Muffler ... what else ?

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Zigomatix
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Muffler ... what else ?

Beitrag von Zigomatix » So Jan 12, 2020 11:23 am

Hi all,
I'm french and I recently bought a 1989 250 NX, blue 27 000 km. It is my every day use motorcycle, I also own a 2006 Triumph 1050 speed triple.
As almost evry one I face the muffler problem.
I began to take off the stainless steel cover in order to check how deep rust went.
As you can see on the picture, the tube looking part is in bad condition. I plan to cut and take off all of it and replace it by a new metal tube.
Fortunately, I'm a teacher and some of my colleague teaches welding so I will ask them for help.
Do you think this is an option ? I think my muffler has already been "renewed", normaly does the stainless teel part is "One piece", including the back part ?
Thanks for your answers and help.

Patrick
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Enola Gay
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Re: Muffler ... what else ?

Beitrag von Enola Gay » So Jan 12, 2020 2:02 pm

Hallo Patrick;

schau mal hier
- da ist schon sehr viel zu diesem Thema geschrieben worden.
Das Problem - hier in Deutschland - ist, auf der Edelstahl-Hülle steht die Nr. des Herstellers und die wird alle zwei Jahre bei der Vorführung beim TÜV wichtig (!)

MfG. Herbert

Zigomatix
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Registriert: Fr Jan 10, 2020 5:25 pm

Re: Muffler ... what else ?

Beitrag von Zigomatix » So Jan 12, 2020 2:23 pm

Hi, this is realy kind of you Enola Gay but problem is : I don't understand a word of german and on line translation suks ...
A will give a try again at on line translation but actualy I can't get translation and pictures at the same time ...
Anyway thanks for the reply.
I finaly manage to rip off the stainless steel part and news are bad !
I will soon bring the muffler to my work and see what the welders can or cannot do.
Fortunately only the rear part of my muffler seem rosted.
I hope I can keep the inside and rebuild the tube part.

See you
Patrick

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scrambler
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Re: Muffler ... what else ?

Beitrag von scrambler » So Jan 12, 2020 2:49 pm

Hi Patrick,
welcome to the board. Sorry, my French is almost non- existent so we’ll have to rely on English ;) .
It’s possible to cut off the muffler and replace it with an automotive universal muffler

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But before you cut off anything let’s see if we can save the original muffler. On the pic the muffler doesn’t look too bad – the endcap (for more details see viewtopic.php?f=20&t=1629) has to be removed, that’s where the mufflers rust through first.

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Try to remove all the rust so we can see how large the holes are. It’s easier to weld the holes than build the muffler from the scratch. With a steel cone the endpipe was re-welded and with some sheet metal the holes were welded.

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thats the second muffler from the bottom from the pic with the four mufflers.

Zigomatix
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Registriert: Fr Jan 10, 2020 5:25 pm

Re: Muffler ... what else ?

Beitrag von Zigomatix » So Jan 12, 2020 4:44 pm

Hi Scrambler,
I'm ok with english as long as we use simple words ...
Here are few pictures of my muffler.
DSC_0130.JPG
DSC_0129.JPG
DSC_0128.JPG
As you can see on the last picture, I went too deep with the saw on the cap :(
DSC_0131.JPG
But before taking off all rust I want my welding friends to have a look.

By the way I'm glad to hear from you because if I manage to repair my muffler, I would like to fit 500 CB whells on it (spécialy front one) in order to get 17" tires, here, in britany it's often rainy and I want to fit 100% road tires. I had a look on your KTM looking NX and you've done a wonderfull work.

See you
Patrick
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Zigomatix
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Re: Muffler ... what else ?

Beitrag von Zigomatix » So Jan 12, 2020 4:47 pm

I have to add that luckyly for us, in france, we don't have TUV yet. So I think I will just cut the part where Honda wrote the registrations numbers, then pop it on the new muffler and so it goes.

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scrambler
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Re: NX250 muffler ... what else ?

Beitrag von scrambler » Mo Jan 13, 2020 7:00 am

Zigomatix hat geschrieben:
So Jan 12, 2020 4:47 pm
As you can see on the last picture, I went too deep with the saw on the cap

No, it’s ok – the muffler is a bit shorter than the golden cap (see red line). But the muffler is really in bad condition – with so much rust, the remaining steel is very thin and almost impossible to weld.
patricks muffler.JPG
So I guess cutting off the cylindrical part is an option. These universal automotive mufflers are very efficient in keeping an acceptable noise level https://www.ebay.de/itm/Universal-Edels ... 1438.l2649
Diameter 100mm, length 250mm , inlet diameter 50mm

But they need some kind of db-killer - I took one from the Arrow Paris-Dakar muffler https://shop.motorbikeadventure.com/DB- ... ER-EXHAUST I guess other db-killer will work, too.

Then a 45° bended pipe was welded to the muffler and the Arrow db-killer mounted. It’s removalbe though I would not recommend it in inhabited areas ;) . It has a very nice sound, deeper and stronger than stock but not too loud at all. Unfortunately it’s almost impossible to get something like this legalized by the German TüV (nightmare europe: English food, Italian organisation and German TüV :) ).

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Doesn’t look too bad for a self-made muffler, if I may say so myself :)

Bild
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scrambler
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17'' front wheel on NX250

Beitrag von scrambler » Mo Jan 13, 2020 7:57 am

Zigomatix hat geschrieben:
So Jan 12, 2020 4:47 pm
I would like to fit 500 CB whells on it (spécialy front one) in order to get 17" tires
Sounds like an interesting project but I should mention that I was not very happy with the front 17’’ wheel. As known, the NX250 has short wheel base so I already expected that a smaller front wheel would affect the driving stability. To counteract this I used a longer and stronger NX650 fork. With that the driving stability was ok but I felt it was too nervous in curves – I had to pay too much attention to “find the line”. Maybe its just me and someone else will like it better.

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So I switched back to the front 19’’. If you want street tires you could lace a 17-3.00 rim (for instance from a BMW F650) to the rear hub and use a 130/70-17. In front a 100/90-19 fits (but there are some legal issues with the damn German TüV) and there are lots of good street tires in these dimensions available.

Bild

Zigomatix
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Re: NX250 muffler ... what else ?

Beitrag von Zigomatix » Mo Jan 13, 2020 10:05 am

Hi Scrambler.
First of all thank you for the links. I will surely give a chance to the ebay muffler.
I need more informations :
Did you keep the front part of the honda muffler ?
If so then the ebay one has to be welded on it right ?

What about any power loss with this solution ? My NX is 239 cc, so I would like to keep all the HP it has. But as long as I use the bike to go to work, wich means almost only urban path, I don't want to wake up every one nor the cops to pay attention to me :D

I will go on the 17" wheels disctions later.

And yes you can congratulate yourself It realy look nice :lol:

Patrick

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scrambler
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Re: NX250 muffler ... what else ?

Beitrag von scrambler » Di Jan 14, 2020 6:36 am

Zigomatix hat geschrieben:
Mo Jan 13, 2020 10:05 am
Did you keep the front part of the honda muffler ?
If so then the ebay one has to be welded on it right ?
What about any power loss with this solution ?
Yes, the 250mm ebay muffler was welded on the front part of the stock NX250 muffler. Even though it’s hard to tell I felt that with this muffler there was even a bit more power on top. So no loss of power at all.

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Since that worked out so nicely I had two mufflers produced (I can’t do something like this myself) made entirely out of stainless steel. One with the 250mm ebay muffler and one with a longer 420mm https://www.ebay.de/itm/Universal-Schal ... 1438.l2649
Because usually the power output of these absorption mufflers is improved if the volume is larger.

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As said, with the Arrow db killer (here is the bended pipe that has to be welded to the muffler https://www.ebay.de/itm/Edelstahl-Bogen ... 1438.l2649) both versions performed very well, no loss of power and not loud at all. Actually a friend of mine managed to get the long version legalized by the German TüV, which is only possible because the noise does not exceed legal levels.
That's the long version.

Bild

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