ESE's works engine tuner

[wobbly]

Tapering down the green area will effectively reduce the transfer duct volume , this it may not like.
Remember back to the old TZ cylinders , where it proved that the A port duct shortened by 10mm with the B port duct left stock length made a good increase.
Putting the bore edge radius on the duct entry has worked every time for me.

[wobbly]

Katinas , can you post a pic of the " milled " plug nose please.

[jfn2]

Wobbly is this what you mean?

[F5 Dave]

Tapering down the green area will effectively reduce the transfer duct volume , this it may not like.
Remember back to the old TZ cylinders , where it proved that the A port duct shortened by 10mm with the B port duct left stock length made a good increase.
Putting the bore edge radius on the duct entry has worked every time for me.

So it draws from that duct like reservoir ready to be used you are perhaps implying? So even though it will continue to draw from the cases that plug ready is beneficial, even if in some cases there is reverse flow first.

When I modified my MB100 I lowered the port floor to match at BDC, possibly 2mm, then glued a curved section onto the inner wall and worked for ages to get it even and checked shape with moulding rubber again and again so the passage didn't contract then expand at the port.
Lost 1.5hp out of 27.5.

I suspect that I did some good things but then took 2 steps back by reducing the volume, and my next step was to be to grind more area in the outside of the cup handle. . . . and then I had a bout of gravity and development stopped. Need to urge the new owner to let me loose on the barrel when its next off.

Does that make sense?

[ceci]

Totally agree with creating a dedicated thread. Something simple like: "A clean 2 stroke". Probably under Buckets, though Oddball is another option.

Hi Ken. Excuse me for the nonsense that I am going to suggest, but I am beginning to wonder if we have not gone in the wrong direction regarding the anti-pollution solution.
The denial of the manufacturers to the use of an auxiliary piston pump (attempt to keep the 2S as simple) to carry out a load stratification (solution to the short-circuit effect) led the researchers to choose the lines of research in which the crankcase only can have clean air, this research line begins with "Multi-Layer Stratified Scavenging (MULS)" by Blair G. P, until the rest of the investigations both with auxiliary compressor (pre-pneumatic injection system) and without it.
And why not twirl he omelette "a typical Spanish saying", instead of using the air from the compressor to create the mixture of air and fuel, we use it to create a wall as a solution to the short circuit

I have a fuel injected 2 stroke scooter. 2001 Aprilia SR50 Ditech. I bought it not running. Was at 2 shops that
couldn't figure out how to fix it before I bought it. It sat for 2 years in my possession before I decided to look at it last weekend. Got it running in an
hour.

Runs pretty good until the fuel pressure regulator starts acting funny. I'm pretty sure this was the original culprit of problem for previous owner. Regulator isn't available for separate purchase.

I'm installing an external adjustable regulator and then doing some mods, and having a little fun with trying performance mods

In case you do not end the problems of the fuel pressure regulator and decide to change to the use of a carburetor (something very common "if you look in the Aprilia forum there are many cases").
Why not try something different, keep the air injection system (create the "avoid short circuit" wall) together with a carburettor supply

[katinas]

Wob, add plugs from testing with NS engine, all milled on lathe, but my friend doing the same with a grinder, even on 10 mm plugs for sx 50/65.
Its good to use 22mm deto type plugs and after milling 3 mm, use them like 19mm with std washer. Otherwise some correction on the head is needed.

With fixed advance timing on kart engine, maybe you noticed that, resistor plug together with bigger gap, little bit delay ignition and opposite, non resistor plug with small gap, advances ignition. I am not sure, but sometimes, engines react that way. Testing with Suzuki RGV 250, that sapc stock ignition timing is set at safe retarded zone and pick ups is fixed. I try non resistor plug with small gap and non resistor plug cap. Engine goes more aggressive. But maybe this is just coincidence.

[WilDun]

Hi Ken. Excuse me for the nonsense that I am going to suggest, but I am beginning to wonder if we have not gone in the wrong direction regarding the anti-pollution solution.
The denial of the manufacturers to the use of an auxiliary piston pump (attempt to keep the 2S as simple) to carry out a load stratification (solution to the short-circuit effect) led the researchers to choose the lines of research in which the crankcase only can have clean air, this research line begins with "Multi-Layer Stratified Scavenging (MULS)" by Blair G. P, until the rest of the investigations both with auxiliary compressor (pre-pneumatic injection system) and without it.
And why not twirl he omelette "a typical Spanish saying", instead of using the air from the compressor to create the mixture of air and fuel, we use it to create a wall as a solution to the short circuit

In case you do not end the problems of the fuel pressure regulator and decide to change to the use of a carburetor (something very common "if you look in the Aprilia forum there are many cases").
Why not try something different, keep the air injection system (create the "avoid short circuit" wall) together with a carburettor supply

I am fairly certain that Neil (Flettner) did use a plug of fresh air between the charges in his earlier OP engine - but he can speak for himself! - (Blair was using it in a conventional cylinder).
Also, using the crankcase as an (under piston) pump has the disadvantage of preventing the use of four stroke type lubrication (either wet sump or dry sump) will have oil suspended in the air, being burnt with the charge and not addressing the problem of a smoky exhaust, which was really the cause of the whole road going two stroke versus public 'misconception' in the first place!

I hope I have not misunderstood it all!

Sorry Ken, I only butted in because I'll be going to bed soon! .....

[Frits Overmars]

My question is about the shape of the transfer runners. My question is do I trim some of the bottom off or is it better to leave it alone? The red lines show where I would taper the runner. Should I make it more of a 2 1/2 finger teacup handle rather than a 4 finger "D" handle?

Radiusing the bore edge, like Katinas and Wobbly suggest, works every time. A radius of 6% of the bore would be a good value.


As for the remainder of the transfer duct inner walls, it should be noted that the smallest radius will be decisive for flow detachment. It's no use making that radius big in some places when it reduces the radius in other places, so go for a the biggest constant radius that can be fitted in within the available space.

[katinas]

DiTech
Remember the Aprilia manufacturer's strong recommendation for dealers. Before selling DiTech, after the first start of the engine run it as soon as possible at maximum speed, so that the preservative oil would not burn into the nozzle and the spray system would be cleaned as soon as possible.
DiTech biggest problem was not properly atomized fuel spray and because of that, fouled small 10 mm nearly up side down located plug. Maybe bigger 14 mm vertical located plug resist better.

Honda RS 500 with Hans Humel's cylinders. Just want to take under the armpit.

[jonny quest]

On a Ditech SR50 the fuel is injected through the head as piston closes exhaust port.

It still has a standard looking cylinder with case reed.

I'd like to get more performance out of cylinder, but transfers are just moving air.

I'd like to hear some of your ideas on how to increase performance with the cylinder porting

[Haufen]

Thank you all for your encouragement, I just created a new thread under Buckets.

https://www.kiwibiker.co.nz/forums/s...post1131166129

I am looking forward to many interesting discussions!

Clean 2T and 2T revival is very interesting. My two cents worth. Continuing here is OK or adding to this thread https://www.kiwibiker.co.nz/forums/s...2T-EFI-Project might be interesting or a new one altogether but still within the Bucket forum where most of the inventiveness with new ideas is done.

Thanks, I was thinking back and forth over the last couple of day and then went for a seperate thread under buckets. Let's see how that goes.

Yes a separate thread might be good. But are the best ideas going to be published? Just to get used by industry with no recognition as to where the concept came from. I was / am all for publishing everything but if its any good it will get pinched. We will all need to understand this up front, and that 'industry' will try to patent it for themselves, so we will have to keep a good eye on provisional patents. Rats run 'industry'.
You can actually provisionally patent stuff relatively easily and cheaply, but you will only have 12 months after that, full patent, or let it go. And the buggers (rats) know this.

Edit, you can get up to eighteen months protection but that will cost a little extra.

I fully agree, and I have also experienced the same as you with one of my ideas in the past. The company was not as big as KTM in my case, but it made me much more attentive to intellectual property and the behaviour in the industry. Good thing is, once something has been published, it is free for everyone to use. Other (cheaper) variants to a patent are for example sending some new stuff to one's self in a sealed parcel or envelope and best with a post stamp showing the date directly on the seal. But these are problems we yet have to have, although it's never too early to keep this in mind.

I think that you'll have to spend a bit of time going over all the other threads and find out just who your interested people really are - or try and get some interest started! - difficult one - do your best.

BTW we don't know if you are a Kiwi or not! - some possibly do.

if you happen to know some people that you think might be perfect contributors to the thread, please give them an hint.

I am from Europe, but if I ever happen to move to NZ, one of the first things on my list is getting a bucket, that's for sure!

Please go ahead and start a new thread with clean two strokes.The game of wringing more power out of a given amount of cubic is dying.
Two strokes can improve environmental issues on small aircraft engines.There is no catalyst demand and some of the pigs use leaded petrol.

https://www.homebuiltairplanes.com/f...-angels.32119/

Absolutely, even if two-strokes might not get 'car engines clean' in the end, every bit cleaner than now will open up new possibilities in other areas.

Seriously though, a thread along the lines of what is being considered would be great and all we really need to do is listen to those who have "been there" but at the same time, have the ability for everyone to put forward some proposals, (good or bad), accepting the fact that we might be talking crap and get crucified for it! (I do!) - BTW no place for PC crap here!.
The clean two stroke should be the big focus, with minimal digressing from the subject - now lots of other threads around here for that!

- go for it Haufen!

Yes, let's see what happens. Worst case is we learn something

Totally agree with creating a dedicated thread. Something simple like: "A clean 2 stroke". Probably under Buckets, though Oddball is another option.

Just what I thought.

-------

The starting post in the new thread is not yet completed (emissions part still in progress), but please just start right away, no need to wait.

[JanBros]

I don't think I'd be interested in a 2-stroke without exhaust port(s) and without an expansion chamber, even if it's very clean.

[Flettner]

Twin rotary valves, although these cases are for a uniflow project, they are able to be set up as a twin rotary valve. Crank can be 48 up to 58, so plenty of room to make it a 100cc bucket engine. Gearbox is 175 Kawasaki. Clutch is 250F. Bit of paint and a sand next.

[jamathi]

It would be really interesting.
Other thing to worth to try, milled spark plug, that Frits and Jan advice to try, is very helpful.
With this year Huqvarna TC 85 we ended at 31,53 hp with std spark plug.
Then milled plug 31,1 hp
Then retard ignition with woodruff key (approx 3mm retard at lobe) 32.06 hp 11876 rpm (from rear wheel with triangular 16 inch woody 1992 GP Dunlop front slick tire)
Std plug with retarded ignition 31.45 hp and lower everywhere except at over 12500rpm.
Looks like milled plug shortens the burning time, maybe due to the plug inserted deeper into the chamber, closer to piston and/or due to the more open ceramics.

We tried this at Aprilia about 20 years ago. It gave about 0,7 HP more. The problem was that we could not possibly modify hundreds of plugs to satisfy all our customers. Asking the plug manufacturer to produce plugs that way would have meant to throw our advantage away...… So it was never done anymore.... Another interesting thing: a plug was returned to us after a race with the earth electrode completely broken off. But it had finished the race, so it was tried on the dyno: about 1HP more! Very nice, until after a couple of runs the ignition coil failed.... It might have worked with a better ignition coil.... Which we didn't have!

[jamathi]

Radiusing the bore edge, like Katinas and Wobbly suggest, works every time. A radius of 6% of the bore would be a good value.


As for the remainder of the transfer duct inner walls, it should be noted that the smallest radius will be decisive for flow detachment. It's no use making that radius big in some places when it reduces the radius in other places, so go for a the biggest constant radius that can be fitted in within the available space.

The Aprilia cylinders had a constant inner and outer radius in the transfer ducts. Doing this gave a really big improvement!. The narrowest point of the duct was the port itself, 12,25mm. Transfer timing remained the same for all 12 years of development. Maybe I should have tried a shorter timing, now I regret that I never did.... One of the biggest improvements came from making the port UNDERSIDE being made exactly as high as the piston in BDC! Many cylinders are wrong in this respect, the piston top causing severe disturbance to transfer flow, and detonation.... The most sensitive point in the cylinder proved to be the A-port front side, the nearest to the exhaust port. It's direction was machined to be very much angled away from the exhaust, as far as material thickness allowed. In this way it could be made wider, giving good improvements. Wall thickness was 1,5mm between water passage and duct.