresh air obviously includes oxygen which when mixed with hot exhaust gas (with 90% burnt fuel) ignites any remaining unburnt fuel, which is noticeable as popping on over-run.

This additional combustion creates flashes of heat, particularly on tick-over/over-run or very little throttle opening. As a result the header pipes are super heated and create the blueing. This can be cleaned but will return unless the SAI system is circumvented, which can be done in one of 2 ways :

1. There is an SAI pipe which come out of the air box on the lhs of the bike; remove the pipe from the air box and using an item of suitable size - ball bearing/marble/what have you - insert into the pipe so the item blocks the pipe. Now reinstall the pipe back into the air box;

2. Remove the SAI completely. This is straightforward to do but requires further explanation.

Try method 1. and if you like the results, go onto method 2.

Cheers
Dave