Date: 05-03-24  Time: 07:49 am

Author Topic: HOW TO: Remove your downpipes and re-paint them  (Read 24622 times)

John Silva

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HOW TO: Remove your downpipes and re-paint them
« on: 03 January 2011, 06:38:55 pm »
Originally posted by NeoPanther on 26/10/2006

Right - I thought I'd have a bash at fleshing out this guide a bit.

The first point is preparation. A lot of people change/repaint their downpipes after several years, so the header nuts are going to be a pain to undo if you don't get some penetrating spray on them. A few members can contest to having to either remove the broken studs from the engine (not pretty) or taking it to garage to get them done.
The ideal solution would be Plusgas. This comes in an Aerosol can and can be bought from motor shops, but generally not the larger ones like Halfords. I used 3-in-1 Penetrating spray myself, which seems to do the job fine.
When I first was going to paint the downpipes I sprayed each of the header nuts liberally with WD40 once a day for a week before I changed them in the weekend, with a final spray of penetrating spray just in case.

Once this has been done you want to place your bike on the centre stand, and remove the exhaust. The bolt is a 14mm IIRC and mine is also held at the bottom from the link pipe to the header pipe.
The picture below shows it off:
pic 1

Next start to loosen the header nuts. Try to be gentle as you don't want to snap any studs or round off the bolt.
I used a 1/4" socket wrench and you'll also need deep sockets and extender bars to be able to get to the header bots from the front. Poor focus, but the picture gives you an idea what you want:
pic 2

I sat in front of the bike with my legs under the exhaust in advance of when they will fall off the bike when it's all undone.
Once you've undone all the bolts on the front, move to the side where the end of the header pipes are. Undo and take out the bolt that attaches the headers to the frame. You will need to make sure the headers don't drop and bend any of the studs at the front too.
Holding the headers steady, take the nuts off the front now, and store them in a safe place. You will now be able to pull the headers towards you to take them off the studs at the front, and move them to one side.
Behold - mucky pipes!
pic 3

pic 4

As you can see. They are in need of TLC!
You now need to thoroughly clean the headers in preparation for painting. If you are replacing them with nice shiny stainless steel headers, then ignore the next steps. However, you may want to spray some degreaser, or strong cleaner on the front of the engine and give it a bit of a scrub (making sure you tape off or block the headers to stop anything getting in there first). Careful where you're spraying the water too. I should have done it to mine...
pic 5

First you want to clean the crap off your pipes. A strong solution of shampoo/specific bike cleaner with a stiff brush is good. Then you'll need to degrease them (I'll advise wearing gloves when doing this too) so you can key the paint, or do what I did, where I took it down to bear metal with wet and dry paper. I used paraffin and a cloth to degrease the pipes, and left them to dry.
Looking a bit better here:
pic 6

Then you need to get the pipes prepared to take the layers of paint. This can be done in two main ways.
If you want to be thorough (or just are a masochist) you can do what I did, where I used wet and dry paper (wet) and scrub the headers until it's down to the bare metal. Or you can 'key' what paint is left with wire wool and paint over that. This allows the paint to stick.
After quite a bit of wet n drying I was making progress!
pic 7

It's hard work!
pic 8

I managed to get most of the paint off, bar some where it's hard to reach between the pipes. Although I think I took several layers of skin off my hands in the process! 
Then you need to ensure they are dried off and clean. Next is the painting process.
I used Sperex VHT black paint which is designed for exhausts and engines. Since this is aerosol based, you need to spray in layers and in long sweeping motions.

Don't keep spraying away either, as the paint will just run. Spray in thin layers to cover the entire pipes (with the backwards and forwards sweeping motion). Leave to dry for 10 minutes or so and continue to layer the paint until you've got at least 5 or so layers. This should provide adequate protection. I didn't do as many as that and it didn't last as well as hoped.
Here's what they should look like:
pic 9

pic 10

Once you've left the pipes to dry (or use some heat to help the process), they are ready to fit. Be careful not to chip your freshly painted pipes! (Lay down a sheet or something under the bike possibly)

Adopt the similar position to when you took them off. I held the pipes up under the bike with my feet/legs to slide them back onto the header studs. I'd like to note that when you're replacing your exhausts, even to repaint them, it's best to replace your header gaskets. They can be pulled out with a bit of determination and a screwdriver! You can hold the new gaskets in the header holes with a bit of copper slip or something similar, as you'll find they keep falling out!
As you push the pipes back onto the studs and the bits surrounding the header ends to screw them on, you might want to get someone to bolt on the end of the headers, to help you keep them steady when you tighten up all the header nuts.
Tighten up the two end headers to make it easier for yourself too.
So to finish, ensure you tighten all the nuts (including the end can bolt) at correct torque and if you're fitting new header pipes, check the header nuts after 100 miles or so to be of correct tightness as they generally loosen off as they settle.

Hope this helps!
« Last Edit: 07 January 2011, 03:52:24 pm by John Silva »
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John Silva

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Re: HOW TO: Remove your downpipes and re-paint them
« Reply #1 on: 04 January 2011, 01:49:52 pm »
Couple of questions and answers

Q. What’s the best paint to use?
A. Any high temperature paint should be OK such as Sperex VHT spray paint, Plasti-kote BBQ paint or Hammerite.
(Sperex seems to withhold higher temperatures than PJ1, 315 C as opposed to 260 C.
A normal heat-resistant grill paint I saw in a Pound-saver's, which withholds 465 C
Hammerite barbecue paint resists up to 600 C)

Q. How do you get off the rusty header nuts?
A. Spray them with a penetrating oil (rather than WD40) each day for about a week. Or use oxy-acetylene

Q. What tools do I need?
A. I used a thin 10mm socket with extender.

Q. Do I need any special grease?
A. Use copper grease on all the nuts, bolts and studs to prevent future seizing.

Q. Do I need to replace any bits?
A. Copper header gaskets should be replaced Yamaha part number is 3YF-14613-01
(If needed Studs Yamaha part number is 90776-06475 and Nuts Yamaha part number is 90179-06668.)

Q. What are the torque settings?
A. The torque setting for the nuts on the downpipes is 10Nm.
« Last Edit: 07 January 2011, 03:53:46 pm by John Silva »
Biking is about the Journey NOT the Destination...