ESE's works engine tuner

[MotleyCrue]

The ring will probably pop out into the huge transfer holes, and wreak havoc - as there will be no guide radi to ease the ring back into the piston groove.
With no support due to the Ex port hole, as well as the huge transfers, the small areas actually holding the ring in a roundish shape, will be worn very quickly - tears will follow.

Actually I wouldn't be taking the cast iron divider out of the cylinder wall between the A and B, just the aluminum divider which runs down through the transfer passageway, so the rings would still have the usual contact with the cylinder wall. I just wasn't sure if the aluminum divider was there for any other reason than flow reasons.

[wobbly]

Sorry misread that then, but I have twice seen unsupported cast dividers break off as well.
The ring pressure approaching BDC as the Ex radi push the ring back into its groove, means the narrow septums are subject
to high loading, and with no support from behind the cyclic load means they fail - quickly.

[Lightbulb]

What happens if you have a carb of some form introducing some fuel into the incoming air prior to the main carb ?
Is there any advantage to having a mix of air that has a small amount of fuel already mixed with it ?
The idea is that the initial amount of fuel has time to mix with the air before it gets to the carb to help make a better air
fuel mix for the engine .
Neil

[SwePatrick]

44hp, well done, party time ...

Yes! i´m still in shock

[SwePatrick]

SwePatrick,

Cool. Did you ever post any pics showing your ports? Maybe you did but this thread is so big I have only read a fraction of it. If you did please point us to that for a refresher.

Here´s a pic in between pulls, when checking state after i blown reedplates though the carb *lol*
I hope you can see it, it is linked to my facebook page.



Since pic below i have ported a bit more at the boreskirt at the intake side, smoothen it out and made the passages down in crankcase more smooth.

[J.A.W.]

Actually I wouldn't be taking the cast iron divider out of the cylinder wall between the A and B, just the aluminum divider which runs down through the transfer passageway, so the rings would still have the usual contact with the cylinder wall. I just wasn't sure if the aluminum divider was there for any other reason than flow reasons.

A major function of rings is heat transfer, & that heat so transferred has to be carried away through the cylinder wall/sleeve..

If the aluminium sleeve support is removed, then so is its heat sink/transfer - duty/functional capability..
& thus allowing formation of a potential hot spot location - to flare off lubricant & promote a nip up..

[MotleyCrue]

Sorry misread that then, but I have twice seen unsupported cast dividers break off as well.
The ring pressure approaching BDC as the Ex radi push the ring back into its groove, means the narrow septums are subject
to high loading, and with no support from behind the cyclic load means they fail - quickly.

Thanks. I guess what I'll do then is leave some decent thickness of aluminum right behind the cast divider then eliminate the rest of the divider further down the transfer passageway and build up a new sectional replacement there with epoxy.

The epoxy will not disintegrate with fuel it stays hard as a rock, but it always seems that every epoxy eventually lifts off the base metal (aluminum) sooner or later. Small screws and rough surfaces help and keep the epoxy from going into the engine, but is there anyway to keep it from lifting off the base material? It just seems that the oil gradually gets in under the epoxy maybe by capillary action and at some point the epoxy lifts. Maybe some kind of sealant that keeps the oil from getting under the epoxy ?

[SwePatrick]

Yes..
You can 'paint' above the epoxi to get a seal.
Just need to find a really resistant paint.

[jfn2]

wobbly:
Do you have any more comments or pics of the ktm250 exhaust (in port or portmap) of the work you did? Thanks Jeff

[seattle smitty]

I had the occasion to be out the back of Siberia some years ago. The Russians had chainsaws with Villiers type engines. I was interested to see that the way the chainsaw was tilted was to tilt the carburetor as well. Butterfly screws and a revolving connecting angle manifold, wow!
Can't remember how the fuel tank worked?

One of the dusty boxes buried in the back of my shop contains a Titan 40 chainsaw, circa about 1952, IIRC. Rotary valve through the crank, crossflow cylinder and deflector piston, worm-drive, and a float-type carburetor. The blade-bar and drive section rotates in the manner you describe, affixed by a big ring-clamp that is very quickly released for re-orienting the bar to keep the powerhead and carb upright. I believe Titan was the first or one of the very first makers of gasoline powered chainsaws, at first big 2-man saws for logging, later one-man saws like this one that I have (see the ring-clamp on the sixth row of photos):

https://www.google.com/search?q=tita...HSdRCUgQsAQIIw


As usual with Google images, only the first few rows of photos apply to the subject you asked for.

My saw was the first chainsaw for the Smith family, bought by my dad from a neighbor, many times second-hand. A big, heavy brute by modern standards. Before he got it, I had cut a lot of trees on the property with a bow-saw, cut them down, cut them into logs for the fireplace, split the logs with sledge and wedge. Amazing how much you can get done when you're young, with energy to spare, a strong back, and a weak mind.

Maybe a year after the Titan 40, Dad found a couple of early-to-mid-'50s Sears "David Bradley" chainsaws, also very much used. Also cross-flow, with VERY early reedvalve into crankcase induction, and very early little pumper carburetors (so no more need to rotate the bar). The blade-drive was geared-down to about half engine speed (I think there were direct-drive versions, too). The reeds on these saw engines were few and TINY!! The powerheads were made by Power Products, a name well known to the first generation of kart racers; Power Products kart motors fought it out with McCullough, West Bend, and maybe a few others I don't now recall. Here are some of the saws (I have a couple of these):

https://www.google.com/search?q=1956...adley+chainsaw

. . . and the PP kart engines:

https://www.google.com/search?q=powe...f3DksQ_AUIBygC

[seattle smitty]

Some of you might get as big a laugh as I did from this offering by a gal on a van enthusiasts' site. There aren't a whole lot of girls/women directly involved in motorsports, and many of those are only drivers/riders of machines that are built and maintained by the men in their family. But the gals who do get grease under their nails, some of whom have real mechanical ability, tend to be very interesting individuals in other ways as well. I love this one for her comment about mis-laying tools:

Annaleigh,


(QUOTE) "Yes tools!!! I could spread out a white sheet, sit in the middle of it, open my tool box and lay each tool out as I inventory them on paper. Having never moved, when putting the tools back in the box, 3 or 4 would be missing . . . " (end Quote)

[wobbly]

Here are some more pics of the road racing KTM250.
It has a long rod from an earlier model with a Wossner flat top single ring piston from CR250, needed an 8mm plate under cylinder
that corrected the case com, and got ports close - still needed 2 days of grinding as the ring pinned on centre enabled huge B ports.
The reed is a VF4 off a late model KTM and the inlet length is tuned to 10,000 rpm with a 42mm bored SPJ carb of late model RS250 to use the
solenoid PJ for overev power.
This has a screw adjustable powerjet on a CNC carb bowl.
I cut off the kickstart gear housing to get the intake dead straight.
Water route has been changed with CNC head and has bronze insert.
The Aux ports were welded then made triangular and twice the area around to bore centre, Ex port floor and corner rads are welded.
Port setup is with B,C highest and set in EngMod for 72 Hp on Avgas.
Servo driven PV is used as it drops over 1500 rpm into 5th gear due to MX gearbox ratios.

[TZ350]

Old air cooled Suzuki GP100 soon to be a 30+hp water cooled 110cc six speed Suzuki GP-NSR Frankenstein engine. Backstory.

The whole build can be seen by following the backstory posts like a trail of bread crumbs.

The Dry Sump and Gear Oiler, not to sure how well this idea will work so I am going to try it on the old air cooled engine first.



The oil spray bar. The oil level in the crankcase will be minimal and well below the gears and clutch hub. The bulk of the oil will be held in a sump tank.

The oiler drops oil onto the gear pairs, I sure hope the oil mist generated will find its way to the gear bearing surfaces and the ball races.



The oiler lubricates the clutch hub gear through a small hole near the end of the spray bar and the end of the tube sprays oil onto the outside of the clutch hub itself, some of it will hopefully dribble down to the output shafts plain bush bearing. There is a new hole in the input shaft to lubricate the clutch hub bearing. The input shaft hole was a challenge as the shaft is as hard as the hobs of hell. Thankfully Chambers found a way of doing it with Dremel and diamond bit.



Oil is feed to the spray bar and up the inside of the gear box input shaft to lubricate the clutch hub and release bearing.



As well as the dry sump and gear oiler I am trying a longer rod for more crankcase volume.

The motor was going together really well until I fitted the cylinder. Then I found the fatter rod was jamming around TDC. Now the cases need relieving, bugger, I have to take them apart again.

[jfn2]

Wobbly:
Thank you for the pics and reply. If I may, a question about the intake length. It looks a bit long and is the long red spacer block just a transition from the round carb to the square reed? Another question, from the 4mm build-up at the bottom of the exhaust port, are you adding 4mm of fill the whole length of the port or is it 4mm at the port window and tapering to 0mm at the spigot end? I am building a 250 KTM now for hill climbing and very interested in what you did.Thank you, Jeff

[wobbly]

No,and no.
The intake length isnt long at all, just remember that the "normal " 250 intake is the same as a 125 - simply so the carb can fit in behind the suspension etc.
How can that possibly be correct for an engine that peaks all of 2000 rpm lower.
The built up Ex floor is full length, as the roof is set by the PV blade, and that is flat to begin with.
The red block is simply a spacer to adapt the differing bolt patterns and get the length correct.
The round to squarish transition is done in the manifold rubber.