Post by: Bioflex on June 25, 2011, 03:08:14 AM
I imagine the gp bike would be tuned as the ultimate top end screamer but would like to know the difference between the two.
Post by: ford832 on June 25, 2011, 05:16:28 AM
http://www.google.ca/url?sa=t&source=web&cd=2&ved=0CB4QtwIwAQ&url=http%3A%2F%2Fwww.topspeed.com%2Fmotorcycles%2Fmotorcycle-reviews%2Faprilia%2F2010-aprilia-rs-125-ar76549.html&rct=j&q=125%20gp%20motorcycle%20technology&ei=JtIFTvaaD6bd0QHX9fjlCw&usg=AFQjCNGCbezs_jXYnzNtfngkR-DzJOe8LA&sig2=B--8lUeGI_39izgwAQwtpA&cad=rja (http://www.google.ca/url?sa=t&source=web&cd=2&ved=0CB4QtwIwAQ&url=http%3A%2F%2Fwww.topspeed.com%2Fmotorcycles%2Fmotorcycle-reviews%2Faprilia%2F2010-aprilia-rs-125-ar76549.html&rct=j&q=125%20gp%20motorcycle%20technology&ei=JtIFTvaaD6bd0QHX9fjlCw&usg=AFQjCNGCbezs_jXYnzNtfngkR-DzJOe8LA&sig2=B--8lUeGI_39izgwAQwtpA&cad=rja)
Yes please.
Post by: msmola2002 on June 25, 2011, 05:25:18 AM
What I can tell you about mine, is that it is a 91 model honda, based on the cr but no kicker setup, and no power valve, also a 6 spd trans.
stock, the cr based ones like mine make around 28hp rwhp on a dynojet, mine has been tickled to about 34.5, peak power at 12.5 and revs to about 14. the NX honduhs (mine is the NF variant with cantilever rear) also have the powerjet carb which buys a few more top end hp before it falls off the cliff, maybe 1000rpm
Gearing makes a big difference, very tall. In first i can do like 40odd mph, so is a bitch to get off the line
for reference:
RS125 Oran Park (http://www.youtube.com/watch?v=BbkH9o8HMUE#)
Super clutch clip required.
the later NXhondas (95-) don;t use the MX based engine and they make more powahs for a variety of reasons - the pipe does not have a big bend as soon as it leaves the engine for one - the cylinder is canted further forward, the power jet carb.
The TZs are a pretty good package, they rock a balance shaft, power valve, dry clutch (the fcc dry clutch for the rs is rocking horse shit and tend to go for about 1k) and a few other bits and pieces.
For more info and tech nerdery, paging the 2 stroke institute... He could write a book.
Post by: msmola2002 on June 25, 2011, 05:33:31 AM
Other differences, the nf has an MX based high voltage ignition stator, the nxs run a 12v system as they tend to run more electrickery, the nf is just the coil, in the nfs you get 12v to run the power jet, often a deto counter and other toys.
Jetting is more on a knife edge than for an MXer, I have a weather station you haul out to the track, measure the temp, baro pressure and humidity to calculate RAD (relative air density) and jet accordingly - have a nice excel spreadsheet that allows you to select you theoretical jet based on a known good jet at a known RAD.
these things are jetted real fine and will not make power too rich, and seize too lean (duh) but there is far less wiggle room than for an MXer
Post by: msmola2002 on June 25, 2011, 05:37:34 AM
They aren't far removed from your typical 125 mx.
the big boy international stuff - respectfully disagree, and the honda customer spec stuff has not run an MX based engine since 94.
The world champ 125s run stuff like disc valves, and rock billet CNC cases. like saying a kids tricycle is like a racing bicycle.
And the RS125 you linked is not a GP bike. It is a GP replica, flogged to learner riders - the same as my RGV250 in teh garage back in oz is a GP replica, that makes 50hp with a tailwind and weighs 125kg vs teh honda RS which even in pleb spec makes 90hp and weighs 100kg. Apples and oranges!
Post by: 2T Institute on June 25, 2011, 05:58:07 AM
Given both road racing gp and mx 125's run the same engine, does anyone have any info in terms of what hp each makes, as well as the rpm of the redline ?
I imagine the gp bike would be tuned as the ultimate top end screamer but would like to know the difference between the two.
Not really Ben, they are the same bore/stroke but ends there. I hear stories of 40odd HP MX 125's but have yet to see the dyno graph. GP 125's are not peaky at all they are very forgiving, they have peak power at about 12,700. The gold standard for many years has been the Aprilia RSW and followed by the RSA, developed by Jan Thiel. Which is a 54 X54.5mm 125 rotary valve engine, has a 120mm long rod connected to a 107g piston with a 0.8mm ring.42mm magnesium flatslide Delorto carb with S-DAS 2 electronic control.Fully programmable ignition that controls ignition/power valve and power jet. The S-DAS system links ,ignition to power valve to TPS to gear position to fueling to detonation(the 250 to lean angle), so in an instant if the detonation counter has hits, ignition is retarded fuel is added, if the dets stop, timing restored and fuel reduced......all in the blink of an eye.
Pipes are universaly titanium construction.
Safe to say a decent 125 GP engine in a MX frame would lap the best mx engines, unfortunately this is the last year for 125GP at a world championship level. You will not find a better tuned 2T engine
HP
(http://img851.imageshack.us/img851/4505/indexphpactiondlattacht.jpg)
Post by: spainYz250 on June 25, 2011, 07:11:20 AM
Post by: spainYz250 on June 25, 2011, 07:15:59 AM
Post by: 2T Institute on June 25, 2011, 07:35:12 AM
Post by: ford832 on June 25, 2011, 08:24:20 AM
They aren't far removed from your typical 125 mx.
the big boy international stuff - respectfully disagree, and the honda customer spec stuff has not run an MX based engine since 94.
The world champ 125s run stuff like disc valves, and rock billet CNC cases. like saying a kids tricycle is like a racing bicycle.
And the RS125 you linked is not a GP bike. It is a GP replica, flogged to learner riders - the same as my RGV250 in teh garage back in oz is a GP replica, that makes 50hp with a tailwind and weighs 125kg vs teh honda RS which even in pleb spec makes 90hp and weighs 100kg. Apples and oranges!
More details please msmola.I still don't see that much of a difference.PJ's and tps's are nothing new on mx bikes,nor are servo controlled pv's.Can Ams ran a rotary valve.Impressive engineering and,as in all racing stuff,more adjustable than something you'd buy off the floor and of course are set up for something completely different with different power requirements.I just don't see much design difference in the engine.
I know the RS link is a street bike but I just think it's cool-and would like to have one.Back when I bought my first RZ,the sales brochure had the RZ on one side and the TZ250 on the other.I would have rather the TZ but as you couldn't plate it,and it was ridiculously expensive,I bought the one I could ride :)
Post by: SachsGS on June 25, 2011, 09:27:45 AM
Post by: 2T Institute on June 25, 2011, 05:34:26 PM
Are the RSA/RSW Rotax based?
You can trace the DNA back to the Rotax 128 (125) and Rotax 256 (tandem twin 250) which is what Aprilia began racing with, in the early 90's Rotax released the 258 Vtwin, that became the basis for the 250.
The 125 took a different path, both the 125 and 250 engine development was taken from Rotax and brought in house to Aprilia Corse(under Jan Witteveen), output steadily rose. The 125 retained the same layout as the orignal 128 engine (side disc/carb) with the cylinder and electronics constantly updated.
Meanwhile a small Spanish company (Derbi) was starting to make in roads on the 125GP scene(under Harald Bartol) after Bartol left and went to KTM did Derbi draught Jan Thiel in. A clever Derbi engineer designed a rotay valve engine with the disc/carb behind the cylinder about the same time a young Jorge Lorenzo hit the GP scene. The Derbi went on to win the 125cc championship.
Not long after Piaggo (Aprilia parent company) bought Derbi and merged the race departments, Aprilia were mighty miffed that a very small outfit could out do a race dept with 100 staff.
The the Aprilia cylinder got grafted onto the Derbi bottom end and became the Aprilia RSA.
So VERY loosely based on the Rotax ;D
The Aprilia RSW/RSA both 125 and 250 is the absolute pinnicle of current 2T engine development.
Post by: Bioflex on June 29, 2011, 05:18:50 AM
The fact they moved away from the MX engines many years ago and the development since that point is impressive. Really makes you wonder how one of these engines would go slotted in an MX bike.
It would have been very interesting to see a "full house" Mx bike on a dyno in comparsion to these, from the sounds of things the MX bike would have struggled in comparison.
Lozza, apologies for not getting you that motor already. 6 weeks ago my wife decided to bring back a new "machine" one like I have never seen before. It requires massive amounts of maintenance, needs a refuel after the shortest of spells, and needs several good cleans a day.
Once we've got it running a bit more regularly should have a bit more time!
Post by: VintageBlueSmoke on June 29, 2011, 07:39:51 AM
Post by: 2T Institute on October 06, 2011, 05:29:18 AM
(http://i1105.photobucket.com/albums/h356/redmer_bootsma/RSWdyno1.jpg)
Post by: SachsGS on October 06, 2011, 07:54:07 AM
Post by: citabjockey on October 06, 2011, 10:12:59 AM
I really wonder what a case reed engine could really do? That dyno chart also shows a very 4T linear progression of power the higher you go in the range, no bumps anywhere. WOW. Does seem like it would make a great dirt bike engine (except you would NEVER have enough traction or you would need wheelie bars). ;D So, using similar engine control technology could you tone it down to a reasonable HP number for an MX bike? it seems like you could make a single cylinder and have a very usable powerband. 450 4T would not stand a chance against such a 250!
Now, where is it????
Post by: 2T Institute on October 07, 2011, 04:37:35 AM
Rotary valve is a bit tougher on MX, where you would like to keep the cases narrow. Back in the '70s CanAm built a long tunnel to at least get the carb away from sticking out the side of the engine cases (like a Kawasaki of the time) but its still bigger and heavier than a piston port or case reed engine. Machine work for a disk is also more expensive too. With that dyno chart saying HP significantly past 100 :o for a 250,
I really wonder what a case reed engine could really do? That dyno chart also shows a very 4T linear progression of power the higher you go in the range, no bumps anywhere. WOW. Does seem like it would make a great dirt bike engine (except you would NEVER have enough traction or you would need wheelie bars). ;D So, using similar engine control technology could you tone it down to a reasonable HP number for an MX bike? it seems like you could make a single cylinder and have a very usable powerband. 450 4T would not stand a chance against such a 250!
Now, where is it????
it's called a Kawasaki Big Horn F9 350(well the engine anyway)
Post by: bearorso on October 07, 2011, 07:59:55 AM
For dirt use, you'd have to keep the revs up higher than MX 125 engines, once / if you could adapt to that (and blokes going genuinely fast on worked 250fs, are bouncing around the 10 to 13 +K revs) it would work on the dirt, but you'd have to be bloody talented. Not easy to use in the dirt, due to the Revs required to get into the working zone. That's the hard part with 125MX engines, the RR power spread would make it harder again. But, definitely blazingly fast if you could master it, and, if you could afford to keep it running. HP, costs, basically. If they could have been affordable / reliable to run, and easy enough for the average bloke to use, you would have seen 50HP MX oriented 125s.
The 250 TWINS, in the last years - the 'favoured' riders / teams were into the 120 +HP, just, from what a friend that worked in a 250 team told me.
As I've written many times before, we can blame Aprilia, just as much as Honda, et al, for the demise of 2ts in road racing. When it cost almost as much to lease a first line 250 2t twin, as it did to lease a Moto GP bike, it sure as hell made it easier to go for the 'cheaper' option of warmed over control Honda 600s (I think the engines are at a lower spec thank World Super Sport bikes - at least that's what I've read - how do you go from that level, to Moto GP 800s and 1000s, cleanly?), in bespoke frames. Same goes for the 125s - if you were not a 'favoured' rider, or team, you had / have, not a hope in hell of doing well.
'Controlled' class 125 and 250 2ts would have sorted this out, but the 4t push, is backed by the big boys. Controlled 125s, and 250s, of any stroke type, is what should have been implemented, if there was any sense to the FIM / Dorna series. Fat chance of that ever happening.
Post by: 2T Institute on October 07, 2011, 04:33:32 PM
There is not reason why a MX 125 could not take a big jump up in performance.The Aprilia does not use RPM or tricky ignitions or big carbs to get it's HP. They use very clever duct geometry and perfect piston and cylinder cooling. Aprilia kept developing engines the Japanese stopped in the late 90's.
Post by: Premixed on October 07, 2011, 05:27:19 PM
in 2001, the 500gp bikes made 190hp.
you will have to google to find it. but there was a man who combined 2 CR500 jugs and made a 1000cc two stroke. it made 240hp.
Post by: 2T Institute on October 07, 2011, 06:43:37 PM
The Aprilia 250 fires both cylinders at the same time, but multi's do make more top end than a single. However in 250cc National (single cylinder) karting which is under going a resurgence here a CR250 powered kart lowered a lap record by 3 seconds, was very close to the twins.
The customer GP 250's are massively lighter than the road going bikes(they have to be) most are around the 100kg mark, the road bikes around 130kgs.
Can anyone find eveidence of the Trick Racing CR500 twin running?
Post by: factoryX on October 07, 2011, 07:51:09 PM
http://www.myspace.com/video/austin941/cr1000/4072493 (http://www.myspace.com/video/austin941/cr1000/4072493)
Post by: TMKIWI on October 07, 2011, 08:16:15 PM
Nice. ;D
Post by: 2T Institute on October 07, 2011, 09:39:00 PM
pics are pure bike porn
Post by: Premixed on October 08, 2011, 03:23:01 AM
(http://www.whitehorsegear.com/media/catalog/product/cache/1/image/5e06319eda06f020e43594a9c230972d/m/3/m350_1_1.jpg)
Post by: mrhp on October 08, 2011, 09:34:08 PM
KTM certainly knows how to build more power than that - their gp efforts I'd put in the high 40's or very low 50's...but they never made it work for an mx bike...
The yz motor is around the 32-33 mark on that scale - and has an awesome character - rolls on at various throttle openings very low in the rpm range. makes them easy to ride - and easy to corner very fast....which turns good lap times because the rider can get on the throttle early and smoothly while cranked over.
Im told an honest 39-40hp is the absolute limit gp ktm 125 saw that would hold up during a race. Between huge RPM fluctuations and the riders over revving them in the air, the dirt, and poor cooling compared to a road race bike..and whatever other elements...it does not seem over 40 is possible for an mx 125.
Im told husky had 40 hp motors that wouldnt make it one race, 38hp motors that were 50/50, and 36 horse motors that would make every race to the finish line...
In any event - the pipe designs are certainly much more aggressive for the gp bikes than the mx bike...and I thikn that plays a role. I've always wanted to build a "GP" style engine and try it on the moto track - but experience tells me it will suck..as with common modifications that currently add power - some rideability almost always goes out the window!
Even 4 strokes experience this - as many dirt track engines are just too hard to ride fast on an mx track, and although they crank out lots of hp - they go slower...even with a dyno chart that looks brilliant compared to any two stroke (of half displacement)
Post by: SachsGS on October 10, 2011, 07:59:04 AM
Post by: Super Trucker on October 10, 2011, 10:56:33 AM
SRS racing in Itali sells a .8 ring piston, called the racing piston, for Honda 125,s. Pistons for other makes are available, flat top for the RM, etc. Would a .8 ring piston have a shorter life span and how many hours do you think it would last ? thanksGiven both road racing gp and mx 125's run the same engine, does anyone have any info in terms of what hp each makes, as well as the rpm of the redline ?
I imagine the gp bike would be tuned as the ultimate top end screamer but would like to know the difference between the two.
Not really Ben, they are the same bore/stroke but ends there. I hear stories of 40odd HP MX 125's but have yet to see the dyno graph. GP 125's are not peaky at all they are very forgiving, they have peak power at about 12,700. The gold standard for many years has been the Aprilia RSW and followed by the RSA, developed by Jan Thiel. Which is a 54 X54.5mm 125 rotary valve engine, has a 120mm long rod connected to a 107g piston with a 0.8mm ring.42mm magnesium flatslide Delorto carb with S-DAS 2 electronic control.Fully programmable ignition that controls ignition/power valve and power jet. The S-DAS system links ,ignition to power valve to TPS to gear position to fueling to detonation(the 250 to lean angle), so in an instant if the detonation counter has hits, ignition is retarded fuel is added, if the dets stop, timing restored and fuel reduced......all in the blink of an eye.
Pipes are universaly titanium construction.
Safe to say a decent 125 GP engine in a MX frame would lap the best mx engines, unfortunately this is the last year for 125GP at a world championship level. You will not find a better tuned 2T engine
HP
(http://img851.imageshack.us/img851/4505/indexphpactiondlattacht.jpg)
Post by: 2T Institute on October 10, 2011, 10:09:04 PM
You can get a 0.7mm ring even the thin rings are to stop the ring getting trapped, I have seen no problems and no reduced life span using them. Try Wossner 54mm 125 rings they are pretty much 0.8mm
Post by: bearorso on October 11, 2011, 08:07:23 AM
I'll take my sources over your 'Institutes' knowledge .
Lorenzo's last 250 was in 2007, and I've heard of more than 109HP from his mount. Simoncelli and Aoyama had another 1, and 2 years developement. And the claims that circulated of how Aoyama was running on 'spares' are complete and utter BS - Honda threw their weight at that engine, to get the last ever 250 World Championship. A hell of a gamble though, placing their efforts into one rider, but, it worked for them.
My information comes from a couple of close friends who have worked in GPs for over 20 years. And others.
HP take off at gearbox, for the amounts I've been told. Perhaps that graph is a rear wheel take off?
If the power / rev combinations of 125RRs was usable, and reliable, in MX / Offroad, the 250fs wouldn't be able to be sold with their 34 /39 std HP ranges. Hell, there would still be 125s being used from the club level through to the highest levels in World MX, in droves, to go up against the 40 - 45 (+?) hp modified / works 250fs. Somehow I doubt that Roczens KTM used in the final round had HP similar to that shown on your dyno graph, from 2010, for the RSA and RSW Aprilias. The other, I assume is the curve of a 'real' Derbi engine. And if anyone had the talent to make use of a 125 Road Race power curve, it is Roczen.
When you seem to dismiss DFI, for example, with the cooling aspects of an air And fuel charge being vital for a 2t (as it indeed is, in current / old tech power plants), you seem to ignore / not realise that that loss, would be addressed by appropriate measures, be it through materials, or other cooling methods. For any change, change is required - a simple, and true axiom. I appreciate your enthusiasm, and input both here and on other sites, but there's a lot of people around with a fair amount of experience, that won't necessarily take your opinions, as being the gospel of 2ts. I happily defer to those who I know that are far more knowledgeable with regards to ICE tech, than I. And I think you might well come under that heading, to a certain extent. I'm lucky enough have access to / friendships with, quite a few people that conduct their ICE careers at extremely high levels. And the reports I get from them, is of 60+(just), and 120+(just) HP from the last of the 125s and 250s. I'll go with their information and knowledge.
Post by: 2T Institute on October 11, 2011, 06:20:34 PM
I'll be in a 125 team that runs a RSA this weekend I'll get the answer then.
Again I'm quite happy to run with Jan Thiel's explanation as to why the Aprilia makes so much HP for a tiny displacement engine. Jan had aspects of engine thermodynamics incorporated into I had to see in the best japanese 125/250 GP or mx engines. If Jan Thiel tells me they could 'jet down until it lost power without detonation' I'm happy to accept his word.
Can I make that any simpler?
Assumptions are just mistakes no realised, the lower line on the dyno graph is Jorge Lorenzo's Derbi that he won the title with, about 5HP down on the Aprilia's.
Ayoama's 250 had pure carbon pistons, that's the only way it got to compete with the Aprilia's.They won the title through Ayoama's consistency and Aprilia riders punting each other off the track.
Post by: TMKIWI on October 11, 2011, 08:41:22 PM
The company that hates 2 strokes goes all out to win the last 250 championship on a type of machine that they have buried. WTF!!!!
Why would they want that on their CV ?. Wait a couple of years and there will be no mention that it was a 2 stroke. >:(
Bunch of fucken hypocrite's. >:(
If they were really that "Green" they would not have developed that bike.
Post by: Premixed on October 15, 2011, 06:02:38 AM
Post by: 2T Institute on October 18, 2011, 05:32:20 AM
(http://i155.photobucket.com/albums/s297/Lozza85_2007/010-3.jpg)
125cc Iveco Australian GP winner Sandro Cortese's trophy's
(http://i155.photobucket.com/albums/s297/Lozza85_2007/070.jpg)
Got to spend the weekend with a Grand Prix winning team, learned how a GP team goes about winning a GP and about the ballsy call to stick on slicks when a shower of rain hit on the warm up lap. Got all my questions answered on tuning the RSA 125(have 56HP DIN on german dyno's at the countershaft sprocket) also managed to pick up a nice momento
(http://i155.photobucket.com/albums/s297/Lozza85_2007/078.jpg)
Post by: TMKIWI on October 18, 2011, 08:34:40 AM
Question. What motors are the Mahindra's running ?
I understand they have entered the 125's this year to get ready for Moto3 next year.
What will they be running next year ?
P.S. Well done Casey.
Never used to rate him much but he has changed my mind.
I think he is 5th on the all time premier class winners list.
Thats damn good.
Post by: Recovered on October 18, 2011, 09:06:01 AM
i cant find it on the internet, but motocross action magazine did a YZ125 on an alcohol kit in about 1995ish that pulled on a 250 running petrol. i want to say it made about 41hp, back when 125 mx bikes made about 32 stock. i cant find it on the net anywhere, and i can not find the alcohol kit anywhere, but i remember the magazine.
Post by: msmola2002 on October 18, 2011, 10:24:01 AM
they did it because you can still log on to honda's website and buy an RS125. its ALWAYS a sales ploy.
Nope, the last year they made a run was 09 and they are all long gone.
Post by: Recovered on October 18, 2011, 03:57:04 PM
Post by: msmola2002 on October 20, 2011, 06:08:22 AM
http://rscycles.com/Bikes/125/04_rs125/125cc2.htm
Quote
NEW 2009 production year
2004 RS125R
. . . BIKE w/setup kit : $12,500.00 approx
SOLD OUT - Last production year was 2009
Post by: 2T Institute on October 20, 2011, 11:43:04 AM
Sounds like a good weekend.
Question. What motors are the Mahindra's running ?
I understand they have entered the 125's this year to get ready for Moto3 next year.
What will they be running next year ?
P.S. Well done Casey.
Never used to rate him much but he has changed my mind.
I think he is 5th on the all time premier class winners list.
Thats damn good.
Better than good, I always wondered what the Mahindra ran but it appears to be an Aprilia RSA engine. I don't know(or care) what they will be using next year, though I have heard some rumours.
Casey Stoner is a all time great, his out lap is done at 95% every other lap at 110%. Slides the bike everywhere.
Sandro Cortese fastest P1 in Malayasia
