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-   -   Are there any two stroke bikes in the Dakar this year? (http://www.advrider.com/forums/showthread.php?t=538827)

MitchMan 01-04-2010 03:23 PM

Are there any two stroke bikes in the Dakar this year?
 
Surely something like a KTM 300 EXC would be pretty competitive, reliable and simple to fix if anything went wrong?

MitchMan

tehdutchie 01-04-2010 03:25 PM

As would be a Honda Cub50...

mutt2jeff 01-05-2010 02:34 AM

Mixed fuel isnt available at the stops, so you would have to carry all your oil for the day and mix it as your filled up, not terribly practical.

MitchMan 01-05-2010 02:40 AM

Quote:

Originally Posted by mutt2jeff
Mixed fuel isnt available at the stops, so you would have to carry all your oil for the day and mix it as your filled up, not terribly practical.

Good point, however at 1:60 mix ratio the amount of fuel for the day probably wouldn't be that huge? It certainly wouldn't weigh as much as the additional weight difference of the 4 Stroke Bike.

Is that the only reason then stopping the 2 Strokes from competing?

MitchMan

fetid_swamp 01-05-2010 03:33 AM

the 690's can carry 34-36l when they need it.
wonder how much a 300exc would need to carry to go the same range??
:loaded

neduro 01-05-2010 05:48 AM

Quote:

Originally Posted by MitchMan
Surely something like a KTM 300 EXC would be pretty competitive, reliable and simple to fix if anything went wrong?

I think a 2 stroke is not desirable for 3 reasons:

1) Half the Dakar is paved or at least untimed and open and boring, usually. That's a lot of km both for wear and tear and also for discomfort.

2) Power and power delivery: The big 4 strokes have an edge both on power and how it is delivered for carving up two track, which is the order of the day.

3) Fuel Economy: my 300, ridden at a fast pace and on the mainjet, burns substantially more fuel than my 530 ridden alongside it. Both are jetted to the best of my ability...

Don't get me wrong, I love the 2 strokes, but I'd hate to sit on one a few hundred klicks of pavement a day, between the good bits no less...

troy safari carpente 01-05-2010 07:04 AM

Quote:

Originally Posted by MitchMan
Surely something like a KTM 300 EXC would be pretty competitive, reliable and simple to fix if anything went wrong?

MitchMan

This question was (kinda) raised last year too...

Gerard Barbazant made a career (several times IIRC) of trying to get a 125 EXC to the finish... and as Rallye pointed out below... he used up a lot of pistons, cylinders etc. in the process...

Another guy from France named - Luc Grajwoda (spelling not quite sure) - made a habit out of riding a monocoque framed KX 500 creation in the Dakar and various other rallies in the early to mid nineties...

The thing used to vibrate that much that it often split/fractured the welds on the chassis and aluminium fuel tanks/subframe construction... and his eyeballs were still going up and down a half hour after he climbed off the thing at the bivouac of a night... :lol3

So basically the answers to all your questions are summed up nicely in Ned's post above... :clap

Quote:
<TABLE border=0 cellSpacing=0 cellPadding=4 width="100%"><TBODY><TR><TD style="BORDER-BOTTOM: 1px inset; BORDER-LEFT: 1px inset; BORDER-TOP: 1px inset; BORDER-RIGHT: 1px inset" class=alt2>Originally Posted by rallye
a french dude Gerard Barbazant tried for many years to finish the dakar on a ktm 125 exc with a 28 liter tank fitted to it , i don't think he ever finished one but went through many a piston tying.

</TD></TR></TBODY></TABLE>

This may be his taken in Barcelona at the start of the '05 Dakar, KTM125

http://ktim.smugmug.com/photos/13710513_X7bfn-L.jpg

rjf 01-05-2010 08:01 AM

Honda had a go at a 2 stroke Dakar bike in the mid 90's too.

http://img319.imageshack.us/img319/939/exp2015sq.jpg

troy safari carpente 01-05-2010 09:09 AM

Quote:

Originally Posted by rjf
Honda had a go at a 2 stroke Dakar bike in the mid 90's too.

http://img319.imageshack.us/img319/939/exp2015sq.jpg

With all the talk of developmental direct injection/FI two stroke motorcycle engines back in vogue of late... the EXP Honda idea might come out of retirement for the Dakar in the near future again...?

UngaWunga 01-05-2010 09:12 AM

Quote:

Originally Posted by rjf
Honda had a go at a 2 stroke Dakar bike in the mid 90's too.


Funny that Honda, killer of 2-strokes in any other form of racing, actually built that bike. Direct injection engine, I believe.

mutt2jeff 01-05-2010 05:14 PM

It would be very interesting to see a modern technology effort to race a 2-stroke though, I would be very interested in seeing a KTM 300 take a shot at the Dakar. After all, 2-strokes have come a long way.

BDKW1 01-05-2010 10:54 PM

Quote:

Originally Posted by troy safari carpente
The thing used to vibrate that much that it often split/fractured the welds on the chassis and aluminium fuel tanks/subframe construction... and his eyeballs were still going up and down a half hour after he climbed off the thing at the bivouac of a night... :lol3

LOL, I know how the poor guy felt. I have "lost" more than few parts of My KX500. Really sucks when you kill it in the bottom of a ditch and realize your kick starter is no longer part of the bike.........

troy safari carpente 01-06-2010 01:29 AM

Sacré blue!
 
Quote:

Originally Posted by BDKW1
LOL, I know how the poor guy felt. I have "lost" more than few parts of My KX500. Really sucks when you kill it in the bottom of a ditch and realize your kick starter is no longer part of the bike.........

Or that the only reason that your bike has not been engulfed in flames (the rear aluminium monocoque subframe/fuel tank has split and is leaking fuel directly onto the red hot rear exhaust pipe)... is that you are still travelling across the desert floor at 80 km/h plus... and the breeze is wicking away the flames from the 30 odd liters of fuel you are seated on... :eek1 Don't slow down my friend... don't slow down! :lol3

MotoMike 01-06-2010 08:12 AM

By the time you hung all the added weight on a 300, ie roadbook holder, nav equipment, large fuel tanks etc, the poor thing would really be wheezing by the time you got to the dunes. And an XC would be a poor choice as well. EXC would be the way to go. I'm one tooth up on the CS sprocket on my XC and it's all done at 75mph.

jake28 01-06-2010 08:40 AM

Don't forget the marketing aspect of bike choice as well: Dakar, like any MotoGP, supercross event, or motorcycle tradeshow, is an opportunity for companies to show off the 'best and brightest' of their motorcycle stable.

If Honda, KTM, Yamaha,... want to sell four strokes, and there is no doubt that every company does, the racers will be atop four stroke race bikes.


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