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.