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

[dashmoto]

Just out of interest, what does the stock 690 motor weigh anyway?

[neduro]

Originally Posted by dashmoto

Just out of interest, what does the stock 690 motor weigh anyway?

A bunch- I've got one in a crate and also have a 450XCW motor sitting next to it. I'd guess the 690 motor is ~20lbs more, although given I don't have a scale and am guesstimating the weight of the crate, that could be complete malarky.

On the flip side, I believe that weight goes to things that count. A 690 will go, as Jenny said, a very long way with no maintenance at all, where a 450XCW really wants its oil changed often to get decent life from the engine.

Curious about FI vs Carb as well!

[JMo (& piglet)]

Originally Posted by barrier

Surely they could sleeve it a little without being too small for the valve layout.
But hey what do we know!

That was the other option of course, however, when John stripped the engine down, he realised that the difference between the size of the [450cc] bore and the shape of the original head would have such a pronounced lip, the combustion chamber would be all to cock (to use a phrase pioneered by James May)...

Of course technically you could also machine a new head to mate up to the new cylinder bore, but that is getting way beyond what is realistic both time and expense wise - the idea is to produce a kit of parts using the least number of parts required to change - sleeving the stock barrel would be more complicated (and not a DIY job), while a new head as well would just not be cost effective...

As a bit of background to the project - John was actually on his way back home from seeing the start of the Heroes-Legend Rally in Spain last year (he was due to ride, but had broken his wrist a few weeks beforehand so had to drop out), and stopped off at a vintage bike rally in the mountains. By chance he got talking with an American guy called Drino Miller - who as it turns out is head engine tester for Pro Circuit in the US:

http://motocrossactionmag.com/Review...s-Su-5959.aspx

As is the way in Spain, they of course got yakking over a bottle (or two) of red wine about the pros and cons of the various ways to build this engine, and it was basically Drino who pointed John in the direction we are now taking...

Today's nerdy photo is of a shiny new con-rod!



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...

Jx

[JMo (& piglet)]

Originally Posted by neduro

A bunch- I've got one in a crate and also have a 450XCW motor sitting next to it. I'd guess the 690 motor is ~20lbs more, although given I don't have a scale and am guesstimating the weight of the crate, that could be complete malarky.

On the flip side, I believe that weight goes to things that count. A 690 will go, as Jenny said, a very long way with no maintenance at all, where a 450XCW really wants its oil changed often to get decent life from the engine.

Curious about FI vs Carb as well!

Hi Ned - yes, without getting them side by side and on the scales (which we will do in time, just for the number crunchers out there), I reckon you are probably in the ball-park with around 8-10Kgs, which is what we've factored in.

Otherwise though, the total bike itself (that is the rolling chassis and the Evo2 tank & fairing kit) is near as dammit going to be the same as a 450RR, so the weigh penalty is not all that huge.

Regarding the EFi vs Carb debate - when I was chatting to Niles [Follin] at Scuderia last year about the project, he asked a similar question and suggested using carbs as a preference (bloody old-school mechanics!), but John is confident that he has got the EFi dialed-in on the customer 690 rally bikes he builds already, and again, the desire to keep the bike spec as close to stock (not for any reason other than to minimise the variables of changed parts going wrong) means we're planning on running the stock EFi system with a custom map for the 450cc kit.

Obviously there is (or was) a known issue with the 690 fuel pump, but John has various safeguards in place - and if all else fails, fortunately replacing the standard fuel pump (in the rear tank) is not too much a trial with trail tools, if it ever came down to it...

On balance though, there seems to be far more benefits (not least fuel consumption and automatic altitude/temperature adjustment) to retaining the EFi than trying to make to all work with a carb too?

Jx

[JMo (& piglet)]

Originally Posted by neduro

I don't think this machine would be eligible for Marathon in any event- looking at an older rulebook but:

When I studied the book in depth, Marathon has become largely irrelevant to anything but the KTM 450RR- you're not allowed to change anything from standard (down to handlebars), meaning there's only one machine that is capable box stock.

I think they've made the category largely irrelevant, but what do I know.

Long rod motors are cool. The longer rod means a longer dwell time, which can really change (and increase) power characteristics. With that said, that's a pretty darn oversquare motor!

One last thought- the Dakar has become increasingly technical in years past, and I think that trend will continue. Do you think the LC4 based machine (with higher weight than a comparable converted enduro bike) will be a disadvantage in that light?

These are good points Ned!

I ran my WR450F in Marathon in 2010, as I was fortunate that my bike was built around a European spec WR (that comes fully road legal and most importantly, with homologation papers and a specific chassis number designation compared to the Enduro spec bikes you get in the UK and USA), but almost fell foul as I also presented my spare 'just incase' engine for scrutineering, as you have to do... Patsy ended up sweet talking the officials and they let me stay in Marathon, but also scrutineered the second engine*

*Just for info for anyone else reading this thread (as I'm sure Ned is aware), any spare engine/s you may have with you for Dakar need to be scrutineered as well as the main bike - presumably in an effort to stop people changing out a 450 EXC lump for a 530 engine for example (or a bigger bored version of any other brand).

I think you are probably right that the scrutineers may consider this bike is too far removed from a stock or homologated machine - although that said, the chassis and engine numbers will correspond to the paperwork, so technically it might be eligible - the wheels, brakes, swing arm, forks and exhaust will all be stock (or manufacturer options - we intend to run an Akrapovic end can for example), and you are of course allowed to add tanks and a fairing...

Ultimately though, it is not so much the [Marathon] class as the principle we are trying to follow here - as Doyle says above, the Dakar is continually evolving, with lighter machines and more technical terrain (although to listen to Lyndon's final thoughts video from this year, he said he was [pleasantly] surprised that the stages were not as technical as he had feared), and certainly at the sharp end, it has become essentially a two week series of daily sprints - with a total overall every night, so the bikes are essentially as new again.

As I said in my introduction to this thread, as each year goes buy, the Dakar gets more and more expensive for the privateer to enter, or at least to be competitive. However, to start considering an engine as a 'consumable' still goes against the grain for me, and for many people [outside of a professional racing team] I suspect?

This project is really about retaining a degree of [financial] realism for the privateer rider who wants to use their participation in the Dakar not so much as a race against the other competitors, but more a personal journey of endurance against the Dakar itself...

Jx

[JMo (& piglet)]

Originally Posted by doyle

With the cost of Dakar nowadays, the cost of a second motor and a spot on a truck the bring it along are relatively minor in the grand scheme.

I do really like where this is going though, I am just not sure that the ASO is heading in a direction that is compatible with the true privateers/amateurs any longer.

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

[KASUYAHO]

Originally Posted by JMo (& piglet)

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...

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

[dakardood]

..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

Originally Posted by JMo (& piglet)

That was the other option of course, however, when John stripped the engine down, he realised that the difference between the size of the [450cc] bore and the shape of the original head would have such a pronounced lip, the combustion chamber would be all to cock (to use a phrase pioneered by James May)...

Of course technically you could also machine a new head to mate up to the new cylinder bore, but that is getting way beyond what is realistic both time and expense wise - the idea is to produce a kit of parts using the least number of parts required to change - sleeving the stock barrel would be more complicated (and not a DIY job), while a new head as well would just not be cost effective...

As a bit of background to the project - John was actually on his way back home from seeing the start of the Heroes-Legend Rally in Spain last year (he was due to ride, but had broken his wrist a few weeks beforehand so had to drop out), and stopped off at a vintage bike rally in the mountains. By chance he got talking with an American guy called Drino Miller - who as it turns out is head engine tester for Pro Circuit in the US:

http://motocrossactionmag.com/Review...s-Su-5959.aspx

As is the way in Spain, they of course got yakking over a bottle (or two) of red wine about the pros and cons of the various ways to build this engine, and it was basically Drino who pointed John in the direction we are now taking...

Today's nerdy photo is of a shiny new con-rod!



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...

Jx

[JMo (& piglet)]

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

[KASUYAHO]

Originally Posted by JMo (& piglet)

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

[BigMike40]

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?

[barrier]

Originally Posted by dashmoto

Just out of interest, what does the stock 690 motor weigh anyway?

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

[640 Armageddon]

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

[oossie]

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?

[barrier]

Originally Posted by BigMike40

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?

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?