Motad Nexxus: a can of worms

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Crimson
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Thu Jun 08, 2017 3:33 pm

A bit shocked today, after I had had a good chance to look at the Nexxus 4-into-1 system I removed from my bike.

I'd removed the exhaust pipes, which look absolutely great (shiny!) in order to solve a stuck sump plug issue (finally solved by not solving it - just draining the oil via the oil level sensor instead). The exhaust came away very nicely and easily- the bolts were new and had probably been copper-slipped when they were installed. First of all, I was surprised the system is so light - you could walk around town carrying it in one arm. But I didn't examine it closely as I was focussed on the sump pan.

I got my new exhaust gaskets and was ready to reinstall the exhaust system. I thought it would be a good time to clear up all the black greasy gunk that had collected around the fitting places and between the joining pipes and the downpipes with some Coke and wire wool. All was going well, until the pressure of my finger created a hole in the joining pipe. Quite a big one, just under half an inch across. Continuing to clean carefully, I discovered a smaller hole on the opposite side, covered up by rust. As if that weren't bad enough, the underside of the silencer has 3 tiny holes, as it appears that the silencer, too, is just ordinary mild steel, very, very thin like the rest of the exhaust system, albeit covered with a thin layer of chrome. And the weld going down the silencer's length is terrible!

Fortunately, I have quite a bit of experience repairing exhausts without resorting to welding. I know what to do to fix these issues, but what surprises me is that an exhaust that's no louder than stock, which was installed to deal with the original exhaust's rusting issues, is itself rotting from the inside out. It seems that even though it's made by a famous aftermarket exhausts manufacturer, this exhaust is really poor quality - the choice of mild steel for the entire system except the downpipes suggests short-termism with no regard for the maker's long-term reputation. The previous owner of the bike said he fitted this exhaust. So it was most likely fitted in the last 5 years. A really poor show for an aftermarket exhaust. And it's stamped with an embossed 'Nexxus' badge, and has all these EU and other markings engraved in it, as if it were a quality thing...
A record of maintenance items carried out on my bike:
https://crimsonxj.wordpress.com/

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mikee112
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Motorcycles Owned Currently: '99 Yamaha XJ 600n
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Great Britain

Sat Jun 10, 2017 9:04 am

Crimson wrote:
Thu Jun 08, 2017 3:33 pm
A bit shocked today, after I had had a good chance to look at the Nexxus 4-into-1 system I removed from my bike.

I'd removed the exhaust pipes, which look absolutely great (shiny!) in order to solve a stuck sump plug issue (finally solved by not solving it - just draining the oil via the oil level sensor instead). The exhaust came away very nicely and easily- the bolts were new and had probably been copper-slipped when they were installed. First of all, I was surprised the system is so light - you could walk around town carrying it in one arm. But I didn't examine it closely as I was focussed on the sump pan.

I got my new exhaust gaskets and was ready to reinstall the exhaust system. I thought it would be a good time to clear up all the black greasy gunk that had collected around the fitting places and between the joining pipes and the downpipes with some Coke and wire wool. All was going well, until the pressure of my finger created a hole in the joining pipe. Quite a big one, just under half an inch across. Continuing to clean carefully, I discovered a smaller hole on the opposite side, covered up by rust. As if that weren't bad enough, the underside of the silencer has 3 tiny holes, as it appears that the silencer, too, is just ordinary mild steel, very, very thin like the rest of the exhaust system, albeit covered with a thin layer of chrome. And the weld going down the silencer's length is terrible!

Fortunately, I have quite a bit of experience repairing exhausts without resorting to welding. I know what to do to fix these issues, but what surprises me is that an exhaust that's no louder than stock, which was installed to deal with the original exhaust's rusting issues, is itself rotting from the inside out. It seems that even though it's made by a famous aftermarket exhausts manufacturer, this exhaust is really poor quality - the choice of mild steel for the entire system except the downpipes suggests short-termism with no regard for the maker's long-term reputation. The previous owner of the bike said he fitted this exhaust. So it was most likely fitted in the last 5 years. A really poor show for an aftermarket exhaust. And it's stamped with an embossed 'Nexxus' badge, and has all these EU and other markings engraved in it, as if it were a quality thing...
And unfortunately, you can't just bolt another end can on to the motad because of the stupid design ( the linkpipe is part of the end can :huh: )
I think they were built to a price point, hence the mild steel, I think Delkevic are the only full stainless system on the market for our bikes..... but they're expensive :o

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Crimson
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Sat Jun 10, 2017 9:40 am

mikee112 wrote:
Sat Jun 10, 2017 9:04 am
And unfortunately, you can't just bolt another end can on to the motad because of the stupid design ( the linkpipe is part of the end can :huh: )
I think they were built to a price point, hence the mild steel, I think Delkevic are the only full stainless system on the market for our bikes..... but they're expensive :o
They really are a terrible design. They clearly realised too late that the exhaust gets in the way of the oil sump drain bolt, so they put a dent in it so you could supposedly get a spanner in there. The only thing is, you still can't. So that odd dent being there, which looks like an afterthought by Thor, casts some doubt on how thorough their bench flow testing processes were. I doubt they calculated the effect of that dent on backpressure, rebound pressure wave, gas velocity, etc. And when you look up Motad online, you find that this company employed people to protect their reputation on internet forums rather than solve the problem! Their customer service rep went on a forum and told a guy with rusting issues that it was his fault the exhaust was rusting, because he hadn't ridden the bike enough, and Motad exhausts weren't supposed to be left standing... It doesn't surprise me that the company folded.

I think you could get an aftermarket end-can on there, but it would be no improvement. It could be affixed by a combination of epoxy putty, strips of beer can and jubilee clamps, and the join could be disguised by a combination of matt black paint layered up with sand along with artfully folding the strips of can to make it into a diamond shape. Want to know how I know? I've done it before. :lol: I think I have a photo of it somewhere...

I can keep this exhaust working and MOT-worthy using my other techniques. Here's what they look like (took it for a proper run today, and it wasn't blowing):
https://crimsonxj.wordpress.com/2017/06 ... -repaired/
A record of maintenance items carried out on my bike:
https://crimsonxj.wordpress.com/

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sleekitwan
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Fri Jul 07, 2017 12:57 pm

Yuk!

Yes, the corrosive soot just needs you to add water to form acid - oh, waddaya know, the internal combustion engine supplies that too.

I kept bodging the original exhaust system until it blew on me and was partly responsible for my having to break off a Highland tour with my brother and his mates, they went way up to John O'Groats on the North East tip of Scotland, and so on...so not pleased.

The replacement was the most expensive 4-into-2 possible I think. No seriously. Full stainless steel throughout, downpipes, mufflers (silencers old boy), the full monty as they say here in Yorkshire.

I did not find it a particularly good fit, and I notice the welding is somewhat cheap and nasty in just one area - they obviously take the stainless steel muffler, set it on a jig, and weld the short stub pipe that takes it to the downpipes (original or their own replacements). This weld, looks like normal cruddy steel welding rod droppings. The cost? Nigh on 500 GBP or I guess, almost $700 US. Gag.

If that doesn't prove I love my bike, nothing will. The style, interestingly, is like the Diversion 900 shaft drive mufflers, with 'dimples' on the very tail end of the cans, leading to the final exhaust hole popping gases out the back.

But, they work and only leak out the water drain hole like they ought to, and have not blown (used two jubilee clips). Fit quality is pox as well, TBH, so although they look fine, I know the alignment was poor 'cos I fitted them myself. Looks though, they are good, and functionally, they do not obscure anything or foul anything. Let's call it a win!
Current bike year 2000 Yamaha XJ600N also called Seca II or Diversion 600. On an older bike air cooling is a blessing, no sludge and complexity of badly-maintained liquid cooling. Other bikes were: BMW K100 roadster; Honda VF750S Sabre with anti-dive.

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Crimson
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Sun Jul 09, 2017 3:53 pm

sleekitwan wrote:
Fri Jul 07, 2017 12:57 pm
Yuk!

Yes, the corrosive soot just needs you to add water to form acid - oh, waddaya know, the internal combustion engine supplies that too.

I kept bodging the original exhaust system until it blew on me and was partly responsible for my having to break off a Highland tour with my brother and his mates, they went way up to John O'Groats on the North East tip of Scotland, and so on...so not pleased.

The replacement was the most expensive 4-into-2 possible I think. No seriously. Full stainless steel throughout, downpipes, mufflers (silencers old boy), the full monty as they say here in Yorkshire.

I did not find it a particularly good fit, and I notice the welding is somewhat cheap and nasty in just one area - they obviously take the stainless steel muffler, set it on a jig, and weld the short stub pipe that takes it to the downpipes (original or their own replacements). This weld, looks like normal cruddy steel welding rod droppings. The cost? Nigh on 500 GBP or I guess, almost $700 US. Gag.

If that doesn't prove I love my bike, nothing will. The style, interestingly, is like the Diversion 900 shaft drive mufflers, with 'dimples' on the very tail end of the cans, leading to the final exhaust hole popping gases out the back.

But, they work and only leak out the water drain hole like they ought to, and have not blown (used two jubilee clips). Fit quality is pox as well, TBH, so although they look fine, I know the alignment was poor 'cos I fitted them myself. Looks though, they are good, and functionally, they do not obscure anything or foul anything. Let's call it a win!
Sounds like a perfect solution! Reading your post, I'm beginning to think that as consumers, one of the best ways we can get value for money out of the products we buy, and to extend the life of shoddy products, would be to learn to weld. Just imagine, if we could weld, we wouldn't have any jubilee clips on our exhausts. We could keep them running and in service almost indefinitely, by hammering bits of stainless steel into shape, and welding patches in. We could also do things like half-and-half exhaust systems, e.g. taking the downpipes, fabricating a joining pipe, then taking any end-can at all, even a cheapo Ebay one, and welding it all together into a reliable custom exhaust system, saving hundreds of pounds...
I wouldn't know where to start, unfortunately. But welding is very much on my to-learn list.
A record of maintenance items carried out on my bike:
https://crimsonxj.wordpress.com/

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