ESE's works engine tuner

[wobbly]

1.43 case com is insanely small and will not help power production in any way, shape,or form.
You will need to do everything you can to get some volume in there, heading for 1.33.
Barrel spacers ( long rods will help here as well ), reed spacers, cut the case for crank clearance etc etc

[Flettner]

Hey TZ. Is there a chance that the ball valve you're using with the bike injected, is screwing with the air flow at part throttle and causing the detonation?

I see the two sharp edges creating a wicked flow disruption when I picture the valve partially open, and I recall Malcolm (koba) once showing me a simulation of air going through different shaped carbs and trying to explain the pros and cons of each scenario.

If the ball vale was a problem, it would have shown up on the Kawasaki F9 ( same valve ). Could it be any worse than the back side of a carb?

[Drew]

If the ball vale was a problem, it would have shown up on the Kawasaki F9 ( same valve ). Could it be any worse than the back side of a carb?

Only gets disturbed once with a carb, on the bottom of slide. Not on the leading edge and then the trailing edge.

[wobbly]

A slide with corners front and rear, 1/2 way down, has a big round hole in front of it - and a big round cavity on the other.
Sounds like a huge 2X flow disruption to me.

[Flettner]

Only gets disturbed once with a carb, on the bottom of slide. Not on the leading edge and then the trailing edge.

Have a close look at how the ball works.

[husaberg]

likely overstated a bit, artistic licence.but...

[TZ350]

Only gets disturbed once with a carb, on the bottom of slide. Not on the leading edge and then the trailing edge.

True there is a sharp trailing edge at part throttle but at wide open WOT there is an unobstructed and smooth tract. The Kawasaki F9 made 45 rwhp with this style of throttle.

[TZ350]

Hey TZ. Is there a chance that the ball valve you're using with the bike injected, is screwing with the air flow at part throttle and causing the detonation?

True as well as the EFI the throttle is different too, hadn't considered that, but the runs are done at WOT and I get patches of deto and deto at 11 to 12K+rpm and heaps of deto on over run with a closed throttle.



The Blue line is my best with transfer port injection the Green line is where I have got to today with the twin injectors aimed down the inlet throat. It was the same map as the transfer port injection, and better than yesterdays single injector effort. But not as good as the transfer port injection and no where near as good as my best with a carb. Today I just fiddled with the injection endpoint then a bit of map tweeking.

Anyway today was not a total bust, as I got to have lunch with Kel at a neat little cafe in Ellerslie.

[peewee]

1.43 case com is insanely small and will not help power production in any way, shape,or form.
You will need to do everything you can to get some volume in there, heading for 1.33.
Barrel spacers ( long rods will help here as well ), reed spacers, cut the case for crank clearance etc etc

disregard the 1.43. originally i had 1.34 with all standard oem parts measured with oil. engmod was saying 1.43 but the only thing that i can think of that changed was a oem reed block to the vf4 which would decrease volume alittle but not much i wouldnt think. ill have to do some digging and find out why the numbers aint matching up. maybe its not that important because i know how much oil i poured in, i can just base any further parameter changes off the original oil number.

do you think 1.324 is to much volume ? if anything the performance might gain nothing but lose nothing either

[husaberg]

I have never noticed this cylinder Nor do I know what variant it is, Anyone?Attachment 306581

I think this is a DEA cylinder

Right. In fact it's two DEA cylinders; the left and center pictures show a 2013 cylinder; the right pic shows a 2014 cylinder from the DEA superkart tandemtwin with RSA-based cylinders. The notches in the bore surface are supposed to retain some oil for the benefit of the exhaust bridges.

They look a bit more than just notches...Do they go through to the transfer ducts ? When i saw them in the pic I wondered if they matched holes in the piston skirt at BDC for a little under piston cooling/mixture moving through but assumed not for reasons you'd already mentioned.

No Grumph, notches don't. This picture shows under what angle and how deep the cutter went in.Attachment 306604.

Thank you Frits - much better angle to see how deep the notches are. I suppose the question is - did they work ? If they weren't used on the later engines, the assumption is, it wasn't worth doing....

That picture was from a 2013 DEA cylinder because it showed the notches best. But the 2014 cylinder has them too, so they can't be all bad.
Andrea degli Esposti (DEA) is a free thinker who does more than just copy Aprilia stuff. Here he is with his home-built pulsating flow bench.

I was watching the gnani making a GP bike Video and I was pretty surprised to see this.


https://www.youtube.com/watch?v=I-2rJtnkYq4

Also I don't speak Italian ...Anyone what the heck is this all about?

[breezy]

Stay away from this dentist stuff, unless you can get it for free. Doing one 125 cc cylinder once took me five dentist sets. When the cylinder was ready, all five sets were binnable. The bevel gears and bearings are just not up to the job.
If you can afford it, look for a hand tool with a swiveling head. I can't find a picture so I will try to describe it: there is a 30° kink at the business end of the handgrip. The right-angled head can swivel around the kinked axis, so the angle between the handgrip and the cutter can vary from anything between 60° and 120°.

It won't be any different from what we are used to, Breezy. On the flow bench the central scavenging column created by the six incoming transfer streams has proven to be very stable; even if I blocked one of the transfer ducts completely, that column remained intact, albeit off-centre. And the exhaust characteristics depend on the gas dynamics in the pipe. The gas will be the same, the pipe proportions will be the same, so the pipe behaviour and the engine characteristics will be the same.

Here:
http://www.pit-lane.biz/t117p318-gp1...-part-1-locked
http://www.pit-lane.biz/t117p333-gp1...-part-1-locked
(it took me over an hour to find those links; I think I should cut back on my forum activities. Which one should I drop first? )

Like any other pipe resonance-dependent two-stroke.

Sure, also like on any other pipe resonance-dependent two-stroke: programmable ignition, power jet, power valves, trombone pipe.
But since I am under the impression that you can build anything you can think of: how about shrouds in the transfer roofs? If you lower them, you will lower the transfer timing, so wrongly-timed exhaust pulses will have less chance of shoving fresh cylinder charge back into the transfer ducts. Moreover, lowering the transfer timing while leaving the exhaust ports alone will increase the blowdown angle.area. That will put an end to the dreaded part-throttle detonation that plagued all Aprilia racing engines.
Taking this thought a little further, you could even use the movable transfer ceiling instead of a throttle.

I am, and I wonder why you would think so. Like I mentioned above, the engine character will be no different from what we're all used to at the moment.
Having said this, I am all in favour of CVTs.

frits, would this barrels scavenging sytem be defined as " reverse flow"?

[wobbly]

As I have said before I have never seen a power increase when going bigger than 1.3 ratio with a reed.
But it seems that the worse the transfer ducts are - the better the engine performs with a slightly tighter case.
So around 1.32 will be fine

[peewee]

im about to join the aux tunell into the main tunell. is there any general rules for how far the divider should extend into the main tunell ?

[F5 Dave]

More metal mass in that area has to help I'd think to pull heat away to the rest of the cooler barrel.

[peewee]

i checked a unporterd 250 cylinder and the divider was 20mm long. cant imagine i need to be any more than that, maybe even less but it should be a good place to start i guess