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

I would agree to a point - however, at least half the field are still what one would call 'amateur' riders (ie. not sponsored in any meaningful way and essentially footing the bill themselves), and I believe that ASO still need them - as the part of the reason the Dakar is so impressive is the shear size of the entry list?

As for the costs - the current Dakar entry fee is €14,200 Euro.

If you enter Malle Moto (€500 extra) - then technically you are not allowed* any outside assistance to carry stuff on your behalf, other than the two trunks & wheels the Orga transport for you... and I guess at a push you could squeeze a spare engine into a trunk...

(*of course in reality I know of at least one Malle Moto rider who asked/paid a team to carry their extra tyres and mousses for them x)

Therefore, if you are going to play it by the book - buying a spot with a third-party assistance team essentially costs the same again - in the region of €12-14,000 Euro with a shared mechanic, then add in the the cost of at least one spare engine (say €2500 Euro for anything decent, or €4-5000 Euro if you buy a brand new one) and you are looking at more than double the budget you'd need for a single-engine Malle Moto entry and a few sets of tyres?

Now I'm not suggesting for a moment that this bike/project is going to be the answer to making the Dakar any more affordable for the vast majority of people who choose to enter - as you say, in recent years especially the Dakar has evolved into far more of a race and far less of a traditional endurance event - but what it does offer is at least offer an option for the hardy privateer to perhaps make the start-line after all, without having to typically re-mortgage their house!

Jx

Seeing your using the same compression height as the stock piston,
and using a longer connecting rod, with the shorter stroke.
this will change your rod ratio dramatically.

With this combination it will like a smaller port volume.

Thats why i did this




Good piston guys like,
Venolia, BME, etc etc
Those guys can copy your combustion chamber shape,
upload that profile into the C&C and then can machine the crown of the piston to suit.

It saves alot of time than the old days.

Good luck

..and if Carlton Kirby doesn't mention what went into this project to the viewers at least once in the Dakar 2014 coverage, there'll be hell to pay

Thanks Kasuyaho - that is good information!

It so happens that Rally Raid are just up the road from Cosworth Engineering in Northamptonshire (as many people know, that county is essentially the hub of F1 engineering in the UK) and John has already been talking with their development guys about exactly this issue.

He has a profile already mapped that ought to reinstate the compression ratio to where we want/need it, based on the new stroke characteristics, and will be machining a prototype piston on his own CNC machine in the next few days, together with the custom crank...

Nerdy photos of shiny metal to follow soon I hope!

Jx

Thats the way to do it for sure, talking to Cosworth is the go.

The guy that did my head work runs Top Bike.

The guy who did my valves "650R" was involved in the development
of the Repco / Brabham F1 engine etc etc
And later the Honda F1 engine.
Valve train.
A bit of trivia Jenny, the 650R runs the same size valves as the Honda F3 engine.

And Dave's where i used to work "USA" held many NHRA records over 30 years,
had a porting shop and consulted to Edelbrock and camshaft manufacturers etc etc

As Henry Ford said,
I may not know the answers to your questions,
but i employ people who do.

Looking forward to seeing some pics and seeing how it all comes together

This is probably an ignorant question, but can I ask why you couldn't just take a 690 frame and drop in an RFS engine? Or just use an RFS bike and strengthen the frame and subframe?

IIRC I weighed a 530 EXC motor and that was 35kg.
690 motor anyone?

From a KTM 690 SMR review: ''the engine weight is 38kg''

just read about youre project great.

With the guys from TractiveSuspension you got a lot (understatement) of knowledge in your project, those guys live for suspension solutions and of course are fine Dutch lads

Are you gonna ride with the brandnew fully adjustable suspension? i mean with full active suspension?

Hi Mike, I am sure JMo can....will explain this better but this project is to achieve a bulletproof, low maintenance incredibly strong motor that is within the 450 limit for participation in Dakar. By reducing the CC of the motor down to 450 you end up with a bottom end, valve train, clutch and gear box that was engineered for greater power/torque and is now working within only .......... (insert figure) percentage of its designed/proven capacity. The only possible penalty of this endeavour is the weight of building in all of this redundancy. Knowing that you shouldn't need anything more than a filter change every night, a change of oil every few days and a check of the valves on rest day would in my mind be more of a weight off my mind than an extra few kilos low down on the bike. A worthwile tradeoff I believe and I wish JMo all the best in nailing this project.
The other options you mentioned have been done to death previously and run a lot closer to their maximum designed serviceability (often beyond), hence requiring stupid amounts of maintenance and inevitably a number of spare engines for a 14 day event. Luis on his 150 two stroke is obviously at the exact opposite of this project but as painfully demonstrated for us all to follow and enjoy he has a finishers medal to show for his chosen solution to the hardest event on the planet. Luis on a 125 for Dakar '14?

Ssssssssssssh! I thought that was meant to be a huge secret?!

But yes - we are trialling the new [non active] shock on John's bike at the Tuareg in March, but the intention is to ultimately run with the electronic valving version once it is full proven...

Jx

Hi Big Mike! - not an ignorant question at all, but as Barrier has just reiterated above, there are a number of additional benefits to retaining the basic 690 bottom end, and of course the 690 engine is EFi too.

That said, it is certainly another option to drop in a different [Enduro based] engine - basically what the Factory did with the 450RR... and the older (RFS design you refer to) engines are one of the few that might well go the distance... unfortunately they are very hard to come by now (and are all of course secondhand), while the newer XC4 design engine is even more highly strung and has had issues of its own regarding oil circulation etc.

Ultimately, we feel the 690 Enduro (with the addition of the Rally Raid Evo2 tank and faring kit of course) is a solid and dependable 'open class' rally bike for the privateer... what we are doing is making it conform to the Dakar 450cc regulations with hopefully the minimum of changes - allowing us to showcase it on the world stage, and prove it's reliability in what is undoubtably ultimate endurance event. If it is successful, then the engineering offers other riders (and owners of older 690RRs for example) the option to campaign a similar machine in the future.

And yes, perhaps we're just a little bit crazy too!

Jx

Little ?

Don't know about crazy, I think it's an awesome idea... Careful of checking, double checking and checking again on the scrutineering part for the Dakar, I seem to recall a whole bunch of modified quads (Macachek included) being disqualified at the last minute for Dakar '12... that would suck big time, not trying to be a nay-sayer, just pointing out the sometimes fickle ways of the organizers

This is certainly a platform I would be looking into for the future, maybe not for the Rally Lite races around my neck of the woods, where all you need is an enduro bike with a larger tank + basic nav equipment (think Sardegna), but seeing as the Africa bug has bit hard, I am looking into some races like the Africa Eco Race (where you can still race a 690) or the Tuareg... this looks to be awesome, and I don't just mean the engine conversion but the whole Rally Raid UK Evo2 kit.

Onwards & upwards team LC4-50

+1 to this!!!!!!

Hi Jenny,

I don't have much to add, other than I'm stoked that we'll get to check in on the project in person at the Tuareg.

I was initially skeptical about the project, but as you've taken the time to explain the project I have grown increasingly interested and impressed. This is no simple re-sleeve or parts swap! I think it's a pretty great idea.



Dave

As John explains above, the combination of a longer rod and adjusting the position of the crank pin will give the necessary stroke to retain the standard bore/cylinder etc. As he explains,the trick[y bit] will be to create a piston profile that creates enough compression while at the same time misses the valves when they are extended - the 690 Rally cam (which should help boost power) has a longer overlap than the stock cam, so things could be a bit tight in there - hence the prototype build and bench test before we go to production with the final specification...

Having wasted my youth on law school and financial management, I would like a little more "schooling" from the folks on the thread-

in order to get to 450 cc. displacement with the same bore, the stroke has to be reduced to 55mm. Moving the crankpin 12.5 mm closer to the crankshaft center achieves the stroke reduction. However, this also drops the the top of the piston below the cylinder deck height at TDC, producing an unacceptable loss of compression.

How does a longer connecting rod fit into the picture? If the rod is lengthened to move the top of the piston to the necessary height (and proper compression), doesn't that also decrease the displacement (piston higher at BDC)?

It's probably obvious to everyone but me - still, a little more education will help.

Thanks

Greg

Stroke is determined by the diameter of the circle travelled by the bottom end of the connecting rod. The closer the big end is to the center axis of the crank, the lower the stroke. If you reduce the radius of the the circle travelled by the big end you need a longer connecting rod to get the piston back up where it needs to be. Just draw a picture of a crank, connecting rod and piston at TDC. Then imagine moving the lower end of the connecting rod closer to the center axis of the crank while keeping the piston in the same place.

Great. So you could use the same piston?

Thanks