Ideas bank

[gpnewhouse7]

I know that plenty of you on here have suggested that us two stroke fans should buoild our own bikes for some time now, so after realizing how little innovation happens in motocross these days I thought I'd start a thread where everyone could share their ideas on what the ideal motocross bike should have whether it is already in use for other applications or has been used but not to its full potential in motocross, please just post up your thoughts and ideas.

As I say post up ANY ideas as to how to improve the modern motocrosser and PLEASE BE RESPECTFUL of other peoples ideas, disagreeing is fine but keep it relevant.

Thanks.

[citabjockey]

Step one, get enough political clout and will to boycott races that are not CC for CC (or at least a reasonable handicap for 2T). This includes ticket sales to national events. Yeah, I know, good luck with this.

There is a thread for comparison between the current KTM250SX and a RM250 in which I wrote about a need for a smoother/wider powerband on 2T engines to make them faster on the track. I will not repeat it here but just reference. http://twostrokemotocross.com/forum/general-two-stroke-talk/2012-ktm-250sx-vs-2007-rm-250-comparison

Beyond that, environmental regulations  continue to get more stringent year after year. As there are also fewer and fewer tracks available for riding. The decision for a manufacturer to develop a 2T motor for MX (only) is getting tougher and tougher. Its much easer for them to keep up with current 2T technology if the motor or other parts can be used on other, no closed  course, models. With DI an engine should be clean enough to run on the road which would allow many more of the same unit to be put in other models. The engine controls required would also make it an easier engineering challenge to get a flat powerband which probably would make it a faster race motor for most riders.

[gpnewhouse7]

Well surely most chassis, suspension and engine ideas can crossover from the dirt to the street and even to quads up to a point, can't they? And besides that I was more meaning with my original post as to a bike that we built ourselves rather than waiting for a manufacturer to build it for us (lets face it they won't build anything revolutionary unless they need to in order to make more money).

[citabjockey]

Ok, building it outselves. Take a SkiDoo etec 800 and hacksaw it in half, would be a great starting point but then the engineering challenges begin: How to re-orientate that massive injector so it fits in a frame with a backbone. Then, where to get enough electric jiuce to run the computer, which other bike's, cases and gearbox to use (or do we fab completely new crank case sections and mate the bombardier top end to those?). Mount up the computers and the oil injection tank. Come up with an insanely clean air filter system. Fab a completly new expansion chamber. THEN start to reprogram the power output to what nets the fastest lap times. That 400cc engine should be able to achieve a 50HP completely flat powerband over a mile wide range.

THEN, do we add more sensors to the computer? Traction control? Antilock rear brakes? handlebar buttons to enable/disable those when the rider wants on demand? That is probably too complex for a rider to control during a race I would think but it would be possible... Gyros to prevent looping/endoing on jumps? GPS to map the track such that the bike refuses to do a jump if you don't have enough speed to clear a double/triple?  And if all that gets stuffed into a MX'er do the rules change instantly to disallow all this?

How about active suspension that senses jump faces and helps in preload of suspension at the bottom of the face to get longer launches? Traction control that is in effect only while the holeshot device is still holding down the forks?

Probably take a million dollar budget to start prototyping even a subset of the above. And then after its done this 400cc bike STILL would not be legal in any AMA pro class.

[metal_miracle]

What i would like and wish for, is that the weight rule getting a revision.. lighter bikes


And i would welcome injection, since i see so many that never even touch their air screw

[TMKIWI]

As Citabjockey said, Start with 1/2 a Ski-Doo engine.
Would be a torque monster which would allow a 4 speed tranny to keep the width down and also lighter weight then a 5 speed, while allowing larger gears to handle the power.
The fuel tank should be under the seat and the expansion chamber can go where the fuel tank would have been then out the side as normal. No more smashed pipes.

OR. Have a backwards engine with twin expansion chambers (TZR style) running out under the seat. The Idea behind twin chambers is so the exhaust would have enough volume to work properly where as I don't think there would be enough room for a large single system under the seat. You also have a problem with suspension travel on a MX bike compared to a road bike with a single system.You should be able to have the rear wheel run between the tail pipes as the chambers will finish around the shock.
I have no idea if a twin system will work on a single, Just an idea.

[motoman356]

id like to see a revised rm125/250.  or even an rm150 purpose built unlike the husky and yz. with a new steel frame along with the new showa separate fork stuff along with new plastics

the yamahas id like a to see advancments in the motors and body work along with a purpose built 150.

kawi should bring back the 2ts with new frames. i say not aluminum. with new KYB susp that yamaha runs

overall id like to see a shift away from the 125 to a 150 motor that isnt a " big bore" and a purpose built 150 motor like the ktm. this stronger motor would cater to ppl of a bigger weight such as myself (190) as well as kids and the bike would be better against 250fs since rules arent really changing to cater to the older motors

[TMKIWI]

I'ld have to disagree on the 150 idea.
I would like 125's to become relevent again.
With the success of the European 125 Championship I would like it to become a proper world champ class again. It should replace the MX3 class which is irrelevent today.
Bring it back into the MXDN again and make the youth rider in each team have to ride the 125 class. Then you would have a proper 125,250 & 450 class system like the old days instead of 2 450 classes like we have now.

Alot of smaller country's still have a 125 class for junior riders and some have senior classes as well. I think everyone agree's going from a 85 to a 250F is too big a step.

Save the 125.

[Jeram]

Ok, building it outselves. Take a SkiDoo etec 800 and hacksaw it in half, would be a great starting point but then the engineering challenges begin: How to re-orientate that massive injector so it fits in a frame with a backbone. Then, where to get enough electric jiuce to run the computer, which other bike's, cases and gearbox to use (or do we fab completely new crank case sections and mate the bombardier top end to those?). Mount up the computers and the oil injection tank. Come up with an insanely clean air filter system. Fab a completly new expansion chamber. THEN start to reprogram the power output to what nets the fastest lap times. That 400cc engine should be able to achieve a 50HP completely flat powerband over a mile wide range.

THEN, do we add more sensors to the computer? Traction control? Antilock rear brakes? handlebar buttons to enable/disable those when the rider wants on demand? That is probably too complex for a rider to control during a race I would think but it would be possible... Gyros to prevent looping/endoing on jumps? GPS to map the track such that the bike refuses to do a jump if you don't have enough speed to clear a double/triple?  And if all that gets stuffed into a MX'er do the rules change instantly to disallow all this?

How about active suspension that senses jump faces and helps in preload of suspension at the bottom of the face to get longer launches? Traction control that is in effect only while the holeshot device is still holding down the forks?

Probably take a million dollar budget to start prototyping even a subset of the above. And then after its done this 400cc bike STILL would not be legal in any AMA pro class.

I started a motor build like this but got distracted and ran out of money half way through.
Bighorn Kawasaki disc valve bottom end, ends up pretty light and compact once your replace things like the 64oz flywheel with one from a late model 250 haha
then put one snowmobile 700 cylinder on it, starting with a carbied version first to prove the concept.
In Engmod 2T the 350cc disc valve single made 70hp and more torque at idle than a 450 four stroke does at peak torque, and something crazy like 60ftlbs at peak (all at the crank)

I personally think thats too much for MX

I reckon the answer is simply a 250 two stroke mx bike with the cylinder turned around so the exhaust faces backwards and the carb/airbox at the front.
you could then have a servo motor controlled sliding exhaust which keeps the bike on the pipe at ALL rpms from idle to overrev which has shown alot of potential in a road racer that I saw running recently in a video.

[gpnewhouse7]

Some good ideas so far, here's another that TMKIWI posted on another thread that I thought would make a great engine for AF bikes.

Great discussion guys.
I think the motor you guys are talking about is this one.



Quote:
Future two-strokes will have capacities on a par with four-strokes, allowing a milder state of tune than that which earned them their peaky reputation. The result trounces the four-stroke for power, torque, flexibility and even service intervals says Orbital ? whose experimental (and under-developed) 450cc single-cylinder two-stroke produced these curves against a rival 450cc four-stroke. The stroker also proved smaller and lighter, cheaper to build, less thirsty and with identical emissions.

A 450 2 stroke could easily make over 60Hp but at the expence of ridability.

Same thing could be done with a 250.

[SachsGS]

Keep 125's and bring back the 175.

[citabjockey]

I would love to see documentation on this. That is truly unbelievable (more torque at idle than a 450F at peak). That said I do believe it was true that rotary valve motors could produce better powerbands because of the independent control of open and close points of the valve. Yet the idea has been mostly abandoned I would think because of the massive reed cages in use these days that make the intake timing be "on demand" and thus perfect all the time (abeit with some amount of flow restriction). Also, the rotary valve motor design is inherently wider but that issue was negated by CanAm and Puch back in the day.

In Engmod 2T the 350cc disc valve single made 70hp and more torque at idle than a 450 four stroke does at peak torque, and something crazy like 60ftlbs at peak (all at the crank)

I would have to agree. 450F bikes do quite well with 50HP. And I have yet to hear of a 500AF that regularly wins against them with rider's of equal ability (blasphemy on this site I know... ;-)  )

I personally think thats too much for MX

But do please point me at the documentation on the 350cc rotary valve  torque master.

[VintageBlueSmoke]

I'm not so much for developing new bikes as I am for developing an environment for creativity in motorcycle development.

I would think that the FIM and AMA should create a box class (anything goes as long as it fits in this box) with very simple rules for safety and for aiming the technology development in a particular direction. For instance, an class open to any technology, any capacity, any fuel, and weight. However, since the idea is developing "greener" equipment (and not Kawasaki Green  ), there would be a limit on the amount of fuel you could use per moto as well as an emissions and sound test at the finish...for ALL participating bikes.

Then, although the factories could dump gazillions inot development, the little guy could come up with something smart and do well as well is the small factories (Can-Am, Bultaco, Maico, etc come to mind) might be able to beat the Big 5 due to economies of scale.

[citabjockey]

An all electric bike whose battery will only last a single 30 min moto might just clean up in your proposed box class in the next handful of years. And boy would it be simple. That said I do like the "run what you brung" class idea. BTW - how would the "safety" rules be adminstered?

I'm not so much for developing new bikes as I am for developing an environment for creativity in motorcycle development.

I would think that the FIM and AMA should create a box class (anything goes as long as it fits in this box) with very simple rules for safety and for aiming the technology development in a particular direction. For instance, an class open to any technology, any capacity, any fuel, and weight. However, since the idea is developing "greener" equipment (and not Kawasaki Green  ), there would be a limit on the amount of fuel you could use per moto as well as an emissions and sound test at the finish...for ALL participating bikes.

Then, although the factories could dump gazillions inot development, the little guy could come up with something smart and do well as well is the small factories (Can-Am, Bultaco, Maico, etc come to mind) might be able to beat the Big 5 due to economies of scale.

[gpnewhouse7]

Okay so after much thought and research I have come up with an idea about actually building my own bike, my thoughts so far are to create my own frame from steel, use BMW duolever front suspension (looks rather interesting and could help to stop the front wheel locking and sliding out under hard braking) with the angle of the forks being adjustable atleast in the early testing stages, use an updated/upgraded version of the Suzuki full floater system on the rear and also to convert my KTM engine from reed valve to disc valve via gearing from a cog which will replace the flywheel weight, this gearing should hopefully then go on to power a mechanical fuel injection system using a cam and cam follower to compress a small pocket of fuel forcing it into the engine at the same point in the stroke everytime along with the air which should do the same do to opening of the disc valve being the same with every turn of the crank.

Can anyone tell me whether that should work or not aswell as if people have other ideas on what I could do, help would be much appreciated.