ESE's works engine tuner

[MotleyCrue]

Good to hear you are having success with your EFI system.

Yes, I found it relatively easy to get to full power runs but it is that part throttle, especially the full to closed then open again like you would throttling off for a corner that I am struggling with.

I found a lambda sensor did not help me much as the fuel lost with the inevitable short circuiting always made things look to rich when in fact they were not.

I think Wob has talked about putting the sensor at the stinger, I would like to know more about that.



True, sounds simple, well maybe, anyway it is pretty much what I have tried. I have had some success, but it is funny that the smallest part of the map. The area below 25% TP that I am having the most trouble with and it is this area that affects the rideability of the bike the most.

320621

I had to do a little learning to get here but these are dyno runs from a map developed the way you suggested. With the various dyno runs in 10% steps from 100 down to 20%TP below that fueling was so bad the engine would not run well enough for any data to be recorded.

Now that I understand it a bit more I will follow your advice and take it to the track for practice on a Saturday. That way, if I stay out of everyone else's way I can play with the map and different sized primary injectors.

Another reason for calculating it all out carefully is that with staged injection you need predictable even steps between cells in every direction otherwise the ECU becomes confused when trying to swap between injectors.

320622

The cross over in the 4,000 rpm area in the EngMod simulation is interesting too, I saw hints of this on the dyno but did not understand the reason for it until I saw the simulation.

If it was a dragster non of this low speed stuff would matter but a road race bike needs to be rideable under every condition. Including just trickling around the track to line up for the start.


Have you found anymore power with Ecotron or is this just an exercise to learn about FI ?

[wobbly]

I must admit I was very skeptical about using a lambda on a 2T, especially as several dyno operators told me they wouldnt use
the sniffer on a Dynojet ( even with its inline filters etc ) as it continually shit the probes.
But in 07 when we first went to USA racing the SKUSA CR125 box stock class,I saw a probe mounted thru an alloy bung welded
right at the front of a muffler.
The Lambda read the A/F going past inside the perf tube.
I asked to look at the data on the PI system, and there it was, a perfect readout varying with throttle and track position, between 12:1 and 15:1.
The fact it was 12.8:1 at full noise down the shute,told me it was saying the right things, as the egt was 1280*F, just as we were running - right on the edge.
The Yanks were obsessed with trying to get the fueling number correct the whole lap, and this made the corner exit ratio " correct " but slower.
And that jetting was too lean down low to get the kart launched at the starts as well.
So I ignore the numbers in this area and do all the bottom end response against the rear brake, on the stand.
If it will snap off the bottom when given instant full throttle from idle, then the pilot/needle/tube/slide are correct.
If it snaps from 1/2 throttle,without hesitation, or blowing a heap of rich smoke,then the mid jetting is correct.
We shot for a specific egt number in accordance with the weather, and this always corresponds with a A/F around 12.6 to 12.8.
So as we can use the egt ( but not Lambda ) in races I can then track the weather and jet change on egt alone.

[TZ350]

Have you found anymore power with Ecotron or is this just an exercise to learn about FI ?

No, not expecting to find any significant power advantage with EFI.

320630

I needed to learn about fuel injection in a two stroke because my plenum idea suffered from enormous amounts of fuel drop out.

This both affected the fueling accuracy and left doubts about how much pre mix oil was making its way to the engine.

EFI is an attempt to get away from the fuel dropout problem in the plenum.

[dmcca]

I must admit I was very skeptical about using a lambda on a 2T, especially as several dyno operators told me they wouldnt use
the sniffer on a Dynojet ( even with its inline filters etc ) as it continually shit the probes.
But in 07 when we first went to USA racing the SKUSA CR125 box stock class,I saw a probe mounted thru an alloy bung welded
right at the front of a muffler.
The Lambda read the A/F going past inside the perf tube.
I asked to look at the data on the PI system, and there it was, a perfect readout varying with throttle and track position, between 12:1 and 15:1.
The fact it was 12.8:1 at full noise down the shute,told me it was saying the right things, as the egt was 1280*F, just as we were running - right on the edge.
The Yanks were obsessed with trying to get the fueling number correct the whole lap, and this made the corner exit ratio " correct " but slower.
And that jetting was too lean down low to get the kart launched at the starts as well.
So I ignore the numbers in this area and do all the bottom end response against the rear brake, on the stand.
If it will snap off the bottom when given instant full throttle from idle, then the pilot/needle/tube/slide are correct.
If it snaps from 1/2 throttle,without hesitation, or blowing a heap of rich smoke,then the mid jetting is correct.
We shot for a specific egt number in accordance with the weather, and this always corresponds with a A/F around 12.6 to 12.8.
So as we can use the egt ( but not Lambda ) in races I can then track the weather and jet change on egt alone.


This fits exactly with what ive found... I use a wideband o2 on the dyno and it is extremely reliable... made up a simple vacuum setup using a funnel held up against the main extraction fan for the room and it pulls exhaust gasses up through a 1/4 inch diameter copper tube thats pushed up the silencer. Reading are basically taken from the beginning of the silencer and drawn up past the sensor via rubber hose. The numbers are highly repeatable and after doing enough bikes you get to know exactly what AFR each bike likes at each rpm/throttle position. My dyno is an eddy current so i hold it at 4 or 5 rpm points and then test each point at 1/4, 1/2, 3/4 and full throttle... end up with a matrix of AFR's and its then very easy to make adjustments to pilot, needle or main to alter the AFRs at each point. Before using this setup i went through about 3 sensors a month ($$$ :o), now i use 1 or 2 a year and the dyno is used 3-4 days per week. I also find 12.6-12.8 to be a good range to aim for up top, then slightly leaner around 13.5 at mid throttle and mid rpm, and leaner again around 14 at low throttle and low rpm.... this is for offroad and MX bikes though.

Im about to setup a KTM330 with an Ignijet so we'll see how this method goes with EFi....

[Flettner]

Where are you injecting?

[TZ350]

This fits exactly with what ive found... I use a wideband o2 on the dyno and it is extremely reliable... I find 12.6-12.8 to be a good range to aim for up top, then slightly leaner around 13.5 at mid throttle and mid rpm, and leaner again around 14 at low throttle and low rpm.

That is interesting because I saw similar numbers when I was playing with our wideband O2 sensor, I just did not understand them at the time, thanks.

[TZ350]

I want to see race 2 of this ....

https://www.youtube.com/watch?v=HcK1As59jkI

The great sound of a two stroke Bucket, real music.


GP Boneshaker...


https://youtu.be/8EwKlNBTgsc

Tokoroa GP

[dmcca]

Where are you injecting?

Similar to your YZ setup with one injector into each B transfer duct just inside the port window. Will be coming in from the rear of the cylinder rather than downwards like yours... Simply due to clearance issues. Using an electronic fuel pressure regulator and a dead head system, so no return to the tank and it should cut power consumption down... Pump is only fed enough power to maintain pre-set fuel pressure.



Sent from my iPhone using Tapatalk

[adegnes]

Checked the balance factor of the Spx crank today.
Without any added weight to the small end it's heavier on the crank pin side.
Small end = 27g
Reciprocating mass = 109g
27/109 = 0.25.

Balance factor < 25%.
Explains the shakes i suppose.

[Frits Overmars]

Checked the balance factor of the Spx crank today. Without any added weight to the small end it's heavier on the crank pin side.
Small end = 27g
Reciprocating mass = 109g
27/109 = 0.25.
Balance factor < 25%.
Explains the shakes i suppose.It may explain the shakes but it doesn't explain how you arrived at that balance factor - not to me anyway. Would you care to show your calculation step by step?

[AndreasL]

You lost me during your calcs adegnes...
There have to be some numbers missing here, doesn't it?

[adegnes]

It may explain the shakes but it doesn't explain how you arrived at that balance factor - not to me anyway. Would you care to show your calculation step by step?

I used TZ's instructions from here, was there something I didn't get right?
My conclusion is hat the balance factor is less than 25%, not exactly 25%, if that was misleading.

.

Re-Engineering to find the Balance Factor of a CrankShaft.


Pic-1 Hang things of the little end untill.............

Pic-2 ...........the crank no longer rolls and stays in whatever position it's placed.

Pic-3 Weigh the washers and the little end.

Pic-4 Weigh the Reciprocating Mass.

Divide the Weight of the Washers + weight of the Little End by the Weight of the Reciprocating Mass and there you have the Balance Factor.

Rearanging the formula I posted earlier.


Let:- "Washers"+"Little end" = A "Reciprocating Mass" = B and "Balance Factor" = C

Then Balance Factor C = A/B .............."Weight of the Washers"+"Weight of Little End"/"Weight of the Reciprocating Mass"




.

[AndreasL]

adegnes, when adding mass to the little end (to make it "stay in any crank position") you will get a higher balance factor %, not a lower one.

So the linked explanation is correct, but I think you have misinterpreted it a bit.

[Frits Overmars]

I used TZ's instructions from here, was there something I didn't get right?
My conclusion is hat the balance factor is less than 25%, not exactly 25%, if that was misleading.I can't find anything wrong with your conclusion. Sounds like you will need a couple of heavy metal slugs - or an angle grinder.
Still makes me wonder: who on earth built the crankshaft like that?

[AndreasL]

.

The KISS method of balancing a single cylinder 2 or 4-stroke.

Its all in the pictures:-

Pic-1 Find the total reciprocating Weight (Mass)
Pic-2 Find the Little Ends reciprocating Weight (Mass)
Pic-3 Find the Balance Facter (Ie. 65% is 0.65 X the ToTal Reciprocating Weight (Mass))
Pic-4 Leave the Little Ends reciprocating Weight (Mass) on the Scales
Pic-5 Attach the rest to the crank.
Pic-6 Balance the Crank.

From Phill Irving. page 109 "the wheels will roll freely along the straight-edges and show no tendency to settle in any one position; if not, the pin will go to the top or bottom according to whether the Counter Balance is to heavy or to light. Correction is usually made by drilling the rims."

Very simple, very effective, a very accurate way to balance a single cylinder crankshaft staticaly. If anyone can come up with a better static balancing method, Thomas and I would like to hear about it.

To find the existing balance factor of a crank shaft, you just more or less work through this process backwards.

.

A summery of TZ's method.

[AndreasL]

Ok, I think I got it now!

Sorry adegenes, I didn't get that you got the resulting masses AFTER performing the "add washers" step.

I'm slow today...to. ;)

The numbers so weird it tricked me.

[adegnes]

adegnes, when adding mass to the little end (to make it "stay in any crank position") you will get a higher balance factor %, not a lower one.

So the linked explanation is correct, but I think you have misinterpreted it a bit.

I think I didn't explain my process good enough. When I arrived at the stage where you're supposed to add weight to the small end to balance the crank my small end was already too heavy.


I can't find anything wrong with your conclusion. Sounds like you will need a couple of heavy metal slugs - or an angle grinder.
Still makes me wonder: who on earth built the crankshaft like that?

Apparently Doppler does...
What I was expecting to find was too much counterweight, cause this crank is typically ment for 70cc "racing" cylinders.
Obviously they didn't give a shit, or they just don't have a clue.

I'll start with removing the aluminium slugs in the balancing holes and go from there.

[adegnes]

Ok, I think I got it now!

Sorry adegenes, I didn't get that you got the resulting masses AFTER performing the "add washers" step.

I'm slow today...to. ;)

The numbers so weird it tricked me.

No worries!

[AndreasL]

So much for "high level brand" parts...

Less than 25% is weird on its own, but can the up side down orientation of your cylinder make things more noticeable/worse?

Need to check my Rito. Guess the answer can be anything between here and eternity.

[Haufen]

I also find 12.6-12.8 to be a good range to aim for up top, then slightly leaner around 13.5 at mid throttle and mid rpm, and leaner again around 14 at low throttle and low rpm

Sounds logical to me, as rpm increases, so does the trapping of fresh charge. So you might actually have the same A/F ratio inside your cylinder during the whole rpm range in reality.

[peewee]

frits you staying safe over there ? sounds like all hells breaking loose in that neck of the woods

[adegnes]

Checked the stock crank, clocked in at 55%.
Why Doppler, why!?

[JanBros]

frits you staying safe over there ? sounds like all hells breaking loose in that neck of the woods

Frits lives in another wood, it's my wood that exploded :msn-wink:

[TZ350]

Sounds logical to me, as rpm increases, so does the trapping of fresh charge. So you might actually have the same A/F ratio inside your cylinder during the whole rpm range in reality.

Yes I think so to, and is why trying to get the AF meter showing the correct reading had me chasing my tail.

[Frits Overmars]

frits you staying safe over there ? sounds like all hells breaking loose in that neck of the woodsThanks for asking Peewee. France and now Belgium were hit hard by those bloody idiots; the Netherlands were spared so far.

[dmcca]

Yes I think so to, and is why trying to get the AF meter showing the correct reading had me chasing my tail.

Trying to run 12.5 at low/mid rpm will run very badly, way too rich. I aim for idle around 14-14.7 then progressively get richer from there with the numbers I posted earlier, up to 12.5 around peak then if everything is working at the right rpm itll naturally lean out in the overrev to 13+. Seems to work very well on most bikes. The exact number at each rpm/ throttle point will vary for each individual engine though, that's when you've just got to listen to what the engine is telling you and decide if it want more or less fuel.

I'll try to post up an example of the matrix of afr vs rpm that I record on the Dyno.., might have to wait til Tuesday though due to the public holiday.

Due to the nature of a carb low rpm/high throttle will always run leaner than the ideal numbers and high rpm/low throttle will run richer than the ideal numbers. With EFI you'd probably want to get rid of the low rpm/high throttle lean condition but keep the high rpm/low throttle rich condition for protection during deceleration.




Sent from my iPhone using Tapatalk

[TZ350]

I'll try to post up an example of the matrix of afr vs rpm that I record on the Dyno..

Great Thanks, it will be a great help.

[mr bucketracer]

Great Thanks, it will be a great help.did not know your all taking A/F in here

[TZ350]

did not know your all taking A/F in here

I prefer Nitrus but you know how killjoy the rules are ..... :p

[mr bucketracer]

I prefer Nitrus but you know how killjoy the rules are ..... :phell yes , got some of that here , had it from my rc days , waiting for it to turn green then biff it on the ground to see if it does blow up lol

[mr bucketracer]

here is my 50 , rg50 A/F reading , running a nsr 28mm carb , runs rich to lean then a slop to rich and lean on over rev320676engine struggles to pull past 8- 8.5 rpm as seems to rich on A/F , but gets up and go's past that

[TZ350]

320682

Water cooled head? some other interesting looking motors in the background.

320681

Assuming the AF ratio of all the air passing through the engine is 12:1 or so over the full rpm range then this graph shows a neat correlation of the trapping efficiency and torque curve. Very interesting.

[Yow Ling]

here is my 50 , rg50 A/F reading , running a nsr 28mm carb , runs rich to lean then a slop to rich and lean on over rev320676engine struggles to pull past 8- 8.5 rpm as seems to rich on A/F , but gets up and go's past that

The sensor is measuring excess oxygen, not mixture, maybe its not so much the jetting being wrong as the airflow being wrong

[TZ350]

The sensor is measuring excess oxygen

Yes excess oxygen in the AF that was not trapped and burnt.

[TZ350]

320686 320687

The new Beast is ready for a test run on the Dyno, maybe get to it Tuesday night.

[goose8]

320686 320687

The new Beast is ready for a test run on the Dyno, maybe get to it Tuesday night.

Very cool can't wait to see it go.

[mr bucketracer]

320686 320687

The new Beast is ready for a test run on the Dyno, maybe get to it Tuesday night.may need a new name now (-; looks real good

[mr bucketracer]

The sensor is measuring excess oxygen, not mixture, maybe its not so much the jetting being wrong as the airflow being wrongwas going to try reads first but can't fine any , gave my spring steel ones to help my mate out now want to try them dam it, think some with more tenison may help . May run some cut down reeds on top of reeds to change pivet point for more tenison

[TZ350]

may need a new name now (-; looks real good

Thanks. Maybe I could call it Queen Anne'S Revenge. That was Black Beards ship.

[TZ350]

was going to try reads first but can't fined any , gave away my spring steel ones.

Are you looking for standard RG50 reads? Could find you some if it would help.

[husaberg]

Thanks. Maybe I could call it Queen Anne'S Revenge. That was Black Beards ship.

Mr. Bigglesworth
http://i.imgur.com/MIfAknD.gif

[TZ350]

Yes we could call it Mr Bigglesworth, the bike is crazy enough.

[Frits Overmars]

320686
The new Beast is ready.. .I like the double footrests and the long seat. Are you guys doing much pillion racing over there?

[jasonu]

320682

Water cooled head? some other interesting looking motors in the background.

320681

Assuming the AF ratio of all the air passing through the engine is 12:1 or so over the full rpm range then this graph shows a neat correlation of the trapping efficiency and torque curve. Very interesting.

The round cast head looks like a Chris Ziffle creation.

[mr bucketracer]

The round cast head looks like a Chris Ziffle creation.I built 3 like that. Ziffles one is at the old mans .going to get these classic buckets going .maybe could be a fun class if run on 17s

[mr bucketracer]

I like the double footrests and the long seat. Are you guys doing much pillion racing over there?lol maybe build for me the fat so

[mr bucketracer]

Are you looking for standard RG50 reads? Could find you some if it would help.it's my big reed block engine .yz80 or tzr type reeds

[TZ350]

320696


I like the double footrests and the long seat. Are you guys doing much pillion racing over there?

LOL ... it is built for comfort, and them is Harley heel hooker highway pegs.

320695

A few details required to get Mr.Bigglesworth race ready.

320697

Then it is onto the plenum chambered EFI water cooled 110cc motor for Mr.Bigglesworth if the air cooled engines EFI thing and dry sump gearbox testing works out Ok.

[TZ350]

320699

Well that didn't go so well, the family took a vote and Mr.Bigglesworth is not going to be the new bikes name, I liked Husa's idea but I was out voted .... :facepalm:

Looking for new ideas.

[speedpro]

Hopefully you aren't really using YZ80 reed block or reeds.

[husaberg]

Hopefully you aren't really using YZ80 reed block or reeds.

If he was it wouldn't mater they are the same reed block as plenty of other more legalish ones
The early ones are the same as a RD250.

slightly later ones
83-84 are the same as
DT250's

later ones again are the same as a Blaster
Pretty sure all bar the first model have the same or more reed area than the TZ750 reeds.

[F5 Dave]

1KT are pretty nice. Swhat I run in the MB full case reed motor.

[mr bucketracer]

Hopefully you aren't really using YZ80 reed block or reeds.what ever pete had in the gt50 motor?

[mr bucketracer]

If he was it wouldn't mater they are the same reed block as plenty of other more legalish ones
The early ones are the same as a RD250.

slightly later ones
83-84 are the same as
DT250's

later ones again are the same as a Blaster
Pretty sure all bar the first model have the same or more reed area than the TZ750 reeds.ta . Hate robbing things .ag175?

[husaberg]

ta . Hate robbing things .ag175?

I think they were the same as a RD250 as well the Ag100 were smaller reeds but same bolt spacing.

[jasonu]

I built 3 like that. Ziffles one is at the old mans .going to get these classic buckets going .maybe could be a fun class if run on 17s

You had to be careful with the Ziffle ones. They were horrible to weld and horrible to machine too. Once together they worked fine.

[jasonu]

320697

.

Are you going to run an outrigger for this one???:cool:

[mr bucketracer]

You had to be careful with the Ziffle ones. They were horrible to weld and horrible to machine too. Once together they worked fine.320700they bread

[jasonu]

320700they bread

I made a watercooled TF with a Ziffle head and a straight exhaust port. It was shit...

[TZ350]

Are you going to run an outrigger for this one???:cool:

Tricycle .... :D

320701

[mr bucketracer]

I made a watercooled TF with a Ziffle head and a straight exhaust port. It was shit...all these go prity good

[TZ350]

320700 they breed

Classic Bucket engines, maybe we could have a pre 82 Bucket class based on crankcase and cylinder being pre 82.

[Yow Ling]

Classic Bucket engines, maybe we could have a pre 82 Bucket class based on crankcase and cylinder being pre 82.
Just pre FXR wouldd get most of them

[jonny quest]

Anyone have any experience with the Aprilia RS125 Rotax 123 engine? I'm in the USA, where they're rare. I test rode one that's completely de restricted. Now, I haven't torn into it... just quick test ride to see if I would like it for a personal commuter bike.

It's dog ass slow on bottom end, is this common? Fairly zippy on top end for what it is. For me to be happy riding this, I'll need to drastically fix this.

So, are they really that bad power wise down low? Does anyone have any pipe specs, cylinder specs?

[TZ350]

Anyone have any experience with the Aprilia RS125 Rotax 123 engine?

Fairly rare down here too and being a water cooled 125 they don't fit into our class rules for Buckets, so sorry don't know much about them. But maybe someone else may have ridden one.

[wobbly]

Several companies do aftermarket big bore cylinder kits for the 123.
The ports are not that clever, but with some detail grinding,the kitted bike is fast everywhere.
From memory it made +8 Hp at the bottom of the powerband.

[jonny quest]

Good to know. Thanks Wobbly. I was probably going to do a big bore and stroker out the stock parts. Just kind of wanted an idea of what others have found.

Everything is typically geared more towards upper peak power when talking performance. I don't even really care about that much in this case.

No one talks much about pipe measurement, to find out unknown dimensions. Here's a quick run down of what I used to do.

On a stamped pipe, 90 deg from seam I would mark stamping every 1/2". Measure each diameter there, and write down numbers. You would start to see a pattern in each progressive number. When you could see this pattern change, go back and mark the gross taper changes 1/8" and measure. You can then determine each section, header, diffuser and so on. Mark the pipe out in it's header, diffuser diameters, then take a cloth tape measure, measure inside and outside of these separate sections, and divide by 2 for length.

Anyone else have a better way?

[ief]

Guess it will depend on the pipe but given the fact most designs are 1,2 or maybe 3 step diffusers and at most 2 step baffles..

I just look for the changes in dia and check with a caliper and measure with a piece of wire the circumference, that + length gives the angle, subtract material thickness x 2. Sometimes they aren't round so I take the average.

Will allways be off a bit but close enough unless top tuned... but then a stamped exhaust wouldn't be used so...

[JanBros]

I'm making a DIY dyno in "bucket" tradition (meaning on a tight budget as in no money involved, only scrap :whistle: ). if anyone has done this or has some idea's - do's or don'ts - or whatever, I've opened a topic about it here :

http://www.kiwibiker.co.nz/forums/showthread.php/178284-DIY-dyno?p=1130959381#post1130959381

[lodgernz]

Good to know. Thanks Wobbly. I was probably going to do a big bore and stroker out the stock parts. Just kind of wanted an idea of what others have found.

Everything is typically geared more towards upper peak power when talking performance. I don't even really care about that much in this case.

No one talks much about pipe measurement, to find out unknown dimensions. Here's a quick run down of what I used to do.

On a stamped pipe, 90 deg from seam I would mark stamping every 1/2". Measure each diameter there, and write down numbers. You would start to see a pattern in each progressive number. When you could see this pattern change, go back and mark the gross taper changes 1/8" and measure. You can then determine each section, header, diffuser and so on. Mark the pipe out in it's header, diffuser diameters, then take a cloth tape measure, measure inside and outside of these separate sections, and divide by 2 for length.

Anyone else have a better way?

Same, but put the dimensions into Excel and draw a line graph from the length and diameter data. The transition points become very obvious and reasonably precise.
I actually made a third column in Excel with the same diameter values *-1 and drew a double line graph. Looks like a pipe...

[dark art]

Had a 2003 Rs 125 with a Arrow pipe and never liked the engine. Too peaky for road use, too slow for track use.
The exhaust valve opens on the low end until ~4000 rpm (from memory), probably to ease the starter motor life. It opens around 7500 and the arrow pipe is too short for the engine spec, it only hits around 8500, so the engine have 1000 rpm dead spot. :shit:

There are some mods to the CDI and exhaust valve controller to make it better but is never a smooth engine without some serious tweaking. Made a new pipe for it and the low end improved quite a lot, almost rideable on the roads...

If was today I would kept the bike and spend some time tune it. Could be made quite fast and rideable, even with the stock cylinder. :shifty:

[jonny quest]

Good info. So the bike I rode was performing as designed. I seriously can't believe people like these things. It was awful. I expected a tame smooth power out of a stocker with not much hit, and fairly mellow top end.

Even though I've never riden a early 60's 125 single full on race bike... I bet they performed exactly like this motor.

[breezy]

Anyone have any experience with the Aprilia RS125 Rotax 123 engine? I'm in the USA, where they're rare. I test rode one that's completely de restricted. Now, I haven't torn into it... just quick test ride to see if I would like it for a personal commuter bike.

It's dog ass slow on bottom end, is this common? Fairly zippy on top end for what it is. For me to be happy riding this, I'll need to drastically fix this.

So, are they really that bad power wise down low? Does anyone have any pipe specs, cylinder specs?

i repaired one for a friends son, who seized it, couple of years back. i rode it round for a while afterwards , i found it ok for a 125. i raced one last year pretty much standard, arrows exhaust, power valve held open, ecu de-restricted. once on the pipe i found it a joy to ride, as long as you screamed the nuts off it where ever possible.

[cotswold]

Good info. So the bike I rode was performing as designed. I seriously can't believe people like these things. It was awful. I expected a tame smooth power out of a stocker with not much hit, and fairly mellow top end.

Even though I've never riden a early 60's 125 single full on race bike... I bet they performed exactly like this motor.

I liked mine, pootled through traffic sweet as then if you wanted to go play it went real well, best handling small road bike I have ever had, bit of a sod to start if you left it for a week or so between uses though ( Gianelli pipe )

[2T Institute]

Anyone have any experience with the Aprilia RS125 Rotax 123 engine? I'm in the USA, where they're rare. I test rode one that's completely de restricted. Now, I haven't torn into it... just quick test ride to see if I would like it for a personal commuter bike.

It's dog ass slow on bottom end, is this common? Fairly zippy on top end for what it is. For me to be happy riding this, I'll need to drastically fix this.

So, are they really that bad power wise down low? Does anyone have any pipe specs, cylinder specs?

I have built many many 122/123 engines big bore, stroker, long rod, stroked and big bored. Best of all was the plain 125cc engine. If it has no bottom end it is only de restricted not tuned with a VHSB 34mm Dellorto(PJME speced carb are only good for UK conditions) the 28mm PHBE with a TPS can be tuned very well too. Big gains are with the ignition and the power valve is sensitive to opening point especialy on constant throttle. TYGA pipe works the best as does a Honda RS 125 pipe. VHM heads have a habit of cracking. Standard squish is 1.2mm and that has to be fixed. To make it go fast suspension is the key, it's way to heavy for a race bike but as a commuter/scratcher it's unreal especialy if you have a quickshift. Water temp runs way to high and easy fix is to swap to the Rotax MAX thermostat.

[F5 Dave]

I rode a mates recently and it was a hoot. Even managed up this crazy 1st gear uphill goat track ok. On the dyno it looked like the pic posted. Sweet.
Perhaps you have a Stuck pv?

[cotswold]

My Dutch friend has sent me his spare cylinder and a few bits and bobs to go with it, his good one makes 17bhp so I am keen on measuring things up against what I have. There are a couple of exhaust spacers which I have not looked at doing on my pipe so that is something else that could be of interest. Might be of some interest to you and Fast Fred, Tee Zee?
I put some pictures on the 50 thread

[TZ350]

There are a couple of exhaust spacers which I have not looked at doing on my pipe so that is something else that could be of interest. Might be of some interest to you and Fast Fred, Tee Zee?

Look forward to seeing it all, maybe run it up on the dyno when its all ready.

320748

Put the new Suzuki GP125 powered Bucket up on the dyno tonight. The dyno is great for cranking the bike over to check things out. But no joy, some sort of electrical issue. Kept blowing the 0.5A ECU fuse. After a bit of a look the finger of suspicion points to a bad injector coil, no biggy. The engine would fire up on "Start You Bastard" engine starter so the ignition is all Ok and the injector pulse width at cranking speed looked good, all in all things are encouraging. Maybe tomorrow night I will get the electrical fault sorted and an initial run.

[mr bucketracer]

will be intresting how the newer rs125 chamber go's

[F5 Dave]

. . .

. . The engine would fire up on "Start You Bastard" engine starter .
Otherwise known as `brake cleaner` in this parish. Started an 11yr layup gsxr in the weekend with a squirt or two of wynns.

[FastFred]

More satisfying to shout Start You Bastard Start You Bastard :angry2: than Break Cleaner Break Cleaner...........:laugh:

[breezy]

More satisfying to shout Start You Bastard Start You Bastard :angry2: than Break Cleaner Break Cleaner...........:laugh:

i prefer the" c "word... as its evolved into a term of endearment in the uk:shit:

[husaberg]

Look forward to seeing it all, maybe run it up on the dyno when its all ready.

320748

Put the new Suzuki GP125 powered Bucket up on the dyno tonight. The dyno is great for cranking the bike over to check things out. But no joy, some sort of electrical issue. Kept blowing the 0.5A ECU fuse. After a bit of a look the finger of suspicion points to a bad injector coil, no biggy. The engine would fire up on "Start You Bastard" engine starter so the ignition is all Ok and the injector pulse width at cranking speed looked good, all in all things are encouraging. Maybe tomorrow night I will get the electrical fault sorted and an initial run.

Rob give us a run down on the bike and chassis as it now is on Mr Bigglesworth.
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It appears to have a lot less steel than the old Yamaha based set up.
I note the number of Honda parts seems to be increasing.

[TZ350]

I note the number of Honda parts seems to be increasing.

:laugh: ...... Love that Mr.Bigglesworth.

Basically a Honda with an air cooled Suzuki GP125 engine in it.

MC18 frame. (yours from CHCH)
RS250 front forks.
RS125 rear shock.
2 of RS250 3.5x17 magnesium front wheel for the rear. Quick change slick and wet.
2 of Honda 2.5x17 front wheel. Unsure of the model. Quick change slick and wet.
RS125 style seat made in a heavier gauge of fiberglass to withstand push starts and crashing.
RS125 style tank (copy).
Honda RS 125 pipe.
Ecotrons EFI system.
Special 24mm ball valve type inlet system.
Dry sump gearbox.
Lots of extra copper fins for cooling.
Copper combustion chamber. 1.5mm of copper metal sprayed onto an original but modified Suzuki head.
Long RD400 Rod 115mm between centers.
RGV250 bigend bearing.
Clutch modified for an extra friction plate (originally six now seven friction plates)
Engine angled down so a cooling blast of air can be ducted to the center of the head.
Weight, as yet unknown.

Still struggling with a mystery electrical problem. The bike can sit there for as long as you like with the battery powered electrics switched on but shortly after I begin turning it over to start it, it blows a fuse. Isolated the issue to the ECU side, eliminated the injectors and injector wiring so what is left? maybe the unused O2 sensor heater wiring that was cut back. Everything was running fine when I took it out of the Beast for transplant into Mr.Bigglesworth????

Anyway with a bit of patience I will find it.

[husaberg]

:laugh: ...... Mr.Bigglesworth.

Basically a Honda with an air cooled Suzuki GP125 engine in it.

MC18 frame. (yours from CHCH)
RS250 front forks.
RS125 rear shock.
2 of RS250 3.5x17 magnesium front wheel for the rear. Quick change slick and wet.
2 of Honda 2.5x17 front wheel. Unsure of the model. Quick change slick and wet.
RS125 style seat made in a heavier gauge of fiberglass to withstand push starts and crashing.
RS125 style tank (copy).
Honda RS 125 pipe + 25mm in the header.
Ecotrons EFI system.
Dry sump gearbox.
Lots of extra copper fins for cooling.
Copper combustion chamber. 1.5mm of copper metal sprayed on an original Suzuki head.
Long RD400 Rod 115mm between centers.
RGV250 bigend bearing.
Clutch modified for an extra friction plate (originally six now seven friction plates)
Engine angled down so a cooling blast of air can be ducted to the center of the head.


If its the single disk front wheel in 2.5X17 its likely from a CBR250R MC19.
Doesn't it have a pretty flash rear disk set up as well as a 6 speed and a Fletner one off Spacer, plus a biggerererer disk valve as well.
320754

[TZ350]

Doesn't it have a pretty flash rear disk setup as well as a 6 speed and a Flettner one off Spacer, plus a bigger disk valve as well.

No this is the original air cooled motor resurrected to finish proving the EFI and dry sump ideas. The Flettner case and cylinder spacers are for the six speed 110cc water cooled version which may or may not have EFI depending on how things go when I finally get this sucker running.

[husaberg]

No this is the original air cooled motor resurrected to finish proving the EFI and dry sump ideas. The Flettner case and cylinder spacers are for the six speed 110cc water cooled version which may or may not have EFI depending on how things go when I finally get this sucker running.

I haven't noticed from any pics but are the bottom of the transfers in the crancase more gently curving with the wider bottom end of the LC6SP110 engine.

Also what's the new model weigh in at, compared to the former Yamaha chassis'ed Beast

[MotleyCrue]

Anybody know if the Ryger engine is something that is still promised to come about, or is it a dead deal, or still an unknown ?

[cotswold]

Thanks to TZ and Fast Fred for the help on the Dyno, we got the 50 running last night with the new insert head and it made more power but something odd happened to the rev range, previously it revved to around 14000, if we can get those back it should be pretty quick

[sonic_v]

Thanks to TZ and Fast Fred for the help on the Dyno, we got the 50 running last night with the new insert head and it made more power but something odd happened to the rev range, previously it revved to around 14000, if we can get those back it should be pretty quick

That's a BMEP of 13.8 bar at rear wheel or pushing 15 bar at crank, at 9400 revs/min. That's some going for such low revs.

[mr bucketracer]

Thanks to TZ and Fast Fred for the help on the Dyno, we got the 50 running last night with the new insert head and it made more power but something odd happened to the rev range, previously it revved to around 14000, if we can get those back it should be pretty quickholy cow , must be some high com?

[Flettner]

Anybody know if the Ryger engine is something that is still promised to come about, or is it a dead deal, or still an unknown ?

Still unknown, but I think from what I've scavenged, the engine is capable of a high HP/RPM but is unreliable. I heard 100% failures but thats just hearsay. I think perhaps Luc spoke up too soon. Now I understand Ryger/Luc are away somewhere quiet, refineing ,trying to get it reliable, perhaps what should have been done in the first place.
Or, the above statment is just Bullshit;), who am I to say.

[TZ350]

What's the new model weigh in at, compared to the former Yamaha chassis'ed Beast

Not had it on the scales yet but would be bitterly disappointing if its not a lot less than the old Beast which was in the high 90's from memory.


I haven't noticed from any pics but are the bottom of the transfers in the crancase more gently curving with the wider bottom end of the LC6SP110 engine.

320773

A is the normal layout but the NSR cylinder transfers are narrower than the GP cases. So I was thinking something like B that way I get to keep all the extra crankcase volume. No idea if its a good plan or not.

[cotswold]

[QUOTE=TZ350;1130960230]Not had it on the scales yet but would be bitterly disappointing if its not a lot less than the old Beast which was in the high 90's from memory.



Koff koff 105kg on the scales at Taumaranui koff :eek:

[richban]

So I have had this software for a week now.

Read all the help info and used the sample files. Yeah well thats all good.

Plugged in the info for the 300. People rave about this software and what it can do, but they don't mention the down sides.

I don't sleep anymore. I just want to do one more run, one more pipe change! What if I richen it up at 12K? Holly shit people! Crack is less addictive. I have a problem!

[Grumph]

So I have had this software for a week now.

Read all the help info and used the sample files. Yeah well thats all good.

Plugged in the info for the 300. People rave about this software and what it can do, but they don't mention the down sides.

I don't sleep anymore. I just want to do one more run, one more pipe change! What if I richen it up at 12K? Holly shit people! Crack is less addictive. I have a problem!

Your brother was the same...I'd go in there and it didn't look like he'd got any sleep running sims....there's an addictive gene in there somewhere IMO.

[41juergen]

But the good thing is: you pay once and can get the kick as much you want for free, no need to ask the dealer every time.... :rolleyes:

[TZ350]

320776

Sorted the mystery electrical problem and gave Mr.Bigglesworth a trot on the dyno.

320775

Initially it would only run up to about 8.500 rpm. It was a bit of a puzzle for a while, spent a bit of time messing with the best of the old maps and advanced EFI settings until I realised it was an ignition soft limiter starting at 8K and hard limit at 8.5k (Blue line).

Once it was sorted it would run on to near 13K (Red line). The best I have had from this cylinder is 28 rwhp with a carb and 29 fuel injected. The gearbox diaphragm oil pump worked a treat. It will be interesting to see where we get to with the gearbox dry sump arrangement and if more power gets to the back wheel now that there is not a lot of oil to churn around.

Hopefully get to try the new map sometime next week.

[richban]

Your brother was the same...I'd go in there and it didn't look like he'd got any sleep running sims....there's an addictive gene in there somewhere IMO.

Funny. Yeah I know. He has been addicted much longer than I. It's great software. Now time to build what its telling me.

[breezy]

Still unknown, but I think from what I've scavenged, the engine is capable of a high HP/RPM but is unreliable. I heard 100% failures but thats just hearsay. I think perhaps Luc spoke up too soon. Now I understand Ryger/Luc are away somewhere quiet, refineing ,trying to get it reliable, perhaps what should have been done in the first place.
Or, the above statment is just Bullshit;), who am I to say.

nice bit of fishing;) but no bites yet:lol:

[twotempi]

[QUOTE=TZ350;1130960230]Not had it on the scales yet but would be bitterly disappointing if its not a lot less than the old Beast which was in the high 90's from memory.



Koff koff 105kg on the scales at Taumaranui koff :eek:

Isn't 105 kg just another way of saying "very high nineties" !!

[lodgernz]

Not had it on the scales yet but would be bitterly disappointing if its not a lot less than the old Beast which was in the high 90's from memory.


I'm pretty sure you know this, but you don't have to go to the track to weigh your bike. Do it at home using bathroom scales. Put scales under front wheel and record weight, then switch to back and repeat. Add together. Gives you the balance bias too. To be be totally accurate, the wheel not being weighed should be sitting on a bit of wood the same height as the scales to eliminate any horizontal vector.

[Flettner]

nice bit of fishing;) but no bites yet:lol:

Perhaps I'm using the wrong bait? I should put some REAL bait on the hook:devil2:

[TZ350]

Not had it on the scales yet but would be bitterly disappointing if its not a lot less than the old Beast which was in the high 90's from memory. Koff koff 105kg on the scales at Taumaranui koff :eek:

Hmmm I knew the Beast was weighty, just could not remember how much. Sort of good news because the new bike has surely got to be lighter than that. Monday I might get to try Lodgernz's idea with the bathroom scales.

[Haufen]

Anybody know if the Ryger engine is something that is still promised to come about, or is it a dead deal, or still an unknown ?

I guess that depends on who you ask. From the ryger side one keeps hearing "just a couple more weeks, be patient etc." every couple of weeks. The latest status including Jan's interpretation of the situation is on Pit-Lane (http://www.pit-lane.biz/t6315p300-2stroke-ryger-engine), afaik.

Regarding the emissions claim, it turned out that the emission values of the ryger can easily be halved by BRPs E-Tec engines, which are into mass production for quite a while now. And this is without having to run as lean as on that ryger emission printout.

[sonic_v]

There is an interesting cik regulation that might just have caught Ryger team out.

Article 12
Specific Regulations for KZ2 & KZ1
* Power unit: it must not be possible to dissociate the
engine from the gearbox. Engine case must be made of only 2 parts
(vertical or horizontal). Only inserts for crankshaft bearings and
fixing elements (drilled holes, dowels) are authorised.

With 50 engines, that's a lot of aluminium welding to rectify that little oversight.

Some how the Brains trust have manufactured an engine with 3 parts.

[JanBros]

There is an interesting cik regulation that might just have caught Ryger team out.

Article 12
Specific Regulations for KZ2 & KZ1
* Power unit: it must not be possible to dissociate the
engine from the gearbox. Engine case must be made of only 2 parts
(vertical or horizontal). Only inserts for crankshaft bearings and
fixing elements (drilled holes, dowels) are authorised.


I do not see the problem, as the engine csases are simply taken from another homologated engine and the Ryger itself has been homologated to.
or am I missing something ?

[sonic_v]

I do not see the problem, as the engine csases are simply taken from another homologated engine and the Ryger itself has been homologated to.
or am I missing something ?

True. But the crankcase is no longer used for the inlet induction so a plate has been bolted in place of the reed block/inlet rubber meaning that the crankcase has 3 parts.

[Flettner]

I do not see the problem, as the engine csases are simply taken from another homologated engine and the Ryger itself has been homologated to.
or am I missing something ?

I guess what Sonic is saying is that a normal KZ ( or whatever they are called ) is not allowed to have a spacer fitted under the cylinder. This is what the Ryger effectively has. Something smelly going down at CIK I think!!

[sonic_v]

I guess what Sonic is saying is that a normal KZ ( or whatever they are called ) is not allowed to have a spacer fitted under the cylinder. This is what the Ryger effectively has. Something smelly going down at CIK I think!!

The funny think is that it is the alloy plate blanking of the now redundant crankcase inlet that appears to be causing the problem.

However it certainly could be argued that the spacer plate is an additional component of the crankcase.

[tjbw]

The funny think is that it is the alloy plate blanking of the now redundant crankcase inlet that appears to be causing the problem.

However it certainly could be argued that the spacer plate is an additional component of the crankcase.

It's homologated with the blanking plate and the spacer, so no problem.

Except that they might want to make changes to improve reliability.

[Grumph]

It's homologated with the blanking plate and the spacer, so no problem.

Except that they might want to make changes to improve reliability.

Mr Thiel makes some good points about the piston metallurgy and the rod geometry on the pit lane thread previously linked...

You can imagine it at Ryger central - another day, another combination of bearing materials to test....

[dark art]

This is mainly for cafe racer use but can easly adapted for racing.
How to PROPERLY hone cylinder bore and correct the piston clearance: :yes:

https://www.youtube.com/watch?v=bT1nRq-cM7M

The carb floats video is probably as useful as this one. :laugh:

[Flettner]

Mr Thiel makes some good points about the piston metallurgy and the rod geometry on the pit lane thread previously linked...

You can imagine it at Ryger central - another day, another combination of bearing materials to test....

I don't know why Ryger just don't give up and do it the way WE told them to:laugh:

[Frits Overmars]

I don't know why Ryger just don't give up and do it the way WE told them to:laugh:
Ken, the sliding cylinder, it might be a good candidate for HCCI as well. In stead of a separate head with oring and piston ring that the cylinder slides up and down in, the head could be a short stroke piston working in the same extended cylinder with it's crank case attached to the water jacket. Rubber diaphram to seal cylinder to top of the water jacket. The tooth belt drive would then become the crank joiners and the drive out to the dry clutch as well, saving one gear. The wheels are turning.You're determined to make it look like a foul-stroke, aren't you Neil?:D
I imagine you won't be using a three-part water jacket any more then. I've never really understood why you chose that 3-part jacket for the present sliding cylinder.
I like the thought of using one tooth belt for the lot; it sort of brings KISS back into the idea.

[husaberg]

You're determined to make it look like a foul-stroke, aren't you Neil?:D
I imagine you won't be using a three-part water jacket any more then. I've never really understood why you chose that 3-part jacket for the present sliding cylinder.
I like the thought of using one tooth belt for the lot; it sort of brings KISS back into the idea.

Using the belt to drive the clutch and primary also saves a lot of friction in the general lack of seals needed to make the clutch dry. As well as it supposedly being a few % more efficient than gears.

The only issue is an engine would still need some gears mounted to run a contra rotating balance shaft.
Unless its mounted inboard of the primary or uses special PTFE gears.
The open belts also make a cool noise like Mad Max's Gilmer drive super charger and the dry clutch's make a nice racket as well, shame the noise meter will not like either.
his silly go on off super charger button is actually a hi low selector of a Road ranger truck, chuck on one of those too Neil.
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[Flettner]

You're determined to make it look like a foul-stroke, aren't you Neil?:D
I imagine you won't be using a three-part water jacket any more then. I've never really understood why you chose that 3-part jacket for the present sliding cylinder.
I like the thought of using one tooth belt for the lot; it sort of brings KISS back into the idea.

Tell you what Frits, I'll hide the belt inside some carbon fiber:bleh:
Opps, that might look more like a fourstroke:confused:
I'm sure there is a simpler way to get rapid pressure change after TDC, but I haven't opened that Ryger box yet.

[Frits Overmars]

Using the belt to drive the clutch and primary also saves a lot of friction in the general lack of seals needed to make the clutch dry. As well as it supposedly being a few % more efficient than gears. The only issue is an engine would still need some gears mounted to run a contra rotating balance shaft.I think there are belts with teeth at both sides; they could drive the balance shaft.


I'm sure there is a simpler way to get rapid pressure change after TDC, but I haven't opened that Ryger box yet.If there is a simpler way, you won't find it in that box of Pandora.

[husaberg]

I think there are belts with teeth at both sides; they could drive the balance shaft.



I never knew that.
The other possible advantage is you can then put both crank seals inboard and then run a positive supply of oil to the main bearings. Rather than the hit and miss supply drip of petrol oil.
The Honda MB50/MB100 main that is feed immersed from the gearbox never fails, but the other side fed by only petrol oil often does.

[Frits Overmars]

http://www.gates.com/products/industrial/industrial-belts/synchronous-belts/powergrip-htd-twin-power-belts

[sonic_v]

It's homologated with the blanking plate and the spacer, so no problem.



Really! If the CIK were to accidentally homologate an engine that in actual fact does not meet their regulations then I would think that the legal eagles at the competitor companies might just do something about it.

Some years ago when the CIK 100cc direct drive kart class was dying a death due to competition from non CIK one make kart engine series that used clutches and electric starters, the CIK decided they would go "green" and change over to four-stroke engines. The Italian kart industry with one voice told the CIK that they will be staying with two-strokes, that four-strokes were too expensive to manufacture.

The Italian kart industry comfortably represents over 90% of all CIK engines produced. Ryger is not Italian and neither is VM - the manufacturer of the Ryger engine.

[Niels Abildgaard]

I'm sure there is a simpler way to get rapid pressure change after TDC, but I haven't opened that Ryger box yet.
Hello Fletner


Will it be possible to adjust the compression ratio with the small upper piston?
I mean get that toothed belt away and and put a handle on the upper crank
The compression needs only to be adjusted as fast as load,fuel supply and temperature varies and this does not sound difficult with modern electronics and a servodrive and a couple of traingauges on cylinderbolts that tell when combustion is to early or correct at TDC.

[ken seeber]

I think there are belts with teeth at both sides; they could drive the balance shaft.

I have thought about the Freetech 50 cc bikes and saw a few pics of these with CVT running directly on the crank, 15/16,000 rpm. I would think this would create a lot of friction compared to a CVT running much slower, eg 1/2 engine speed. So, combining this with a balance shaft running off the back of chain or double sided timing belt, one could create a layout something like this:

320803

Another benefit would be to be able to run a much smaller rear wheel sprocket.

[lohring]

Hello Fletner


Will it be possible to adjust the compression ratio with the small upper piston?
I mean get that toothed belt away and and put a handle on the upper crank
The compression needs only to be adjusted as fast as load,fuel supply and temperature varies and this does not sound difficult with modern electronics and a servodrive and a couple of traingauges on cylinderbolts that tell when combustion is to early or correct at TDC.

That's called a "diesel" engine by model engine builders. They run on a mix of kerosene, ether and oil. They've been around for years and are still used in a variety of applications. See http://www.davisdieseldevelopment.com/index.htm

Lohring Miller

[Niels Abildgaard]

That's called a "diesel" engine by model engine builders. They run on a mix of kerosene, ether and oil. They've been around for years and are still used in a variety of applications. See http://www.davisdieseldevelopment.com/index.htm

Lohring Miller

Thank You

I am fully aware of that ,but they were never regulated during running to keep combustion/explosion /Knock or wharever exactly at TDC.
The engine Neil has made will be very suitable to test that .The idea of combining a normal piston movement plus one that runs double so fast corresponds to a movement with a single piston on a shorter connecting rod.The worlds most efficient engines (danish two strokes from Man B&W)
have connecting rod to crankthrow under 3 that is a 125 connecting rod of less than 81 mm between eyes.

[Frits Overmars]

Will it be possible to adjust the compression ratio with the small upper piston?I mean get that toothed belt away and and put a handle on the upper crank. The compression needs only to be adjusted as fast as load, fuel supply and temperature varies and this does not sound difficult with modern electronics and a servodrive and a couple of traingauges on cylinderbolts that tell when combustion is to early or correct at TDC.In theory it can be done Niels, but in practice we need a pressure rise that is much steeper than can be achieved with just one piston; with the latter you won't have sufficient control over the ignition timing, notwithstanding all these modern electronics.


The idea of combining a normal piston movement plus one that runs double so fast corresponds to a movement with a single piston on a shorter connecting rod.Again, in theory you are correct, provided we confine ourselves to what happens in the vicinity of TDC (around BDC it's a completely different kettle of fish).
But did you calculate how short that con rod ought to be in order to achieve the same effect that Flettner achieves with his double-speed compression crank?
It would be completely impractical, not even counting the effect of such a short rod on piston friction.


The worlds most efficient engines (danish two strokes from Man B&W) have connecting rod to crankthrow under 3 that is a 125 connecting rod of less than 81 mm between eyes.I did not know Wärtsilä was Danish :p. And they have not only short con rods, they also have pressure-lubricated cross-heads. And finally they are diesels; their ignition timing is governed by the fuel injection pump, not by compression pressure.


I have thought about the Freetech 50 cc bikes and saw a few pics of these with CVT running directly on the crank, 15/16,000 rpm. I would think this would create a lot of friction compared to a CVT running much slower, eg 1/2 engine speed. So, combining this with a balance shaft running off the back of chain or double sided timing belt, one could create a layout something like this:
320803
Another benefit would be to be able to run a much smaller rear wheel sprocket.Ken, if you run the CVT at half the speed, it has to cope with double the torque, so you'll have to double the clamping force of the pulley sheaves or the belt will slip. That won't do much good for friction reduction. Moreover, if you lay out the system for more torque, everything becomes heavier.
Most CVTs have a gear reduction somewhere between the secondary pulley and the rear wheel, so the sprocket size isn't that important.
Here is some more reading on the subject.
EDIT: darn, can't attach the 6,69 MB file.

[Flettner]

Twice engine speed balance shaft? Can the crank in the head be used as a balance shaft as well? Have to have a think about that.

[Frits Overmars]

Twice engine speed balance shaft? Can the crank in the head be used as a balance shaft as well? Have to have a think about that.Yes it can, but then you will need two of them. L4 car engines sometimes employ them.

[tjbw]

Really! If the CIK were to accidentally homologate an engine that in actual fact does not meet their regulations then I would think that the legal eagles at the competitor companies might just do something about it.

...

If CIK decided that they'd make that mistake, then Ryger could replace the blanking plate with something that looks like a carb.

The spacer plate replaces the lower end of the cylinder, and is not part of the crankcase.

[jonny quest]

Has anyone tried putting seals on inside of main bearings, and let gearbox oil lubricate mains? And just let oil splash on flywheel like a four stroke?

[FastFred]

Has anyone tried putting seals on inside of main bearings, and let gearbox oil lubricate mains? And just let oil splash on flywheel like a four stroke?

The Suzuki RG50 and TF/TS range of Suzuki's (and probably others) drive side main bearing have the oil seal on the crankcase side with the gearbox oil lubricating the main brg.

[Niels Abildgaard]

I did not know Wärtsilä was Danish


Wartsila is Finnish and has sold the Swiss Sulzer two stroke division to China.
Are these engines more efficient than the MAN B&W examples developed in Copenhagen?

[dark art]

Has anyone tried putting seals on inside of main bearings, and let gearbox oil lubricate mains? And just let oil splash on flywheel like a four stroke?

Gas Gas trials engines are like that. a real PITA to change a crank seal :whistle:

[jonny quest]

I'm wondering if there's a performance advantage of having bearings and seals "reversed". Better lubrication being the advantage

[husaberg]

Yes it can, but then you will need two of them. L4 car engines sometimes employ them.

Honda 250T and N and 400T&N had two.

320812320819320818

Yamaha TX500 had a Omi phase something
Well I am not totally so sure looking at it (that it is two shafts) but its pretty unique.
320813

[Flettner]

Hello Fletner


Will it be possible to adjust the compression ratio with the small upper piston?
I mean get that toothed belt away and and put a handle on the upper crank
The compression needs only to be adjusted as fast as load,fuel supply and temperature varies and this does not sound difficult with modern electronics and a servodrive and a couple of traingauges on cylinderbolts that tell when combustion is to early or correct at TDC.

Good plan. But I want to "ignite" after TDC and this is what my design allows for, if a little complicated.

Well, I could fire it up tonight if it wasn't for my clumsy fingers breaking the piston ring:(

Apprently there are three sets of rings (at .5 oversize) in Australia, I got my eye on one of those sets. Or I just bore it out to 40mm and there are plenty of pistons:rolleyes:

There must be the second set somewhere in my workshop!?

[TZ350]

Page 1510 .... already


first race meet at Kaitoke on the 2 smoker:- https://youtu.be/WVmNVIHHU5E

That is real Bucket racing.


https://www.youtube.com/watch?v=nZ5CzJco5Mw

Lambda O2 sensor can be useful for tuning a two stroke in spite of the short circuited O2 showing up in the readings.


The Ecotrons EFI has barometric and air temperature sensors for automatic fueling compensation so hopefully once I am on the money with the dyno the ECU's auto compensation will give pretty much the same results as changing the jets 3 times a day.

I feel very comfortable with tuning the EFI system for maximum power, above 50% throttle position that is relatively easy.

The problem I am struggling with is at the low end, if this was a carb then the EFI bit that is challenging me now is the area covered by a carb's pilot jet and transition to the slide cutaway.


May I ask why you're not using a wideband O2 to tune this area? It would be relatively straightforward with a wideband and a brake dyno.

I started out trying to get a 12.5:1 A/F everywhere on the map, as you do if you don't know any better. Things weren't going well and I gave it away when it was pointed out to me that it was the short circuiting fooling the O2 sensor into thinking the system was running lean when it was not.

It really confused things and it looked like the O2 sensor was not going to be very useful so I discarded it. But your experience encourages me. And it looks like that with a bit more experience myself. I might be able to get somewhere with it now I have a better idea of what is going on and can see that 12.5 in the peak torque area is good and something like 14 in other areas might be a good number.


Why a brake dyno? Then you would be developing an engine for a set of circumstances that it will never see on a race track. Going through the revs on an inertia dyno and registering revs, torque and lambda simultaneously is an excellent way of establishing an injection map. Besides, running constant revs on a brake dyno with too little fuel or too much ignition advance may kill your engine, whereas it might survive on an inertia dyno.


When i say brake dyno i mean an eddy current or similar that allows both constant rpm tests and normal 'runs'... Im sure that doing only constant rpm tests is not ideal.

Personally I do a combination of both to tune an engine and so far it has worked well for me, especially when tuning the low throttle area that TZ was talking about... in saying that ive only ever had an eddy current dyno, never an inertia-only dyno. And have developed my own methods of tuning without ever seeing first-hand anyone else's process for tuning a two stroke... maybe its a case of ignorance is bliss, however I find my process to be very quick and very reliable for a wide range of engines.

I find that the lambda sensor is a little slow to react at low revs and part throttle. Its fine at higher revs and higher throttle. By holding the engine at a certain rpm point for 3-5sec at each throttle position it gives the readings time to stabilise and gives much better, more repeatable data.

I start by doing a range of fixed rpm tests at different throttle openings, with the revs building higher each test... eg 4000, 6000, 8000, etc at 1/8, 1/4, 1/2, 3/4, full throttle. By doing this you can easily see the areas that need changing (pilot, slide, needle diameter, clip position, needle taper, main jet, etc).

If there is a serious problem with the tune you will always catch it before doing damage as you’ll see AFR's begin to lean out or detonation begin to show before you get too high in rpm. Once I’ve done basic tuning like this then i do full runs and constant load testing and fine tune if necessary, but these are normally only very minor changes.

Whether the AFR reading is showing true AFR or not doesn’t really matter, the numbers can still be used to tune an engine... around full throttle and peak torque it is fairly reliable to use ~12.5:1 and leaner readings below that, down to around 13.5-14:1 at part throttle/low rpm.

Of course you still need to use experience and 'feel' to do the fine tuning but the AFR numbers will get you close. Even if the engine is not actually seeing 14:1 at part throttle/low revs, its still a repeatable data point that can be used to tune an engine. Its certainly a lot better than guessing, especially when tuning the part throttle areas.


+1 the above.Adding that putting the Lambda in the stinger, seems to be way more stable and repeatable when logging the A/F data.

Using data this way is something that you really don’t appreciate how good it is until actually doing it.
Hence TeeZees surprise when I related that every time you change a small item in the engines tune - the dyno result for sure is not telling you really what you want to know, unless you reject every time to hit a predetermined baseline.

As Jan Thiel said, most all of the pipe testing at Aprilia was a complete waste of time, when he finally realised allot of the power differences were down to how the egt reacted to that pipe.

Not that the pipe was "better " for some aspect of scavenging, or trapping efficiency in making more or less power.


STA or Specific Time Area, (Port Time Area) is at the heart of 2-Stroke port timing design.

For what its worth and as I understand it. How to determine the STA numbers you have.

Mean open Port Area is the effective port aperture seen when the piston is positioned half way in terms of crank angle between the port starting to open and fully open.

For an Exhaust port that starts to open at 80 deg ATDC and is fully open at 180 deg ATDC. Then the mean port area will be the area of the port uncovered by the piston with the crank angle set half way between 80 and 180 ie, at 130 deg ATDC.

The rough rule of thumb is that this exposes about 70% of the port window, rod length and the bore/stroke ratio influence the actual amount.

The units for STA numbers are Time Area per Unit Displacement or “sec-cm2/cm3”

Derived by dividing the Mean-Port-Area in “cm2” by the cylinder volume in “cm3” and then multiplying it all by the time in seconds “sec” that the port is open (time of total duration).

The number of revolutions in one second = RPM/60

The total number of degrees the crank has turned in one second = (RPM/60)*360 or RPM*6

Finding the Time in seconds of the Total Port Duration. = Total Port Duration / (RPM*6)

Your STA = (Mean Port Area / Cylinder Volume) * Time of Total Port Duration

After measuring Yamaha’s TR3 GP racer and as many other good racing engines as he could using only graph paper, compass and a ruler. And doing the “(Mean Port Area / Cylinder Volume) * Time of Total Port Duration” math, Jennings came up with these numbers and called them Port-Time-Area.

Exhaust 0.00014 to 0.00015 sec-cm2/cm3
Transfer 0.00008 to 0.00010 sec-cm2/cm3
Piston Port Inlet 0.00014 to 0.00016 sec-cm2/cm3
Rotary Valve Inlet 0.00018 to 0.00019 sec-cm2/cm3

In his ground breaking reveal all book that showed the budding tuner how to modify their own cylinders to get GP like porting.

243287

Jennings didn’t give a number for Blow Down. And for that reason, I think the importance of the “Blow-Down-Time-Area” and its affect on power output was largely over looked by the old style home tuners.

Bells book with its useful list of port timings for various engine capacities and RPM was also a blessing and a curse as it also didn’t emphasis the importance of blow down. It was great to see what the ballpark timings were, but too many tuners just used the numbers blindly.

With the result cylinders were packed up with spacer plates to get the transfer timing numbers right and the inlet and
exhaust was then ported to match their own set of essential numbers found in Bells book without much regard for blow down area.

Whether you used Jennings Port-Time-Areas or Bells numbers for the inlet, transfer and exhaust the end result was that the essential Blow Down Time Area was often overlooked and a lot of the old engines were less successful than they could have been.

243284 Port timing by itself does not mean much, its the STA numbers that are important.

243285 243286 Early Honda RS125

Low and wide for the transfers is the trick to getting good Blow-Down STA numbers.

Gordon Blair after studying many 2-stroke engines and their behaviour developed a number of formulae that covered the various ports. The beauty of these formulas is that they allowed the designer to start from a target RPM and BMEP or Power-Output and use a computer to crunch the numbers.

Blair called the results of a port time area calculated by his formula based on a specific rpm and target power output, a STA or Specific Time Area for that design criteria.

Blairs STA numbers for a GP racer turning 11,500rpm and producing 26.5kW at 11 Bar

Exhaust 0.000162 sec-cm2/cm3
Blowdown 0.00113 sec-cm2/cm3
Transfer 0.0086 to 0.0185 sec-cm2/cm3
Piston Port Inlet 0.0162 sec-cm2/cm3

Blairs calculated STA results and Jennings Port-Time-Areas are both physically measured in the same way. = (Mean Port Area / Cylinder Volume) * Time of Total Port Duration. The difference is that Jennings very cleverly figured out what the Factory was up to and Blair developed a method of predicting what is required.


Even the basic CAD type programs that use STA as a basis for getting the ports in the right place for the rpm,power needed and swept vol are hugely better than the old references.

A handy (and cheep $16 USD) Porting Calculator from:- http://www.porting-programs.com/ it is based on Blairs and Jennings work. Use the Blair data for STA and blowdown required for a selected power output.

Kel gave me this link to Blairs very interesting book. www.prme.nl/download/engine-1.pdf (http://www.prme.nl/download/engine-1.pdf)

The decade pages from p80 have link collections, links to Jenning and Bells books can be found there somewhere.

[Grumph]

I'm wondering if there's a performance advantage of having bearings and seals "reversed". Better lubrication being the advantage

Doubt it...the optimum for rolling element bearings is an oil mist. I'd pick that the opposite is a bearing full of oil, churning....

[Grumph]

Yamaha TX500 had a Omi phase something
Well I am not totally so sure looking at it that it is two shafts but its pretty unique.
320813

And right there is the problem...both the 500 and the TX750 broke in service. Is it surprising ?

Actually, what usually put the 500 off the road permanently was the heads cracking...

[husaberg]

And right there is the problem...both the 500 and the TX750 broke in service. Is it surprising ?

Actually, what usually put the 500 off the road permanently was the heads cracking...
Not looking at the pic of the drive, no.
320821
I finally found a pic TX750
320820
I must admit I have never seen one.
I have had the misfortune of riding a CB250N though, which would have to rate as the most gutless fugly overweigh POS ever.
The 400 was okay though for what it was. But the far older K4 Hondas would piss all over them both,likey the CB72/77 would have as well.

[F5 Dave]

Using the belt to drive the clutch and primary also saves a lot of friction in the general lack of seals needed to make the clutch dry. As well as it supposedly being a few % more efficient than gears.

The only issue is an engine would still need some gears mounted to run a contra rotating balance shaft.
Unless its mounted inboard of the primary or uses special PTFE gears.
The open belts also make a cool noise like Mad Max's Gilmer drive super charger and the dry clutch's make a nice racket as well, shame the noise meter will not like either.
his silly go on off super charger button is actually a hi low selector of a Road ranger truck, chuck on one of those too Neil.
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<iframe width="420" height="315" src="https://www.youtube.com/embed/HrgpJcZMzzI" frameborder="0" allowfullscreen=""></iframe>
As unlikely as it is for me to fantisise about foulstrokes, i went on a trip in the van this weelend with a couple of dirtbikes and gear, gas etc. Regularly on these trips the madmax pursuit car comes into my mind as i approach a hill, back off to get a run up, try to time it so i can pass the fecker just as the passing lane comes available with enough momentum that i can stay ahead.
If only i could double- de-clutch and switch that supercharger on.
Sometimes for the benifit of a passenger i press the hazard light button and fein being pressed back in the seat by the force of the nitrous. . . also the same movie. Oh the fun we have on long journeys in underpowered vehicles.

[husaberg]

As unlikely as it is for me to fantisise about foulstrokes, i went on a trip in the van this weelend with a couple of dirtbikes and gear, gas etc. Regularly on these trips the madmax pursuit car comes into my mind as i approach a hill, back off to get a run up, try to time it so i can pass the fecker just as the passing lane comes available with enough momentum that i can stay ahead.
If only i could double- de-clutch and switch that supercharger on.
Sometimes for the benifit of a passenger i press the hazard light button and fein being pressed back in the seat by the force of the nitrous. . . also the same movie. Oh the fun we have on long journeys in underpowered vehicles.

Only thing I wonder about is how the well did the MAD MAX pursuit special engine actually run, when trying to breath through a non running supercharger and running with a low comp ratio.
But seriously though, what the van needs Dave, is nitros oxide or if its a turbo Diesel, LPG injection. Or both.
http://www.nitrous.info/
His old site was better. He was the fat guy who had the Dyno burger Van PB used to use in the 1990's.
I used to have a 280HP Hilux SR5 now that was fun passing stuff. Had a gay auto though

[Muciek]

No thinning, no lathes. We will have Laser cut new ones. They are the same as Honda RS250, 2mm steels. Ali is an option as well.

Do you remember what kind of steel You used for those friction plates? And how they worked in bike?

[richban]

Do you remember what kind of steel You used for those friction plates? And how they worked in bike?

Steel was just cold roll standard stuff. They ave been working great in all 3 bikes. They have had plenty of hard race starts and still looking good. Still working great. I had to go back to the normal springs to get some better clutch feel.

[TZ350]

320844

Well.

The good news is that after months of work I have finally given Mr.Bigglesworth a thrashing on the dyno.

The bad news is that there is still a reluctance to come back on the throttle.

320845

Fortunately the Ecotrons EFI software has a data capture function. Max power was at 12250 rpm and max over rev rpm was 12888.

320846

Looking at the left hand courser the yellow line is Inj0 (the small injector) and the blue line Inj1 (the big injector) and the brown line is maximum injection time available. It can be seen that both injectors are topped out at 10,325 rpm. This suggests that Inj1 (the big injector) is to small.

320847

With high rpm and the TPS at 0% Inj0's pulse width is 1.140ms (right hand courser) which is less than the allowable minimum opening time of 1.8ms so on over run Inj0 is still to big.

So the big injector is a touch to small and the small injector is still to big for good tun-ability when throttling off and opening the throttle again like you would negotiating a corner at speed.

Ok, so off to Ecotrons to buy some more injectors.

[wobbly]

But I still dont get how you can deduce what the injector performance is, if you have no idea what the A/F ratio is or what the egt value is.
Sure the small injector may be maxed out, but that simply may be because the fuel volume it was being asked to supply was far too much - who knows.
Same for the big injector - was the pulse width it was programmed into delivering over the recommended max, but was that just because the resultant mixture was way rich.
Data info ,gives you a knowledge base to make informed decisions in the right direction, for the right reasons.

[F5 Dave]

And in absence presumably one leans off the mixture and see if the power rises or falls.

[TZ350]

But I still dont get how you can deduce what the injector performance is, if you have no idea what the A/F ratio is or what the egt value is.

Plenty of people have managed to select the right sized main jet without being able to measure the A/F ratio or the EGT. But I agree, the more info the better.

The small injector is expected to max out and that means max out time wise. Time and injector size determines the tuning range and the outer limits both minimum and maximum amount of fuel that can be delivered.

When the small injector max's out then the system swaps to the big injector and as that max's out the small injector is brought in again to help out. But if they both max out together time wise without over fueling the engine then combined they are not big enough.


Sure the small injector may be maxed out, but that simply may be because the fuel volume it was being asked to supply was far too much - who knows.

In this case the small injector is not small enough to deliver the minimum fuel required, even at the minimum possible injector on time allowed for an injector it is delivering to much fuel.


Same for the big injector - was the pulse width it was programmed into delivering over the recommended max, but was that just because the resultant mixture was way rich.

Did try bigger and lessor numbers like you would and the graph was the best achievable and is similar to the best dyno results for this motor achieved with a carb.


And in absence presumably one leans off the mixture and see if the power rises or falls.

Did try richer settings for the small injector and the symptoms were worse. Suggesting its to rich.

Looking at the graph, the small injector has simply hit the floor and can not be turned down any further to match the engines minimal fueling needs on over run. Its tuning range can not go low enough so a smaller injector is required.

[TZ350]

320857

A fuel injector has a tuning range just like this jet kit has. And just like when you get down to the smallest jet in the kit and still need to go leaner you need a smaller jet kit or injector to move to the next lower tuning range.

That is my problem with the current small injector, it is just not small enough to give me the tuning range required to handle the minimum fueling requirements on high rpm over run on a closed throttle. I need the next smaller injector (kit).

[breezy]

320857

A fuel injector has a tuning range just like this jet kit has. And just like when you get down to the smallest jet in the kit and still need to go leaner you need a smaller jet kit or injector to move to the next lower tuning range.

That is my problem with the current small injector, it is just not small enough to give me the tuning range required to handle the minimum fueling requirements on high rpm over run on a closed throttle. I need the next smaller injector.

maybe you'll need to have three injectors.. one for low rpm ... one for mid rpm.. one for balls out rpm..

[wobbly]

Yes i agree that the injectors do give you a good indication of whats going on via the duty cycle.
But the " plenty " of people that select the main jet without any data get easily beaten by people that change jets 3 times a day based on RAD,and the
dyno best power data..
We won the Kart Nationals at Easter, as our main competition, a European factory driver with the best engines money can buy,selected his main size
by guessing.He poled it,but detoed an engine to death the next cool morning,he had to change engines then ran well rich in the final just to ensure he finished.
We changed jets every race,based on the weather station,and the piston looked brand new after 60 laps of racing.

[TZ350]

But the " plenty " of people that select the main jet without any data get easily beaten by people that change jets 3 times a day based on RAD,and the dyno best power data.

I expect that is very true.

The Ecotrons EFI has barometric and air temperature sensors for automatic fueling compensation so hopefully once I am on the money with the dyno the ECU's auto compensation will give pretty much the same results as changing the jets 3 times a day.

I feel very comfortable with tuning the EFI system for maximum power, above 50% throttle position that is relatively easy.

The problem I am struggling with is at the low end, if this was a carb then the EFI bit that is challenging me now is the area covered by a carb's pilot jet and transition to the slide cutaway.

[F5 Dave]

I feel a hybrid coming on.

[TZ350]

I feel a hybrid coming on.

Yes possible, if the "24 carburetor or equivalent" actually has to flow fuel too then a hybrid could make sense.

[dark art]

The problem I am struggling with is at the low end, if this was a carb then the EFI bit that is challenging me now is the area covered by a carb's pilot jet and transition to the slide cutaway.

is there any chance to vary the fuel pump pressure with RPM and/or TPS? It may be slow to respond but enable a lot more tuning options.

[TZ350]

is there any chance to vary the fuel pump pressure with RPM and/or TPS? It may be slow to respond but enable a lot more tuning options.

That might be possible, cars have a simple way of varying the fuel pressure in relation to manifold pressure by plumbing the back of the fuel pressure regulator into the manifold, a bit like the old vacuum advance/retard setup of last century.

Flettner used this trick by plumbing a car pressure regulator into the expansion chamber so as the bike came on song and pressure in the pipe built up it increased the fuel pressure.

[mr bucketracer]

That might be possible, cars have a simple way of varying the fuel pressure in relation to manifold pressure by plumbing the back of the fuel pressure regulator into the manifold, a bit like the old vacuum advance/retard setup of last century.

Flettner used this trick by plumbing a car pressure regulator into the expansion chamber so as the bike came on song and pressure in the pipe built up it increased the fuel pressure.wonder if a bleed off useing a solanoid valve tap in back to the tank would lower pressure

[TZ350]

320874320875

A cars fuel rail with variable pressure fuel pressure regulator. The hose at the back of the regulator plumbs into the inlet manifold plenum.

The varying pressure in the manifold plenum varies the fuel pressure in the fuel rail so that a constant un varying pressure differential is maintained at the injector nozzle for consistent fuel delivery.

By plumbing the regulator into the chamber we can use this feature to increase the fuel pressure as the pressure inside the expansion chamber increases as the two stroke engine is getting up on the pipe and starting to make real power. Flettner used this feature on his Kawasaki running E85 fuel.

[Lightbulb]

Can anyone enlighten about any Ryger failures, if they do fail, what is failing ?
Thanks , Neil L

[Flettner]

Can anyone enlighten about any Ryger failures, if they do fail, what is failing ?
Thanks , Neil L

No one is saying nothing! :no:
It has been speculated piston to rod connection failure but it's all hear say.

[husaberg]

Can anyone enlighten about any Ryger failures, if they do fail, what is failing ?
Thanks , Neil L

Pretty sure (with all due respect) its failings tend to fall into the Expectations vs Reality category. :msn-wink:
It should be remembered it took until the 1960s for the conventional two stroke to consistently beat the diesels. So there is still plenty of time for R&D on the Ryger.

[marsheng]

No one is saying nothing!

means everyone is saying something.

I presume you mean
No one is saying anything or
everyone is saying nothing!!!

[marsheng]

320857

A fuel injector has a tuning range just like this jet kit has. And just like when you get down to the smallest jet in the kit and still need to go leaner you need a smaller jet kit or injector to move to the next lower tuning range.

That is my problem with the current small injector, it is just not small enough to give me the tuning range required to handle the minimum fueling requirements on high rpm over run on a closed throttle. I need the next smaller injector (kit).

Send me one and I'll make you a smaller set.

Cheers Wallace.

[dmcca]

The problem I am struggling with is at the low end, if this was a carb then the EFI bit that is challenging me now is the area covered by a carb's pilot jet and transition to the slide cutaway.

May I ask why you're not using a wideband O2 to tune this area?
It would be relatively straight forward with a wideband and a brake dyno.

[Frits Overmars]

May I ask why you're not using a wideband O2 to tune this area? It would be relatively straight forward with a wideband and a brake dyno.Why a brake dyno? Then you would be developing an engine for a set of circumstances that it will never see on a race track.
Going through the revs on an inertia dyno and registering revs, torque and lambda simultaneously is an excellent way of establishing an injection map.
Besides, running constant revs on a brake dyno with too little fuel or too much ignition advance may kill your engine, whereas it might survive on an inertia dyno.

[FastFred]

320857

A fuel injector has a tuning range just like this jet kit has. And just like when you get down to the smallest jet in the kit and still need to go leaner you need a smaller jet kit or injector to move to the next lower tuning range.

That is my problem with the current small injector, it is just not small enough to give me the tuning range required to handle the minimum fueling requirements on high rpm over run on a closed throttle. I need the next smaller injector.


May I ask why you're not using a wideband O2 to tune this area? It would be relatively straight forward with a wideband and a brake dyno.

TeeZee's has been saying, as he sees it, the problem is he needs a smaller injector, the one he currently has can't be turned down enough for the minimum fueling required.

And from what I have seen on here an O2 sensor is better at reflecting the engines "trapping efficiency" than the correct A/F ratio. As I understand it, anywhere away from peak torque a lot of correct A/F mixture escapes a two stroke engine un-burnt and the O2 sensor registers this as a lean mixture because of all the O2 in it.

[Cheesy]

Dont some injectors partially use the fuel pressure to increase the closing speed? If so dropping the fuel pressure may not be that useful. That said if it would work does the ECU have a programmable PWM output that you could use to drive the fuel pump and run it with no regulator?

[TZ350]

Dont some injectors partially use the fuel pressure to increase the closing speed? If so dropping the fuel pressure may not be that useful. That said if it would work does the ECU have a programmable PWM output that you could use to drive the fuel pump and run it with no regulator?

There is no PWM option available on my Ecotrons EFI unit.

320883320884

But car fuel rails have these sort of fuel pressure regulators. The small pipe goes to the inlet manifold. When the regulator sees less pressure in the inlet manifold it changes the fuel rail pressure so that the relative injection pressure seen at the injector nozzle stays the same and is constant. Whether the motor is in a high vacuum on over run situation or near atmospheric pressure near WOT wide open throttle or maybe even positive pressure in the inlet manifold with turbo boost the injectors are working with a constant relative pressure differential.

I am going to try one of these because currently my fuel rail is constant 3 bar but the injector nozzles see a differential of 3 bar and crankcase vacuum or pressure. So effectively although the fuel rail is a constant 3 bar my injector nozzles are experiencing widely fluctuating injection pressure differentials so I guess the fuel amounts being injected are fluctuating wildly too.

[dmcca]

Why a brake dyno? Then you would be developing an engine for a set of circumstances that it will never see on a race track.
Going through the revs on an inertia dyno and registering revs, torque and lambda simultaneously is an excellent way of establishing an injection map.
Besides, running constant revs on a brake dyno with too little fuel or too much ignition advance may kill your engine, whereas it might survive on an inertia dyno.

When i say brake dyno i mean an eddy current or similar that allows both constant rpm tests and normal 'runs'... Im sure that doing only constant rpm tests is not ideal. Personally I do a combination of both to tune an engine and so far it has worked well for me, especially when tuning the low throttle area that TZ was talking about... in saying that ive only ever had an eddy current dyno, never an inertia-only dyno, and have developed my own methods of tuning without ever seeing first-hand anyone else's process for tuning a two stroke... maybe its a case of ignorance is bliss, however i find my process to be very quick and very reliable for a wide range of engines.
I find that the lambda sensor is a little slow to react at low revs and part throttle. Its fine at higher revs and higher throttle. By holding the engine at a certain rpm point for 3-5sec at each throttle position it gives the readings time to stabilise and gives much better, more repeatable data. I start by doing a range of fixed rpm tests at different throttle openings, with the revs building higher each test... eg 4000, 6000, 8000, etc at 1/8, 1/4, 1/2, 3/4, full throttle ... By doing this you can easily see the areas that need changing (pilot, slide, needle diameter, clip position, needle taper, main jet, etc). If there is a serious problem with the tune you will always catch it before doing damage as youll see AFR's begin to lean out or detonation begin to show before you get too high in rpm. Once ive done basic tuning like this then i do full runs and constant load testing and fine tune if necessary, but these are normally only very minor changes.


TeeZee's has been saying, as he sees it, the problem is he needs a smaller injector, the one he currently has can't be turned down enough for the minimum fueling required.

And from what I have seen on here an O2 sensor is better at reflecting the engines "trapping efficiency" than the correct A/F ratio. As I understand it, anywhere away from peak torque a lot of correct A/F mixture escapes a two stroke engine un-burnt and the O2 sensor registers this as a lean mixture because of all the O2 in it.

Whether the AFR reading is showing true AFR or not doesnt really matter, the numbers can still be used to tune an engine... around full throttle and peak torque it is fairly reliable to use ~12.5:1 and leaner readings below that, down to around 13.5-14:1 at part throttle/low rpm. Of course you still need to use experience and 'feel' to do the fine tuning but the AFR numbers will get you close. Even if the engine is not actually seeing 14:1 at part throttle/low revs, its still a repeatable data point that can be used to tune an engine. Its certainly a lot better than guessing, especially when tuning the part throttle areas.

My main question to TZ though was why he wasnt using AFRs to tune his engine? Since he has employed a lot of technology so far it seems only a small extra step to be using a wideband O2 senor to help with the fine tuning as it will save a lot of the guess work.

[wobbly]

+1 the above.Adding that putting the Lambda in the stinger, seems to be way more stable and repeatable when logging the A/F data.

Using data this way is something that you really dont appreciate how good it is until actually doing it.
Hence TeeZees surprise when I related that every time you change a small item in the engines tune - the dyno result for sure is not telling you
really what you want to know, unless you rejet every time to hit a predetermined baseline.

As Jan Thiel said, most all of the pipe testing at Aprilia was a complete waste of time,when he finally realized alot of the power differences were down
to how the egt reacted to that pipe.
Not that the pipe was "better " for some aspect of scavenging, or trapping efficiency in making more or less power.

[crbbt]

Hey Wob,

I think you would be the man to ask. Is there much difference between a Keihin SPJ and PWK? (with tps and power jet)

I'm almost ready to bring my RS into the early 00's.

I'm tempted to go a dual "power jet" Lectron with one under solenoid control but I'm worried about control over the slow speed jet equivalent. having it set rich enough to not seizing into turn 1 at PI (again) because Im a girl and can't hold my kids bike flat there. then setting it lean enough when I go to a go kart track and burn through rear brake pads.

or is that just adjusting the metering rod length on the lectron?

[TZ350]

... putting the Lambda in the stinger, seems to be way more stable and repeatable when logging the A/F data.

Definitely going to do it this way if there is a next time.


My main question to TZ though was why he wasn't using AFRs to tune his engine? Since he has employed a lot of technology so far it seems only a small extra step to be using a wideband O2 senor to help with the fine tuning as it will save a lot of the guess work.

Already have please see below, I started out trying to get a 12.5:1 A/F everywhere on the map, as you do if you don't know any better. Things weren't going well and I gave it away when it was pointed out to me that it was the short circuiting fooling the O2 sensor into thinking the system was running lean when it was not. It really confused things and it looked like the O2 sensor was not going to be very useful so I discarded it.

But your experience encourages me and it looks like that with a bit more experience myself I might be able to get somewhere with it now I have a better idea of what is going on. But I don't really need it for finding max power now and my low throttle fueling issues seem to be related to injector size and not map adjustment. Don't really feel the need for going back to the complication of an O2 sensor at the moment, but that could change.



Below are my previous efforts with a O2 sensor and EGT.


291873

Ok finally got the O2 and exhaust temperature sensors installed.

Ecotrons has been pushing me to do this, they need the Lambda info so they can better help me develop a good Alpha-N map.

No idea if they are in the optimum place but they will do for a start.

Had to change to un-leaded fuel but still have to drop the compression a touch to suit the 96.

291872

The air fuel meter and Lambda controller/transmitter.

291871

Using the cursors, with Cursor-1 I can see that at N_b 7206 rpm LamWO2 is rich at 0.85 and Cursor-2 lean at 1,247 Lam at 9120 rpm.

291875

Now that it all seems to be working I am really looking forward to getting a bit of time on the dyno to play with this thing.


292062

With Lambda at 0.76 its a little rich at 11.6K rpm, the Lambda (bottom line) hovers mostly around 0.9 - 1.0 so a little lean for best power every where else.

But look at the Lambda line, there is no big peaks and hollows now, Ecotrons recorded data and data analyzer software is sure a big help with sorting out the fueling.


I am now starting to make some headway with tuning the Beast and I am beginning to enjoy using the Ecotrons small engine EFI kit for two strokes and its 2T tuning softaware.

291979

Recorded some RPM and TPS data along with the Lambda O2 sensor.

This is an expanded section of the recorded data with TPS at the top, RPM in the middle and Lambda at the bottom. The curser shows the Lambda is 0.86, rpm 6.5k and TPS 99%.

291980

Exported the Alpha-N map to Excel. Using a spreed sheet makes it easy to manipulate the map and keep the steps between cells smooth.

291981

The thick blue line is the Lambda and its max lean where its flat on top and the bottom of the dips is Lambda 0.8 - 0.88 ish. The red line is TPS and thin blue is RPM.

By printing out the Alpha-N map and studying the Lambda-RPM-TPS data I can see where to make changes in the table.

Its starting to feel like progress but I have not got so far as to have a worthwhile dyno graph to show off yet.


292203

Ok, making progress, that's if you can call getting it wrong progress.

292202

Ecotrons has a very clever self tuning feature where you tell the map what Lambda you want at what RPM and the ECU will read the ALM O2 sensor and adjust the mixture for you.

292204

The green squares on the map are where the ECU has completed the tuning process and delivered the Lambda asked for.

But :o you do have to ask for the right Lambda value for the engine. And this is where I went wrong tonight, I made the lower end to rich and eventually after a lot of auto tuning work the motor could not pull the skin of a rice pudding and drag itself into the power band.

On a rolling road dyno you can only do this auto tuning at low RPM and light loads because the Auto Tuning function needs the throttle and rpm to be held steady for 10 seconds or so to work.

The auto tuning feature works better and you can cover more of the map if you can ride on the road and use the head wind as a load or better yet, use a dyno with a brake to hold the engine steady.

292205

My mistake was asking for to rich a Lambda at low throttle settings, and having the bike struggling to pickup on the dyno. I had made the map 0.85 Lambda everywhere, I should have stuck with the default map that had Lambda 1 at low RPM and dropping to Lambda 0.85 - 0.82 at max power.

But being able to make planned mistakes is a step better than just making ignorant mistakes and not knowing why.

So .... its progress ... :D

[wobbly]

Having twin PJ with one solenoid controlled is a great idea.
But when running Avgas be sure to only switch on/off a small ( 35 ) jet.
The tuning with the Lectron needle length is only for what would be normally the pilot/airscrew and slide adjustments ( idle and transition only ).
From 1/4 throttle and up is set by the 2nd needle number.
A PWK is shit ( 3 Hp in 40 on a SKUSA Honda ) compared to an SPJ, but the SPJ is very similar in performance to a PWM as they are the same length.
A PWM is way cheaper, but then you have to add a PJ at then a TPS.
I thought the longer PWK would make better mid, but no free lunch there at all.

[crbbt]

Thanks for your response!

my only concern was parts availability into the future for the SPJ

Might look at modify a lectron for a uni project (and a 12v generator for a cr125)

[husaberg]

Having twin PJ with one solenoid controlled is a great idea.
But when running Avgas be sure to only switch on/off a small ( 35 ) jet.
The tuning with the Lectron needle length is only for what would be normally the pilot/airscrew and slide adjustments ( idle and transition only ).
From 1/4 throttle and up is set by the 2nd needle number.
A PWK is shit ( 3 Hp in 40 on a SKUSA Honda ) compared to an SPJ, but the SPJ is very similar in performance to a PWM as they are the same length.
A PWM is way cheaper, but then you have to add a PJ at then a TPS.
I thought the longer PWK would make better mid, but no free lunch there at all.

Wob the 1999 to 2007 ish Kx125 and KX250 plus a few KTM's and I think Suzukis of the same era (I will have to check the years) have a PWK shorty (PWK-S) is 75mm with TPS and solenoid PJ (36mm 38mm )
http://www.brokenmx.co.uk/media/catalog/product/cache/1/image/650x/040ec09b1e35df139433887a97daa66f/t/1/t109-_1_.jpg


Is the SPJ and PWM shorter again or just the same length.



05-11 YZ250 PWK carbs (with TPS)
02-08 RM250 PWK carbs (with TPS)
??-07 KX250 PWK carbs (with TPS)
2000 CR250 PWK (no TPS)
http://www.thumpertalk.com/topic/879109-pwk-conversion-infomation/

As far as I know all the PWK bodies from 36mm through 39mm that are made to accept a throttle position sensor (TPS), are of the same length. They will be 75mm inlet to outlet. Some of them don't actually contain a TPS but use the same body, such is the case with the newer KTM's, most of which are 36mm but they used some 38mm's on certain models. I have a 99' KX-250 TPS PWK, and a 06' KTM 250 SX PWK which is the TPS body but doesn't actually contain a TPS. They both measure 75mm inlet to outlet, which is the same as my 03 YZ 250 TPS PWK.

[crbbt]

I just picked up a PWK with the tps and pj off a 1999 kx250 to put into my CR125.

the kx carb is 75mm but i was under the impression that the current PWK's on the ktm's and yamaha's were also 75mm but lack a power jet. at least on the yamaha's

[wobbly]

Yes I think there are versions of the PWK that are short like a PWM or SPJ, but the ones I have seen all have the so called " air striker " fences on the bellmouth
floor.
This may be fine for a MX bike but in every test I have done the power is well down with this system,can it be removed - probably.

[richban]

I just picked up a PWK with the tps and pj off a 1999 kx250 to put into my CR125.

the kx carb is 75mm but i was under the impression that the current PWK's on the ktm's and yamaha's were also 75mm but lack a power jet. at least on the yamaha's

YZ250 PWK's with tps and pj. I have a KX version as well only difference is the power jet connections and the needle in the KX carbs is richer on the tapper. Actually I think the KX version has a slightly leaner slid cutaway.

They work great at the moment on the 300. But really measure 37mm. I will bore them to 39 when I get the new engine mods done.

320912

[KKT]

Hi.

I'm not allowed to start a new thread, so i will risk an eye..and ask here, if inappropriate please delete.

I have been looking in many books about twostroke engines. and also searched on google, but i never found a definitive answer.

Many gokarts run coolant temperatures around 50-55 degrees C, the same goes for outboard engines, and some run even colder.
I have read about many road race bikes, from 50cc to much larger bikes, that also seems to run at these same temperatures.

Why it is so ? Do twostrokes make most the power within this particular temperature ?

Best regards
KKT

[JanBros]

Do twostrokes make most the power within this particular temperature ?



This.
Jan Thiel has tested this at Aprilia, up to even running constant tap water through the cooling system.

[wobbly]

The cooler the water, the cooler the case and more importantly the cooler the transfer and Ex port ducting.
This maintains charge density, as well as keeping cool the slug of A/F sitting in the Ex duct waiting to be shoved back in
by the rear cone wave action.
With a new water regime I developed for KZ2 kart engines we run between 40 and 45*.
A 125 cylinder will drop at the very least 2 Hp, when lifted from 50 to 60*C

[TZ350]

321009

Happy afternoon playing on the dyno, making some progress with improving the drivability.

Green line is 20% throttle the other curves are 30-40-50-60-70-80-90-100%, Interesting that 90 and 100 are basically the same.

Making power is not my EFI tuning issue, the big problem for me has been getting the engine to pick up again after closing the throttle when slowing down for a corner.

Things have started to improve as I carefully shave the map down in the low throttle rich areas 0.5% a time.

321008

Making progress, in the area where the 20% Green line is, the motor is almost behaving it self. I expect that with some more careful work sanding the map down in the rich areas either side of the green patch things will get better yet, maybe even ride-able.

[husaberg]

321009

Happy afternoon playing on the dyno, making some progress with improving the drivability.

Green line is 20% throttle the other curves are 30-40-50-60-70-80-90-100%, Interesting that 90 and 100 are basically the same.

Making power is not my EFI tuning issue, the big problem for me has been getting the engine to pick up again after closing the throttle when slowing down for a corner.

Things have started to improve as I carefully shave the map down in the low throttle rich areas 0.5% a time.

321008

Making progress, in the area where the 20% Green line is, the motor is almost behaving it self. I expect that with some more careful work sanding the map down in the rich areas either side of the green patch things will get better yet, maybe even ride-able.
That's the problem that Cagiva had with the 500E ,as the injection keeps on pumping fuel on overrun.
A pumper carb does the exact same thing, not as problematic on a kart or a car, but can lead to highsides on a bike, when it finally clears the full crankcase and chimes back in.
http://www.kiwibiker.co.nz/forums/album.php?albumid=4844&attachmentid=302540

[Haufen]

TZ, if the injector is only slightly too big, then you might be able to work around the problem by retarding the ignition in the low throttle opening range until you find / get a smaller injector.

This way, you need more throttle opening = more air for the same power which should get you closer to the AF ratio you need for a smooth pick-up. If this does not improve pick up, then your rich pick up situation could also be caused by a puddle of fuel somewhere in the engine.

[TZ350]

TZ, if the injector is only slightly too big, then you might be able to work around the problem by retarding the ignition in the low throttle opening range until you find / get a smaller injector.

This way, you need more throttle opening = more air for the same power which should get you closer to the AF ratio you need for a smooth pick-up. If this does not improve pick up, then your rich pick up situation could also be caused by a puddle of fuel somewhere in the engine.

I will try that.


That's the problem that Cagiva had with the 500E ,as the injection keeps on pumping fuel on overrun. http://www.kiwibiker.co.nz/forums/album.php?albumid=4844&attachmentid=302540

Thanks Husa, I haven't got it as ride-able as the Cagiva yet. But their low throttle high rpm fueling issues are exactly my problem too.

[husaberg]

I will try that.



Thanks Husa, I haven't got it ride-able as the Cagiva yet. But their low throttle high rpm fueling issues are exactly my problem too.

if it had a reed valves you could put spacers under the reeds so they don't fully close.
What it needs is a way of interrupting the fueling enough on over run without it causing it to seize. (which would be a fine fine line)
what do the sensors actually read out on overrun conditions?
Maybe it needs skip strokes or a rider that doesn't ever throttle off. AN idle set to 4000RPM

[speedpro]

With the throttle closed there is a lot less air flowing through the engine. Completely stopping the fuel above certain revs on a closed throttle may not be such a big problem. With no fuel there will be no combustion and without the airflow the oil remaining will possibly continue to lubricate things sufficiently. With no fuel at all being injected on a trailing throttle at revs it might come back on throttle a bit cleaner as it wouldn't have to clear that puddle.
With an autolube system when the throttle is closed the oil injection essentially stops but the engine could still be doing a lot of revs. Think about a long downhill.

[Grumph]

With an autolube system when the throttle is closed the oil injection essentially stops but the engine could still be doing a lot of revs. Think about a long downhill.

One of the quoted benefits of the autolube systems when they were introduced was just that - no seizures coming down hills with a shut throttle as there is always a minimum of oil coming in.
If you're worried about lube vs fuelling, you could always refit the autolube so as to separate the two functions...at least until you've got the mapping a bit closer. Eliminates one variable anyway...

[husaberg]

With the throttle closed there is a lot less air flowing through the engine. Completely stopping the fuel above certain revs on a closed throttle may not be such a big problem. With no fuel there will be no combustion and without the airflow the oil remaining will possibly continue to lubricate things sufficiently. With no fuel at all being injected on a trailing throttle at revs it might come back on throttle a bit cleaner as it wouldn't have to clear that puddle.
With an autolube system when the throttle is closed the oil injection essentially stops but the engine could still be doing a lot of revs. Think about a long downhill.


One of the quoted benefits of the autolube systems when they were introduced was just that - no seizures coming down hills with a shut throttle as there is always a minimum of oil coming in.
If you're worried about lube vs fuelling, you could always refit the autolube so as to separate the two functions...at least until you've got the mapping a bit closer. Eliminates one variable anyway...

Maybe a hybrid with the throttle position delivery rate on the autolube pump disconnected,so just a small amount would be delivered at all revs used in tandem with premix.
Or maybe just a simple auxiliary injection system like the KTM used just to do over run only.

[wobbly]

NSR250 Hondas have a solenoid control on the oil pump - at high rpm with closed throttle the pump runs at full output.

[TZ350]

Completely stopping the fuel above certain revs .... With no fuel at all being injected on a trailing throttle at revs it might come back on throttle a bit cleaner as it wouldn't have to clear that puddle.

Will try a couple of zeros at the high end of the map to see what happens.


NSR250 Hondas have a solenoid control on the oil pump - at high rpm with closed throttle the pump runs at full output.

That would be possible.

To save weight and mechanical drag I have long ago done away with the internal parts needed for a mechanical auto lube pump.

But I could fit a small diaphragm pump and solenoid switch that the Ignitec ignition uses for the power jet and re configure it to switch on the oil solenoid to oil the engine at high rpm and closed throttle.

:niceone: .... If I could use engine lube to oil the gearbox then I could just switch some oil discharged from the gearbox pump to the engines auto lube system when needed.

In fact I probably could use the current ATF gear box Auto trans oil. Maybe not the best there is for an engine but I bet it is plenty better than nothing. Also it seems compatible with the pre mix we use as plenty of our bikes have sucked their ATF gear box oil and kept going.


Maybe just a simple auxiliary injection system like the KTM used just to do over run only.

A high rpm closed throttle solenoid oiler may be quite easy to do, thanks for the ideas.

[Grumph]

A high rpm closed throttle solenoid oiler may be quite easy to do, thanks for the ideas.

High RPM, closed throttle - high vacuum. Vacuum triggered switch or valve ?
I'd point out in the interests of KISS that Bultaco used a drip feed into the inlet for supplementary oiling....

And i'm old enough to remember wiring Suzuki T20/T500 pumps about 1/4 open as an addition to what was in the fuel.

[morini155]

Hello, i like this forum and i have a question: i work on a Yamaha DT 200 engine, but i want block the YPVS valve on a fixed position. Can match the valve operation benefits with a proper tuning of exhaust pipe? Can have a broader powerband, from 5000 to 9000 rpm?

[wobbly]

In 2 words - no way.
An even better idea is to dump the spinning PV regulator and drive it with cables and a servo.
More power is easily dialed in below the best operating range of the pipe - so it can be tuned for better mid or top end depending on the end use.

[morini155]

The engine its for use on off-road use, trail woods,etc, and i see the Yamaha Blaster 200 quad engine perform well and this engine its no YPVS. The Banshee 350 its another example.
For this use whats guidelines on ports timing and compresion ratio?

[TZ350]

321060

The big injector is maxed out well before max rpm. This must mean at least two things, one its firing fuel all the time so there are no breaks for timing the mass of fuel to coincide with some ideal point in the engine cycle. And two, worse, at some point it is the maximum time available that is controlling the amount of fuel delivered instead of the map. And that probably has some down sides to it.

My new injectors from Ecotrons arrived today, five days from order to delivery, not bad. Looking forward to trying them.

[F5 Dave]

The early DT200 engine uses a servo and ypvs controller just like the RZ. The later full case reed version I can't say. Powervalve wins every time. Examples stated prove the concept, they were omitted for cost and infrequently used battery killing trail bikes but that was not impossible to overcome.

[crbbt]

TZ, are you able to run two injectors with the same total capacity/flow rate as your big injector off the one injector driver? or would that draw too much current

[TZ350]

TZ, are you able to run two injectors with the same total capacity/flow rate as your big injector off the one injector driver? or would that draw too much current

Yes you can and its what I currently do for the big injector. Its two physical injectors but one logical injector in the software.

321065

Left and right are the two big injectors fired together as one logical injector and the central one is the small low speed injector. It handles low rpm fueling and tops up the two side injectors under power. It also fires upwards under the inside of the piston crown for extra piston cooling.

321066

I can't find a picture of my piston but it is slotted like this one.

[2T Institute]

The engine its for use on off-road use, trail woods,etc, and i see the Yamaha Blaster 200 quad engine perform well and this engine its no YPVS. The Banshee 350 its another example.
For this use whats guidelines on ports timing and compresion ratio?

Having built fairly wild DT200 engines ditching the servo power valve is plain stupid. The DT engine is held back by the ignition and the truly crap pipe. Change those and away they go.

https://www.youtube.com/watch?v=V3wicdQKcn0

[JanBros]

dyno is working, used a complete unit (electric motor with double reduction to the traction wheel) :

http://s201.photobucket.com/user/jan...dyno2.mp4.html

[TZ350]

And it works like a charm :Punk:
http://nl.tinypic.com/r/2zf1kbk/9
So now I need to have a vario in a fixed position so I can see engine improvements, and than find the best vario setup, all without having to leave my shed :woohoo:

Great work, I love it.:niceone:

[chrisc]

I dropped into the Team ESE headquarters/research facility yesterday after work to catch up with Cully and Rob. I've been following Rob's progress on the EFI AC GP125 with interest so it was good to see it mid-testing on the dyno. I'd hate to think how many runs that poor engine has endured! It still kinda blows me away that it makes 28hp with a modified 1970s road bike cylinder!
It was interesting to see in person how the bike reacted to variations in the throttle as Rob has shown he's having problems with. It certainly has no problem making wide open throttle peak power!

We checked out how each injector was running and saw improvements in the data from the previous injectors. We chatted about how each injector reacted to the throttle, closing timing and positioning in the engine. A lot of the data and observations are pointing to the smaller middle injector that fires through the piston being the problem. We decided it would be worth an experiment to change where this injector is placed in the engine by moving it into the inlet tract and seeing if there is any noticeable improvement. We can then see if the theory on its positioning stacks up.

Looking forward to seeing more progress Rob, it's a total wheelie machine in the making!

[jasonu]

Pretty sure (with all due respect) its failings tend to fall into the Expectations vs Reality category. :msn-wink:
.

Claims vs Relality category more like...

[TZ350]

I dropped into the Team ESE headquarters/research facility yesterday after work to catch up with Cully and Rob. We checked out how each injector was running and saw improvements in the data from the previous injectors. We chatted about how each injector reacted to the throttle, closing timing and positioning in the engine. A lot of the data and observations are pointing to the smaller middle injector that fires through the piston being the problem. We decided it would be worth an experiment to change where this injector is placed in the engine by moving it into the inlet tract and seeing if there is any noticeable improvement. We can then see if the theory on its positioning stacks up.

321088

Well that didn't work any better ... :facepalm:

So what is it with this Beast, rich lean or anything in-between. End of injection before TDC after TDC, 90 deg or 180, bottom or top, anything under 20% throttle and on the small injector, it still runs like a pig. ... 22% and over its on the big injectors and it runs great. Whats that about??? It must be something to do with injector position and fuel homogenization.

321094

Two small injectors for low speed on the outside and one really big one in the middle is about all that is left to try, so lets see how that goes, other than that, I have pretty much run out of ideas.

[ken seeber]

Rob, is it time to do a total fundamental reality check? Could it mean taking off all the injectors and chuck on a carb? Means getting rid of the neat throttle valve, but maybe you need to understand if it's some form of injector peculiarity or some unique characteristic of the engine as it has been built.

[dark art]

If the main problem with the carb setup was the fuel and oil that eventually may not reach the engine, maybe, is possible to build the chamber only upside of the inlet pipe, so the gravity kept fuel and oil always on the inlet. May be quite a bit of work and possibly more work/benefit than with the EFI setup, though...

[jonny quest]

I'm picking up a MC21. The inner crank webs have the crank pin machined on as one piece.

Has anyone heard or seen of machining these inner webs to accept a pressed in pin?

I understand the reason it's one piece, it's fairly narrow there.

[jonny quest]

By crank pink, I mean lower rod pin

[Grumph]

Rob - I'd try the low speed injector on the downstream side of the throttle valve - and aimed at a port wall. From what i've read on 4T injection in low airspeed conditions, you get better results if the injector stream can be made to splatter - for want of a better word...
And yeah, I can see there's not a lot of room.

Jonny - there's a lot of Hondas been written off because of their habit of forging cranks with the pin integral to one wheel. If you can find a practical way of doing what you ask, there's a market....

[F5 Dave]

OK Sketchy, time to move into mass production.

[wobbly]

I originally built the BSL crank with integral pins ( it made the engine 17mm narrower - big deal )
Sadly no matter how it was done, with big radi and shot pienning etc the bastard pins kept cracking.
This was due to some form of harmonic or torsional twist from firing 2 of the 3 cylinders together.
In the end I tried a crank with the same dimensions ie only 12mm of press fit on the side where the pin originally was one piece.
We made a jig that kept the pin dead square in the crank hole, and tigged it right around the outside face.
Never had a crank issue after that.

So I would suggest spark eroding new pin holes, in the integral side,and welding in new pins may in fact work.
But from memory the Honda and the RGV/RS250 may be even thinner than 12mm.

One thing to be aware of - the original crank had the pin holes on the non integral side moved inward 0.008mm,as when the pin was pressed in
the wheel material would bulge outward,changing the stroke length by that amount.
Thats not an issue if both sides are pressed in, and both wheels are identical.

In this case it might take a couple of cranks to get the new hole position dead on such that the thing will straighten correctly due to the thin press width.
Having the stroke lengths not matching is easy to detect, with 2 dial gauges on each end of the same axle, both will rise and fall together - impossible to correct.

[Muciek]

Measuring that 0,008 mm would be pretty hard to do most normal measuring gauges go to 0,01mm , unless You are talking inches then 0,008 it's 0,02mm but would that make a big difference? Guys here used to be doing thing like this on RZ cranks since it was cheaper than buying new one from overseas and they were not that available like they are now.

[wobbly]

You are not measuring it at all, you would be programming a CNC spark eroding machine to bore the pin hole at a reduced the stroke of 0.008mm.
But if the wheels are thinner than 12mm as the BSL ones were, then 0.01 would probably be closer.
And yes 0.02mm runout in a crank is nowhere near "straight ", it would destroy the main bearing and or fret the cases due to the wobble in no time.
This is why I have probably 10 RZ cases that are junk, because the main bearing journal faces are worn oval, from crank rebuilders who didnt know what they were doing.

[Muciek]

I got You wrong (lost in translation)I thought that stroke would change that 0,008mm and You would have one side with other stroke than other.
Wouldn't it be better to grind the hole instead of EDM'ing it? You would probably get "rounder" hole and better surface finish , anyway machining with tolerances under 0,01 is trick stuff.
offopic what was the acceptable run out for those twin's cranks , (honda, yam, and suzuki) , not talking about racing but normal use , did factory always was getting it at 0 and in service manuals was stated like this? Many bikes have limit at 0,02mm and it is normal.

[jonny quest]

Not saying you're wrong Wobbly, but even at ,04mm shouldn't fret or damage cases.

Crank rebuilding is an art, I do a lot of singles, and it's not uncommon to see them come out with 5 hours run time at ,15mm runout.

You put a hairdryer to a crank with ,02mm runout and it will move almost twice that

[jonny quest]

Edm is probably more precise than grinding. Edm was the way I was going to put the pin holes in the crank.

Is there a rule of thumb for press fitment of pins?

There's a place making Kr1 Inner webs with the pin machined on. From the pictures they look super close. I wonder if they would fit, or fit with some slight mods

[wobbly]

The problem with the twin is that if you are prepared to accept 0.02mm or 0.03 runout like Yamaha says , then this can be at both ends.
It can also easily be on opposite sides, so in effect you then have 0.06 runout across the outer mains - this is why the tunnels are wreaked, being oval or with no crush
in most every old RD/TZ/RZ case I measure these days.

Edit - yes I agree about cranks moving after being run, but in my opinion this is due to having excessive amounts of hammering to get them " true ".
The metal in close contact is very springy, and I have found that if the wheels are held dead in line in a die set so that there is no need to hammer the shit out of them
they dont move at all.
If hammered they will always spring back a little in the direction they came from.

[TZ350]

Rob, is it time to do a total fundamental reality check? Could it mean taking off all the injectors and chuck on a carb? Means getting rid of the neat throttle valve, but maybe you need to understand if it's some form of injector peculiarity or some unique characteristic of the engine as it has been built.

Have been hoping to avoid reality, this engine has run very well in the past with a carb. But its looking like you are right, it is shaping up to be something about the injectors. Maybe they need to be angled differently.


If the main problem with the carb setup was the fuel and oil that eventually may not reach the engine, maybe, is possible to build the chamber only upside of the inlet pipe, so the gravity kept fuel and oil always on the inlet. May be quite a bit of work and possibly more work/benefit than with the EFI setup, though...

Yes, good idea, we had thought of it but like you say, hard to do on the rotary valve engine but could be very possible to arrange the plenum in such a way it drains into the inlet on a reed or piston porter.


Rob - I'd try the low speed injector on the downstream side of the throttle valve - and aimed at a port wall. From what i've read on 4T injection in low airspeed conditions, you get better results if the injector stream can be made to splatter - for want of a better word...

Good idea, thanks, I might need to look at how I could do that.

321102

Initially it looked like it was anything less than 20% throttle (left cursor) was the problem. But after a bit of time studying the recorded data it is beginning to look more complex.

As the rpm picks up (top line) you can see the rough running smooths out (right cursor) as the difference between injector on time (green line) and the total injector on time available (red line) reduces to 30%. 30% is about the amount of time the transfers are open.

To my surprise the engine runs rat shit when the injector on time is much less than the transfer open time and it gets better when the injector is on for longer than the transfers are open and best when the injector is on the whole time. Actually I suppose that should not be such a surprise because a carb is on for the whole time too, and they run Ok.

After looking at quite a lot of data it looks like the engine runs rough when the injector on time is less than the total transfer open time. The engine runs better the longer the injector is turned on. And of course anything less than 20% throttle there is not much injector on time and the thing runs like a pig.

It must have to do with fuel homogenization. A carb adds fuel to all of the air that passes through it but with an injector, under 30% on time I must be getting big patches of air with no fuel in it. And when the injector has to be on for much longer the air is getting a more consistent mix that is more like that delivered by a carb.

On over rev with the throttle shut there is very little injector on time. So because I can't fire the injector for the full transfer open time. I guess the trick is to find a way to thoroughly homogenize the air fuel mix or at least time the injection point to coincide with the air that will eventually be trapped in the cylinder.

321103

Up till now I have had the big injectors on either side with the slow speed injector in the middle. Maybe worth my while reversing that and trying two small slow speed injectors either side with a really big power injector in the middle. If that results in better mixing and works well then as an extra up side I would be also getting lots of underside piston cooling from the power injector.


The big question is, is how to get a homogeneous mixture of the correct air fuel ratio in the cylinder when the injector is only on for a much shorter time than the transfer window is open.

[dark art]

321103

Up till now I have had the big injectors on either side with the slow speed injector in the middle. Maybe worth my while reversing that and trying two small slow speed injectors either side with a really big power injector in the middle. If that results in better mixing and works well then as an extra up side I would be also getting lots of underside piston cooling from the power injector.


The big question is, is how to get a homogeneous mixture of the correct air fuel ratio in the cylinder when the injector is only on for a much shorter time than the transfer window is open.

That makes a lot of sense, and it seems the middle injector is spraying directly on the boost port. I guess the obvious step, is to move the injectors away from crankcase so there is more time to mix things up...

[Grumph]

Fuel homogenisation is best achieved in a turbulent stream. You get this in a carb when the air passes the slide. Is the ball valve throttle too streamlined ?
Traditionally most throttle bodies for injection are either butterlies or a flat plate sliding.
Quick test would be to put a carb body on it and use the slide as the air throttle, injecting close to the downstream side of the slide...

[TZ350]

321107

Thanks Husaburg for the Cagiva story, its the same problem I am having.

Mr Bigglesworth's Dyno runs.

321106

.... rich areas ....

Initially I thought these were rich areas and to get it running nicely all I had to do was carefully adjust the corresponding parts of the map.

But I now think the problem is with the injection on time being much less than the transfer port window open time and consequently poor fuel homogenisation.


Fuel homogenisation is best achieved in a turbulent stream. You get this in a carb when the air passes the slide. Is the ball valve throttle too streamlined ?
Traditionally most throttle bodies for injection are either butterflies or a flat plate sliding.
Quick test would be to put a carb body on it and use the slide as the air throttle, injecting close to the downstream side of the slide...

321109321108

I have a butterfly type throttle body, it will break my heart if I have to discard that ball valve throttle. But I guess you are right, and in the interests of science I will have to try it.

[TZ350]

That makes a lot of sense, and it seems the middle injector is spraying directly on the boost port. I guess the obvious step, is to move the injectors away from crankcase so there is more time to mix things up...

There is no wall on the cylinder side of the boost port and the middle injector sprays through a slot in the piston in the hope of cooling the underside of the piston crown. If I can I would like to retain that feature and put the big injector there. Small injector in the throttle body and big injector in the boost port.

321111

[Haufen]

The big question is, is how to get a homogeneous mixture of the correct air fuel ratio in the cylinder when the injector is only on for a much shorter time than the transfer window is open.

Did you try varying the injection timing, eg starting just when the transfers closed?

Otherwise, a smaller low speed injector, or a lower fuel pressure should allow for a longer injection time.

[TZ350]

Did you try varying the injection timing, eg starting just when the transfers closed? Otherwise, a smaller low speed injector, or a lower fuel pressure should allow for a longer injection time.

Yes...

In the Ecotrons EFI software there is a way of mapping (seperate to the fuel map) the injection end point.

321118321117321116

As best as I can tell, in the manual the picture is a 4T map and the Injection end point is so many degrees before TDC on the next firing stroke.

For me it would be something like 120 degrees if I wanted to finish the injection squirt as the transfers close.

I have tried 90 - 180 - 120 - 270 and 360 before TDC, and 180 ( or BDC) worked the best.

[husaberg]

Initially I thought these were rich areas and to get it running nicely all I had to do was carefully adjust the corresponding parts of the map.

But I now think the problem is with the injection on time being much less than the transfer port window open time and consequently poor fuel homogenisation.



321109321108

I have a butterfly type throttle body, it will break my heart if I have to discard that ball valve throttle. But I guess you are right, and in the interests of science I will have to try it.

Those Cagivas were throttle body injected, so I don't think that's the full answer.
I think massive amounts of injector pressure is couple with small injectors with their light and super quick responding pintles are though.
321119
You could also do a base line fuelling with something like a old cold start injector which were not pulsed at all.
These crude injectors were used as a form of a choke on early 80's cars.This down and dirty system was used on modded turbos cars up to the nineties pre aftermarket programmable ecu's.
This could allow for you to use the smaller injectors while still getting enough fuel and time.
321120
Failing that you could always try to set up a skip a stroke system with the bike set up as a 180 twin with the ECU controlling alternate strokes. this would by some time and allow some additional fuelling overlap.

[TZ350]

you could always try to set up a skip a stroke system with the bike set up as a 180 twin with the ECU controlling alternate strokes. this would by some time and allow some additional fuelling overlap.

Clever idea, for slow speed, use two injectors half the size so as to cover twice as much time.

The irony is that we thought that the injectors would not be quick enough, so short on injection time at high speed and power but that is all good and the real problem turns out that at low speed we have to much spare time. LOL

It might be possible for the digital ignition at low speed to turn of the EFI's slow speed injector and to turn on a very small injector that flows 100% of the time like the starting injector you posted. Ecotrons has very small injectors suitable for model aero engines, one of those might do.

...... I thought I was beaten but people have come up with lots of good ideas.

We might get this thing working yet, thanks. :niceone:

[breezy]

Yes...

In the Ecotrons EFI software there is a way of mapping (seperate to the fuel map) the injection end point.

321118321117321116

As best as I can tell, in the manual the picture is a 4T map and the Injection end point is so many degrees before TDC on the next firing stroke.

For me it would be something like 120 degrees if I wanted to finish the injection squirt as the transfers close.

I have tried 90 - 180 - 120 - 270 and 360 before TDC, and 180 ( or BDC) worked the best.

wouldnt you think that as the fuel held in the transfer tunnels, is what is actually pulled into the cylinder when the transfers open, to charge the cylinder , that this would be the place to inject the fuel? some of the transfers would supply air only and injected transfers a mixture of both or even closing a couple of transfers off from the crankcase and using them to supply fuel only.:sherlock:

[wobbly]

The problem with that idea is that you will end up with differing A/F ratios within the scavenging streams.
This will then in effect produce almost a stratified charge scenario within the compressing mixture.
Unless you can do a heap of CFD or try an endless combination of air, or fuel, or both in different places, the chances of fluking
the best ( or even a good ) charge distribution is near zero.

[ken seeber]

Didn’t Harold Bartol ages ago have a hybrid style system, essentially a carb covering all the low load/speed operation and then an injector to do all the high speed stuff? All as a result of not being able to emulate the metering and fuel distribution/mixing characteristics of a carb at the lower settings. Obviously when he was doing this the computing power, software and injectors available would have been crude to what is available now.

As Wobbly says, there would be all sorts of stratification going on with just injecting into only one pair of transfers. In saying this though, Fletto seemed go get his going and the Athena was the same I think.

Maybe 5 injectors is the go. :facepalm:

[ken seeber]

The 5 injectors concept was a bit of a joke, However, what about drilling a hole thru the material between the A & B passages, the hole being directly in line with the injector axis? This would allow some of the spray to enter the A passage, possible minimising the stratification.

321126

[husaberg]

Didn’t Harold Bartol ages ago have a hybrid style system, essentially a carb covering all the low load/speed operation and then an injector to do all the high speed stuff? All as a result of not being able to emulate the metering and fuel distribution/mixing characteristics of a carb at the lower settings. Obviously when he was doing this the computing power, software and injectors available would have been crude to what is available now.

As Wobbly says, there would be all sorts of stratification going on with just injecting into only one pair of transfers. In saying this though, Fletto seemed go get his going and the Athena was the same I think.

Maybe 5 injectors is the go. :facepalm:

I am pretty sure the system Harold employed on the KTM's was a carb covering all the fuelling other than an injector augmenting the overrun to stop it seizing.
It was on either pitlane or Frits or Wob spilled. Riley Will said pretty much the same thing as well.
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=309434&d=1425089570
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=309439&d=1425089727
http://www.kiwibiker.co.nz/forums/album.php?albumid=4857



KTM's 125 FRR features a unique and exclusive fuel injection system that is not designed to replace, but instead to work in conjunction with the carburettor. It allows fine tuning of the fuel supply and lubrication under extreme circumstances -- such as over-revving whilst back-shifting with closed throttle -- and it does it with unparalleled precision. The engine can be set up to run lean at any rev range and under any load, without the dangers of piston seizures.

With the right set-up, the KTM engine is not only very fast, but also strong in acceleration, with smooth, easily controllable power delivery. "Riders aren't robots. And if the power kicks in too aggressively, they will feel a risk factor at the exit of each turn. It's like shying at an abyss. They will open the throttle later and more cautiously, and inevitably lose time,"� explains the Red Bull KTM 125 Team. "Therefore, we won't stop working on our carburetion until our engines run like electric motors, with a very linear and predictable power curve."�
http://www.roadracingworld.com/news/ktm-talks-about-top-speed-and-carburetion-in-its-preview-of-the-grand-prix-of-china/

Another snippet from Riley Will was.
Riley later says he timed the injector to squirt 10deg before inlet open and finish 10deg after inlet close (this was for his own mule engine not the KTM)

[TZ350]

wouldn't you think that as the fuel held in the transfer tunnels, is what is actually pulled into the cylinder when the transfers open, to charge the cylinder , that this would be the place to inject the fuel? :sherlock:

Yes I certainly did think so too and I thought the injection cycle should be timed to match the transfer window, but I was wrong. The engine seems to run better the longer the injector fires for. Which can be for way more than the transfer period.


321127
I have drawn myself a picture so I can visualise it.


321128
With transfer port injection it looks like timing is critical and the length of the injection cycle has to match the period that there is bulk outward air flow in the transfer duct and I guess this will be significantly shorter than the transfer open period.


At 12,000 rpm the transfer is open for 1.8ms and looking at the Ecotrons run data the injectors at 12,000 rpm are open for 1.9ms so we are pretty stuffed for much more progress.

Maybe I think its time to change tack and start thinking about Injection into the inlet.

321129

Transfer injection on an engine that revs to 8-9k would work very well (Flettner has done it on a big Kawasaki single) and with careful timing you could get some fuel efficiency's but the much reduced time available at 12k rpm to get things done. Lack of time makes it hard to do on my little 125.

321130

The Injector is timed to fire when the transfer is open. But the areas on the map that are giving me trouble are areas that the injector is firing for less than the transfer open time.

321131

The engine can make good power and in this test, at 12,000 rpm the injectors are firing for 100% of the total time available ie 360 deg of crank revolution.

[TZ350]

what about drilling a hole thru the material between the A & B passages, the hole being directly in line with the injector axis? This would allow some of the spray to enter the A passage, possible minimising the stratification.

321133

321134

My side injectors are aimed across the transfer ports to hopefully get some fuel into both the A and B ports.

321132

Hard to do on an air cooled motor. But I would have prefered to have my injectors vertical and spraying against the air flow as I think this is the best way to get good mixing.

I think this is Flettners YZ250 cylinder. It only has injectors in the B ports but it runs Ok, in fact very well. The difference between a YZ250 and my 125 is that the YZ is running E85 and less than 9,000 rpm. Above 9K seems to take 2T EFI onto another level of complexity.

[Grumph]

E85 is very misleading as far as setting up injectors goes. Any Methanol or Ethanol base fuel can be run very rich without adverse effect on response.
Look at how long the Hilborn constant flow system has lasted for methanol use - crude metering but it works.
As an aside i'd remind you that Irving suggested constant flow via one mainshaft and the big end....

[ken seeber]

OK, I was looking at this pic.

321135

[TZ350]

OK, I was looking at this pic.

321135

Yes that setup was pretty crude.

321136

The current setup has the side injectors splayed out a bit and the middle one aimed up under the piston.

[Moooools]

Yes that setup was pretty crude.

321136

The current setup has the side injectors splayed out a bit and the middle one aimed up under the piston.

I have a question in the midst of all this talk of injector positions:

Why not start with the injector where the carb would normally be situated before trying all of the crazy positioning?

I am sure there are benefits to the transfer port injection, but surely getting a handle on the injector sizing and mapping before delving into that area will at least remove a few unknowns from this largely uncharted territory.

[TZ350]

I have a question in the midst of all this talk of injector positions: Why not start with the injector where the carb would normally be situated before trying all of the crazy positioning?

Probably because we are not trying to emulate a carburetor. I particularly want to avoid the fuel laden blow back associated with a carburetor and see if I can take advantage of the possibilities offered by EFI. Its the learning that is rather challenging and very interesting.


I am sure there are benefits to the transfer port injection, but surely getting a handle on the injector sizing and mapping before delving into that area will at least remove a few unknowns from this largely uncharted territory.

You are right, it's pretty much uncharted territory, for me anyway. But I am beginning to feel confident that I have started to get a handle on what size injector to use and some idea of what shape the map should be. Now that I am getting on top of those things I am starting to see other issues that need addressing.

There is not much helpful information about 2T EFI on the net. So I have had to figure out most of this from first principles for myself, I have posted a lot of original work, and constructive help on this journey is gratefully received.


Riley says he timed the injector to squirt 10deg before inlet open and finish 10deg after inlet close (this was for his own mule engine not the KTM)

The injector turns on for as long as it needs to to deliver the fuel required. You cant just turn the injector on 10 deg before the inlet opens and off 10 deg after closing. But the timing of the inlet gives a window of opportunity of about 6ms at 6,000 rpm and 3ms at 12,000.

321142

From the screen shot it can be seen that at 6,000 rpm the small injector fires for 3.8ms and at 12,000 rpm the big injector fires for 2.7ms.

So the injection events can fit inside the inlet window.

But the fly in the ointment is that air does not continuously flow inwards but there are periods in the rpm range where air in the inlet tract blows both ways. So its just as likely to carry the fuel out of the engine as in.

321143321146321145

I have tried external injection, both low and low + high injectors together timed to the inlet event but they did not run as nearly as well as the internal injectors did.

The big high power high rpm transfer injectors are working passably, its the low speed, trailing throttle less than 20% load injector that is causing me grief.

321144

The next move is to try the slow speed injector in a throttle body and as its only on for 60% or so of the inlet event I will try varying its timing. Hopefully there will be a sweat spot .

[husaberg]

The injector turns on for as long as it needs to to deliver the fuel required. You cant just turn the injector on 10 deg before the inlet opens and off 10 deg after closing. But the timing of the inlet gives a window of opportunity of about 6ms at 6,000 rpm and 3ms at 12,000.

321142

From the screen shot it can be seen that at 6,000 rpm the small injector fires for 3.8ms and at 12,000 rpm the big injector fires for 2.7ms.

So the injection events can fit inside the inlet window.

But the fly in the ointment is that air does not continuously flow inwards but there are periods in the rpm range where air in the inlet tract blows both ways. So its just as likely to carry the fuel out of the engine as in.

321143

I have tried external injection, both low and low + high injectors together timed to the inlet event but they did not run as nearly as well as the internal injectors did.

The big high power high rpm transfer injectors are working passably, its the low speed, trailing throttle less than 20% load injector that is causing me grief.

321144

The next move is to try the slow speed injector in a throttle body and as its only on for 50% of the inlet event I will try varying its timing. Hopefully there will be a sweat spot .

I think Riley was referring to the max flow duration used rather than all revs
Funny enough the rest sounds like 3 times past the main Jet..........;)

[TZ350]

I think Riley was referring to the max flow duration used rather than all revs.

Yes, the window of time is wide enough. Was there any on track drivability comments.


Funny enough the rest sounds like 3 times past the main Jet..........;)

..... :D

[jonny quest]

I've been searching the World Wide Web, but haven't found anything, which I'm surprised.

Looking for some pipe specs for a NSR250 MC21. Stock, or aftermarket.... even both preferably. I don't have bike yet, so I can't do any measuring, trying to get a good start on how I want to dimension out the 2 into 1 I'm going to build for it.

https://youtu.be/hGAR539cmAs

I have never been able to get this lovely sound out of my head, I will gladly lose some HP to have my NSR sound like this.

[breezy]

The problem with that idea is that you will end up with differing A/F ratios within the scavenging streams.
This will then in effect produce almost a stratified charge scenario within the compressing mixture.
Unless you can do a heap of CFD or try an endless combination of air, or fuel, or both in different places, the chances of fluking
the best ( or even a good ) charge distribution is near zero.

Wobbly, what would identify that the engine was having this problem of stratification of the mixture?, erratic running at lower rpm? or all over the rpm range ? poor or erratic emissions?:sherlock: is there any noticeable difference in speed of air passing through the transfers and air fuel mixture passing through transfer ports?

[speedpro]

Mention is made of problems when the small injector is on for smaller times. Why not put a small injector in and have it on for longer to compensate?

The duration and it's possible effect has me thinking that it is more of a timing issue rather than duration. TZ has already calculated the fuel requirement. If that was all that was required the motor should run OK. It doesn't. TZ has probably tried it but what about radically changing the timing of the injection?

I was just thinking of air flow through the engine at the speeds and throttle settings that are a problem and it seems that a fair proportion of the air would simply pass on through. If that portion contained more fuel than it should, say in comparison to a carbureted engine, that might cause the problem. All the air going through a carb picks up fuel and that air then passes through the engine. With the injectors "on" for longer periods at higher revs and loads it would be starting to mimic a carb as far as having the fuel mixed with air and as TZ says, it works fine up there.

[TZ350]

Mention is made of problems when the small injector is on for smaller times. Why not put a small injector in and have it on for longer to compensate?

This is exactly my problem, in fact the only problem preventing this project from being a runner.

I suspect it is a fundamental problem with fuel injecting performance two strokes and was or maybe still is a problem for BRC too. I have seen video clips of them making noise on the dyno, but I can do that too. Has anyone seen a BRC EFI cart engine running successfully and competitively on the track, it would give me some hope.

I have tried smaller slow speed injectors and being on for longer, they work better and like you say, the rest of the answer could be in the timing. I have tried different end timings and found 180 to be a good number for the big injectors. I have about 20 injection end maps setup. Now that I have a better idea of what the issue is I will take some time to carefully try each one in turn again but with different end points for the small injector.

321151321152

For the slow speed injector I have tried the 128 - 80 - 60 and the 38 g/min units from a UAV, now there is only the 30 g/min unit that is smaller.

[Moooools]

Probably because we are not trying to emulate a carburetor. I particularly want to avoid the fuel laden blow back associated with a carburetor and see if I can take advantage of the possibilities offered by EFI. Its the learning that is rather challenging and very interesting.

Agreed. You are not trying to emulate a carburetor. That doesn't mean that starting with emulation isn't a good option. It is a very kiwi thing (and something that I am often very guilty of) to throw every idea into the air at once and see what happens , as opposed to a more iterative approach. Having the 'Emulate Carburator' box ticked off would be a mighty good step to sorting out many of the problems you have encountered. It is obvious that you have come very far with this. EFI can be a tricky beast, especially in very non standard setups. The further away you get from a 4cyl 4 stroke with a 6000rpm red line, port injection, and a single throttle body, the harder it gets - and you are pretty far off that.



The injector turns on for as long as it needs to to deliver the fuel required. You cant just turn the injector on 10 deg before the inlet opens and off 10 deg after closing. But the timing of the inlet gives a window of opportunity of about 6ms at 6,000 rpm and 3ms at 12,000.



Is that so different to the valve opening times for a high revving 4 cylinder? (Serious question, I don't know the answer)



321144

The next move is to try the slow speed injector in a throttle body and as its only on for 60% or so of the inlet event I will try varying its timing. Hopefully there will be a sweat spot .

This looks like a really good step to compliment your high speed setup, which does look like it is behaving well. Having the injector downstream of the throttle will stop all of that fuel dropping out of the air as it comes up against the stagnant sections before the throttle. Plus lots of time for mixing of the fuel. I would expect you to see some success with that setup.

My last thought is that you (as far as I remember) are running a single tooth crank pickup. At low throttle I would hazard a guess that the engine speed varies substantially throughout each revolution. It is possible that the injection timing is not where the ECU thinks it is, especially if it is on the opposite side (180 degrees out) to the crank pickup. I think the sort-of-standard for EFI at the moment is a 60 tooth pickup with 2 missing teeth, so that cank speed can be checked several times during each revolution.

[husaberg]

Yes, the window of time is wide enough. Was there any on track drivability comments.



..... :D
Message needs more carrot/actors

Riley Will BRC
http://translate.google.co.nz/translate?hl=en&sl=fr&u=http://www.pit-lane.biz/t839p15-technique-2-tempset-l-injection&prev=search
gentlemen,

2 years ago I did an Indirect EFI project was 125cc Disk Valve Kart Racing Engine. I used a Vortex engine qui FC Produced 49HP carbureted. With our EFI, it made 55HP !!! The engine was very easy to start and the tuning Was very simple. Here is how I did it:

Rather than attach sensors to the Figure out everything for me, I Went with information That Was Known to me. I have been tuning Dellorto carbs for years and needle-have used Their charts along with various software That calculate Comparative MainJet Sizes throttle at 10% increments. I used this information to calculate initial year map for the injectors. I did a test on the carbureted version of at Each throttle position to score the EGT That Was Giving the proper performance. Once running with the EFI i tried to tune it to achieve achievement la même EGT numbers as the carburetted versions.

In total I ran for 3 hours on the dyno and ended up with 10% more power everywhere!

The only sensors I used Were Throttle position, engine RPM, Crank Angle, and Water Temp for initial start up enrichment.

How did I get an injector to fire every cycle at 15,000 rpm ?????? I didnt! What I did is used a butterfly Janvey 41mm throttle body with 2 injectors on the engine side of the butterfly. That way When the throttle is closed, fuel still feeds the engine to lubricate it like a Jet Pilot Would do. To get 15,000 RPM, I Had Each injector firing at alternating engine revolutions. Thereby the injectors Were seeing 7500 at 15000rpm pulse of engine speed. I tricked 'em into thinking This was a 2 cylinder 4 cycle engine firing in tandem.

In total I Spent $ 1,600.00 in componentry to validate my "Simple EFI" idea! I will be doing more tests this winter and will be testing track in the spring. We are workind miimum on the battery and packaging requirements.

I used 2.5 bar of pressure and will be more testing. I thing a disk valve engine for the symmetrical inlet timing. I used a valve at the open 137 degrees BTDC and closed at 87 degrees ATDC. I started firing the injector 10 degrees Earlier on the opening and stopped the injector 10 degrees partner after the valve closed.

Upon engine disassembly It was Noted que la lubraction Seemed to be better Dispersed thru-out the engine (only an observation). The engine Would start at less than 800 rpm of speed and crank Would Instantly accept full throttle from 1200 rpm and load up!

The only hurdle I see is to come over the packaging.

I am confidant That my way of Giving the ECU the MAP Rather than calculate the HAVING the ECU map is why I was successful. We-have tuned by EGT for years and continues to see the relevance When using EFI in correlation to EGT. Increase the power cam by better fuel atomization. It stands to reason due to the limited time "tuning" the system That-even more power gains are to be Realized with more work and data collection / analysis.

I am posting this information so more people will try this easy method and post Their results here. I hope you all find the success That I did.




BRC (make Rotax 256 copy kart engines) Riley Will (who contributed to the pitlane.biz RSA thread) spoke the most sense there

The 2002 500cc bikes used 35-36mm carbs with electronic solenoid type power jets.

KTM used a hybrid system where they used an injector to augment the fueling requirements. It was used in their 250cc program, but I'm not 100% sure if they used it in the 125cc bike as well. Probably, but I cannot be certain.

Aprilia was guilty of throwing out what they perfected (carburation)and introducing a totally new concept loaded with technology EFI system. It was an intelligent system that made all the theoretical calculations at light speed..... It was a perfect system....... Too perfect! For years 2 stroke engine development was being done using less than perfect carburetor. This includes rider knowledge, tire construction, and suspension..... The end result was that the riders and machinery (tires) couldn't cope with the instantaneous increase in torque when the throttle was opened while at maximum lean angles.

When I discussed how I was going to do my EFI, their main electronics engineer started clapping..... What I wanted to do (and later did) was to upload a fuel distribution curve similar to a Del'Lorto needle/tube (needle jet) combination and did not let the computer adjust it. I used a TPS, H2O sensor, Air temp sensor, and Hall Sensor for crank angle/rpm. This way I was using what I knew, but getting the benefit of 3 bar of fuel pressure and injector atomization. I had total control and could add fuel to make the fuel curve "imperfect" if need be. I used 2 injectors mounted on the engine side of the throttle valve and I alternated their firing so that I could rev upto 15000 rpm. That way each injector was mislead into thinking it was feeding a 7500 rpm max 4 stroke cylinder. In total I invested $1600 into the total system and had it running pulling load on the dyno in 3 hours.

Riley later says he timed the injector to squirt 10deg before inlet open and finish 10deg after inlet close

[wobbly]

Lots of interesting ideas coming out of this.
And yes doing a sort of simulation of a carb ( that we know can be tuned even with the flow reversing 3 times ) might help along the way.
What about a pair of injectors situated in the transfer case cutouts ( facing each other at right angles to the transfer flow ).
This way the injected streams might collide and help breakup of the mist, but also simulated a full case of fuel as a carb does.
And secondly i really agree with the 60 tooth idea, this is exactly the reason it is used.
But you will need to find out if the ecu is capable of continuous speed detection during a cycle.
Just programming in the number of teeth ( if thats possible ) may make no odds.
I know Ignitech say that their injection ECUs need at least 20-1 teeth to function correctly.

[TZ350]

The injector turns on for as long as it needs to to deliver the fuel required. You cant just turn the injector on 10 deg before the inlet opens and off 10 deg after closing. But the timing of the inlet gives a window of opportunity of about 6ms at 6,000 rpm and 3ms at 12,000.
Is that so different to the valve opening times for a high revving 4 cylinder? (Serious question, I don't know the answer)

Yes I think so, in several ways. Probably the most obvious is that a 4T does not rely on a significant pressure wall in the exhaust port to stop fresh mixture escaping on the compression stroke.

A 4T's exhaust valve is very effective at blocking the exhaust port whereas a 2T has all sorts of problems stopping fresh mixture escaping. I suspect that in my case the escaping mixture carries some, none or all of the injected fuel with it.

[Moooools]

But you will need to find out if the ecu is capable of continuous speed detection during a cycle.
.

Very good point!
I heard a story of some guys who were having trouble with a single cylinder engine, and spent some serious time putting more and more trigger teeth on the flywheel, and changing the settings in the (quite high end) autronic ECU. Problem was, although the ECU could take many teeth, it still only used one tooth per cycle to calculate engine speed! The setting was just there to tell it to ignore the other 19 teeth.