ESE's works engine tuner

[peewee]

commom logic says the full window should be uncovered at bdc but ive seen some piston manufacturers have the windows even lower so the full window will be uncovered when the piston edge is covering about half the transfer window on the upstroke which suggest nothing is going forward through the reedvalve until the piston is well on its way up

[wobbly]

Common logic knows nothing.
There is no flow thru the reeds and thus into the case around BDC.
Flow in most all reed engines isnt initiated until TPC on the upstroke, this is when the reeds have finally opened enough for flow to start.
Thus the most effective intake strategy is to have as much area as is possible at TDC, and as much area as is possible via floor and
Boyesen ports.
Holes in pistons are best as low as possible, along with the biggest piston cutaway as is possible to reduce port masking as it rises and drops from TDC.
Here is a typical ( my TZ400 at 11,000 ) cylinder reed intake mass flow and Mach.

[peewee]

thnx wob i figured yamaha knew where the windows needed to be even 30yrs ago since they were very low on the skirt. some wisecos i seen are much higher and probly useless by the time the reedvalve opens. my ktm cylinder is all but finished with only the plating left to do and cutout the piston windows

do you know of any internal photos of the 2017 ktm stuff with the counter balancer ?

[Frits Overmars]

i figured yamaha knew where the windows needed to be even 30yrs ago.

Yamaha even knew there shouldn't be any holes at all in piston skirts 40 years ago, and they also knew reeds should be on the cases, not on the cylinders.
But they were not going to throw away the cases they had in stock, so they fitted reeds to the cylinders and made holes in the pistons.

do you know of any internal photos of the 2017 ktm stuff with the counter balancer ?

Will this float your boat peewee? https://transmoto.com.au/ktms-two-st...ampaign=buffer


EDIT: It's advisable to keep your brain in gear when reading through the above KTM link, because you will also encounter pearls of wisdom like

Two-stroke engines have.. always been notorious for vibrating way more than their four-stroke counterparts.

[Frits Overmars]

Holes in pistons are best as low as possible.

No kidding!

[husaberg]

Will this float your boat peewee? https://transmoto.com.au/ktms-two-st...ampaign=buffer


EDIT: It's advisable to keep your brain in gear when reading through the above KTM link, because you will also encounter pearls of wisdom like

Frits they are hardly reinventing the wheel there are they...........

That counter balancer looks exactly the same as a NSR125 set up amongst others.

[Frits Overmars]

Frits they are hardly reinventing the wheel there are they. That counter balancer looks exactly the same as a NSR125 set up amongst others.

True, KTM didn't invent anything here; they just implemented it. Which is not a bad thing.
Here's some more interesting reading from KTM:
https://transmoto.com.au/2017-ktm-ex...e-engine-guru/
https://transmoto.com.au/2017-ktm-ex...e-rd-insights/
https://transmoto.com.au/2017-ktm-ex...gn-philosophy/

[peewee]

frits dont you think a dirtbike would be better off with zeroshift type of transmission? maybe faster laps and less gear wear

[Frits Overmars]

frits dont you think a dirtbike would be better off with zeroshift type of transmission? maybe faster laps and less gear wear

Sure, and better still with a CVT. And not just dirtbikes but any vehicle.

[wobbly]

Maybe that piston is part of the new Ryger technology Frits - be careful about the NDA you have in place.
We already have case and cylinder induction, that could just about be described as crown induction.

[peewee]

frits do you know why the people from ryger didnt consult with jan , early in their endeavors? seems like his wisdom may have saved them some grief

[jonny quest]

Honda had an automatic transmission in a dirt bike, early 90's I believe.

Cvt at this point would be difficult to get correct on a dirtbike. Cvt's are excellent at from a dead stop to wide open. What they're currently lacking is the on and off throttle, back shifting.... always being in the best RPM range of a 2 stroke.

What if, what if on the RYGER. Let them figure it out. No big deal. We all want to see something exciting, new revolutionary. If it works in the future, great.... but I'm sick of people chastising them. Let them do their thing.

[peewee]

of course let them sort it out but what if you had another set of experienced eyes looking at it

i hear there were 72 scientists, engineers and mathmeticians involved in the eifel tower construction

[jonny quest]

I have a feeling Jan would want nothing to do with that project. This is me assuming

[jonny quest]

What Ga are the titanium GP 2 stroke pipes made of? And what Ti material?

Can they be welded in atmosphere with just a longer leading cup?