ESE's works engine tuner

[jamathi]

But still, the divider between A-port and B-port on RSA/RSW cylinders also have quite small radius.

Of course a bigger radius was tried.
The result was less power....

[husaberg]

Hopefully next round of improvements well see over 50hp, lifts the front in 2nd with no clutch, can win races outright against GP250's.

Main thing is it is tuned to the point of deto each time it hits the track.

Details of the spec Lozza cylinder carb pipe etc.

[SwePatrick]

Of course a bigger radius was tried.
The result was less power....

As i suspected, the design you ended up with, was not left unattended before choosing it
And it runs hand in hand with my own experiances.

Programs and flowbenches might say one thing, but real life tells you the real thing =)

[Jannem]

Professionals in this board have shared that the CCR of 1.3 is something to aim for w. developed case reed engines. If you can’t maximize carburetion, will you increase CCR?

[katinas]

Thanks Husa. Indeed Eric Gregor write about Cr 125 2000-2003 midrange weakness and resloved this with V3 reed.

Add yesterday footage

https://www.youtube.com/watch?v=U_3pT-ku99o
https://www.youtube.com/watch?v=munV4DRt9nc

[katinas]

one more view.

Interesting, will you choose Jan"s transfers cooling channel.

[Muhr]

As i suspected, the design you ended up with, was not left unattended before choosing it
And it runs hand in hand with my own experiances.

Programs and flowbenches might say one thing, but real life tells you the real thing =)

On flow sim as I did, a divider with smaller radios makes less "noise" on the flow next to it. but it does not help with velocity which the inner and outer radius of transfers does, I think both of these designs fulfill a task.
But on the other hand, the SX cylinder has a design as you advocates.
What is best I do not know, but what I tried to do is imitate the rsa as far as I could.

[Muhr]

Interesting, will you choose Jan"s transfers cooling channel.

Thanks

Have not seen that picture before!

My first sketch I had it in but then it has been forgotten a bit but will look at it

[SwePatrick]

On flow sim as I did, a divider with smaller radios makes less "noise" on the flow next to it. but it does not help with velocity which the inner and outer radius of transfers does, I think both of these designs fulfill a task.
But on the other hand, the SX cylinder has a design as you advocates.
What is best I do not know, but what I tried to imitate the rsa as far as I could.

One should be careful with what programs says in simulations.
They can almost never simulate the pulses correct.
And one need to simulate if doing so, the fact that it isn´t constant flow in the transfers.
It´s more like 'piston builds up pressure' and then it´s like puncturing a ballon when piston opening the transfers, and quickly after that the pipe extends the time the transfers flows and that with less pressureratios.

The faster engine revs the more simularities with constant flow it becomes, but still there is the same function only faster.
Due to air is compressable and tunable with helmholtz one can get very cool features like a shitload of power =)

My new cylinder i experimenting with has increased volume in transfers as i want the 'bulk load' of fresh gas close to the piston ready to be pressed in by crankhousepressure.
But i haven´t increased the footprint against the engineblock.

And by this i also have a question to all.
To securely fill the transfers with fresh load of airmixture when piston is going upwards.
Could it be a good idea to have holes drilled from cylinderliner against the innerradius in transfers?
Just so the piston opens these ones earlier than normal when the cutouts in pistonskirt opens the transfers on the underside.

An old Malossi or Zeta cylinder for Honda MT5 had this idea:

[Jannem]

My new cylinder i experimenting with has increased volume in transfers as i want the 'bulk load' of fresh gas close to the piston ready to be pressed in by crankhousepressure.
But i haven´t increased the footprint against the engineblock.

And by this i also have a question to all.
To securely fill the transfers with fresh load of airmixture when piston is going upwards.
Could it be a good idea to have holes drilled from cylinderliner against the innerradius in transfers?
Just so the piston opens these ones earlier than normal when the cutouts in pistonskirt opens the transfers on the underside.

An old Malossi or Zeta cylinder for Honda MT5 had this idea:

Don't have experience to reply to you exact question, but here's what I intend to try for the same goal:
Keep the transfer volume relatively small and make a radiused outward bulge into the transfer entry in the cases. Puts volume where it needs to be, increases pressure at the entry. It will make the long side of the transfer wall look shorter (more equal length to short side), which should be a good thing, as air is not only compressible, but also elastic fluid.

[koenich]

But on the other hand, the SX cylinder has a design as you advocates.

reg. the 50SX cylinder, in my opinion it always makes sense to keep in mind that it was originally designed for a non-gearbox kids motocross bike and not as a 20+ HP racing cylinder...so in the design are probably some features which the designer wouldn't do for a proper racing cylinder.

[katinas]

Could it be a good idea to have holes drilled from cylinderliner against the innerradius in transfers?
Just so the piston opens these ones earlier than normal when the cutouts in piston skirt opens the transfers on the underside.

An old Malossi or Zeta cylinder for Honda MT5 had this idea:

Very interesting question about cutouts in piston skirt.
Reed and rotary engines works in different way. Zeta MTX is reed valve and this windows can help. But rotary engine exhaust, at the closed inlet condition , can't suck additional fresh mix from carb and this is one of the major difference, that playing on crankcase volume, exhaust, conrod, carb....
When RSA piston (in pic), with very low cutouts, is at TDC, transfers, maybe not open at all ( we need to ask Jan ). Maybe strong fluctuation in transfers is very important on rotary engine with closed crankcase ( more than with reeds) and any holes in the duct, can destroy this nice exhaust-crankcase orchestra.
Interesting, if 125 cc rotary engine with 30 mm carb can reach 47hp like TM.

In addition to this, last year tested piston with deep pockets on sides (add pic ), and when piston moves up transfers open very early, and some part of fresh mix goes directly to trans duct from boyesens. From first ride feels different in comparison with std. piston: from 10500 to 12500 rpm more power, but little less from 8500 to 10500 rpm. Can't remember how many times change these pistons for comparisons and always this piston was a winner. Plus 1000 revs more than with std. piston. But again,this is reed engine, not rotary.

[Jannem]

Very interesting question about cutouts in piston skirt.
Reed and rotary engines works in different way. Zeta MTX is reed valve and this windows can help. But rotary engine exhaust, at the closed inlet condition , can't suck additional fresh mix from carb and this is one of the major difference that playing on crankcase volume, exhaust, conrod, carb....
When RSA piston, with very low cutouts, is at TDC, transfers, maybe not open at all ( we need to ask Jan ). Maybe strong fluctuation in transfers is very important on rotary engine with closed crankcase ( more than with reeds) and any holes in the duct, can destroy this nice exhaust-crankcase orchestra.
Interesting, if 125 cc rotary engine with 30 mm carb can reach 47hp like TM.

Would be also interesting to know where the cutout is located when the transfer begins to open and when it's fully open vs. the cutout in the cylinder.

[Muhr]

Interesting, will you choose Jan"s transfers cooling channel.

This is what I managed to do.

[katinas]

Would be also interesting to know where the cutout is located when the transfer begins to open and when it's fully open vs. the cutout in the cylinder.

Piston, with low cutouts, at BDC masked big part of cylinder bottom cutout and maybe this again work in good way.
Maybe with low cutout piston runs cooler and more masked trans duct help maintain higher density mix in ducts, before trans windows opens. And at very high revs at BDC, more isolated ducts better resist to exhaust gas. But this is only considerations.
Interesting how many times gas fluctuated in trans ducts at different revs, before transfer windows opens: 1/2, 3/2, 5/2.......