Post by: gpnewhouse7 on September 08, 2012, 02:59:53 PM
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.
Post by: citabjockey on September 08, 2012, 04:13:14 PM
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.
Post by: gpnewhouse7 on September 08, 2012, 05:06:59 PM
Post by: citabjockey on September 08, 2012, 05:35:31 PM
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.
Post by: metal_miracle on September 08, 2012, 06:20:27 PM
And i would welcome injection, since i see so many that never even touch their air screw
Post by: TMKIWI on September 09, 2012, 04:15:15 AM
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.
Post by: motoman356 on September 09, 2012, 05:38:37 AM
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
Post by: TMKIWI on September 09, 2012, 07:16:26 AM
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.
Post by: Jeram on September 09, 2012, 09:56:21 AM
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.
Post by: gpnewhouse7 on September 09, 2012, 10:59:46 AM
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.
Post by: SachsGS on September 09, 2012, 02:51:34 PM
Post by: citabjockey on September 09, 2012, 03:22:09 PM
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.
Post by: VintageBlueSmoke on September 09, 2012, 06:12:10 PM
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.
Post by: citabjockey on September 09, 2012, 07:02:38 PM
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
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.
Post by: gpnewhouse7 on September 09, 2012, 11:15:22 PM
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.
Post by: citabjockey on September 10, 2012, 01:02:30 AM
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.
Post by: Jeram on September 10, 2012, 06:27:17 AM
The alternative to disc valve is a mechanical reed valve called the 24/7 valve which aprilia was developing just at the 2T GP bikes were killed off.
at normal RPMs the reed valve operates as normal, at high RPM the reed valve opens up to allow free flow of air through to the cylinder at high RPM via stepper motors.
Post by: Jeram on September 10, 2012, 06:33:37 AM
Post by: motoman356 on September 10, 2012, 06:35:21 AM
Post by: gpnewhouse7 on September 10, 2012, 07:12:56 AM
I know it won't be easy but I like a challenge and I would also love to do this kind of work as a job in the future so while I will be learning at the school of hard knocks I should eventually have a great bike of my own or atleast a good idea of how not to make a motorcycle.
Post by: VintageBlueSmoke on September 10, 2012, 09:30:00 AM
That said I do like the "run what you brung" class idea. BTW - how would the "safety" rules be adminstered?
The safety aspect would be the usual inspection for required items, i.e. spring loaded foot pegs. grips covering the end of the bars, fenders, cross bar pads...and of course, an opening in the rules to allow unforeseen situations such as a minimum weight if bikes are becoming too flimsy and injuring riders or wheels collapsing due to being too thin. That sort of thing.
With rules like these, an engineer or creative person will be able to push the envelope. Sure, old technology (turbos, forced induction will appear but just like in F1, will quickly die out due to the mileage and emissions restrictions. new tech, like electric or alcohol or other fuel (diesel, hydrogen, water!) will have the opportunity to showcase its ability. Hey, how about plutonium!
Post by: Jeram on September 10, 2012, 11:29:38 AM
Kerosene fuel or gas
small micro turbine (size of car turbo) as proposed for future fuel efficient jagaur cars
this turbine powers a generator
generator powers elec motors = domination
(lasts longer than a battery, its lighter than a battery set up, and it got a smaller 'footprint' than a battery)
Post by: VintageBlueSmoke on September 10, 2012, 02:46:24 PM
Post by: citabjockey on September 10, 2012, 05:50:23 PM
If you look at the current crop of zero motorcycles they are getting pretty close to something real world now. If they slant the battery just a bit more to higher current over a shorter duration they may match a 250SX in output that would last an entire moto and not weigh significantly more either. Those days ARE coming. But I would also miss the BRAAP EVEN MORE.
Someone will just get very smart and do the following.
Kerosene fuel or gas
small micro turbine (size of car turbo) as proposed for future fuel efficient jagaur cars
this turbine powers a generator
generator powers elec motors = domination
(lasts longer than a battery, its lighter than a battery set up, and it got a smaller 'footprint' than a battery)
Post by: Jeram on September 10, 2012, 11:39:03 PM
Post by: citabjockey on September 11, 2012, 04:57:31 AM
I myself used to own a honda CX500 turbo. Never noticed the gyro effect -- but turbo lag? it had that in spades. Now a turbine engine would probably have a larger rotor than a turbo charger bolted onto a piston engine. Yes?
Post by: riffraff on September 11, 2012, 06:17:20 AM
Post by: Jeram on September 11, 2012, 07:23:27 AM
a tiny gas turbine that spins furiously at a constant speed, driving a generator to provide charge directly to an electric motor.
Its an electric bike, without the weight of batteries and with a very long range.
similar to this Jaguar concept car, but without the 70km range battery pack, turbine full
but are we getting off topic here a little? I had thought that the intest of this thread started as maybe ideas for improving/building bikes? and here I am talking gas turbines haha
Post by: VintageBlueSmoke on September 11, 2012, 01:05:08 PM
I would think a small turbine (i.e. r/c aircraft motor) might provide enough power to run the electric motor on an MX bike. I might just try that with my kid's OSET trials bike! What he doesn't like about the OSET is that it doesn't go "Vroom vrooooom!" He rather ride his Husqvarna (that scares him because it is too fast for a 2 year old) because of the noise.
Post by: Jeram on September 11, 2012, 01:13:26 PM
We are talking about several different technologies here and I take the blame for confusing folks. My point was with an open (box) class, it would open the door to try different tech (i.e. turbos, turbines, wankels, 2 and 4 strokes, electrical, etc).
I would think a small turbine (i.e. r/c aircraft motor) might provide enough power to run the electric motor on an MX bike. I might just try that with my kid's OSET trials bike! What he doesn't like about the OSET is that it doesn't go "Vroom vrooooom!" He rather ride his Husqvarna (that scares him because it is too fast for a 2 year old) because of the noise.
just make sure you dont kill your son!
Ive heard stories of gas turbines exploding... but I think that was a hydrogen powered backyard made turbine kart!
Post by: SachsGS on September 11, 2012, 03:34:45 PM
Post by: _X_ on September 11, 2012, 10:24:19 PM
Post by: citabjockey on September 11, 2012, 10:54:07 PM
Post by: _X_ on September 11, 2012, 11:10:29 PM
Post by: citabjockey on September 12, 2012, 01:20:36 AM
(that and a couple of mouse clicks)
Post by: msambuco on September 12, 2012, 04:23:23 AM
Diesel dirt bike running on vegetable oil - "carbon neutral" reciprocating fun.Now I am a big Diesel fan and run them in my trucks and boat. They have no place in MX bikes and neither do electric motors. Two stroke explosive power all the way. There are no other options. Unless a four stroke is your flavor. Next best thing if a two stroke doesn't work for you.
Post by: Uniflow on September 12, 2012, 07:55:15 AM
This is the engine you want, 700 tandem twin.
Post by: TMKIWI on September 12, 2012, 08:39:34 AM
Recluse clutch on that thing and a wheely bar out back.
Post by: VintageBlueSmoke on September 12, 2012, 09:28:01 AM
Post by: Uniflow on September 12, 2012, 09:47:11 AM
I like rotary valve engines.
Post by: Uniflow on September 12, 2012, 09:51:55 AM
Post by: Jeram on September 12, 2012, 10:00:36 AM
but hmmm... a properly tuned 700 counter rotating disc valve twin.
if you could get it to pull cleanly from idle you probably wouldnt even need a gearbox haha.
and that would be its advantage!
Post by: Uniflow on September 12, 2012, 10:06:07 AM
Post by: Uniflow on September 12, 2012, 10:08:36 AM
Post by: citabjockey on September 12, 2012, 02:39:40 PM
Diesels are 2 stroke...just sayin...
Post by: VintageBlueSmoke on September 12, 2012, 03:41:59 PM
All it takes is putting pen to paper and everything we know about motocross could change forever!
Post by: SachsGS on September 12, 2012, 03:42:24 PM
Just saying I'd rather go diesel than electric. What I'm really looking forward to is a DI 2T.
Post by: citabjockey on September 12, 2012, 05:34:21 PM
I saw a fire truck on the side of the road about a year ago for sale. Was a model that had a Detroit in it. Was all I could do (and my wife could do) to keep from pulling over and buying it on the spot. ;-)
Diesels can be either 2 or 4 stroke and the Jimmies were 2T with port intake/poppet valve exhaust (supercharged to get the hole thing going).
Just saying I'd rather go diesel than electric. What I'm really looking forward to is a DI 2T.
Post by: twosmoke595 on September 12, 2012, 07:59:38 PM
Post by: citabjockey on September 12, 2012, 08:31:01 PM
http://blog.caranddriver.com/lemons-goodbad-idea-of-the-week-two-stroke-miata/
i'm still toying with the idea of a snowmobile engine in a rear engined bug chassis...
Post by: SachsGS on September 13, 2012, 12:47:55 AM
I sure like the sounds emanating from that Detroit pick up!
Post by: Chris2T on September 13, 2012, 03:32:13 AM
My other day dream is a big bore DI 2 stroke with a rear exiting exhaust. The frame down tubes would part to accomodate the fatty part of the chamber. Since the entire "carburetion" takes place at the top of the cylinder head, there would be a simple intake design in front of the cylinder to channel air into the relocated reed valve.
Post by: citabjockey on September 13, 2012, 07:03:10 PM
