ESE's works engine tuner

[husaberg]

Thanks for the reply lads but I'm unsure if I really grasped the main point of it.
Are you saying that the short straight manifold works best in that configuration (TM125MX) and compared to the NF4 angled rubber, or are you saying that as a rule of thumb that a shorter rubber is best. Even for a practically stock RS125 engine.

I figured the angled rubber would be a bad design given what Wobbly has written here before about the importance of a straight inlet and charge distribution to the reeds.



Interesting point. I can measure a older style carb, newer style carb and long rubber easy enough but that obsolete short rubber I don't have access too. Wobbly, might you have this info? I could always estimate it given I have an angled and long rubber here.

Pretty sure I posted all the dimensions previously that pic wob used as an illustration was part of a photo story on the web somewhere. I added to this thread. about a year ago.

[bucketracer]

TZee's Man Cave.

Ha Ha ... spotted,4T bottom right corner.

[chrisc]

Apologies. Will go digging

[husaberg]

Apologies. Will go digging

Here it is. No call for any applogies Chris.

Yep, thats the trick shit part for the last of the MX based RS125s - NLA,except a few lying around that were used in open class CR125 engines before they stopped them in USA.
Thats worth a couple of Hp and then stick on a short PWM or better SPJ and thats another 1 1/2 at the top ( over PWK ) in the MX or early RS125.

http://www.risingsuncycles.com/image..._isolators.htm
There is a short KR1 manifold that is still being made, that might work with a little finessing its meant for a 35mm
http://www.kiwibiker.co.nz/forums/at...5&d=1419244249
http://www.kr-1s.co.uk/forum/viewtopic.php?t=5197
Swede tech do one
http://eknclassic.com/viewtopic.php?...eec67eea16e744
so does shark shifter
http://sharkshifter.com/zc/index.php...oducts_id=1059
but not as good or as short as the proper ones

[chrisc]

Thanks for that Husa. I was thinking more about this (underlined and bold). If this is saying what I believe it to be saying then I have my answer. Of course, the dyno tells all and it might have to be something I try out eventually on my own engine. Cheers Wobbly, Husa

The CR125 will make around 2Hp with a dead straight intake, over the best bent one.
An old RS125 short manifold one if you are reving to 13.000 or the longer late model RS125 one if you need more mid power.
The VF2 works very well in a CR125/RS125 and I have not been able to get a stock cage of any sort to make as much power.

[Frits Overmars]

Frits, Wob and others who post interesting and informative info, please advise the rest of us where you may be found in the case your efforts are not given due appreciation as there are far more lurkers and those inspired by your efforts than you realise as well as a great deal of implications to our respective sports.

Appreciation is not the point; I do feel appreciated by the majority here and I think so does Wobbly. I just got fed up with what I experience as Wobbly-bashing and I was hoping to raise some positive reactions, which you gave; thank you for that.
I have no intention to stop posting here (and even if I did, I still would not want to miss what's going on here, so I would take a peek every once in a while, like once a day ).
Wob and I and a few other Kiwis are also contributing to a closed community, but that's no use to the rest of you. If I had to name an open forum, it would be pit-lane. Here are some links:
http://www.pit-lane.biz/t117p246-gp1...-part-1-locked
http://www.pit-lane.biz/t3173p657-gp...-part-2#134197
http://www.pit-lane.biz/t117p318-gp1...-part-1-locked
http://www.pit-lane.biz/t117p333-gp1...-part-1-locked

98-2000ish didn't HRC released the redesigned Carb for the RS, shorter overall length and 'closer to slide' manifold mount and shorter bell mouth / intake track. Not having the bits at hand to measure - I wander if the over lengths are the same? (Reed tip to bell mouth). The float bowl extends in front of the manifold mount and behind bell mouth - Must find photos (husa help me out)...

Take your pick:

Is running Ram air box a benefit to these bikes on NZ tracks? The reason I ask is there must be a point at which below that certain speed the ram air would have zero effect but at what speed does this become an advantage?
Also what effect does the ram air have on jetting. Is it required to run richer jetting to compensate for the ram air effect of do the carburettors sort themselves out.
For me it seems like a lot of extra complexity for potentially minimal gains, but I have no experience to know if it might be more than a minimal gain!

There are much larger gains to be made in real nz track conditions just making sure its getting large quantities of fresh clean cool air. You need to be going at least 200km to see the benefit. ie only for a few seconds per lap.

Husa nailed it: the main advantage of an air box is that the engine breathes cool air instead of air that has been pre-heated by exhaust headers, cooling fins or radiators.
The ram effect is proportional to the square of the vehicle speed. Measurements on a 250 cc Aprilia showed a pressure rise of 30 mbar at 260 km/h.
Calculating backward that would be 4,4 mbar at 100 km/h. This may look negligible but it still equals the pressure of a 60 mm petrol column. This is the real-life problem with air boxes: the ram effect tries to push the fuel in a carburettor's needle tube downward and it may even stop the fuel flow from the tank to the float bowl.

The remedy: enclose the whole carb, including all its breather tubes, in the airbox and connect the fuel tank breather to the air box via a large diameter tube.
It has to be large because the volume of air that has to pass through that tube not only has to equal the volume of fuel exiting the tank; it has to constantly adapt the pressure of the total air volume in the tank to the air box pressure (Aprilia circumvented the problem by using an electric fuel pump on the 250 cc racers).

I found a huge mismatch between blowdown angle.area (good for 26500 rpm) and transfer angle.area (good for 44000 rpm)

I have seen plenty of such a mismatch in (great performing) F3D engines, including MB's, although not as extreme as the Profi F2A you described. Have no clue why you'd want that, other than a very loose theory that it could have a positive influence on ignition timing and perhaps combustion.

Hey Frits, what is the fix to the mismatch ? Can it be fixed by making the Exhaust with a higher timing or slightly wider exhaust port ?

Yes it could, but I would prefer to start by lowering the transfer timing; 140° is awfully high. Radiusing the exhaust window's top edge may also help.
But I learned the hard way that matching the blowdown angle.area to the transfer angle.area is not necessarily a good idea on small high-revving methanol-burning glowplug engines. They may need a certain amount of spent gases to pre-heat the fresh charge and help vaporize the methanol droplets, so you'd better be careful.

Lately the Ryger thing has attracted more talk than action and has taken up a lot of space but I have learn't a few things from it and the associated links, like 4T BMEP is pretty much at its potential but 2Ts have a big way to go yet.
And if you only look at the actual fuel burnt, 2T's are way more efficient and less polluting than 4T's. Its the raw un burnt stuff spilled from 2T's that is the problem. Technology like EFI and stratified charge and the way its applied to 2T's is rapidly developing. The humble 2T may yet become the clean engine of choice. Things I would not have thought about if it was not for all the speculation about the Ryger engine.

I regret that I'm still not allowed to say much about the principles behind the Ryger engine; I must wait until I get the green light from the legal experts. But talking about Brake Mean Effective Pressure: it's true that naturally aspirated four-strokes seem to have reached their limit and it's also true that Jan Thiel's RSA two-stroke produces a BMEP that beats even the best naturally aspirated Formula 1 engines, but I must add that the Ryger does not exceed the RSA's BMEP; it about equals it, though at much higher revs, where the RSA would run completely out of breath.

[seattle smitty]

Yeah cmon guys. Most of the issue are 4 stroke riders posting late at night . . .

Dave, has it seemed to you that some here among us 2-strokers maybe go a little too far in baiting the 4-stroke crowd? The razzing can be all in good fun, but it can also get more and more pointed to where it starts sounding like real antagonism. I know that 2-stroke bike racers have reason to be bitter when the governing bodies have rigged the rules to favor 4-strokes, something that has not yet happened in outboard racing. But what did ordinary little amateur 4-stroke racers have to do with that, why should they be targets of our resentment. If a few of them feel provoked enough to come here and respond in kind, as they see it, maybe it shouldn't be a surprise. Personally, in my nearly seventy years of life I have been involved in one way or other with both 2-stroke and 4-stroke racing, from little 125cc singles to 27 liter aircraft V-12s, and all of it was a blast. And all of it was done in the company of good motorsports enthusiasts, and I think THAT is the bottom-line, that in the end we are all brothers of the motorsport world.

You younger guys can certainly argue with me on this one, but it seems to me that (at least in this country, maybe in yours) more recent generations than mine seem to feel that an individual needs to approach life with some attitude, some "Don't even think about crossing me or I'll be in your face!"
The flaw in this is that it doesn't allow for the possibility of misinterpretation of the other guy's intent. Nor does it allow for the sad fact the some of us (like ME) seem fated to live our lives as socially-inept clods, something we can't do much about, as much as we wish we could be cool. Having an attitude means you don't cut anybody very much slack. Yet this is exactly what should be the way a forum like this operates; we should make some allowances for individual styles and mannerisms, and varied abilities to express ourselves.

By the same token, while cutting the next guy a little slack when he has expressed himself in a less than appropriate way, we ought to watch our own reactions. If you asked, most members here would say they have no problem with others disagreeing with what they have said, but you can see that some do tend to take disagreement personally. So some of that attitude kicks in, they give a somewhat snotty answer, and away we go, snottiness begetting more snottiness. I'm lucky to have never been on the receiving end of any of this myself, because my responses always reflect not disagreement but abysmal ignorance, LOL.

Yeah, I know, you're thinking what pathetic stuff and it surely is, but come on, gents; cut each other some slack.


(And vive la France)

[richban]

Its seams the 50cc arms race has well and truly kicked off across the north island of NZ.

I had my first taste of 50 racing on the weekend. As I have said in another thread. I have never had so much fun going so slow. And by slow I mean proper slow on a near stock RS50. The only tools I took to the track were a tyre gauge and a hand pump. Refreshing after a few rounds of racing the NSR300.
Anyway! Its now time to play. And as there is this little event coming up next year. (THE F5 GP). Its time to put the bike on a diet and TRY to double or triple the power.

I will post some pics as I go and share the info here. I know Frits has posted some dimensions for a fantastic pipe in this thread before but buggered if I can find it. Q Moderator of all things internetberg.

What I would like to know is if I wanted to make 18hp. "And who wouldn't" What would the lowest rpm that this might be possible? I know there are quite a few factors to consider but if someone on here has tuned a 50 to that level? It would be nice to know the rpm that it made that power.

[WilDun]

Well said Smitty,

Yes, - vive La France - et aussi vive "le rest of us"!

[lodgernz]

OK, my recent paracetamol-fuelled rant was over the top and ill-advised.
Clearly I have offended people whom I like and admire, as well as some who appear unlikeable, and to all those I unreservedly apologise.

Frits and Wobbly seem to have a soft spot for this thread, despite our occasional lapses of decorum, and they, along with many others, have contributed priceless knowledge and experience that have helped amateur 2T tuners around the world extract previously undreamt-of performance from relatively unsuitable engines.
The loss of any of these precious resources would be to the detriment of the thread, and my talk of repercussions was merely to point out that someone who was seen as the cause of such detriment might not find themselves remembered kindly by their peers.

Hopefully, the details of the Ryger technology will be revealed to the public soon, and with Frits here, this thread could be the best place to learn the secrets and ask the questions.
Without Frits, we'll have to become very good at translating from French and Dutch on other forums.

Once again, I'm sorry for all offence caused.

[ief]

Engmod > Giving it a go myselfs on the little tomos engine, now engmod keeps telling me something exceeds the grid mesh or something, inlet or exhaust pipe to long or short but no mather what I change (nothing weird as far as I can see) it won't go away

Anyone else stumbled into this?

[teriks]

Engmod > Giving it a go myselfs on the little tomos engine, now engmod keeps telling me something exceeds the grid mesh or something, inlet or exhaust pipe to long or short but no mather what I change (nothing weird as far as I can see) it won't go away

Anyone else stumbled into this?

Im sure I did back when I got started, I even managed to model the pipe and inlet bell backwards.. the output of that sim was kind of useless.
In other words, check your model again. Oh, and spending a lot of time in the help-files...helps..

Good luck!

[JanBros]

Its seams the 50cc arms race has well and truly kicked off across the north island of NZ.

I had my first taste of 50 racing on the weekend. As I have said in another thread. I have never had so much fun going so slow. And by slow I mean proper slow on a near stock RS50.

for 2 years now, I'm into moped-cross. MX with automatic scooters/mopeds. rules are simple : 2 working brakes, needs to be 50cc and engine and frame must be from the same model (so no automatic in a Honda MTX frame for example).
great great fun, almost as great as when I won the first motor-race I ever entered with a ZXR400.
As there are a lot of people entering that know how to MX, winning is impossible for me (they ride stock Honda sky's but fly over the track like they are on genuine MX-bikes), so my goal is to built the fastest bike . But it's not easy as the gearing of scooters is fixed, so I need to find power at about 8.500rpm max AND good drive out of slow corners.

our toys (my sons and mine) :

[m4r]

Frits, would engmod be any useful for a rygerized engine?

[teriks]

Hey Frits, what is the fix to the mismatch ?
I am all ears,/eyes
Can it be fixed by making the Exhaust with a higher timing or slightly wider exhaust port ?
Thanks Neil
Neil

Yes it could, but I would prefer to start by lowering the transfer timing; 140° is awfully high. Radiusing the exhaust window's top edge may also help.
But I learned the hard way that matching the blowdown angle.area to the transfer angle.area is not necessarily a good idea on small high-revving methanol-burning glowplug engines. They may need a certain amount of spent gases to pre-heat the fresh charge and help vaporize the methanol droplets, so you'd better be careful.

I agree on lowering the transfers if possible.
For what its worth, I have had best luck with my F3D's running the transfers at 125°-130° and exhaust at around 194°-197°.
My, now dead, all time favorite cylinder had plenty of blowdown thoug:

Why that particular cylinder outperformed everything else I have tested since I will probably never know.
The way i set it up it was a bit tricky to get on the pipe though, at least if you ask Rob about when he called for me in Melnik ages ago.
-There's more to it than port areas for sure, most of it quite difficult to measure in such small scale.