ESE's works engine tuner

[seattle smitty]

That's funny, Jeff. That attachment of Frits' (post #23014) is about the first attachment of his that I ever have gotten to open and read (but I readily admit to being computer-stupid).

[Martin1981]

The cr125 rods are 104mm

Ok. Thanks Jonny!

[Bert]

Spent an enjoyable day playing with the dyno and EFI system.

I took the time to carefully check the actual timing of the injection end point. I did it in much the same way you would check the ignition timing with a strobe light and found that where the software said it is and where it actually is, is pretty much spot on.

After a lot of careful work starting just before the transfers open and making 5 deg incremental adjustments until just after the transfers close. I found the best spot for my engine was to finish the injection cycle at 200 deg before TDC.

The Ectrons EFI system measures everything in deg BTDC, so my transfers open 245 deg BTDC and close 65 deg BTDC and by experiment the best injection end point is 200 deg BTDC, so a lot of the injection cycle into the transfers is happening before the transfers actually open.

Attachment 322261

Now that I have confirmed that the injection end point sweet spot is around 200 deg BTDC. The mass flow simulations make more sense. When you look at the Engmod2T simulation for my bike, of mass flow through the transfers. They all peak at about 200 deg BTDC. Or just before BBDC, and around BDC is where Wob says the pipe should be sucking the hardest.

The Ecotrons EFI software has an injection end map that allows for fine tuning of the injection end point over a range of RPM and Engine Load. So a bit of fine tuning to do but for now I am confident that we are in the ballpark. And that if the software says 200 deg BTDC then that is pretty much what it is, I was never sure before.

Really interesting watching/reading you getting on top of this.
Keep the updates coming.
I had noted that ecotrons did a twin unit for a Ninja250 and have been following this thread with interest for the TZR250 project.

[wobbly]

Yes Martin, something is wrong - I have a second hand cylinder that was measured, and now I have a new one as well.
The new one has no stagger I can see - the second hand one has the big stagger, so im not sure what is going on yet.

[speedpro]

Really interesting watching/reading you getting on top of this.
Keep the updates coming.
I had noted that ecotrons did a twin unit for a Ninja250 and have been following this thread with interest for the TZR250 project.

The Ninja kit is what I have running on my FZR twin. Plugged straight in.

[Martin1981]

I have a second hand cylinder that was measured

Does it have the Stagger "cast in" from the Factory or is it ground in afterwards by someone?

Edit:just thought about it....the stagger can not be ground in afterwards. the no stagger cylinder has the 42,2mm distance from top of the c and b port to the top of the cylinder and the stagger cylinder also. so someone must have "lowered" (epoxied) the a ports roof to achieve the stagger but i think that is not the case.

[jfn2]

Wobbly
I looks like you got a RS 125 cylinder and not a CR 125 cylinder.

[Martin1981]

Wobbly
I looks like you got a RS 125 cylinder and not a CR 125 cylinder.

How can you know? might be an explanation but i think Wobbly is able to distinguish an rs and a cr cylinder.

[wobbly]

I can tell you with absolute assurance that Honda NEVER made an RS125 cylinder with reverse stagger like an Aprilia.
And the 04 CR125 was the ONLY model with a cable operated PV, that is why I got one to test fit on a NSR250 MC21.

[Sketchy_Racer]

So I have a question for the gurus of two strokes.

I have recently made some pretty big changes to my engine (NSR300) and as such have had a significant increase in power, spread and over-rev. These are all fantastic things that make me happy. In this change I have observed a lot stronger signal at the carburetor which has required me to reduce my Jet size considerably despite making more power.

Why is it that as the air velocity through a carb changes the fuel flowing through through the venturi is not proportional to this velocity change?

Cheers,
Sketchy

[wobbly]

Simple, the changes you have made will have contributed to making 1 or more of the 3 main variables, rise in value.
That is Trapping Efficiency,Scavenging Efficiency and or Delivery Ratio.
What accompanies an increase in 1 or more of these, is usually that you change the Brake Specific Fuel Consumption number ie Lbs/Hp/Hr - Kg/Kw/Sec
and thus make the engine more efficient at using the injested fuels energy to make power.
The bottom line, where say making the stinger bigger is a perfect example, is you have reduced the fueling needed to keep the engine alive ie using fuel to cool
the engine and prevent deto or seizure, and using it instead to make Hp.
Thus dropping the BSFC, means a leaner jet will make more power , safely - its a myth that more power automatically needs more fuel.
In fact depending upon the mods done, the carb velocity may well have DROPPED, but the air ingested is being used more efficiently to produce Hp.
And finally all of the above effects are easily seen and graphed in EngMod - not " just " the final effect of more Hp.

[jonny quest]

Does the NSR300 use the NSR150 cylinders?

I just received my MC21 here in the USA. I haven't looked at all my options yet, but I'm either going to do a +2mm over bore on stock cylinders using 00 RM125 pistons, or graft CR125 cylinders on mine. I have 2 05-07 CR125 cylinders already.

Wob, you are correct, 04 was the only year for the servo operated PV on CR.

[TZ350]

My latest adventure with the EFI is to adapt a Dellorto TPS to my favorite 24mm OKO carb.

Then the OKO can be run as an EFI throttle body or Carb for back to back tests.

I also plan to fit a wide band Lambda sensor and EGT and CHT gauges to keep track of things.




Wouldn't you know it, dam carb won't fit now!!!!!!! Ok now I have to cut some of the clutch cover away.



One of the EFI problems I hope to solve by comparing back to back EFI runs to the carb is this funny issue where on less than 20% throttle the EFI engine goes through cyclical patches as it is accelerating. Patches of running smooth and then rough then smooth again. The rough patches have a peak in the middle and diminish in amplitude overall as the rpm increases.

It is obviously a resonance thing, but what is resonating? Pipe? Transfers/Case Volume? Pipe/Case Volume???? Inlet .....



My current EFI issues are all about trying to get it running nicely at less than 20% throttle. Although you can see cyclical humps it looked like I was getting onto the money Ok when I got this <20% TP dyno run.



But I realized later that the nice graph was done in first gear and the spiky one is top gear. So under real load its still a bag of poo.

[TZ350]

The mid chamber bleed re visited .....
The mid chamber bleed re visited as it might be useful for some low end boost......
Ok the mid pipe bleed didn't work for me as a detonation suppressant but it did show a useful low end boost. The interesting thing was that there was very little noise from it.

Attachment 286902

Red line is the bleed in the open position, Blue is closed.

Attachment 286903Attachment 286904

And there was those who scorned me for trying this .......
I will re visit this again, maybe with a bleed system like Frits suggested.

Twotempi has suggested to me to try a different diameter muffler, different pipe and possibly re visit the pipe bleed experiments I did a while back, to see if its really a resonance issue and if some simple changes could help.

[jonny quest]

TZ350, you may have just solved your issues, and created a ton more work for yourself.

Sounds like you need to incorporate a gear position apparatus, and incorporate different maps for each gear