ESE's works engine tuner

[wobbly]

The VF2 from a CR125 makes really good power in the RS125, way better than stock and way better than the later VF3.
I discovered this years ago when I built a TM125 MX motor for karts, I tested 8 different setups and the VF2 blitzed them all.
By product also was that the reeds lasted for 3 seasons with 3 National titles, and around 30 races in total.

[husaberg]

[URL]


There is some real Gold on that Pit-Lane thread.

Not sure if the link will work.
Some of the Jan story in English.
I was Looking for stuff on Herman Meijer and tripped over it.
http://translate.google.co.nz/transl...80%26bih%3D827

[TZ350]

Page 830 links list to go here..

Looking for the good stuff ....

... some may find this useful. Rather than use the site search which usually fails, use Google so to search this site use an ordinary search phrase and after it add

site:www.kiwibiker.co.nz

for example

Frits priceless site:www.kiwibiker.co.nz
or
Frits pisa site:www.kiwibiker.co.nz

the same will work for other sites with the appropriate site address

Mick

Plugging piston pins ......


http://www.pit-lane.biz/t4140-2-stro...troke-wristpin

I have a little question about a Cagiva Mito barrel with large booster; how plug up the wrsitpin, avoiding the "short circuit" between exhaust and transfer?
It's a 16 mm pin, can't fit an Aprilia GP pin!
I'm thinking to put some kneadatite into the pin ID..any suggestions?
Thanks

Aprilia wristpins were made by Pankl.
It was done by welding.
Every different solution we tried was a failure.
Maybe they will make some for you too!

And another approach taken by Wob, if any one is doing the piston pin thing this may be worth a try too.

Why put the plug inside the pin with a "new"" groove,there is already a groove available and also there is a chamfer on the end of the pin that can be used - as it was previously - to force outward, the retainer
into this groove.
Wont say any more as this stuff is Frits intellectual property , but with all the pics flying about its quickly becoming public property.
I made these plastic plugs several years ago using glass reinforced Peek,and tested them with no positive results at all.
But now we have tripple ports reaching around to 1/2 bore, and yes they do work a treat.

Then Wobs thoughts on cylinder heads and plug to piston crown distance.

To do a toroid properly you need to drop the plug tip to approx 6mm from the piston crown.

Means welding the chamber and counterboring the plug seat face.
Very difficult to do repeatable and accurately unless done on CNC.
I model the piston dome and the head shape in SolidWorks to generate a solid then I have an accurate curve the toolpath follows and a calculated volume.

You dont really need the Ex timing to establish the head geometry, and yes the 6mm number seems to work with most " usual " combustion chamber geometries.
Avgas works with anything from around 192 to 202 Ex duration at around 15.8 full stroke.
Smaller bores or lower bmep setups can go 16.2, big bore oversquare or very high bmep like slightly less at 15.5, air cooled of course needs alot less.
As long as you hit the lower mechanical squish depth limit, then adjust the width to hit 38M/Sec MSV you will have good squish turbulence that helps the flame speed - reducing any tendency to deto
the end gasses.
That MSV number is meaningless in the context of all but hitting the head when within the normal rev limits, but as a guide it works every time.
The sharp bowl edge increases the flame speed, and a very deep angle away from that edge into the bowl is synergistic by pulling the turbulence further into the combustion space, again increasing the flame propagation speed,
over a wider band.
Pushing the combustion parameters this hard means a digital ignition is mandatory to balance the timing against the high peak cylinder pressure now being generated.

No free lunch today except that its all been done before and in most cases a guide is available.
It depends upon the stroke length, the piston weight and the crank integrity.
Suffice to say that a 125 single will usually go down to 0.65mm when spinning to 14000
A 250 twin like the RGV with a single middle bearing will go 0.75 spinning to 12,000
A 250MX type with 72mm stroke is OK at 1mm spinning to 11,000.
But I stress again, as I dont want the Honda faggots off their forum abusing me that the NSR wont rev if taken below 0.8mm - the ignition has to be optimised
to work with a combustion chamber that is designed correctly, and does actually do what its supposed to.
A stock PGM simply wont cut it - but then we wont be using HRC parts, so they just cant be any good at all, as everyone should realise.

Yep, looks fine.
The flat squish area should have 0.1mm taper upwards from the bore edge.
As I found the piston will clip the inner edge first when the vertical gap is at the mechanical limit for the rpm.
This is the sort of shape you are after.

There is only one rule grasshopper,NO radius from the squish into the bowl.
The other rule is to pull the squish down to the mechanical limit - ie probably around 0.7mm on an RGV then adjust the width to get around 38M/Sec MSV, usually 45 to 50%.
This generates good response and " torque" as you put it - but for sure will need a digital to retard the top end advance to get the overev back.

[Frits Overmars]

Yes there is lots of good information on the Pit-Lane thread, I hope they don't mind if I re post bits here (with full acknowledgement to the original authors of course) from time to time.

Pit-Lane won't mind at all; on the contrary. And Jan and I will love it .

[TZ350]

Thanks.....

[TZ350]

Finally found a throttle cable in the junk box's at work that is long enough and with the right sort of fitting for the end. And it took some searching around the shelves to find a twist-grip that would open the ball valve in a quarter turn but everything works OK now.



The MAP sensor is usually plugged into the inlet tract just behind the throttle body but it is subject to a lot of strong pulsation there, particularly on a 2-stroke. So I have plugged it into the Boost Bottle in the hope that it will be able to make a more "average" reading of the absolute inlet tract (manifold) pressure from there.



Next move is to start wiring the EFI and IgnTec.



Looks like both The EFI and Igni use the same 5V source voltage for their TPS so I plan on using the EFI as the source and splice in the IgniTecs TPS grey position sensing input wire to the EFIs white sensing wire so both units see the same variable voltage.

I am familiar with setting the Ignitecs TPS range and expect the EFI should be able to be set in a similar way.



Det Sensor

Next week I hope to get all the chopping and changing of the wiring done then I can start playing with setting up the Ecotrons EFI program for a trial run.... such excitement....

[RomeuPT]

The VF2 from a CR125 makes really good power in the RS125, way better than stock and way better than the later VF3.
I discovered this years ago when I built a TM125 MX motor for karts, I tested 8 different setups and the VF2 blitzed them all.
By product also was that the reeds lasted for 3 seasons with 3 National titles, and around 30 races in total.

Many thanks Wobbly

If I remember the stock vforce came with 0.45 thick carbon reeds, and they have a bolt on piece with "high" and "low" in each side, high makes the reeds more pressed against the cage, I always run them in high.... but...

[dmcca]

The basics of good head design have generously been explained here already so I thought id post up this pic to show a new direction that KTM seems to have taken this year with their motocrossers...

Both heads are from a KTM250SX (sorry i know this is a buckets thread!)... in both pics the head on the left is a slightly modded 2011 (same basic shape as stock) and the head on the right is the latest 2014 version (stock)... You can only assume in their testing that its worked for them but it does go against a lot of whats been spoken about here and elsewhere about what comprises a good head design...

[wobbly]

The low tension gives a bit more bottom end, but loses overev and the tips shatter real quick.
At the time KTM125s had this reed as stock, I know VeeForce dont stock it any more.

[SwePatrick]

I´ve searched this huge thread, no luck.

but, do you guys talk about pressure in pipe(middle of belly) somewhere?
I´m researching about how high the averagepressure should be.

Rgds
Patrick

[2T Institute]

All the various capacities use a common VF2 cage with the flange mount screwed to the cage is how they get the cage to fit different manufacturers. KTM use the same cage size for 125-380 only the size of the entry hole differs

[Flettner]

Patrick, I too am interested in total average pressure in the chamber. I'm assuming it's probably two or three psi ?

[RomeuPT]

The basics of good head design have generously been explained here already so I thought id post up this pic to show a new direction that KTM seems to have taken this year with their motocrossers...

Both heads are from a KTM250SX (sorry i know this is a buckets thread!)... in both pics the head on the left is a slightly modded 2011 (same basic shape as stock) and the head on the right is the latest 2014 version (stock)... You can only assume in their testing that its worked for them but it does go against a lot of whats been spoken about here and elsewhere about what comprises a good head design...

That's not very strange, If I remember in a post earlier from this topic (I think was a wobbly post) was said that yamaha test's said the other way about the radius from the squish to the bowl. And most Honda RS head that I have seen use a 2mm radius.

Glad KTM still try to improve the 2 strokes...

[marsheng]

What silicon or similar will standup to petrol and oil in a 2 stroke crank case? I have blanking plates I want to seal in.

[Muciek]

I use Victor reinz it's best IMO http://www.reinz.de/root/eng/afterma...2_ENG_HTML.php this is how it looks http://image.ceneo.pl/data/products/...reinz-70ml.jpg .