ESE's works engine tuner

[husaberg]

This was the 250.

Quite different looking in cylinder detail from the Biagi 250


whoops wrong pic thats the 500.


So the pic on the right is the Biagi cylinders made elsewhere?

These is the cylinders i normally associate with an early Aprilia

I have an DEA almost copy of it

[Martin1981]

Attachment 330177Attachment 330178


My pictures show the ultimate two stroke configuration.
Ligth,even pull ,simple and nobody can claim that it will not work yet.

Does it have a common crankcase for both cylinders?

[husaberg]

Seen this today neat
https://grabcad.com/library/aprilia-...nder-incompl-1
seeing one in 3d is pretty neat
Needs a little work on the AUX exhaust

[Niels Abildgaard]

Does it have a common crankcase for both cylinders?

Yes,thats the big plan and only one common inlet for crankcase.
If the underside of the lagging piston controls this inlet we get the phase skewing as a disc valve without the complication.
I have some parts but lack motivation for the time being

http://i.imgur.com/n36caso.jpg

Hi Martin You are from Trabant country.
Find an used engine and let us make the Trabant engine like this
Should hae been done really many years ago.

[Martin1981]

Yes,thats the big plan and only one common inlet for crankcase.
If the underside of the lagging piston controls this inlet we get the phase skewing as a disc valve without the complication.
I have some parts but lack motivation for the time being

http://i.imgur.com/n36caso.jpg

Hi Martin You are from Trabant country.
Find an used engine and let us make the Trabant engine like this
Should hae been done really many years ago.

yes, indeed. i was born in the GDR. but i am not proud of the trabant and it is engine. it is crap in my opinion. but the reason for that are for sure not stupid engineers but stupid assholish politicans... 26bhp? i don`t agree!

[jonny quest]

Jan you settled on a dome piston. Which other types were tried and what were the results?

[jamathi]

We tried various flat, and radiused pistons, but the original ROTAX dome always gave the best results.
With flat pistons the flow detaches which gives less piston cooling.

[diesel62]

Hi Guys new here
Trying to learn a bit about EGT .I would have thought the temp would have kept climbing to max rpm .Is the lag just the time it takes for the sensor to heat up ? or is there another reason
Any help would be appreciated

[2T Institute]

So the pic on the right is the Biagi cylinders made elsewhere?

That looks like the unloved APD cylinder.

My take on the twin crank is the single crank engines the head angle has to be steeper to over come the gyro effect of the crank. Early Kobas frames used at 27* head angle which is mx territory. The Kobas could run that rake but still change directions a fast as the TZ/RS's. Contra rotating cranks seem to have less tyre chatter as well. Less vibrations make them far easier to ride faster.

[2T Institute]

You may need new glasses its also in Austrian
It was all there was on the Net sorry.
http://www.artmotorsport.com.au/new/...nual%20Pt1.pdf
There are plenty of pics here of the crankcases
including a scaled down wood pattern someone made for 50cc cylinders.

https://www.kiwibiker.co.nz/forums/a...p?albumid=4839

https://www.kiwibiker.co.nz/forums/a...5&d=1413591174
https://www.kiwibiker.co.nz/forums/a...6&d=1413591175
https://www.kiwibiker.co.nz/forums/a...9&d=1413021975

They are 3D printed cases from a 18yr old fellow in Italy (shits me someone so young can have all that talent ) for 125cc he is getting help fram Garbriel Gnani (his cylinders)

http://www.2t-special.it/forum/viewt...hp?f=14&t=5065

[jonny quest]

We tried various flat, and radiused pistons, but the original ROTAX dome always gave the best results.
With flat pistons the flow detaches which gives less piston cooling.

Did you try the hybrid Yamaha style? Flat top with chamfered edge?

[jamathi]

Yes, of course....not better!

[jamathi]

Biaggi's cylinders were named APB, originally designed by AVL in Austria
As designed they were useless, but they were developed very well by my colleagues at Aprilia.
Only Biaggi used them, their development was stopped in the beginning of 1998, when the APC became better.
The APD was a 7-port cylinder which proved useless.
It had been developed using a Jante-type flow bench, made in Brno, Czechia.

[jamathi]

Quite different looking in cylinder detail from the Biagi 250


whoops wrong pic thats the 500.


So the pic on the right is the Biagi cylinders made elsewhere?

These is the cylinders i normally associate with an early Aprilia

I have an DEA almost copy of it

These are APC cylinders, copied by many kart engine manufacturers.....

[jamathi]

Does it have a common crankcase for both cylinders?

No, would not have made any sense.....
See the picture.
On the right the 250 with APB cylinders.
A longer stroke was tried without success.
And during one test the piston pin came out of the carburetor....