Wednesday, 17 June 2015

2004 YZF-R1 Exhaust Flange Replacement

My main transport, surprisingly enough, is not a Ner-a-Car but a 2004 model Yamaha R1. I have had it from new, and have done 100,000 miles on it. If it broke terminally tomorrow I think I would buy another exactly the same.

The bike is still using the original exhaust. It is made of titanium and stainless steel and appears likely to last literally forever. Unfortunately it isn't all titanium. For some unfathomable reason they chose to make the retaining flanges out of mild steel, and after a while they look like this:



Not pretty, that's for sure. 

The clamp-plates are put on the header pipes before the pipes are welded into the collector flange. Once on, they don't come off in one piece. More annoyingly they don't go on in one piece either. 

I had plenty of time to think about this, and in the end I had a batch of these made by a local laser-cutting place.  



If you want to make some, then this is the CAD file I sent them

At this point they won't work for the job, they need a bit of machining. I was going to use the mill, but I am having problems with the PCI card. (probably the motherboard slot). So I found a way to do it on the lathe:



And then with the hole parts half-thickness the result is a flange that can be assembled round the pipe in-situ. It's like the Ying-Yang of combustion gas evacuation. 



Once I had made one I checked that the idea was sound, and was rather pleased with the result:


So I went on to make the others, then cut off the old flanges with a Dremel cutting wheel. 



All in all, it looks (so far) to be a surprisingly great success. 









13 comments:

  1. That's a really neat job!
    Was the laser cutting expensive for such a small batch of parts?

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  2. I paid £28 for 10 of them in 5mm stainless steel.(You need at least 8)

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  3. great job! How is the split flange project looking after nearly 2 years, are they still holding in place, may I ask? I am looking to do exactly the same on my 2011 fazer800.

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    1. Has it really been that long? They have worked perfectly, no problems at all.

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  4. Really is a fantastic job! Thanks for documenting it, really encouraged me to get it done on my bike. Have been looking for a solution like this for a few months now. Well done sir

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    1. I guess this sort of problem serves us right for not crashing our bikes ar 20k miles like the target market do :-)

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  5. lol, I may have missed that 20k memo too :) Would be gladly reach that magical 100k miles and just keep replacing the exhaust flanges.

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  6. Hi Andy,

    Only a quick questions. I haven't had any luck in these past few weeks finding a company that could manufacture these split flanges for my Yamaha fazer 8. Would like to ask if you would be able to produce/ get them, I would be paying for your time / material so please name your price. Again, sorry for asking and I hope you will be able to help.
    Thanks,
    Laslo

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  7. Can you get the machining done if I supply the laser-cut parts?
    Do you have dimensions? (Stud size stud centres, exhaust pipe diameter)

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  8. Hi Andy, unfortunately I don't have any machine to do the cutting. I have spent tha past 2 days to find the dimensions / part number for the flanges but no luck. Since the engine is taken from the R1 I'm guessing it's the same dimensions with 2 stud holes / each.

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    Replies
    1. I was thinking that you could measure your exhaust and studs.

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  9. Hi Andy,
    sorry it's been too long. Is there an email address i can forward you pictures of the flanges? thanks for your help
    Laslo

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  10. I see an email address right at the top right, can you see that?

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