ESE's works engine tuner

[marsheng]

I'm looking for a Yamaha FZR250 front wheel that takes 2 disks. 17" x 2.75 is ideal. I have a single sided rim that I can exchange for your twin or I can buy your twin. Tried TM but none available. Thanks Wallace 03 3237449

[Flettner]

I got my bottom end sorted
I'll post a before and after, after being, picking all the bits up from where they spreed themselves round the yard

Nah, just tricking, there are plenty of engine parts around the yard but most of them got there by osmosis not by explosion. But the "bottom end" will do 3000 revs driven by the milling machine, now to just add another zero. We did however have a small seizure of one crank hydrodynamic bearings, thats just a fancy way of saying plain metal bushing, probably should put an oil pump in it to supply those hydrodynamics. We are talking a ryger style bottom end

[Flettner]

Now, what to do with the top end? I was just going to run an AG 100 barrel ( one of those engine parts deposited around the yard) just to make it work but I'm thinking bugger it, I'll make a "proper" cylinder, one with a high under piston pressure and short transfers ( very short piston ), back three ports will be piston port and 180 dgrees later same ports will feed straight into the cylinder. Got to start somewhere don't we? I'll leave the transfer reeds out for the miniute. Just enough knowlage to be dangerous
If only the ring is in contact with the bore, will the cylinder wall need any coating? Cast from high silicon alloy, no coating, best heat transfer yet.

[Lightbulb]

Either way Neil, your are going to be much wiser. You will learn that it works and all is well, or you will learn it is another thing not to try again.
Neil L

[Flettner]

Either way Neil, your are going to be much wiser. You will learn that it works and all is well, or you will learn it is another thing not to try again.
Neil L

I wish that were true, usually you just end up with more questions. What is it "the more you know, the more you know you don't know" or something like that.

[Lightbulb]

Well with model engines, I have a huge library of what does not work and is a waste of time that people swear is worth xxxx rpm.
Like you say, the more you do, the more you realise you just don't know.
That is what is so interesting about the Ryger engine. Even guys like Frits has had a major challenge to his thinking on how these simple things work.
One day we will all be enlightened and I hope it is not too far away.
Maybe some of the ideas I have about how the engines work may not be so far off track after all, or else I maybe completely wrong and have only had some success from the odds of try enough things and eventually something has to work.
Neil

[adegnes]

"Success consists of going from failure to failure without loss of enthusiasm."
- Winston Churchill

[adegnes]

Now, what to do with the top end? I was just going to run an AG 100 barrel ( one of those engine parts deposited around the yard) just to make it work but I'm thinking bugger it, I'll make a "proper" cylinder, one with a high under piston pressure and short transfers ( very short piston ), back three ports will be piston port and 180 dgrees later same ports will feed straight into the cylinder. Got to start somewhere don't we? I'll leave the transfer reeds out for the miniute. Just enough knowlage to be dangerous
If only the ring is in contact with the bore, will the cylinder wall need any coating? Cast from high silicon alloy, no coating, best heat transfer yet.

Fast forward a couple of months; The Ryger engine turns out to be nothing like this at all, but now The Flettner is churning out 80+ hp @ 20000 and safely reving past 40k.

[adegnes]

Hey, maybe this whole Ryger thing is just a scheme to get alot of minds on the case of making a better two stroke...

[Flettner]

Hey, maybe this whole Ryger thing is just a scheme to get alot of minds on the case of making a better two stroke...

That has certainly happened, this not burning oil is a huge advance.

[WilDun]

Hey, maybe this whole Ryger thing is just a scheme to get alot of minds on the case of making a better two stroke...

I agree, this wave of enthusiasm can't possibly pass without some sort of good spinoff !

[Flettner]

Now, what to do with the top end? I was just going to run an AG 100 barrel ( one of those engine parts deposited around the yard) just to make it work but I'm thinking bugger it, I'll make a "proper" cylinder, one with a high under piston pressure and short transfers ( very short piston ), back three ports will be piston port and 180 dgrees later same ports will feed straight into the cylinder. Got to start somewhere don't we? I'll leave the transfer reeds out for the miniute. Just enough knowlage to be dangerous
If only the ring is in contact with the bore, will the cylinder wall need any coating? Cast from high silicon alloy, no coating, best heat transfer yet.

Thinking about the top end again last night (another sleepless night), the transfer reeds might have to be there even for a half resonable test.
One thing did come to light with yesterdays test, the crank I'm using is one end off a four cylinder and is ballanced as such so it will shake a bit. I WILL have to fit a ballance shaft or make a proper crank. With the engine being made from solid alloy it won't be a problem to bore a hole and fit a ballance shaft. After the way a ballance shaft fixed my 700 twin vibration, I like them.

[WilDun]

After the way a ballance shaft fixed my 700 twin vibration, I like them.

Do they soak up much power?
Just a thought, - the forces we are trying to cancel when using balance shafts are actually still there, the opposing forces are there also and any force requires energy to produce. - then maybe I'm just being a wet blanket?

[AndreasL]

While waiting for the Ryger revealing I might amuse you with my own first steps with two strokes...

I know its so many things that are wrong (look at the pictures) but without showing them and asking for advise I will never learn, and thats why I'm here.

I wanted to have a look at the piston and recheck the squish after my first runs. Glad I did.

Basic info and known issues:
- 60's design, 50cc, lasy commuter moped.
- Aftermarket (OEM copy) cylinder with 2 crap transfer at 129°.
- A too long (straight) header and crap after market pipe.
- 12:1 com and ~0.95-1.0 mm squish all over the squish band except for the outer most part that was 1.05-1.12.
- Mikuni Vm18
- 19-20° straight ignition

The goal was a street engine peaking at 7500rpm.
EngMod has been used to get all data. It corresponds really well, but at a lower power level. (Need to finish the FOS-pipe.)

Things to fix and thoughts about what can be improved:
- Reangle the squish band and set it to ~0.6 mm. Lower will probably be fine but the crank is old and weak so play it safe.
- FOS-pipe like the one in EngMod needs to be made. Have great hopes for this one but who knows...
- Play with the ignition. EngMod says 16°, but to be honest, the effect is small in my sims. Maybe cos of the low revs?
- To me it looks like I'm still rich? Down at 80 main jet started at 110 that was really bad. Started with a 30 pilot jet and now at 17.5. The mixture screw still needs to be turned out to far. Have a 15 and a 12.5 to try but it feels small???
- Running 4% Shell Racing M (castor). I know about the build up of carbon etc. From the pics one might have second thoughts about running such oil in any thing else then racing applications at 15000rpm?
- I have tried to point the crap transfers to the rear wall per Wobblys suggestions at ~60°. I also need to check the axial angle and alter it with the "stucco verde" I recieved the other day if not at around 30°.
- Replace the #8 spark plug with a 9. I'm under the impression that things a bit warm? Hope a decent squish will help lowering the temp.

Any readers left?

Please add any thoughts and suggestions that can be read from the chamber pattern.

Last I would like to thank the Kiwi Biker Forums, Frits, Wobbly, TZ350, Neels/EngMod and all others here that have taught me more or less everything I know about 2T.

And now for the embarrassing part...the pictures.
About 100 km running. 70 km with the 80/17.5 jets, 60/40 slow riding/maximum load.


Ex port to the right


Ex port pointing down

Thanks for listening!

[Flettner]

Do they soak up much power?
Just a thought, - the forces we are trying to cancel when using balance shafts are actually still there, the opposing forces are there also and any force requires energy to produce. - then maybe I'm just being a wet blanket?

It takes energy to shake (move) the engine, as in vibration, so yes the balance shaft does use power but it also saves wasted energy by stopping the engine actualy moving (30,000 times a miniute if it were Ryger)
As in the 700 twins case, I wouldn't want to fly without a balance shaft as I'm sure the engine would rip itself out of the engine mount in a very short order. No more cracked exhausts.