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Old 12-28-2012, 09:29 AM   #31
MitchMan OP
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Just to resurrect this thread I started a couple of years ago, are there any 2 Strokes in the 2013 Dakar?

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Old 12-28-2012, 09:30 AM   #32
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The Bultaco is back.
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Old 12-28-2012, 04:24 PM   #33
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LUIS... number 150 riding a ktm/jvo 150
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Old 01-02-2013, 06:42 AM   #34
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Wicked

The Bulty is Back?

Cool. I read an article onthe bloke / the bike, I think in Enduro Extreme, and got the impression he wasn't coming back for a few years.

2ts, would have no more problems than a 4t, in finishing. Especially when modern ones come out. Such as a 400 /450cc - LCed, PV'd of course - either Carbed or EFI / DFI/ Whatever new tech bikes came out. Auto lube, would be a boon - an ECU controlled Auto lube, could deliver oil in the appropriate ratios, for the loads / revs being used. Not hard to carry oil enough for a day, or for quite a few days.

Another thing a modern 2t could / probably will have, is a counter balancer. Set up using an existing spinning shaft, like what is used on the latest KTM, and you have very little extra complication / weight.

Two Strokes are not more prone to vibration than a 4t. Try riding a 4t that hasn't got a counter balancer some time, boys, and you'll get an idea of the vibration that a 4t can bring you........

Like ES, Auto Lube, and Counter Balancers will be a part of many modern 2 strokes. Along with DFI / Smart Carbs (for more traditional simplicity of the 2t) or "Whatever Technology" is used to make them clean enough to pass legislation.

The EXP, was an AR equipped bike. Honda's take on cleaner emissions, and smooth running of a 2 stroke. It used trapping valve technology, to enable it to 'diesel', thus not running the spark plug all the time. The Trapping valve, prevented re emergence of spent exhaust gasses into the combustion chamber, which contaminated the 'fresh charge', and causes misfiring - the uneven running that you have under constant throttle, under light loads. So - that, and a counterbalancer, can make a 2t as smooth as Emma Stones bottom.

The Trapping valve, also retains fuel charge, so it's not going straight out of the exhaust port, raises the compression for the 'dieseling' feature, and also ensures very good combustion / full burn of the mixture. Hence, seriously better fuel consumption.

I worked at Off Road Imports, for some 5 (6?) years, on and off, so I got to be involved in a bit of the OZ Safari. I still tend to call it the Wynnes........ One year whilst I was there, Olle Olson left his girl friend (now wife?) at Roscoes house for the duration.

Whilst I was there, Herbert Scheck (sp? - I should know, as I've been aware of him since the sixties) did the Dakar with his Daughter - to Water Boy for her. On a 500 Maico . Not sure if his Daughter was on a 500, or 440 / 400 / 380?. I think she broke her arm, and both retired after that. Speaking to him after, he said a big thing he learned, was that they could have had Much smaller tank capacities. The fact that the bikes were Much lighter than the Multi Cylinder , And the Single Cylinder 4ts, and had equal / more power, and more torque, meant they weren't being screamed, like the 4ts. They were "tractors", if I remember his words correctly.

The EXP 400s - 400cc 2 Strokes - with the AR Technology. I read of them as having used Carbs, EFI, and DFI. I believe they ran Carbs. For the same sort of reason as, up till recently, many Dakar bikes used carbs - simplicity..

They had the same Torque level as the 780cc Work Honda Twins, less HP, but had a better power to weight ratio. 100 / 150+lbs lighter, depending on who wrote the article. Plus, less fuel needed to be carried.

I think, that it won the smaller capacity class, and got 5th outright. I thought it was Richard Sainct that did that, but I've had difficulty in finding confirmation of my diminishing thought processes.I'm getting old....... Nope, it was Jean Brucy - winning the Experimental Class (according to the current HRC Dakar Team Manager).

The AR Tech was used on the later models of the CRM250 - the CRM250ARs. So, Honda did make use of the Tech.

Then, they finally became, as Soichiro Honda always wanted them to be, "All Four Stroke, All The Time". And other manufacturers followed suit.

Troy might know who it was - I seem to think it might have been Alfie Cox - well, a South African - but, one year of the Wynne's, there was a KX500, complete with a Down Pipe, entered. I don't think it finished. When I watched it doing the Prologue at Amaroo Park, I thought to myself, "I hope they've got a LOT of spare pipes with them".

I think a 300 could finish, with the right rider. But, things like fuel, make it difficult, I'd assume (though, what did the Bulty Bloke and The KTM200 bloke do?). I don't think there's a limit to top ends - but I'd only think it would be down to dusting the induction system, Jetting (Smart Carb?/ Lectron Powerjet? ) / Heat issues. Bigger rads / fans, like the 4ts use, can easily be fitted. Leaving the vibration that is just part of it being non counter balanced. A good program of balance factor research could help with that . Perhaps a counter weight type flywheel, for different flywheel / balance effects at different revs could be tried?

But, it's something too different, for most blokes to consider, let alone risk. It would still be a 300 - so, caned on transports. A 300cc 4t would be similarly - well more - prone to getting a hiding. Fair Enough, not wanting to take the risk - it's a hellishly expensive endeavour, the Dakar, without adding a big unknown to the equation.

Now, that Honda EXP engine, slightly updated, in a modern chassis, with an "Alien" or two on them - and you could kiss the 450 4ts arses goodbye, barring crashes / injury.

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Old 01-28-2013, 01:50 PM   #35
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Originally Posted by bearorso View Post
I worked at Off Road Imports, for some 5 (6?) years, on and off, so I got to be involved in a bit of the OZ Safari. I still tend to call it the Wynns........ One year whilst I was there, Olle Olson left his girl friend (now wife?) at Roscoes house for the duration.


Troy might know who it was - I seem to think it might have been Alfie Cox - well, a South African - but, one year of the Wynn's, there was a KX500, complete with a Down Pipe, entered. I don't think it finished. When I watched it doing the Prologue at Amaroo Park, I thought to myself, "I hope they've got a LOT of spare pipes with them".


The Sth African you are thinking of was a guy from France named - Luc Grajwoda - he 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 1992 Australian safari was one of them




And above is a photo (taken by moi) from the very prologue at Amaroo park that you remembered...

The thing used to vibrate that much that it often split/fractured the welds on the chassis and aluminium fuel tanks/subframe construction... and as i recall his eyeballs were still going up and down a half hour after he climbed off the thing at the bivouac of a night...
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Old 01-29-2013, 03:39 AM   #36
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There are quite a number of them. But then, I have a feeling that they should be place in their own category as well as other bike types with identical features. This will make the races more exciting and with more reasons to associate them. Managing the races will also be enhanced in that their will be ease in handling different biker in different categories..

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Old 01-31-2013, 01:49 AM   #37
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Originally Posted by wrk2surf View Post
LUIS... number 150 riding a ktm/jvo 150
Yes, and he finally managed to finish on a 150cc KTM 2-stroke... amazing.
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Old 01-31-2013, 03:11 AM   #38
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Yes, and he finally managed to finish on a 150cc KTM 2-stroke... amazing.
In Dakar conditions which would use more fuel....Luis's 150 or a 300 two stroke?
Anyone know the size of his JVO rear tank and what tanks he used up front either side of the relocated air filter. IIRC he has some alloy tanks made for the front.
Anyone guess at a total fuel capacity and if he regularly ran out of fuel before the end of the longer stages?
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