Dakar Dazed II - the return! Part 1: Project LC4-50

[clearandlock]

Originally Posted by tehdutchie

Why not make life easier, get some 450rr engines and sx-f frames. Standard 24 liter tank and you are sorted..

I think that is called a 450 XC-F for the UK and USA market. No linkage rear end thought.

[CPWSAFARI]

Sxf frame, 450 rr engine, sxs suspension - Ready to Race

[tehdutchie]

Originally Posted by CPWSAFARI

Sxf frame, 450 rr engine, sxs suspension - Ready to Race
Attachment 314257

Exactly like that

[rallyman1978]

Interesting concept

[silentwolf]

Originally Posted by CPWSAFARI

Sxf frame, 450 rr engine, sxs suspension - Ready to Race
Attachment 314257

Quick silly question that comes to mind from this pic:

Why do most Dakar bike have the low header pipe silencer? Was it engine maintenance, easy to empty if waterlogged, better straight pipe sound? Some combo of all?

I know it's not a necessity, and this is somewhere in the back of my head but can't remember...

[Motorfiets]

Originally Posted by silentwolf

Quick silly question that comes to mind from this pic:

Why do most Dakar bike have the low header pipe silencer? Was it engine maintenance, easy to empty if waterlogged, better straight pipe sound? Some combo of all?

I know it's not a necessity, and this is somewhere in the back of my head but can't remember...

heat

[Brimstone]

Originally Posted by silentwolf

Quick silly question that comes to mind from this pic:

Why do most Dakar bike have the low header pipe silencer? Was it engine maintenance, easy to empty if waterlogged, better straight pipe sound? Some combo of all?

I know it's not a necessity, and this is somewhere in the back of my head but can't remember...

As far as I understand, it's because most Dakar/Rally bikes are carrying massive quantities of fuel, usually in a fuel tank that otherwise occupies the space that a normal header pipe would occupy. Also, most rally bikes are also carrying rear mounted fuel tanks which also interfere with the normal muffler location. Hence the lower pipe and more vertically oriented muffler. some designs are more extreme than others, all depends on the configuration and size of said fuel tanks.

In the case of the bike in the picture above, the muffler is mounted on the bottom of a stainless steel fuel tank...

[DaveRMS]

Originally Posted by brimstone

as far as i understand, it's because most dakar/rally bikes are carrying massive quantities of fuel, usually in a fuel tank that otherwise occupies the space that a normal header pipe would occupy. Also, most rally bikes are also carrying rear mounted fuel tanks which also interfere with the normal muffler location. Hence the lower pipe and more vertically oriented muffler. Some designs are more extreme than others, all depends on the configuration and size of said fuel tanks.

In the case of the bike in the picture above, the muffler is mounted on the bottom of a stainless steel fuel tank...

+1

[h2o_snow]

Originally Posted by Brimstone

As far as I understand, it's because most Dakar/Rally bikes are carrying massive quantities of fuel, usually in a fuel tank that otherwise occupies the space that a normal header pipe would occupy. Also, most rally bikes are also carrying rear mounted fuel tanks which also interfere with the normal muffler location. Hence the lower pipe and more vertically oriented muffler. some designs are more extreme than others, all depends on the configuration and size of said fuel tanks.

In the case of the bike in the picture above, the muffler is mounted on the bottom of a stainless steel fuel tank...

Thanks for the info! Just a lurker but trying to wet my limited rally/dakar knowledge. Dazed fat and slow in Idaho.

[Brimstone]

Originally Posted by h2o_snow

Thanks for the info! Just a lurker but trying to wet my limited rally/dakar knowledge. Dazed fat and slow in Idaho.

Well, if you are only wanting to wet your appetite, DO NOT and I repeat, DO NOT check out the Official Dakar Rally thread in Racing... Or maybe do... and become another member of Team F5!!

[silentwolf]

Originally Posted by Brimstone

As far as I understand, it's because most Dakar/Rally bikes are carrying massive quantities of fuel, usually in a fuel tank that otherwise occupies the space that a normal header pipe would occupy. Also, most rally bikes are also carrying rear mounted fuel tanks which also interfere with the normal muffler location. Hence the lower pipe and more vertically oriented muffler. some designs are more extreme than others, all depends on the configuration and size of said fuel tanks.

In the case of the bike in the picture above, the muffler is mounted on the bottom of a stainless steel fuel tank...

Originally Posted by Motorfiets

heat

Ah yes... Big thanks - I knew there was a practical reason. Silly that it would be the most obvious one that I forgot.

As I recall Ned ran the regular pipe for simplicity sake. I wonder if the lower pipe would have helped in some of his fuel issues..?

[Brimstone]

Originally Posted by silentwolf

Ah yes... Big thanks - I knew there was a practical reason. Silly that it would be the most obvious one that I forgot.

As I recall Ned ran the regular pipe for simplicity sake. I wonder if the lower pipe would have helped in some of his fuel issues..?

Neduro was running a 6.3 Gallon Acerbis up front and an auxiliary mounted on the left rear side. The Acerbis tank allows for the stock header pipe to be run, with the muffler sitting in the normal stock position on the right side. Given the heat in the Fiambala Desert, it is possible the additional heat of the stock mounted header pipe could have contributed to fuel temperature issues, although, almost every rider if not all, experienced fuel issues. Even Marc Coma on the factory KTM 450RR.

[neduro]

Originally Posted by silentwolf

As I recall Ned ran the regular pipe for simplicity sake. I wonder if the lower pipe would have helped in some of his fuel issues..?

I detest riding with low pipes on an enduro bike, I had two machines set up that way and repeatedly flattened the pipes on both. I don't crash much, but I like soft suspension to avoid deflection and that means I occasionally land on something hard, and bang, there goes the pipe. Also, it heats your boot (and the engine cases), which can be trivial or very annoying, depending on the machine.

My 690RR has low pipes, but, the suspension was designed around them, so it doesn't put them in the ground before it bottoms like an enduro based machine does. Also, I don't tend to ride very technical terrain on that bike, and also, it has pretty stiff suspension relatively speaking. So far, they've been OK... but I still hate low pipes.

[h2o_snow]

Originally Posted by Brimstone

Well, if you are only wanting to wet your appetite, DO NOT and I repeat, DO NOT check out the Official Dakar Rally thread in Racing... Or maybe do... and become another member of Team F5!!

Ha, I have dabbled the last two years - Neduro's tails sucked me right in -have a "Closed Due to Dakar" 8.5X11 above the garage work bench.

A bit concerned - trying to stay away from the hard stuff - easy to get hooked and develop a nasty Dakar habit.

(However this build appeals to my "cheap or free beer" sensibility.)

[Trialsguy]

"Ned's tail sucked me right in"...... all this talk of 'low pipes' isn't some euphemism is it???

Tales of the Dakar are very good, however.