Simple reedvalve for SI carbs

[KTy]

I have rebuilt my PX125E engine, since then, I have very few power at low rpm...

I have re-wired the stator, I have changed for a new SI24/24, ... nothing... I cannot have it work good at low rpm, it simply lacks power !!

So, I am starting to remember that the crankshaft that I changed was maybe not very well appropriate considering that the admission window on the case was not in excellent shape... On one side, the crank cheek is not striped but it is not clean either, and on the other side, the aluminum crank case admission has one little stripe...

All in all, I think the rotative valve is not working anymore...

So, the plan is to build a very simple reed valve system, like the LML one and to put it just below the carb... Does anyone ever investigate this ? I do not want to machine my engine cases as it is my daily rider, I just want to work out something with the carb and the air box...

Mfg,

KTy

[MiNiKiN]

I have rebuilt my PX125E engine, since then, I have very few power at low rpm...

I have re-wired the stator, I have changed for a new SI24/24, ... nothing... I cannot have it work good at low rpm, it simply lacks power !!

So, I am starting to remember that the crankshaft that I changed was maybe not very well appropriate considering that the admission window on the case was not in excellent shape... On one side, the crank cheek is not striped but it is not clean either, and on the other side, the aluminum crank case admission has one little stripe...

All in all, I think the rotative valve is not working anymore...

So, the plan is to build a very simple reed valve system, like the LML one and to put it just below the carb... Does anyone ever investigate this ? I do not want to machine my engine cases as it is my daily rider, I just want to work out something with the carb and the air box...

Mfg,

KTy

KTy,

I reckon it is not easy, if anyway, to achieve this without milling/modifying the cases AND not to get your carb up in mountainous regions.

I built an adapter to fit a Malossi reed valve with a Mikuni TMX. I imagine something similar, adapted to the LML reed and SI Carb, might work. It has got a height of 20 mil only. See picture

Edit adds some missing letters, f****g keyboard

Bearbeitet 16. Januar 2007 von minikin222

[KTy]

Very nice !

But as my engine is "stock", no high-end performance, I was thinking about something very thin, with one or two horizontal reeds, should be feasable in less than 10mm ! I am not looking for pure performances, I just want a better permitivity for the rotative valve admission system !

I will try to draw something...

[KTy]

Here you go... View from the bottom...

The drawing is far from perfect bu basicaly the idea is that the reed(s) can bend into the existing admission window...

Bearbeitet 16. Januar 2007 von KTy

[oli-san]

indian 150 ccm engines have such a reed inlet, I recall.

a guy in bremen once did this due to a worn crankshaft surface. just a piece of sheet metal and an old credit card it work well, though.

[KTy]

a guy in bremen once did this due to a worn crankshaft surface. just a piece of sheet metal and an old credit card it work well, though.

Yup, that's what I want to do...

This is probably simpler and should do the trick...

Bearbeitet 16. Januar 2007 von KTy

[freakmoped]

aufgehts machmal!

go on

sounds nice!

topic should be moved to gsf projects

[MiNiKiN]

@KTy: KIS-principle - good one, though the flow might be a bit crappy - but who bothers? as long as it worx

[KTy]

@KTy: KIS-principle - good one, though the flow might be a bit crappy - but who bothers? as long as it worx

Exactly ! Check the updated drawing... I have put some angle, it's not much, but it's better than nothing !

[Das _O]

Membran unter SI-Vergaser Topic

[KTy]

I guess this is what I am looking for: http://www.germanscooterforum.de/index.php...st&p=282204

[MiNiKiN]

I guess this is what I am looking for: http://www.germanscooterforum.de/index.php...st&p=282204

I assume that will need some milling as well. Didn't you want to avoid that?

[KTy]

Milling on the airbox side is acceptable even though it would be much better to come up with a simpler solution... I'm pretty sure you can fit the reed system in a 5mm-thick spacer...