ESE's works engine tuner

[guyhockley]

Broken link ken?

http://www.cyclenews.com/2017/12/art...ike-back-baby/

More info on the engine would be good.

Don't understand why the race version is 288cc?

[Frits Overmars]

Anyone know if intermediate part of jbb crank were one solid part or welding (press fit) of finger and disk?

It was one solid part Valery, as might be clear from the drawing of the latest JBB crankshaft that I recently posted: https://www.kiwibiker.co.nz/forums/s...post1131072807

I think if I will make crankcase precisiously then will dont need sealing ring on crankshaft.

You cannot make the diameter difference between the crankcase and the crankshaft small enough to avoid leakage because the crankshaft bends too much; it will hit the crankcase walls. You will need the labyrint, formed by the ring and the groove in the center disc.

This is my take on it.

No big end cage? A big end bearing is not only rotating, it is also orbiting. The centrifugal force pushes all needles to the outside of the orbit path; the outermost needles will be pressed against each other by all other needles if there is no cage to keep them separated. Then the friction will generate enough heat to destroy the bearing.

[Muhr]

It was one solid part Valery, as might be clear from the drawing of the latest JBB crankshaft that I recently posted: https://www.kiwibiker.co.nz/forums/s...post1131072807

You cannot make the diameter difference between the crankcase and the crankshaft small enough to avoid leakage because the crankshaft bends too much; it will hit the crankcase walls. You will need the labyrint, formed by the ring and the groove in the center disc.

No big end cage? A big end bearing is not only rotating, it is also orbiting. The centrifugal force pushes all needles to the outside of the orbit path; the outermost needles will be pressed against each other by all other needles if there is no cage to keep them separated. Then the friction will generate enough heat to destroy the bearing.

No, that's right! too lazy to draw the basket, will use standard rollers

[Muhr]

Great Muhr!!! Me make wery close to your design, just medium part a bit wider. I did some 3d modelling and realyze V twin with common finger can be balanced perfectly. When I virtually rotate crank I achieved 0 centre of gravity fluctuation. Just balance should be relatively heavy compare opposites. May be
The main question now how sturdly fix medium part.

Could you show your assembly "exploded"? Seems pin need step in the center.

I made an ellipse with two phases

[Muhr]

It was one solid part Valery, as might be clear from the drawing of the latest JBB crankshaft that I recently posted: https://www.kiwibiker.co.nz/forums/s...post1131072807

You cannot make the diameter difference between the crankcase and the crankshaft small enough to avoid leakage because the crankshaft bends too much; it will hit the crankcase walls. You will need the labyrint, formed by the ring and the groove in the center disc.

No big end cage? A big end bearing is not only rotating, it is also orbiting. The centrifugal force pushes all needles to the outside of the orbit path; the outermost needles will be pressed against each other by all other needles if there is no cage to keep them separated. Then the friction will generate enough heat to destroy the bearing.

Right should be right! Something like that

[guyhockley]

It was one solid part Valery, as might be clear from the drawing of the latest JBB crankshaft that I recently posted: https://www.kiwibiker.co.nz/forums/s...post1131072807

You cannot make the diameter difference between the crankcase and the crankshaft small enough to avoid leakage because the crankshaft bends too much; it will hit the crankcase walls. You will need the labyrint, formed by the ring and the groove in the center disc.

I saw a prototype microlight engine at an aviation expo that was also a 90 degree v-twin with a common case. They were using a plain centre disc that ran in grooves to separate the 2 halves. A bit like the Trabant disc valves you posted. I've tried googling it but apart from a vague idea the designer was called Camus and they had some sort of regional development grant I can't narrow it down.
The Konig radial 2 strokes may have something similar but I've only seen small photos of them.
http://www.compactradialengines.com/mz430parts.html
Worth noting that most microlight engines are fairly low revving?

[jbiplane]

It was one solid part Valery, as might be clear from the drawing of the latest JBB crankshaft that I recently posted: https://www.kiwibiker.co.nz/forums/s...post1131072807

You cannot make the diameter difference between the crankcase and the crankshaft small enough to avoid leakage because the crankshaft bends too much; it will hit the crankcase walls. You will need the labyrint, formed by the ring and the groove in the center disc.

Hi Fritz. Thanks for valuable comments. I havd same fillings, but need confirmation before cut metal. At moment I doing some balancing deflection and stress estimations. I going to make for "V" central part of disk with grove sealing ring and stepped pin.

Right should be right! Something like that

YES, with minor variations!

The Konig radial 2 strokes may have something similar but I've only seen small photos of them.
http://www.compactradialengines.com/mz430parts.html
Worth noting that most microlight engines are fairly low revving?

I have numerous photos of this engine interior. Probably worth to place somethere here, says in "odd engines"

[jonny quest]

There's always a way to make a pipe.

Try a straight pipe into a box, then stinger out of box. That would probably be better than a straight pipe. Remember pipe is 30% of a 2 strokes power

This is for Matt@Tyga, sorry missed the quote button

[wax]

has anyone here tried e85 in their bikes and taken the time to jet it in correctly. What was the result. did you get a power gain. was the engine more reliable due to it being a higher octane and a colder burning fuel.
Do you recut the combustion chamber becuase of the new fuel burn properties

[Matt@TYGA]

There's always a way to make a pipe.

Try a straight pipe into a box, then stinger out of box. That would probably be better than a straight pipe. Remember pipe is 30% of a 2 strokes power

This is for Matt@Tyga, sorry missed the quote button

Sorry, I wasn't totally clear. The pipes run into a silencer box and then out again and through a one way valve system so that it doesn't ingest water when things don't go to plan. Tested with and without the valves and it doesn't make any noticeable difference so they're not causing any issues as far as one can tell.

Anyway, the pipes I can figure out, but the main question was regarding the primary compression ratio in a boxer as I don't have any prior experience.

Cheers.

[F5 Dave]

If you wore jandals could you stand on the pipes? Like if they were structural.

[TZ350]

.

Ok, got the pressure transducer sorted and the 4-20mA output across a 250 Ohm resistor should give me 1 to 5 Volts output suitable for an analog pressure signal into the Arduino.

The yellow pressure line will be threaded through a spring for support and the ends clipped so they don't pull of the hose tails.

I am looking forward to the weekend so I can get it back together and see what the signal looks like on the scope.

[Frits Overmars]

There's always a way to make a pipe. Try a straight pipe into a box, then stinger out of box. That would probably be better than a straight pipe. Remember pipe is 30% of a 2 strokes power.

There is always a pipe effect too, unless there's no pipe at all.
Straight pipes aren't nearly as effective as expansion chambers, but they too can have favourable or unfavourable lengths and diameters.
Start with a long pipe and keep cutting pieces off until the power decreases; then you will have found were the optimum was. But it was probably a relative, not an absolute optimum, because with a different diameter you'll also need a different optimum length: more diameter usually requires more length and vice versa.
By the way, that goes for the headers of full-blown expansion chambers too.

Regarding those 30% of power I think we need to have a wee chat Jonny.
Jan Thiel tested it twice. The first time was with a 50 cc Bultaco that produced about 20 hp. Without the pipe it gave 4,5 hp.
The second time was with an Aprilia RSW125. In those days it produced 52 hp. With the pipe removed, and with carburation and ignition painstakingly re-optimized for the new circumstances, that engine gave 17,5 hp. So it's safe to say that a good pipe on a good engine can triple its power. That's not 30% more; it's 200% more.

[WilDun]

..................... So it's safe to say that a good pipe on a good engine can triple its power. That's not 30% more; it's 200% more.

Frits, you have convinced me about having a good pipe! but, (even though it isn't relavent within the racing rules here) in the wider world of two strokes, is there a way around the bulky pipework - eg the use of straight pipes, being assisted by forced induction? - I realize of course that there are issues with port timing, (probably needing some careful design, like earlier exhaust closure),for forced induction.

Let's face it, the two stroke racing scene will always be a spinoff from the use of two strokes in the wider world. I believe it is essential in the overall 2T scene (and of course for the continuation of the racing two stroke) to address the use of huge expansion chambers in the bigger size cylinders.
This issue will hinder the sales of larger road machines (as will the 2T smoke)!

[nitro2tfx]

is there a way around the bulky pipework

Maybe. Doubtful if there will be any brainstorm good enough to create a smallish exhaust capable of generating the same power as the huge expansion pipes, but something on the order of 2/3 - 3/4 the power might suit some applications.