ESE's works engine tuner

[Frank S.]

Apriliaizing 😀, thats what we do to our twostrokes.
Thanks to the experts sharing their huge knowlege
👍🏻👍🏻👍🏻

[pete376403]

Turned up on facebook - seems appropriate to put it here

[husaberg]

We have moved far along from the old so called A Kit and Jolly/JL pipe designs , all enabled by Neels code , so all I am doing is using experience and technology to improve the mousetrap
.

It just occurred to me that Roberts JR bike was converted to Yamaha pipes dimensions and I think porting in 2000, I wonder if that was by proxy also Honda A Kit. like the KTM also seem to have been, It might explain why that Cagiva came alive in 1995 and why Cagiva and Yamaha keep changing bore and stroke and exhaust porting.

[wobbly]

The Roberts stuff was all Bud Askland , in mid 1999 I was at his workshop and he already had the new square 5KE cylinder and Kit pipe dimensions on the drawing board.
He had a Czech CNC anemometric flow machine running , as did Yamaha in 1999 according to Suzan the head engineer I met at Philip Island where Jaques finalized the 250 title.
Suzan ( ringlish name ) said that with the flow machine he did not need a dyno anymore , and he had brought a set of 500 cylinders with him, that would give a bunch of top end power to suit the track.
No idea though what was done to the Cagiva at the time , a bit before I started getting into the pits.

[41juergen]

Yea well Frits I am trying to optimize a 1991 TZ250 using as much trickery as i can muster.
As I have explained elsewhere this whole 10 year series of Yamaha's were pig slow due to their fixation on the short stroke and adding as many transfer ducts as they could.

Some of the results will help others, but hey all this thing can win is a National Trophy for a set period racebike, big deal , so I feel no need to be a secret squirrel.
The 3XV roadbike has "normal" 5 transfers that can be Apriliaized , and the Ex duct exit hits 0.8Mach at the 50 Hp level with no welding needed.

We have moved far along from the old so called A Kit and Jolly/JL pipe designs , all enabled by Neels code , so all I am doing is using experience and technology to improve the mousetrap
so more people can catch more mice.
Not quite as cool as a Kart World Title , but I have a bunch of those already.

Edit : As I said to Jan a short time ago , his contributions as espoused by your online explanations I use nearly every day - Im just expanding on that with newer , and now tested ideas.

And the idea was born based on your advise: to get power, you have to balance the STA's... thank's a lot for sharing all the wisdom with us!

[husaberg]

The Roberts stuff was all Bud Askland , in mid 1999 I was at his workshop and he already had the new square 5KE cylinder and Kit pipe dimensions on the drawing board.
He had a Czech CNC anemometric flow machine running , as did Yamaha in 1999 according to Suzan the head engineer I met at Philip Island where Jaques finalized the 250 title.
Suzan ( ringlish name ) said that with the flow machine he did not need a dyno anymore , and he had brought a set of 500 cylinders with him, that would give a bunch of top end power to suit the track.
No idea though what was done to the Cagiva at the time , a bit before I started getting into the pits.

Around 94 Cagiva changed its bore and stroke to 54x54 and in my Cagiva album are these pics these would be looking at them much earlier.
George V.....(the short fella)whose last name escapes me came from HRC to Cagiva about the time they started to get competitive.
my understanding was yamaha helped Cagiva but maybe the tech went both ways....they even went to Keihin carbs at the same time.





Then we have this change in 1997 for Yamaha to bridged exhaust from the superior triple port the year before was the move to 54x54mm.
https://global.yamaha-motor.com/show...g_yzr500_0wh0/

On this model, the "V" bank of the 4-cylinder engine was widened from 70 to 75 degrees in order to allow an increased air box capacity. A "T" type exhaust port (existing 3-port layout changed to 2-port) known for its excellent pick-up characteristics was also adopted experimentally on this model. This combined with a new crank assembly spec and a higher drive shaft position to achieve improved handling stability. On this machine Cadalora mounted the winners podium twice with 2nd-place finishes and twice with 3rd place to finished the season ranked 6th

in 98 they went to Honda owned Keihin carbs a well.
it's just supposition of course.

[41juergen]

I got 5 L of this Motul Outboard 2 stroke oil. Is that ok for use in a road going sports bike?

[yatasaki]

I got 5 L of this Motul Outboard 2 stroke oil. Is that ok for use in a road going sports bike?

No, TCW3 oils are made for cool and slow spinning engines.
Believe me, didn't work well on mopeds, chainsaws, and scooters

[wobbly]

CNC inserts done for the big piston/head shape shootout - 4 pairs.
Head covers awaiting some material.
Just have to spend a couple of days grinding ports - my favorite job , Not - then have the plating done.

[Grumph]

i remember seeing a post showing the layout of a thermosyphon system with thermostat.
By wobbly I think.
The search function isn't finding it for me.
Anyone keep a copy or know where it is ?

thanks

[husaberg]

i remember seeing a post showing the layout of a thermosyphon system with thermostat.
By wobbly I think.
The search function isn't finding it for me.
Anyone keep a copy or know where it is ?

thanks

it wasn't wobbly...
he did post a few with thermostats.

https://www.kiwibiker.co.nz/forums/s...post1131218438

[Grumph]

Thanks Husa for that. Memory said it was thermosyphon.
Now looking at pump drives.

[husaberg]

Thanks Husa for that. Memory said it was thermosyphon.
Now looking at pump drives.

for your application look at how a KTM50 drives it

They just drive it off a tab nut on the mag shaft. they have also the sexiest tiny mag you will see. they later ones are digital.
or off the third shaft and accept they have to leave it in gear on the grid

[F5 Dave]

Wonder how long a tool battery would drive an electric pump? If of course you don't have an alternator. A Turbo booster brushless pump worked well on the MB100.
But I did have the CR250 stator and ignitech. Never sagged voltage on the dyno.

[wobbly]

So here is the next interesting project , YPVS 350 classic racebike on pump gas - no deto.
This thing also has the old Yamaha drum PV , but no Aux ports - so way better than the original Banshee.
Its got a Nova close ratio set in it , so it was begging for me to go spastic on the tune.
It went thru the roof in the sim when I added the Wobbly duct and that damn weird concave rear cone - again.
I Apriliaized the porting again like the 3XV, but wont know what head to put on it until those are dynoed in the TZ250 test session.
Only domed TZ350 single ring race pistons are available from Meteor, so it will be ported , then the stock size iron bore plated to be able to keep on using that same piston size.