ESE's works engine tuner

[katinas]

Very interesting. Maybe combination carb diameter, inlet length and total volume in the transfer channels are very important in your concept. Too big transfer channel volume will not create enough suction and inlet air speed to allow piston to compress air at the same time as flow continues through inlet. Too small transfer channel volume, too big carb diameter, will not keep air speed up into transfer channels when piston moving down to compress, giving less total air in. At higher rpm relatively small transfer channel volume holds back the exhaust from entering too deep into transfer channels but the exhaust pressure compresses the fresh air there. While some exhaust is occupied with compressing the transfer channels the rest is going out through exhaust port and most of the fresh air hold back and will later not have time to escape out. A three windowed exhaust port should maybe be a bit lower then? Just a thought..

…..and position, where intake tunnels is connect to transfer ports, must be at the point where average positive pressure in trans ports is the lowest. Maybe intake tunnels, from main reed, must be placed in the “half moon”- between cylinder wall and transfer port inner radius wall, where Jan added cooling.
With RGV engine closed bottom crank space (without side reeds, add photo), testing was done with another type, its like intake tunnels added at the lower, say starting point of transfer port. From 8000 rpm engine stopped and only first gear overcome 8000-10000 rpm dip. Only two16 mm holes on separator sides that depress crankcase, eliminate dip.

Haufen, Frits I fully agree too. But at the moment I am fully illegal on the road. No technical inspection, no insurance, so I feel like a bunny on the road. One eye always ready to recognize police car. But now, as my moto gp commentator job postponed, I have more time finally to travel just 250 km to put all the stuff on my friend's dyno.

Other interesting thing. Accidentally, with spark plug 0.9 mm gap, found how piston/head clearance changed on this particular engine.
Very low rpm, piston just touching ground electrode – gap 0.8 mm
Not warmed engine, shortly to 14000 rpm – gap 0.5 mm
Then full load on the road – gap 0.2 mm (with usually unstable work from low to mid range with such small gap)
So difference is 0.6 mm from piston center, maybe piston squash area approached a similar distance. Maybe this explains why this engine spins freely with no less than 0.9 mm squash height or 0.3 mm that left with heat and revs.

[F5 Dave]

Linisher meets piston
Done that before. Although less subtle on 50. Closed gap completely .

Having extensive dyno use and much experience with one racebike that was always on it, then raced I figured I had a pretty well calibrated rear end. But it made me look silly several times, fortunately with no audience.

[Niels Abildgaard]

Thanks for the interstign insights, katinas!
It would be really really cool - and I guess pretty helpful for your research too - if you had a dyno!

In case you need assistance building one yourself, let me know.
You can also use a road dyno, which gives pretty accurate results if you use the same part of the road for all of your tests (numbers will be relative, but the shape and if it's better than before is what counts anyways).

click here for a link to a free road dyno, description below:

'Very,very elegant method(If I have understood it correctly).
It can even be made absolute if You make two runs with different mass and same air resistance.
A couple of old accumulators in rucksack?

[Dominator Motorsport]

Gedday Guys,

New member to the forum after being introduced by Ken Seeber. I first met Brett and Ken Seeber of Strike Products through my engineering work experience, and ever since, I’ve become a 2 stroke man. Since then, given that almost all engineering in Perth is resource based, I’ve moved to working in Oil and Gas. Which I find unfortunate as I’m an M6 and M8 kind of guy, rather than the M24’s or greater you may find on oil rigs. But I still get my 2 stroke fix through karting, yet another great discovery that Ken and Brett showed me. Which brings me to my questions…

I’ve recently acquired an old TM KZ10 for something to tinker with. I must say this forum has been gold for advice, especially Wobbly’s wise words. Ken and Brett have also been champions (head like a spark plug) with their top tips and for letting me use their equipment. I’m taking it in smaller steps for now, but so far I’ve worked the ports, deepening the auxiliaries based on some of Wobbly’s posts. The other steps will be some odd cooling jobs, including the cooled head insert, drillings between the crank cases and cylinder to get some flow around exhaust, and a few other small details. Finally, I’ll top this off by running a vortex piston with a 38mm flat on top. Undoubtedly small jobs compared to the likes of the 2 stroke legends in this forum, but its somewhere to start.

My question for you guys is what would be your thoughts on radiusing the web above the crank region? So far I have two opinions on this, first being radiusing both sides for a greater net inlet flow, which must be a good thing? But my second idea is to just radius the bottom, thinking that restricting flow into, but not out of the crank region, will help concentrate the fresh charge towards the transfers? Currently I am more inclined to the second option due to the fact the shroud/web is there in the first place, and partly chamfered on the bottom only. Otherwise looking at extremes, why not remove the shroud entirely?

Any wise words would greatly be appreciated.

Thank you,
Dominik

[katinas]

My take SwePatrick would be to go square as you are planning - gives real rev potential with the already short stroke ,plus easy optimum STA values , but then fit alloy liners that are easy to port.
Weld them in at the top and bottom ( easy ) then Nicasil them.
Much better heat transfer and no wear issues with resulting overbores.

ICBM alloy liners www.ibg.co.jp
https://page.auctions.yahoo.co.jp/jp/auction/e397845803
https://www.youtube.com/watch?v=NJsU08ye6HA

[wobbly]

Removing the shroud is dumb - the cranks perifery is rotating against the reed inflow , so the shroud restriction is there specifically to reduce the interaction between the crank wheels and the incoming charge.
Secondly the machined " duct " opposite the boost port is there to direct a tangential exit flow from the crank' s OD boundary layer , out from under the shrouds trapping action, toward the piston and transfer duct entries.
Thus I believe any attempts at enhancing flow into or outward from the shroud slot is doomed to abject failure.
But hey its a motherfucking twostroke , so everything I have just said could be complete bollocks - and should be treated with the howls of derision it deserves.

[TerraRoot]

spoke about this last year, i of course have done shit.



crazy they used the same engine i had/have planned.
could they have done the cylinder any worse? no. it does run tho!

[husaberg]

spoke about this last year, i of course have done shit.



crazy they used the same engine i had/have planned.
could they have done the cylinder any worse? no. it does run tho!

If you richen up the pilot, the needle and mainjet enough, its far far easier, not to mention cheaper to convert a 2 stroke into a 4 stroke.

[ken seeber]

Hello, anyone there ???

Years ago 2 strokes were often criticized for blowing up. Less so these days …

[WilDun]

Hello, anyone there ???

Years ago 2 strokes were often criticized for blowing up. Less so these days …

Good to see you still there Ken, - BTW was that bike a Bridgestone? (before it disappeared through the roof).

[Frits Overmars]

Good to see you still there Ken, - BTW was that bike a Bridgestone? (before it disappeared through the roof).

Nah, it's a Kawasaki 250cc Samurai or its bigger brother, the 350cc Avenger. The two models could be distinguished by the slightly different shapes of their cooling fins, but that's hard to tell in the above picture. But why do you ask? Are you too young to know or too old to remember? I always thought you're older than me....

[WilDun]

Nah, it's a Kawasaki 250cc Samurai or its bigger brother, the 350cc Avenger. The two models could be distinguished by the slightly different shapes of their cooling fins, but that's hard to tell in the above picture. But why do you ask? Are you too young to know or too old to remember? I always thought you're older than me....

Too old to remember! (76) - I should've known better cos i was racing a T20 Suzuki leading a Honda 305? and one of those (350cc) Kwakers at a street circuit here - all very close, and after a few laps I lost it and slid off, the two bikes behind did the same and next thing I was standing looking down at two very injured guys (one had a broken collarbone and was saying nothing and the Kawasaki guy (who had a footrest embedded in this achilles tendon was calling me some very nasty things (I think he was just pissed off because he saw that my 250 had the legs on his 350!) - ... or maybe not! - anyway, I escaped with some gravel rash and bruises! - all great fun really! - hope you guys are all ok! - we're all in it together now!

[Pursang]

hope you guys are all ok! - we're all in it together now!

Best wishes to Everyone who follows ESEswet, and your families - Stay safe & healthy.

If there is a tiny silver lining...Lack of free Time is no longer a reasonable excuse for not completing all those outstanding projects in the workshop
(and around the home)

Cheers, Daryl

[WilDun]

Best wishes to Everyone who follows ESEswet, and your families - Stay safe & healthy.

If there is a tiny silver lining...Lack of free Time is no longer a reasonable excuse for not completing all those outstanding projects in the workshop
(and around the home)

Cheers, Daryl

Good to see you still around Daryl - you Aussie guys sure had a double whammy this year!

[wobbly]

Send me a PM with your email - I will help.