Honda RS125 VS Aprillia RS 125.

Submitted by Blacky on Fri, 07/08/2009 - 20:56
As a layman, I am led to believe the Aprilia is basically the Honda RS 125 with a few mods and an electric start.

Pelly did not want to talk about the Aprillia when I asked him.
Can anyone enlighten me.
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Comments

Hi Blacky,

I'm not an expert on 125's but I believe the Aprilla RS 125 is a road bike engine made by Suzuki for Aprilla and is nothing like the Honda RS 125 engine from a racing GP bike .

They are completely different.

Thanks DLR,
I looked at the Wik site. There was a Rotax link. So the Aprillia RS 125 is made by Rotax.
Some time ago an 'expert' told me the Aprillia was a Spanish company that base there product on a Honda then tweaked it.
Thanks for clearing that up.
With the Honda what is the max hp you can run without it becoming a hand grenade? And what is real hp???

Sorry guys, I was thinking of the Aprillia RS 250 as that was a Suzuki RGV not the 125.

CUT AND PASTED FROM A FORUM
"Aprillia used the rgv engiine for the rs250, just with a slightly changed engine management system (black box). Suzuki sold them the parts from the 1990 model rgv, which had a nasty habit of snapping the power valve pins (due to the power valves wearing), which meant the power valves fell into the barrel and made a right mess of everything. These barrels cant be rebored easily, as they are nicasil plated, so it's quite an expensive job (new pistons, small ends, barrels and powervalves). Unless you got cash, budget on getting a total topend overall every 15000miles, or replacing all 4 powervalves every 10000miles as a precaution. The powervales themselves should be cleaned every 2000miles. Beware, the screw holding them in is made of "peanut butter" strips and breaks for no reason... haha...The RS250 should be regarded as "fragile" because of this."

Chris Parks

Sat, 08/08/2009 - 17:38

The Aprillia road bike motor was designed by Rotax as Rotax now owns Aprillia and it is a close relation to the Rotax motors used in sprint karts being basically the same thing with a gearbox under it. BTW the kart motor has more power than the bike motor. There was one raced with very little success in NSW about 8 years ago, it just did not have the power of the Hondas etc and the driver was very heavy. I have heard of 41hp out of one but anything Aprillia costs a bomb to do anything to it so your bank account had better have plenty of money in it. The newer motor they are racing now must be a very different animal as it makes a Honda RS look silly in comparison as far as HP goes. Mind you it will cost you $12,000 to buy one so it should. I have a dyno graph showing a Honda at 51 HP built in NZ but dyno figures can be fudged as we all know and I wonder how long it lived for and how much it cost.

These are BRAND NEW ENGINES with the backing of Honda USA and Japan for this spec class of CR125 1999 with 6 speed gearbox. The engine supplied in kit form from Honda Japan in 355 odd brand new parts. Purchase engine already assembled is best. Info in PDF link for a couple of USA dealers who support sending to Australia. Ensure you send them these rules if you are going to purchase an engine as rules can vary slightly in USA.

[url=http://www.superkart.org.au/Documents/STOCKHONDASUPERKARTINFO.pdf]http://www.superkart.org.au/Documents/STOCKHONDASUPERKARTINFO.pdf[/url]

Viper Racing UK

Sun, 05/02/2012 - 11:01

Hi Guys

If you are comparing the Honda RS125 GP engine with Aprilia, you should be comparing it with the Aprilia GP motor out of their race bike. This is the last of the Aprilia RSW125 motors, with magnesium cases and magnesium 42mm Dellorto

[IMG]http://i186.photobucket.com/albums/x26/Viperracinguk/ApriliaRSW125.jpg[/img]

Best Regards

Ian :)

Ian,
Money will buy you one of those side induction Aprilia motors but what does it take to get you hands on the factory rear induction Aprilia RS125?
I'm led to beleive money, rider and some good old fashion Italian politics to the select few......but that was in 2011 and prior.......

[img]http://www.samzavaglia.com/hosting/Aprilia%20125/photo2.jpg[/img]

This surely looks like a Yamaha barrel on top of a Aprilia RSA.
What does that make it......Yaprilia.... "Ya-prilia"

Yamaha barrels on Honda's......Yamaha barrels on Aprilia's......the only thing is common here is Yamaha.
What have I been telling ya these last 4 years :D

[img]http://le.renard.occitan.chez-alice.fr/63_img/moteur%20rsa.jpg[/img]

[img]http://i1238.photobucket.com/albums/ff482/samzavaglia/Hosting/IMG_20120206_204313.jpg[/img]

Yes 2T,
Derbi "RSA" engine prior to Aprilia buying them out and developing it further.
The Aprilia RSA bike picture above shows the 3 o'clock port and CNC cases as you mentioned.

But if that is not a Yamaha TZ cylinder (pre drum style powervalve) or direct copy, sitting on top of those Derbi "RSA" cases, I run bare ass the length of Phillip Island garages on last weekend of May. I'd go as far as to say the barrel nuts are the genuine Yamaha item as well (being black colour) :D

The collection of barrels you spoke about are all +2004-2008 SJK Yamaha TZ250 cylinders, not Aprilia.
Better picture now to note the cast patterns on this 2008 TZ250 cylinder vs the Derbi. I don't have an older TZ guilatine style powervalve cylinder to show here for comparision.
[IMG]http://i1238.photobucket.com/albums/ff482/samzavaglia/Hosting/IMG_20120301_154857.jpg[/img]

[img]http://le.renard.occitan.chez-alice.fr/63_img/moteur%20rsa.jpg[/img]

What's the Goss with a DEA cylinder and Head on top of a 12 o'clock port Derbi style cases?
Opps my mistake....Deer cylinder and head... :D :D
[img]http://i45.servimg.com/u/f45/13/15/94/65/20091110.jpg[/img]

Viper Racing UK

Sat, 23/06/2012 - 18:25

Hi Guys

Now those Aprilia cylinders would drop straight on my BRC "scar" engine and take all the square-edged 2-stage powervalve bits, head inserts and head covers. Very tempting, but a bit "old hat" perhaps and too much money (for that purpose). However, if I could get a "deal" and as they are only 50 miles down the road from me!! In fact at one stage the BRC motor was actually supplied with Aprilia cylinders with the "Aprilia" just ground and buffed off.

[IMG]http://i186.photobucket.com/albums/x26/Viperracinguk/brcs.jpg[/img]

Perhaps better to end up on an Aprilia motor in an Aprilia bike as a period restoration project.

Then again there is always this . . . . . now if someone has 2 of those going cheap 8):

[IMG]http://i186.photobucket.com/albums/x26/Viperracinguk/RSWCylinder.jpg[/img]
New only $10,220 AUD for a pair (without powervalves :o)

Now that is DEAR!!!! ;)

Best Regards

Ian :)

Viper Racing UK

Thu, 05/07/2012 - 03:45

Hi 2T

It may be the way I'm reading what you posted, but . . . .

The Rotax 256 shares the stud spacing/pattern with the "non-watercooled case" FPE and SAFE and the "watercooled case" PVP 251.

The BRC shares the stud spacing/pattern with Aprilia, "watercooled case" FPE, SAFE and PVP252. Basically the front studs (exhaust end) are wider spaced which allows wider exhaust boost port throats.

The DEA is on it's own in terms of Superkarts but shares this stud spacing/pattern with the Vortex series 125cc motors.

Perhaps that's what you are saying??

Your spot on with the cylinder kit!!

Oooops, I hi-jacked a thread about 125's ;)

Best Regards

Ian :)

Riley Will

Sun, 29/07/2012 - 07:46

Mmmmm, i made 3 125 engines with various Aprilia/BRC bits. They made phenomenal performance on the dyno, but am still waiting for the track results... They all used Rotax 129 bottom ends.

Also,
BRC never ground off Aprilia's badging. That being said, our current cylinder is a direct copy of a "kit" RS-W spec Aprilia. This became available tu us when they went onto the RSA generation.

Might be time to make a few 250 prototypes this winter with everything we've learned over the past 10 years.....

[quote author=Riley Will link=topic=589.msg18541#msg18541 date=1343511976]
Mmmmm, i made 3 125 engines with various Aprilia/BRC bits. They made phenomenal performance on the dyno, but am still waiting for the track results... They all used Rotax 129 bottom ends.

Also,
BRC never ground off Aprilia's badging. That being said, our current cylinder is a direct copy of a "kit" RS-W spec Aprilia. This became available tu us when they went onto the RSA generation.

Might be time to make a few 250 prototypes this winter with everything we've learned over the past 10 years.....


[/quote]

....and reading some foreign websites ;) ;D Would be nice if you had the demand to manufacture 125 engines.

Ian how much of the cases are water cooled ? Aprilia have a water jacket enclosing the crank housing. Do you still have those 129 manuals?

Viper Racing UK

Wed, 01/08/2012 - 04:03

Hi TSI

Riley apologies, would it be more correct to say that European competitors ground and buffed "APRILIA" of the cylinders (as they had to because of homologation) in times of shortage from BRC? There were certainly a few BRC's about with "ground" Aprilia cylinders at one time.

Top Case is LH BRC (Scarrrrrrr!!). Bottom case is LH FPE
[IMG]http://i186.photobucket.com/albums/x26/Viperracinguk/brcfpe.jpg[/img]

PVP251 cases
[IMG]http://i186.photobucket.com/albums/x26/Viperracinguk/DSC00115.jpg[/img]

SAFE LH Case
[IMG]http://i186.photobucket.com/albums/x26/Viperracinguk/cranksfitted.jpg[/img]

So all with full water cooling around the crank chambers.

The odd one out is the DEA which dosen't have watercooling around the crank chambers, but sorry, I haven't got a picture.

Yes, I do still have the 129 manual in PDF Format.

Best Regards

Ian :)

Viper Racing UK

Sat, 04/08/2012 - 02:34

[quote author=Rolf Greve link=topic=589.msg18627#msg18627 date=1343984969]
So the picture above must be the Aprilla 125 Twin?

Hmmmmm new class.......................
[/quote]

Rolf, That's a 250 V twin.

Those cranks are a work of art and look great with the long rods.

Aprillia did also briefly produce a 500 V-twin (RSW500) which was raced by Harada and McWilliams.

The Aprilia RSW 500 was equipped with a 498cc two-stroke, twin-cyliner engine. It was liquid cooled with a Rave valve on the electronically-controlled exhaust and had two Dell’Orto VHSD 42 caburettors. It had 140hp of power at 11,750 rpm.

One day, I'll get hold of one of those cylinders, however as the last 3 works bikes bikes reputably sold for £XXX,000!!!! perhaps I'll be lucky.

Best Regards

Ian :)

[quote author=TSI link=topic=589.msg18620#msg18620 date=1343915184]
Nice, here is the Aprilia
[IMG]http://i155.photobucket.com/albums/s297/Lozza85_2007/aprilia.jpg[/img]

Note the amount tungsten/mallory metal in the cranks ;)
[/quote]

is all that mallory due to the cranks both spinning the same way unlike an inline twin?

Viper Racing UK

Sat, 04/08/2012 - 12:06

[quote author=SAFE Evolutions link=topic=589.msg18632#msg18632 date=1344036432]
Is all that mallory due to the cranks both spinning the same way unlike an inline twin?
[/quote]

Hi Scott

That's a very interesting question and I believe the answer is probably . . . no.

In terms of the forces generated by each rotating mass it is the same as an inline. Direction of rotation makes little difference as applied through the main bearings. But although they are still in rotational phase with each other the forces are at a different angle of convergance. in fact the vertical (or more correctly, in lne with the cylinder bores) forces converge towards the centre of clutch shaft.

It is my belief that the only effect of this is on directions of load concentration within the cases and that it makes no difference when you view the engine as a lump which emmits power, noise, heat and vibration, except for the gains afforded by the layout of the practical installation (in this case in a motorcycle).

If that is true then the reason for the large amount of heavy metal inserts is purely to adjust balance factor and crankshaft weight the 2 being interrelated and critical with regard to engine performance.

As an interesting aside, it has long been my theory that the percentage balance factor requirement for optimum performance in motorcycles and Superkarts is quite different. It has also long been understood that out-of-balance forces are "handled and dissapated by" the engines surrounding environment, this largely being dictated by the frame design and stiffness.

Whilst a motorcycle frame is ultra stiff in the vertical plane, a Superkart frame is relatively soft. I won't quote figures here, but I believe there are real gains to be had if you design specifically for a Superkart (as the tandem twin family now are) and we can see this trend when looking at offeings from all the current maufacturers. I would say the leaders in exploiting this avenue of technology are on the 4th generation of development, with the first generation being the good old Rotax 256 Wedge cranks.

What also interests me is that with long rods and tall crankcase and hence increased crankcase volume, it goes to prove that with modern exhaust systems, there is a much smaller reliance on crankcase volume to push the mixture into the cylinder, it is more to do with the exhaust "sucking" the mixture into the cylinder when the motor is "on the pipe" and within it's "power band". In fact too small a crankcase volume actually goes to reduce high rpm capability by absorbing power to compress the crankcase gases. As with everything there are limits on these things, but in terms of "the old days", when crankcase stuffing and minimal crankcase volume were the holy grail, it's a different world.

The competition and development has been fierce and we see latest generation offerings from 4 different manufacturers, (PVP have pole position at Assen this weekend), having scored major succes in the global Superkart Arena so far in 2012. In my view this is a brilliant time for our sport and improvements in The World economy could, I believe, see unprecidented levels of growth.

Very interesting stuff (to me at least ;) )

Best Regards

Ian :)


Allan Litten

Sat, 04/08/2012 - 12:56

Hi Ian,
I hope you are right about the growth as Australia could surely do with that.
Next weekend, you will see that for yourself.
It is interesting what you have said about the crankcase volume with a rotary valve motor but I suspect it is different for a reed valve motor. The rotary valve motor takes full advantage of the Helmholtz resonator effect while the valve is open and provides an uninterrupted path for the sonic and pressure waves but the reed valve motor does not enjoy the same uninterrupted path with the reed responding to the pressure changes. Therefore, I suspect there is a sweet spot at each RPM range in terms of crankcase volume for the reed motor. Maybe, you have seen this already with reed valve spacers?

Best regards
Allan.

Viper Racing UK

Sat, 04/08/2012 - 17:43

Hi Allan

Practically, we do see the same thing with regard to the CR250.

Of course you are correct regarding a sweet spot for every rpm, but I believe that this area is so blurred that it's a bit like trying to hit the bulls eye on a dartboard that is swinging on the end of a rope!! and if you do happen to hit it then it almost has no relevance with regard to the total performance of the engine away from that rpm band.

What I will say is that we have only seen overall performance gains within the operating rpm range with increases in the crankcase volume. Yes, this has tended to move the operational rpm range upward, the advantage of this being the ability to run lower gearing than the next man, particularly on a track with a single very high-speed point that is not repeated elsewhere on the track, which gives gains in acceleration out of slower sections.

People always look at the peak power figure (this is what sells engines), but far more important than a couple of horsepower at peak is the area under the powergraph within the rpm range/gearing requirement/inter-gear rev-drop of the slowest hairpin to the fastest straight on any given track.

Days were when you could win races at specific tracks depending on your engine (Most in the Czech republic, comes to mind as a "BRC" track), but now, you have to have it all . . . . . . that's grunt, high peak horsepower and exeptional over-rev.

Poul Peterson said to me at Snetterton a few weeks ago, that with this new generation of engines, they are (all the top boys) fitting a new set of tyres everytime the kart hits the tarmac. Another very experienced driver said to me, it was the first time in his racing career that he felt the kart was driving him.

That's as worrying as it is an indication of the elevation of performance levels. All this may not lead to huge decreases in lap times (as we well know), but the physical attributes and level of fitness required means that serious top-level twin cylinder Superkarting may well become the preserve of the young, fit, sublimely talented and well financed, with the more mature drivers just doing it for fun. My feeling is that this should be embraced and used to attract these kind of competitors who would enhance the image of our sport, leading to an increase in popularity. . . . . . . . but that could also be a double edged sword.

In terms of current reduction in numbers in Europe, this is purely finance driven. When we first went to Europe in 2008 there was an oversubscibed entry to the championship (I think 75 applied for 60 places?), this year meeting entries are hovering in and around the 40 mark.

Best Regards

Ian :)

Viper Racing UK

Tue, 07/08/2012 - 03:40

Hi Riley

You don't have an image of the primary geartrain side do you? That would be interesting

I assume Scott imagined that the 2 crank gears drove onto a common clutch shaft mounted gear (and I know no better), however from your reply I assume this isn't the case and that the primary arrangement is exactly the same as a tandem twin apart from the angular arrangement of the gear train?

What you say regarding the crank weighting does form and important part of the equation.

Best Regards

Ian :)