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Micah / AF1 Racing
10-22-2008, 04:57 PM
I was playing with one of our now 300 track mile old RS125's the other day on the dyno with the Axone connected so I could build an ignition timing map and look for the reason that engine falls flat on its face at anything over 10,700rpm.

I think I sort of figured out a little of each mystery. I think, though not yet confirmed that the powervalve blade is closing over 10,700 rpm. I have not done another test yet to confirm this but the ignition timing is not really the full story on the top end fall off. The igntion timings in this post are for 100% throttle openings and idle. I see a lot of room to make more power with a different, programmable ignition box or inner rotor style igntion.

idle 12 degrees BTDC

4k rpm 25 degrees BTDC
4.5k rpm 25 degrees BTDC
5k rpm 23.5 degrees BTDC
5.5k rpm 22 degrees BTDC
6k rpm 21 degrees BTDC
6.5k rpm 20 degrees BTDC
7k rpm 19 degrees BTDC
7.5k rpm 18 degrees BTDC
8k rpm 17 degrees BTDC
8.5k rpm 16 degrees BTDC
9k rpm 15 degrees BTDC
9.5k rpm 14 degrees BTDC
10k rpm 13 degrees BTDC
10.5k rpm 12 degrees BTDC
11k rpm 11 degrees BTDC
11.5k rpm 10.5degrees BTDC


The way the ignition retards is typical of a two stroke engine, however the advance could definitely be greater for use with leaded fuels such as proper race gasoline. I have used up to 16 degrees of time on a 40mm cylinder at 16k rpm, so these ignition times are definitely far from peak power on a 54mm cylinder at the current rpms.

Replay away!

Micah / AF1 Racing
10-22-2008, 05:09 PM
Here is the dyno file from that run compared to the best run I have ever gotten on a stock based E3 catalyzed bike.

Micah / AF1 Racing
10-22-2008, 05:39 PM
Playing with Photoshop to edit graphs better...still suck at it.

Micah / AF1 Racing
10-22-2008, 06:02 PM
Here is what I was shooting for on the 1st edit.

Micah / AF1 Racing
10-22-2008, 07:25 PM
Does anyone know of a programmable ignition kit for the RS125 that can control timing and opening points for the powervalve blade? I would like to get something that offers full control over the ignition and powervalve opening and or closing points if possible. The idea of an inner rotor kit is also inticing as the reduced flywheel mass would make revs much faster, improve acceleration and such...of course the powervalve would then need to operate on a total loss battery system...like many GP 125cc bikes do.

To get the most out of the RS125/Rotax 127 (according to Axone, it read engine code as Rotax 127 E3?) using leaded race fuel, proper squish clearances and chamber volumes a lot more ignition advance will be required...along with pipe and carb changes as well. For the experimental phase I am thinking Keihin PWM 38mm with tps? Anyone with experience with this carb?

Fuel injection would be very sweet too...another story all together though.

greg_c
10-23-2008, 09:24 AM
Micah,

Finally getting to the tuning aspects I see. Have you removed the cat for your 09 dyno run posted above?


Here are some links to Programable CDI's to get you started. I was under the impression that all units specifically available for the Aprilia 125 were for the older bikes without TPS. However, the DPS Racing spec (HPI unit) claims to work with TPS also. You should be able to contact HPI direct to get the correct info. Also, not sure if the HIP unit is able to control PV timing. (This is the most popular unit on the street with the guys in Europe.)

The Zeeltronic is most likely only for the older style bike. If so you could always go with the 06 wiring harness swap I mentioned before unless you're set on keeping the TPS.

Links:
HPI (click Road Bike box to see Aprilia) http://programmable-cdi.com/applist.htm

HPI from DPS Racing http://cgi.ebay.co.uk/Aprilia-RS125-RS-125-Twin-Curve-Racing-CDI-Unit_W0QQitemZ300254221561QQihZ020QQcategoryZ25623 QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262

Zeeltronic http://www.zeeltronic.com/page/aprilia.php


Greg

Micah / AF1 Racing
10-23-2008, 09:37 AM
Thank you Mr. Greg. I do no know for certain that the powervalve is shutting at high revs so that is secondary right now anyway. I can always manually keep it open for testing purposes. Waiting to see what comes in the way of pipes too. The stock USA spec bikes do not have a cat, they come with the JGP challenge cup expansion chamber and a stock silencer. The cafrburetor also carries a different part number, I have not stripped it down to see if it is actually a different carburetor or simply a different selection of jets in the stock E3 carb. It visually looks the same to what I remember seeing on your bike.

BTW, it is your RS125 in the graph, on it's best run for the E3 to USA spec comparo.

On RS50's up 20 degrees of advance, sometimes as high as 23-25 degrees of advance at 10K rpm was easily tolerated with great results, and that was on 40-47mm cylinders which in theory should burn much faster than our new 54mm chambers do?

More to come...I cannot help myself. Step one is just mapping out what a healthy stock engine looks like to get a baseline for alterations out into the future.

the brit
10-23-2008, 04:53 PM
My local shop had their bike up on the dyno a few times, and from what I remember, were finding a much bigger drop off on the timing at 10.5k that it looks like you're finding. I mean, something like 15 degrees from memory..

Micah / AF1 Racing
10-23-2008, 04:56 PM
This was looking at the timing through the Axone in real time doing a step test on the dyno? I can only assume that the data the Axone tool is reading is accurate? It nailed throttle position nicely and the data seemed uncorrupted to me?

It would make sense with the dramatic fall off in power but I think there is probably another reason for that. I will soon do a proper EGA test (you must sniff from the center of the expansion chamber for CO and HC, not through the tailpipe) and post those results so we have a sort of CO guideline to look at for relatively safe tuning parameters no matter which carb ends up on my bike.

greg_c
10-24-2008, 09:53 AM
The stock USA spec bikes do not have a cat, they come with the JGP challenge cup expansion chamber and a stock silencer.

According to the parts list I have there is supposed to be a GP silencer too. You'd have to check the #'s to see if your bike has the GP or FP silencer. (If you pull one of those expansion chambers off and have it laying around send me an email please as I might like to pick it up.)


So if I'm reading right, your 09 graph is the best "stock" power obtainable from full de-restriction and Aprilia's optimal flowing stock pipe.

Really happy to see that the tuning bug has gotten you since I'm waiting to see what kind of power you are able to get with your mods and the guestimated time to rebuild before I have a go at tuning mine.


Greg

HONDARACER
10-24-2008, 10:02 AM
Dealer had the fairing off mine and I will say the pipe is frikin huge. Also the reed block is 250cc size. This bike should breathe like no other 125 ever made.

the brit
10-24-2008, 10:14 AM
This was looking at the timing through the Axone in real time doing a step test on the dyno? I can only assume that the data the Axone tool is reading is accurate? It nailed throttle position nicely and the data seemed uncorrupted to me?

It would make sense with the dramatic fall off in power but I think there is probably another reason for that. I will soon do a proper EGA test (you must sniff from the center of the expansion chamber for CO and HC, not through the tailpipe) and post those results so we have a sort of CO guideline to look at for relatively safe tuning parameters no matter which carb ends up on my bike.

I am not sure what their setup entails, but I remember seeing the complete timing charted out and that it was having a hard time reading it down at ~3-4k but looked spot on from there up. It was showing around where you were finding, 10-15' from memory, then at 10.5k changed by 15' or so! I'll ask them for a copy next time i'm up there.


I have a wideband O2 setup for my Megasquirt DIY fuel injection and timing ECU on one of my cars, but i've never even considered running it on a bike nevermind a 2-stroke, haha. I know there are lots of people out there running it on bikes (it will run on Palm OS).

Coljones
12-20-2008, 07:07 PM
Hi Micah,

The following info is from a 2006 Aprilia repair manual which suggests that your valve should stay open?

4.4. RAVE VALVE
4.4.1. RAVE VALVE GENERAL INFORMATION
The exhaust valve is solenoid-actuated via a Bowden cable.
The ECU determines engine rpm based on primary circuit
frequency input and operates the solenoid within a preset
rpm range.
NOTE Using the exhaust valve on type-approved 11kW
vehicles makes such vehicles illegal to ride on public roads.
Any such vehicles equipped with this valve may only be used
for racing or on closed-circuit tracks.
“RAVE” valve operation

The exhaust valve opens between 500 and 2500 rpm
to allow for valve stem self-cleaning.
It closes between 2550 rpm and the actuation point
(about 8000 rpm, varies with engine version).
Beyond the actuation point, the valve stays open.
RAVE valve actuation points:
Strada...............................8000 - 8100 rpm.
Sport Pro..........................8300 - 8400 rpm.


Does the carb on your bike have an oval slide?

ThisEndUp
01-09-2009, 09:30 AM
Any new news from the ignition experiments?

Micah / AF1 Racing
02-23-2009, 02:28 PM
Interesting read about Honda RS125 ignition timings:

http://www.iane.co.uk/store/images/uploads/IanE-RS125-16settings%20curve%20changer%20ins.pdf

Notice in their graphs how much more advance the engine has to work with...leading me to think...we need more...

Oystein G
02-23-2009, 05:38 PM
You people got Rotax 127 engine in your's RS125?
I've got a 122 in my 2007 RS125.

Anyone got some info or something about the Rotax 127? :S

Micah / AF1 Racing
02-23-2009, 06:55 PM
It is probably a 122 really but when you connect the Axone to the ecu in the RS125's we have it identifies the engine as a Rotax 127 E3 ? It appears in every way identical to other 122's I have seen.

If you look at the Honda graphs posted in the link above and read through what they have to say about a feeling of the engine just "hitting a wall" at high revs I think we can all relate to what we feel on our 125cc Aprilias. There is definitely more power to be had with more advance, possibly 10 degrees or more required at lower rpms.

Even on the early 50cc Aprilia/Yamaha/Minarelli AM6 engines where timing is fixed at 16-24 degrees BTDC depending on where you set the plate after slotting it I was able to rev several variants to well past 15k rpm. The highest revs ever attempted were over 17k and that was with a static and dynamic ignition lead of about 18 degrees.

Race fuel will most likely be required to get the most out of our Rotax project, not the oxygenated cheater stuff just, a leaded 110 octane fuel. This is the smae fuel I use in Yamaha TZ 125's and Honda RS125's and they both can easily top 35-37 bhp on the same dyno where I am stuck at 28 bhp or so with the Aprilia/Rotax. I am currently limited in rpms to make power with, this dropping dead over 10,500rpm may be fine for a street bike but is not what I want to see from a 125cc race engine, at least for the "sprint" version of the engine.

Gman2005
02-23-2009, 07:51 PM
The RS might close the PV to save the engine from being blowen up. You wont get anymore power out of the RS with stoke fueling and piping.

You need to get the 34mm carb on the RS and use a Jolly moto exhaust system to start getting the power locked away within the engine. But you won't see that from a new engine. You shouldn't be trying to get power figures from a new engine ether.

The old CDI do not have any restriction as I know of but the newer ones do. They are restricted too keep emissions down. Anyway, the new RS has two maps and one of them is for racing ;) lol If you need help, start asking the superteen racing teams over in the british islands.

Gman

Micah / AF1 Racing
02-23-2009, 08:48 PM
None of our engines are "new" anymore, they all have hundreds of miles on them.

I just acquired a 34mm Keihin to test against the 34mm Dell'Orto. I prefer the way the Keihin jets for track use, but that is mainly because I am far more familiar with them than the other options.

I would like to try a Jolly Moto pipe but the price is downright scary...but you know, speed costs money.

There is plenty of power to be had with the stock, Arrow, Tyga or Gianelli pipes too. I agree though that usually Jolly Moto is the last word in pipes for two strokes...unless Metrakit makes a Pro Race pipe for that same application.

Gman2005
02-23-2009, 11:00 PM
well as the gear box needs a good 1000 miles on them to fully loosen up. The 300 miles you said will not be enough. You will find more power the older the engine gets, just down over run the engine before it has time to show you its power. Im still able to keep up with my mates mille in the corners and sometimes pass him. The engine is strong but you will need to show it some resprect before seeing the power.

Gman

keisy
03-09-2009, 03:38 PM
Hi, I have an Rs125 too. I'm from the spanish forum www.clubapriliars125.com .

I have a Dellorto VHSB 34mm, a booyessen reeds and a jolly moto pipe, and now I want to change the VHSB 34 for another Dellorto, the VHSA 32 (was the serial carb for the tzr 125 belgarda), and I want to get an HPI cdi of 2 curvs. What do you think about this cdi unit??


Bye

Gman2005
03-10-2009, 08:32 AM
[QUOTE=Micah / AF1 Racing;2097869]It is probably a 122 really but when you connect the Axone to the ecu in the RS125's we have it identifies the engine as a Rotax 127 E3 ? It appears in every way identical to other 122's I have seen.

Rotax don't make the engine anymore They only make the 122 for the go-kark and Aprilia. Plus, why would Aprilia but a random engine into a RS frame and have to mod the engine mounts. The engine is self if made to have a kick start aswell. You wouldn't see you having a 127 engine.

coffee
03-30-2009, 08:27 AM
guys,
is there any smart clued up IT guys on here that would be able to crack into the ecu, surely for someone half clued up it wouldn't be that hard. That might be a better option than changing it all out if it could be done?

ThisEndUp
03-30-2009, 09:12 AM
guys,
is there any smart clued up IT guys on here that would be able to crack into the ecu, surely for someone half clued up it wouldn't be that hard. That might be a better option than changing it all out if it could be done?

Noassemblyrequired pointed out to me recently that the manufacturer of the CDI is located in Cali. That's a good place to start.
Name is on the CDI.

FUERA.....1
03-30-2009, 03:58 PM
Noassemblyrequired pointed out to me recently that the manufacturer of the CDI is located in Cali. That's a good place to start.
Name is on the CDI.

I thought the cdi was made by denso?

Coffee, Wouldnt it be easyer just to pay the money and go buy a programable hpi ignition system? i gave you the details of the australian importer

coffee
03-31-2009, 05:39 AM
Fuera,
I did takee the suggestions made and called and did not get through. I then emailed last week and still without responce. After talking with Troy Hunt, he advised that he sends the standard kart cdi to small coil industries and for a small fee they will wire thecoil and adjust the CDI to meet your requirments and that the have used them to see the motors make 15,000rpm. If they can do this on the kart motor, why should it be any differenton the bike engines?
I might go to an older loom and setup and use a HPI or Vortex, will see for now. If I could honestly tapinto and make use of the original I would stick with that and simply chhange the coil if required. You would not stick with the original if youwas hacked and adjustable?

Micah / AF1 Racing
05-06-2010, 11:44 PM
Some more random thoughts on the "way forward" on the RS125 for those who are chasing that more pure engine feel and performance.

http://www.apriliaforum.com/forums/showpost.php?p=2520527&postcount=4231