ESE's works engine tuner

[breezy]

[QUOTE=ken seeber;1131058170]Fletto, absolutely. Well done Alex.

Always wondered if this one actually ran or even started. (was a simple Ozzie mod to make a Beeza Bantam to put out more than 3 hp].... things have moved on Ken... bsa bantam 125 aircooled

[oldjohnno]

I can imagine a reed valved engine making more power without the obstruction of the reed in place - but does a rotary valved engine benefit in the same way? A rotary valve, when open, gives no more resistance to flow than if there was no valve at all... and if the longer duration does give a power increase wouldn't this have shown up in the timing tests that so many have done?

A long time ago, when most two strokes were piston ported, I experimented with intake timing and found that too much intake duration helped the top end but also killed the bottom. At low RPMs they'd load up easily from double or triple carburation and lost a lot of torque. On a race bike I guess this isn't a problem if it can be kept on the pipe. The standoff was quite noticeable in Alex's video; it'll be interesting to see where in the rev range it clears up. I can't wait to see the dyno results.

[adegnes]

Fletto, absolutely. Well done Alex.

Thanks!

Funny when one sees a reed valved 125 kart engine not even start/run properly when a reed tip has broken off. Maybe the starting was due to being cranked with an electric starter, whereas that muscly Alex was probably spinning his at well over 2k rpm at least. (Probably could have done more, but didn’t want to wake all his kiddies).

A RV 2T running with no RV, that is truly epic --- --- very much looking forward to hearing if it's ridable.

Haven't been this excited for a long time!
As long as it can rev into the powerband with no load this should work.

I can imagine a reed valved engine making more power without the obstruction of the reed in place - but does a rotary valved engine benefit in the same way? A rotary valve, when open, gives no more resistance to flow than if there was no valve at all... and if the longer duration does give a power increase wouldn't this have shown up in the timing tests that so many have done?

A long time ago, when most two strokes were piston ported, I experimented with intake timing and found that too much intake duration helped the top end but also killed the bottom. At low RPMs they'd load up easily from double or triple carburation and lost a lot of torque. On a race bike I guess this isn't a problem if it can be kept on the pipe. The standoff was quite noticeable in Alex's video; it'll be interesting to see where in the rev range it clears up. I can't wait to see the dyno results.

Good point!
With my setup what's going on below or low in the powerband isn't too important.
Guess it boils down to if ever increasing intake duration when rpm rises beyond peak power is beneficial or not.
If you had a "variable with rpm" rotary valve, how would you set it up beyond peak?

[jfn2]

In the video it looked like some of that blue mixture in the squirt bottle was dripping into the brown mixture in the glass. Good video.

[adegnes]

In the video it looked like some of that blue mixture in the squirt bottle was dripping into the brown mixture in the glass. Good video.

Haha, Thanks!
The blue stuff is Brunox(like WD40). It's good at wicking into places, and also out of squirt bottles.

[Frits Overmars]

Haven't been this excited for a long time!

Two-strokes can do that to you .

[speedboy]

A RV 2T running with no RV, that is truly epic --- --- very much looking forward to hearing if it's ridable.

Why Epic?

A lot of people are riding with broken or missing reed petal
-> Strange idle, weaker performance

[F5 Dave]

My H100 broke a steel reed. Started as easy as the pie I'm currently eating. Actually it's more a corrnish.

Did notice a stutter up top that sent me searching. But that's a small section of a 4 petal reed. Not a gapping hole.

Having experienced load up on a piston port bike which on race start, bogged unrecoverably until the clutch basket was replaced I'd expect a similar load up if thrown too much load quickly. Auto clutch no idea how they behave.

I thought you had no chance of starting that. Until it burbled time before.

I would have lost some money there.

Makes me wonder about the 256 that would either start or tire you out pushing.

[Flettner]

Now I guess if the engine was TPI, this over rich situation wouldn't happen.
I'm sure off the pipe performance must be compromised?

[jasonu]

My H100 broke a steel reed. Started as easy as the pie I'm currently eating. Actually it's more a corrnish.

Did notice a stutter up top that sent me searching. But that's a small section of a 4 petal reed. Not a gapping hole.

Having experienced load up on a piston port bike which on race start, bogged unrecoverably until the clutch basket was replaced I'd expect a similar load up if thrown too much load quickly. Auto clutch no idea how they behave.

I thought you had no chance of starting that. Until it burbled time before.

I would have lost some money there.

Makes me wonder about the 256 that would either start or tire you out pushing.

https://www.google.com/search?q=what...XbKcEoUcuZu9M:

[jonny quest]

What's the story about Cagiva running reeds that didn't clise all the way? To hurt explosive power? Was that on EFI or carb?

[Frits Overmars]

What's the story about Cagiva running reeds that didn't clise all the way? To hurt explosive power? Was that on EFI or carb?

Here is the story Jonny:
https://www.kiwibiker.co.nz/forums/s...post1131051402
And here's a better one I initially missed (thanks Husaberg):
https://www.kiwibiker.co.nz/forums/s...post1130474766

If you know, or can guess, on which site to search, this works fairly well in Google: [word you are searching for] site: [site name]

Here is what I entered in Google Search in order to retrieve the post you were asking about:

Cagiva site: https://www.kiwibiker.co.nz/forums/s...s-engine-tuner

Google still came up with 133 hits that I had to plough through, but hey, what's a little effort between friends?

[husaberg]

Here is the story Jonny:
https://www.kiwibiker.co.nz/forums/s...post1131051402

If you know, or can guess, on which site to search, this works fairly well in Google: [word you are searching for] site: [site name]

Here is what I entered in Google Search in order to retrieve the post you were asking about:

Cagiva site: https://www.kiwibiker.co.nz/forums/s...s-engine-tuner

Google still came up with 133 hits that I had to plough through, but hey, what's a little effort between friends?

https://www.kiwibiker.co.nz/forums/s...post1131051402

This is an MX bike. It's rotary. And it says Honda. Categorical statements are always risky...
Attachment 331416

Reeds need a pressure differential before they will open, and the bulk of that differential is provided by the suction effect of the exhaust system.
When you close the throttle, combustion stops, all pipe effects stop, and the reeds stay almost closed. When you open the throttle again, exiting a corner, nothing happens because there is not enough igniteable mixture in the cylinder. So you open the throttle a bit further, and a bit further still, and at some time the cylinder contents are igniteable again. So combustion starts, the pipe chimes in and it's two-stroke business as usual. But now your throttle is wide open and the next thing you'll experience is a highside.
Cagiva put spacers under the reeds in order to make sure that they never completely closed. It cost power but it helped lap times and saved bikes and riders.
The spacers killed the 'pop' that Kevin Cameron mentioned, so carburation became less than responsive, which inspired Cagiva to experiment with fuel injection.

The better explaination is here
https://www.kiwibiker.co.nz/forums/s...post1130474766

Re the articles by Kevin Cameron which, by and large, are excellent reading:
Cameron mentions large area reeds needing low stiffness which allows them to open almost as soon as the piston rises. But the opening of the reeds has nothing to do with piston motion; the reeds are opened by a pressure differential and that can occur even while the piston is on its way down (imagine pipe suction at really low revs).

Guillotine exhaust power valves in the Yamaha 250 cc V-twin caused a peculiar problem: oil collected in the sheath for the valve of the down-sloping cylinder, acting as a hydraulic block on the valve. We drilled a small leak hole to get rid of the problem.

True, true.Wrong, wrong. The 'plug' of mixture in the intake duct strongly resists being accelerated towards the crankcase; the crankcase pressure has dropped quite a bit (slowing down the transfer flow in the process) before the intake flow starts attributing something useful to the crankcase contents. And the same goes for rotary inlet engines; they too need large crankcase volumes to make real power.
Wob, the pipe does suck like hell on the cylinder and hence on the crankcase. It just doesn't show at the reeds until a lot later because of, like you say, petal stiffness and column inertia.
By the way; the Aprilia RSW's crankcase volume at TDC (that means including the transfer ducts) is about 650 cc; the RSA's volume is about 675 cc. But they open their rotary inlets when they want to; they're not at the mercy of any stubborn reeds.

Several riders of the Cagiva 500-4 works racers experienced a painful demonstration of this stubbornness:
When closing the throttle for a corner (a 500-4 will need that from time to time) engine power dropped. But when they reopened at the corner exit.... nothing happened. The reeds had to be opened by the suction of the exhaust pipe, but when there is no combustion, there is no suction. So the riders opened up a little more. And a little more. And more.... And then, at some point, there was once more sufficient combustible mixture in the cylinder to be ignited. The pipe suction returned from its coffee break and the whole two-stroke resonance cycle was reinstated - with the four carbs wide open. That hurt....
The problem was solved by inserting thin strips under the reeds, so they never really closed completely. It messed up the carburation and cost over 10 HP, but it improved both the lap times and the mileage you could put on a rider.
Later, because of those carburation problems, Cagiva was one of the first to switch from carbs to injection.

as you were.........15 seconds.........
I used Cagiva reed and user name Frits Overmars
i knew you had posted it here though

The Kb search function needs a few paremeters spec'd
try this
First start from the ESE page to search the thread.
Then hit advanced search
Then search single content
Then Make sure the bottom dot is in post rather than thread.
Attachment 331652

You can also select the author whose post you wish to search for instance Wobbly, Frits etc
by searching under their user name or multiple usernames.
this narrows down the number of posts to go through dramatically.

or you can use Google with a few key words that you are looking for but include "ESE works Engine tuner" you need " " the so Google only searches those words with the ESE thread.

[adegnes]

Having experienced load up on a piston port bike which on race start, bogged unrecoverably until the clutch basket was replaced I'd expect a similar load up if thrown too much load quickly. Auto clutch no idea how they behave.

Mine is currently set up to start grabbing well into the powerband, hoping that'll work.

I thought you had no chance of starting that. Until it burbled time before.

I would have lost some money there.

Without that burble I would have given up after a few more pulls and tried the reed. We would never have known that it could start without it.

Now I guess if the engine was TPI, this over rich situation wouldn't happen.
I'm sure off the pipe performance must be compromised?

Luckily my fuel is pretty tolerant to rich running.
Too bad it's difficult to test off pipe performance with my current setup.

Really looking forward to seeing how it behaves on the roller!

[Lightbulb]

When do you plan on running the engine and seeing what happens and if it is ride-able?
Neil