YZ 250 EFI

[TMKIWI]

Yes Fletther and Uniflow are one and the same. Crazy bugger with a dodgy hip.

[rsmith]

Yes Fletther and Uniflow are one and the same. Crazy bugger with a dodgy hip.

Okay then, I guess I don't need to let him know!

I would be interested in where this project went though. 

[Flettner]

The YZ if you remember is not my bike, I made most of the hardware on it and helped with the tuning. The owner damaged a piston (I had the ignitec ignition too advanced) So it's not running at the moment.
But the F9 Kawasaki (mine) is still running fine, in fact better than ever as I've widened the exhaust port somewhat. The fuel injection has not been touched in years now. Chews through the ethanol but the result is 50 crankshaft HP, well worth it.
There is another YZ project running in Australia, Nathan Coleman. His bike is used on the street and he has a very good go pro video of it running around. On youtube.
 

[rsmith]

Thanks, this is the kind of stuff I wish I had a full enough skill set, and a big enough budget to tackle, so I find it fascinating. 

It is also interesting to see how much hasn't changed now in 2017. There were several post with speculations that EFI would be stock on the 2015 bikes. Now of course we know that hasn't happened outside of OSSA's trials bike.

Back around page 6 in this you had pictures of case half forms for a rotary valve intake if I remember correctly.

Did you end up making those?

[Flettner]

You are talking about the 360 reverse crank rotary valve engine (ECU) controlled)?
There was a lot of work done on this engine about two years ago (perhaps more?) and its to the point where I made an error in the RV housing. At the same time the Kawasaki (the ideas test engine for this 360) was running well but not exceptional so I lost interest. BUT now the Kawasaki is going so well I've got renewed interest in the 360 engine. I've also worked out a way around the RV housing problem, i'm going to use two slide gibs, one as I am now to alter the shut time and a second one that will change the open time. Both gibs will also act as the ECU controlled throttle.
To be fair I've been off on a bit of a tangent with the sleeve valve engine (running now) and an experimental HCCI (homogenius charge compression ignition) engine. And the casting of some other unusual cylinders.
Also part of the problem with the 360 was getting a decent cylinder casting, now all fixed, I've got three nice clean cylinders with blade type power valves. Best of all is I now can consistently cast porous free clean cylinders, also learnt to use LM13 alloy, better for nikasil to stick to. ALSO the Link controller I wanted to use has come down in price and has shrunk physically too, small enough to fit to a motorcycle now. 
But as usual these projects are after hours and funded by me so time will always be an issue.
And lately I've been spending a lot of time riding the Kawasaki in different events, sooo much fun! Love that power!
 

[rsmith]

Wow, you do get up to some interesting things.

Is the HCCI design similar to what Honda was calling Activated Radical Combustion back about 20 years ago?  Where is switches between SI and CI at a certain RPM?

That Kawasaki is awesome. Good thing your racing organization is not like AHRMA, those guys have a rule against everything. I think next they will be requiring period correct spoke nipples to go with there existing rule about having to run fanged rims.

[Flettner]

To be fair, the VMX guys didn't know about the Kawasaki's insides for a long time. AND I have to say, doesn't matter how much power I have, I still can't win. Some of those old riders are bloody good, I enter the Kawasaki in Vinduro now and various trail rides.
No, my HCCI is full time, a bit like a diesel in that it has an open inlet and is regulated by fuel only. problem with diesels is they can't mix and burn the fuel fast enough for true high speed operation but if the fuel is pre mixed like any fourstroke petrol engine then it's just a matter of raising the combustion chamber pressure at the right time to cause combustion. Mine has a small piston in the head running at twice the crank speed, this ensures a rapid pressure rise at the right time. It's on youtube somewhere, running. Just a modified Yamaha AG 100 engine. The video is pretty crappy but it does show the engine running and I've learn't a lot from this. I can now regulate it with the fuel volume. 

[rsmith]

The theoretical side of engine dynamics has always been something that I have been interested in, your lucky you live on a different continent or you'd have me lurking around your shop all the time

That's pretty damn cool. I will go hunt up the video.

--Ron.

[Flettner]

found it   https://youtu.be/TOHKls3Cxjs

[rsmith]

Cool. It ran away at the end there huh?

The spray gun as a carburetor substitute was an interesting approach, did you do that for better control?

[Flettner]

it's interesting, the run away at the end.
I thought the surging was because, as the revs increased the volumeric efficiency drops off (no pipe) so effective compression drops, so combustion stops. revs decay until the cycle starts again. If there was a load on the engine it would have run constant without surging. The little piston in the head on this version had only just enough compression to run so didn't take much reduction in induction volume for there to be not enough compression to run.
The run away at the end I think was caused by the little piston heating up (even though there were water cooling pipes from the head there was no water, too lazy to hook it up) and initiating the combustion with the aid of the pressure rise. Pressure and extra heat.
This little piston also aids in recovering energy from the combustion.
An interesting side note, the little piston is at it's TDC when the big piston is at BDC and TDC so technically it's volume doesn't come into the measurement for cc rating of an engine (for racing purposes). But mid stroke the cylinder will have more volume to accept more fuel air (than a normal engine) AND mid stroke on the other side the little piston will have helped expand the gases (for a give cc rating) . Neat aye.
I'm in the process of building a new cylinder for this engine and a new crankshaft. The crankshaft is a crank within a crank. It produces a straight line motion for the rod so the rod can be sealed off. Top end will be sealed from the oiled bottom end, engine will burn no oil.  https://youtu.be/-2AhNvDFNlQ
The rod in this video was dissolved by my local Anodizer so I'm building a new one. It's going to be sent to the US for hard chroming, we can't hard chrome 7075 alloy in NZ, allegedly.   

The spray gun was used as I needed an 'injection system' of some sort. I can't throttle the inlet and the jetting would have been too hard to adjust on the fly. Engine is controlled by fuel only. A bit like the diesel in that no matter how small the amount of fuel inducted, the pressure rise will set it off. We don't need a 12 to 1 fuel air ratio around the spark plug like a normal engine, there is no spark plug!

[Flettner]

Sleeve engine for those interested   https://youtu.be/6keqpL3rmwk
And walk around  https://youtu.be/TmXFkbD3s5g

[eprovenzano]

I've been following since you 1st posted it...  and it still fascinates me..  it's way out of my backyard mechanical skills...  but still fascinating 

[rsmith]

So I was thinking about your fuel delivery challenge.

What about something like a Lectron carb with a metering rod? Machine the slide so it just acts as a guide for the metering rod and only creates minimal restriction.

--Ron.

[Flettner]

Or just fuel injection.
I have a cunning cylinder (or at least I think so) based on the FOS system lined up for this HCCI job.
The FOS system is a cylinder where there is a ring of exhaust ports, then underneath a ring of transfers. In this cylinder I've run three of the transfers direct into the cylinder from atmosphere and the other three are boost type ports pointing up into the combustion chamber from the crank case. This system uses the same direct inlet transfers as piston port to the crank case, double jobs.
The injectors (x3), located in the direct transfers, these injectors only fuel as the crank case inducts and are shut off as the direct transfers feed air into the cylinder via the "pull" from the chamber. This will supply fuel air up into the combustion chamber and fresh air under this charge. SO only fresh air should be lost to the exhaust and fuel air trapped in the combustion chamber. This type of cylinder offers enormous blow down time, needed for high rev's.
In reality I don't know but lets see what happens?
I'll see if I can find a picture of this cylinder.