58 replies to this topic

[Stormtrooper]

I have been toying with the idea of making up a flanged pipe with a larger diameter for the tip, but I'll have to get really bored before going ahead with the idea... maybe.

The original pipe is 25mm. The red lines would be the new exit at ~38mm, it would be flanged and mounted by rivets (green).


I expect the larger exit diameter would allow lower frequencies out (sound wise), and also more free flowing gasses... maybe a bit more usable torque... but just guesses so far.

I'm liking your skills of an artist, Azza

I've got time here and there and will be happy to lend my pipes for photos of the procedure. I think you've done a pretty good job with the diagrams though!

[AzzA]

I'm liking your skills of an artist, Azza

I've got time here and there and will be happy to lend my pipes for photos of the procedure. I think you've done a pretty good job with the diagrams though!

Yeah, ain't paint.exe a cool toy in the hands of a child.

Thanks ST but I think this should have nailed it though, real photo's might just confuse the matter. "K.I.S.S."

Anyone wanting to post photo's of their methods is welcome, of course.

[dandywarhol]

Due to the use of catalytic converters these mufflers are designed to let water out, how much they can cope with I can't say, but if you look at the rear lower end you will see a hole... you will see another in the band of the heat deflector, just behind the cat's... keeping the holes clear and clean, with wire, should keep things OK.

If storing outside in horizontal rains, or when pressure washing, get some plugs. Like these:


Any dirt bike shop will have them, most other bike shops too.

Nice ideas here Azza - and easy to understand drawings

I don't thing water ingress would be able to get past the baffle plates and as you say, the drain hole is at the lower end of the silencer, just after the cat.

As for your butt plugs - they must be a 900 bhoyo's dream................

[AzzA]

Nice ideas here Azza - and easy to understand drawings

I don't thing water ingress would be able to get past the baffle plates and as you say, the drain hole is at the lower end of the silencer, just after the cat.

As for your butt plugs - they must be a 900 bhoyo's dream................

Thanks Dandy',

well picked (wondered who'd be the first to make the connection), they do look quite similar... and I'm sure many poor apprentice bike mechanics shudders at the sight of them.

I can just imagine you running around with this one yelling "BOOM-BOOM, look at me I'm Basil Brush!"

[Stormtrooper]

Thanks Dandy',

well picked (wondered who'd be the first to make the connection), they do look quite similar... and I'm sure many poor apprentice bike mechanics shudders at the sight of them.

I can just imagine you running around with this one yelling "BOOM-BOOM, look at me I'm Basil Brush!"

Wrong.... so wrong....

[AzzA]

OK. It's taken a while but I've arrived at an end. A modified 900 exhaust that doesn't break the bank or the law, not too blatantly at least.

Using the afore mentioned methods I have had fabricated some tips, they go something like this:

Exit left, muffler right.

Further more, they're reversible... 30mm length to the outside delivers a deep and throaty tone without pops and bangs, whilst with the 20mm length to the outside the sound is very near stock. Handy should you need to satisfy your dictatorial administrators.

Shown in the picture in the loud setting, when the centre chamber of the muffler is bypassed. When reversed the 30mm length overlaps the original 25mm pipe and effectively puts the centre chamber back in circuit. Simple really, and effective.

The tips are loosely based on those in the pdf document (click here), but my method of modification is not as brutal and the sound effect is reversible should you need to (ie MOT or RWC time).

Yes, I know I should have taken pictures of the bits before fitting... but they're just 50mm long bits of 32mm diameter SS pipe with a flange welded on at an offset of 30mm/20mm. The flange is cut to just fit inside the heat-shield of the muffler, 55mm. I'll try to take a picture of the finished result soon, but it looks quite stock unless you know exactly what you're looking at.

Enjoy.

Edited by AzzA, 25 January 2010 - 11:51 am.

[vicens66]

OH yes please for the pictures. what about the noise??.

[AzzA]

As requested:

Free file hosting from File Den!

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It's a bit hard, damn near impossible really, to replicate the sound for you via MP3 etc... it just doesn't do it justice.

I might try to catch up with Stormtrooper this w/e and do a side-by-side with his Staintunes, the ultimate litmus test I guess.

[willsTDM]

Mods look very good Azza. I had a racing exhaust builder mod the stock pipes on my 2007 TDM about two months after I bought it in Dec 2007. He drilled about eight holes in the flat section between the inner outlet and the outer muffler wall. Four of these holes also go through the next internal baffle stage that were done with a huge long drill. It actually sounds like a 900 twin now, better low rpm response and a 'fruity' cackle at low rpm on the overrun. I like it. Not so loud as to not make through a NSW Blue Slip inspection but great to listen to Could be easily brought back to stock sound by fitting a couple of stainless 'washers' over the drilled holes if need be. I've had it side by side with a Staintune fitted 2008 model and it sounds very similar indeed!

[vicens66]

Look good Azza ,thanks foR the picies

It is a south hemisphere thing to put the whell nut
on the brake side.I am pretty sure in the noth it is
on the chain side
TA

Edited by vicens66, 29 January 2010 - 10:08 am.

[Kang]

Mods look very good Azza. I had a racing exhaust builder mod the stock pipes on my 2007 TDM about two months after I bought it in Dec 2007. He drilled about eight holes in the flat section between the inner outlet and the outer muffler wall. Four of these holes also go through the next internal baffle stage that were done with a huge long drill. It actually sounds like a 900 twin now, better low rpm response and a 'fruity' cackle at low rpm on the overrun. I like it. Not so loud as to not make through a NSW Blue Slip inspection but great to listen to Could be easily brought back to stock sound by fitting a couple of stainless 'washers' over the drilled holes if need be. I've had it side by side with a Staintune fitted 2008 model and it sounds very similar indeed!

Any photos?

Thats my kinda cave man approach.

Edited by Kang, 29 January 2010 - 10:43 am.

[TimH]

Mods look very good Azza. I had a racing exhaust builder mod the stock pipes on my 2007 TDM about two months after I bought it in Dec 2007. He drilled about eight holes in the flat section between the inner outlet and the outer muffler wall. Four of these holes also go through the next internal baffle stage that were done with a huge long drill. It actually sounds like a 900 twin now, better low rpm response and a 'fruity' cackle at low rpm on the overrun. I like it. Not so loud as to not make through a NSW Blue Slip inspection but great to listen to Could be easily brought back to stock sound by fitting a couple of stainless 'washers' over the drilled holes if need be. I've had it side by side with a Staintune fitted 2008 model and it sounds very similar indeed!

I did the same to mine except just through the first plate - sounds a lot better than stock but certainly not offensively loud. I started with 8 x 5mm holes and ended up with 8 x 7mm, could go a little bigger maybe but not game to try.

And I'm not posting any photos cos, even though I made a template and centre punched the plate, you can tell I had a couple of courage beers before I did it. still, it sounds good and looks fine standing looking at it, just looks a bit shoddy in closeup photos.... I'm certainly not the craftsman Azza is. Best part is this mod is completely free (if you own or can steal a drill and drill bits).

[AzzA]

Mods look very good Azza. ...
It actually sounds like a 900 twin now, better low rpm response and a 'fruity' cackle at low rpm on the overrun.
...

Thanks willsTDM,
before I put the new exit pipes in place (like the picture below) there was plenty of fruity cackle, and it got fruitier as the system got hotter.
The new exit pipes act as a sound filter, a low-pass filter to be more definitive, they effectively remove the high frequencies that give the sharpness to the cackle whilst still allowing the extra flow.

Look good Azza ,thanks foR the picies

It is a south hemisphere thing to put the whell nut
on the brake side.I am pretty sure in the noth it is
on the chain side
TA

Cheers vicens66,
well spotted on the axle direction. The manual indicates the other way, doesn't say it has to be though. But I can see why it would be best, as per the manual, and that's because it allows you to torque the bolt against the levered weight of the bike... were as the way mine is now, you could end up lifting the back of the bike while trying to get a purchase with the flat spanner supplied in the stock tool kit. My dealer's mechanics are the only ones to have touched that bolt, I might add.

Any photos?

Thats my kinda cave man approach.

This is an 850, but it shows the principle in use:

I did the same to mine except just through the first plate - sounds a lot better than stock but certainly not offensively loud. I started with 8 x 5mm holes and ended up with 8 x 7mm, could go a little bigger maybe but not game to try.

And I'm not posting any photos cos, even though I made a template and centre punched the plate, you can tell I had a couple of courage beers before I did it. still, it sounds good and looks fine standing looking at it, just looks a bit shoddy in closeup photos.... I'm certainly not the craftsman Azza is. Best part is this mod is completely free (if you own or can steal a drill and drill bits).

G'day cypher,

I did it rough for my testing and had someone "better at it" make the final fittings.
Not sure going through the second plate would make much, if any, difference. If you look at the cutaway section below, the external holes are the only ones that will allow more flow out of the system. Which is precisely why I left that pipe, almost, still intact on my mod'.


Gas under pressure, electrons, and sailors will all take the easiest root... or is that "route of least resistance"?



I had experimented with different exit pipe lengths and had eventually decided to make them 40mm long, however the metal fabricator stuffed up (AKA deviated from the drawings) when he made them and I ended up with 50mm lengths rather than have him refab'... which has turned out just fine.
30mm was loud with a fair degree cackle and a tad excessive pop on over-run if you were tired or lazy on the throttle, acceleration noise was sharp. It sounded cheap if you weren't attentive to throttle control 100%... and who is.
40mm shifted the note down in tone and cackle was turning into a "refined bass sigh with malevolent sharp undertones" and popping was less frequent. It only sounded bad when you really got lax on the throttle.
50mm has turned out to be a nice deep tone, cackle is all but gone and it's popped only once (all be it just) in 400kms and that was at the sore lazy wrist'd end of the sweaty 38deg C day. It sounds good (to me at least) under all conditions.

I have a Tiger Screen coming soon and it will be interesting to discover how much more exhaust will be audible whilst riding with it fitted. I usually ride with earplugs to combat the wind noise and I still get good audible feedback from the bike. Exhaust note tells you so much more than a tacho, "engine load" for example, which is really handy on a bike with the TDM's long rev range in each gear. Idiosyncratic maybe, but up to A$1200+ for off-the-shelf pipes says there's more in it than just hype.

It's all about the experience and if you can make a better experience for only a little time and labour invested, then it's a no brainer.

Cheers,
AzzA

Edited by AzzA, 29 January 2010 - 03:38 pm.

[AzzA]

These are some prototypes used. The flange in just a washer and the whole thing was glued to the muffler with JB Weld epoxy. True!
The pipe is the same, 32mm diameter with 1.6mm wall, that was used in the final fittings. This proto was held in place using clothes pegs wedged against the heat-shield of the muffler, short ride testing only.

Free file hosting from File Den!

[willsTDM]

Any photos?

Thats my kinda cave man approach.

I'll post a cuppla pix when I can get the bikes outta the shed, mind it's easy to tell which holes the exhaust builder did and which ones i did

[dandywarhol]

I did a similar thing to my TRX pipes - good mod

http://www.trx850.mo...e...?f=6&t=5014

[AzzA]

I did a similar thing to my TRX pipes - good mod

http://www.trx850.mo...e...?f=6&t=5014

Dandy, That URL requires a log in.


PS I was getting the odd pop on over run yesterday, nothing major but worth mentioning, so it seams that 50mm length of pipe is right at the verge and atmospherics can tip it.

[dandywarhol]

Dandy, That URL requires a log in.
PS I was getting the odd pop on over run yesterday, nothing major but worth mentioning, so it seams that 50mm length of pipe is right at the verge and atmospherics can tip it.

OK - try here http://smg.photobuck..... bafflectomy/

[tdm850rider]

This is an 850, but it shows the principle in use:

Darn, that looks familiar.....