ESE's works engine tuner

[adegnes]

Yes, the work is delightful. But using one variable and one fixed pully will give you only half the range that you could have with both pullies variable.

Thanks!

Yep, it acts like a one speed setup (like ktm sx50) until the clutch locks.
With clutch stall at 13000 and gearing to hit 130kmh - no variating before ~40kmh.

[ken seeber]

Fellas, it's all gone quiet. Something someone said?

So, as part of musing the old brain, I kept thinking about the world of 24/7, transfer port vanes and transfer port throttling and I got an idea of combining the latter two.
I herewith offer the shitty attached sketch. Fairly self explanatory.
Sort of obvious and, as usual, has its advantages and disadvantages. As is always the case, probably been done before.

Advantages: Possibly improved transfer port flow and directional control, ability to throttle engine air flow
Disadvantages: Leaves a trapped volume above vane when closed, difficult to implement

Ken

[husaberg]

Fellas, it's all gone quiet. Something someone said?

So, as part of musing the old brain, I kept thinking about the world of 24/7, transfer port vanes and transfer port throttling and I got an idea of combining the latter two.
I herewith offer the shitty attached sketch. Fairly self explanatory.
Sort of obvious and, as usual, has its advantages and disadvantages. As is always the case, probably been done before.

Advantages: Possibly improved transfer port flow and directional control, ability to throttle engine air flow
Disadvantages: Leaves a trapped volume above vane when closed, difficult to implement

Ken

if that was mounted higher up with the pivot point to the rear it could double as a variable transfer height as well ...........kind of like a Honda nsr pv swinging gate........
can't be assed drawing it

[Frits Overmars]

I kept thinking about the world of 24/7, transfer port vanes and transfer port throttling and I got an idea of combining the latter two....probably been done before. Advantages: Possibly improved transfer port flow and directional control, ability to throttle engine air flow. Disadvantages: Leaves a trapped volume above vane when closed, difficult to implement.

I like combining things, preferably to the extent that one component performs the job of several other components that will then be made redundant.
Your vane will work, Ken. Throttling will work too. And I haven't seen this before in a two-stroke, though it reminds me of variable-vane turbocharger technology.
Problems: the vane will not prevent blowdown gases from mixing with the fresh charge unless it's fully closed. The vane itself must be thin, a continuous shaft would be too much of an obstruction in the transfer duct, and it will be difficult to attach shaft stubs to the vane.

[adegnes]

In the process of reading this whole thread, I saw this:

Most us cut the squish angle of our heads on the lathe. With a domed piston which is a radius... the squish angle is slightly mismatched being a straight angle.

Any performance benefit to CNC the head squish to match piston dome?

You don't need CNC gear. Just organise an adjustable tie-rod with standard rod-ends mounted between the tailstock and the cross slide.

Adjust the length to match the piston dome radius, lock the tailstock and engage the cross slide feed. Done.

If your head is countersunk into the barrel(if not you'll have to precisely cut and glue matching pieces of emery cloth to the piston top), here's an easy way to get the squish to match the piston without the "proper tools"(the way most of my projects are done):

1. Spin the head in some more or less sketchy way - I mount an electric drill in my vice, fasten a sparkplug in the chuck and thread the head onto it.

2. Use a strip of emery cloth and a piston with the right radius, use the piston to push the emery cloth against the squish area while the head is spinning.

3. Check the "fit" frequently by pointing a flashlight up the plug hole and sliding the piston from side to side(kind of like rotating a ball), when there's no light until the piston clear's the squish area, you're done. Also, when they match up real good, if you apply a thin coat of oil on the squish area and place the piston on it, it really "sticks" - you can slide it around easily, but it resist's being pulled off.

4. Beer.

I also cut combustion chambers this way, spinning the head and using a ball carbide bit in a dremel to cut the shape I want.

[seattle smitty]

I don't understand the problem, since he had access to a lathe. Grind yourself a very sharp form-tool (profile-tool) to the shape of the piston crown. Put some bluing on the head, mount it on the cylinder, and lightly scribe a witness line where the bore meets the head (maybe you have to take a facing cut first, to get rid of some or all of the existing squishband). Remove the head and mount it on a faceplate, centered. Put the lathe in back gears, lowest speed, and slowly hand feed the form-tool into the squishband area until the cut just meets your witness mark. If the tool chatters a little, smooth the ripples via something like Adegnes' method, or live with it since you're going to have at least half a millimeter of squish clearance anyway, so how perfectly smooth does it have to be? Don't you make the radiused corners of combustion chambers with a form-tool?

But Adegnes, you certainly seem to be getting things done without a lathe!!

(EDIT) There's a wonderful device, the Armstrong S-32 spring-shank parting tool holder, which is very effective in taking chatter out of cut-off operations in the lathe, reducing the tendency to hog in which can make parting a tense operation. I've never seen a spring-shank toolholder for form-tools . . . wonder how it would work . . . maybe I could make one, hmmm . . . .

[seattle smitty]

Frits, thank you for taking the time to comment on my various goofy ideas.

My ideal was, and is, to get rid of carbs altogether. And I certainly would not want to use two of them. Been there, done that.

Well, I like simple (I won't ever again own a car newer than mid-1960s!!). But for racing, other than endurance racing, I like horsepower even better than simplicity. Maybe you too; two pipes per cylinder is an added complication, right? The blower on a fuel dragster engine is a complication, but they hit 330mph in 1320 feet in less than four seconds (I know you know this, but I enjoy citing it just to marvel at it; when I was a kid, Garlits was only doing 185 . . . and THAT was amazing!!).

(QUOTE=Frits) ...Assuming that the engine will still breathe through that primary carburettor, even though there are more and perhaps easier ways for it to inhale. And even if it does, air speed through that primary carb will drop and the mixture will go lean. Yeah, you can correct that with the second carb; the one that I don't want. Remember KISS?[/QUOTE]

I watched the development of the record-setting four-carb Anzani fuel-burning parallel-twin (photo Pg. 1038, #15558)(Frits, I tried repeatedly to copy/paste that link, no luck, I'm sorry). Originally, a single big Vacturi carburetor fed the engine through a barrel-valve type rotary-valve (a big hole in the center of the center-main section of the crank, not uncommon in the old days), AND also via piston-ports.

When the engine was modified so that the Vacturi only fed the rotary-valve, and a second carb (Tillotson pumper from a kart) was added to feed the piston-ports, the engine gained 300 rpm against a given test load. Two more smaller kart carbs were added, feeding into the case through little kart reedblocks, and this added a further 100rpm against the load. Not only did this engine set straightaway record that was a marvel in its day, but later, with no change other than a modern electronic ignition replacing the Lucas magneto, it proved very reliable during a season of closed-course competition, winning race after race against simpler but less powerful engines.

Presumably each cylinder of that old brute was inhaling harder at some of those carburetors than others, as I certainly would expect for my idea, but the net result after re-tuning was positive.

I certainly take your other point about altering ports (I offered several possibilities), and know that trying to assert my little attempt at creativity by departing from proven port configurations which were painstakingly developed by experts is not likely to uncover anything new and exciting.

But I'm OLD, Frits. So far as I can tell after a long life, it's all meaningless, other than what meaning we choose to assign. Given that attitude, what better way to use some of the little time I have left than getting creative with 2-strokes, even if I turn them into scrap?!!

[TZ350]

A great read about plugs:-

Motorcycle ignition systems are the weak sisters of the world's spark generators. Bikes therefore need all the ignition help you can give them, which brings us to yet another useful group of special spark plugs: those with precious-metal electrodes. Conventional plugs have thick, blunt electrodes made of an alloy that's mostly iron, with a little nickel added to lend resistance to erosion. Special-electrode plugs have a side (ground) post made of ordinary nickel-iron alloy, but a center electrode of something much more costly - which may be a silver alloy, or gold-palladium, or platinum, etc. Bosch still favors platinum; Champion, ND and NGK offer plugs with electrodes in materials ranging from silver to tungsten. Gold-palladium seems to be the alloy that offers the best price/performance advantage; we don't entirely trust silver electrodes, which if overheated will over-expand and crack the insulator nose.

The rest of the artical can be seen here:- http://www.strappe.com/plugs.html

[husaberg]

A great read about plugs:-

Motorcycle ignition systems are the weak sisters of the world's spark generators. Bikes therefore need all the ignition help you can give them, which brings us to yet another useful group of special spark plugs: those with precious-metal electrodes. Conventional plugs have thick, blunt electrodes made of an alloy that's mostly iron, with a little nickel added to lend resistance to erosion. Special-electrode plugs have a side (ground) post made of ordinary nickel-iron alloy, but a center electrode of something much more costly - which may be a silver alloy, or gold-palladium, or platinum, etc. Bosch still favors platinum; Champion, ND and NGK offer plugs with electrodes in materials ranging from silver to tungsten. Gold-palladium seems to be the alloy that offers the best price/performance advantage; we don't entirely trust silver electrodes, which if overheated will over-expand and crack the insulator nose.

The rest of the artical can be seen here:- http://www.strappe.com/plugs.html

http://www.strappe.com/plugs.html

[Frits Overmars]

when I was a kid, Garlits was only doing 185 . . . But I'm OLD, Frits.

You're old? I dare you! When I was in my late twenties, Don Garlits took part in a dutch dragrace event. His right rear tire hit a damp spot on the track and lost traction, so the left rear tire violently pushed the whole car into a right turn, right into the crush barriers where it landed upside down with Garlits trapped under it.
I helped pull the barriers away before a fire could break out. Not something you forget...

[F5 Dave]

A great read about plugs:-

Motorcycle ignition systems are the weak sisters of the world's spark generators. Bikes therefore need all the ignition help you can give them, which brings us to yet another useful group of special spark plugs: those with precious-metal electrodes. Conventional plugs have thick, blunt electrodes made of an alloy that's mostly iron, with a little nickel added to lend resistance to erosion. Special-electrode plugs have a side (ground) post made of ordinary nickel-iron alloy, but a center electrode of something much more costly - which may be a silver alloy, or gold-palladium, or platinum, etc. Bosch still favors platinum; Champion, ND and NGK offer plugs with electrodes in materials ranging from silver to tungsten. Gold-palladium seems to be the alloy that offers the best price/performance advantage; we don't entirely trust silver electrodes, which if overheated will over-expand and crack the insulator nose.

The rest of the artical can be seen here:- http://www.strappe.com/plugs.html

Why? Was it written in the late 70s?

[wobbly]

Would have been written when the norm was a HT winding to supply the cdi with power, when a B10EGV was a trick plug.
Trouble with this simple setup is that to get around 300V going to the CDI and then to the coil, the stator winding wire needs to be thin
to enable enough turns to generate that voltage.
The thinner the wire the more turns, but unfortunately a higher static resistance and the lower the current capability.
Thus the system is limited in its ability to supply power Watts ( Joules ) = V.A into the spark gap.
The amount of energy stored in the capacitor determines the burn duration, and thus the size of the initial flame kernel - generated after the initial arc over.
The race plugs we use now have Platinum fine wire ground electrodes ( that unshroud the firing tip ) plus Iridium centre electrodes.
This combination requires hugely less voltage to create arc over in the ionised gap, and the Iridium doesnt expand creating ceramic cracks
that then end in the insulator falling off.
Also the Platinum ground strap is laser welded to the body, fixing the other issue of these falling off as well.
Bulletproof, and simple to read.

[TZ350]

Why? Was it written in the late 70s?

Yes you are right, Gordon Jennings - reprinted from Cycle Magazine, October 1977.

I am working on a RG50 for myself and have been thinking about using 10mm diameter plugs instead of the usual 14mm ones. My interest in the 10mm plugs is the smaller disruption and intrusion into the very small 4cc combustion chamber of the 50 and the greater wasted volume around the insulator of the 14mm plug compared to the 10mm one.

I would be interested in any ones thoughts about whether a 10mm plug would be a performance advantage in a 50.

[husaberg]

Off topic

We have one of these

it can be driven as a tiptronic with a paddle shift
yet it also runs as a CVT, I had no idea how it works at all.

its hydraulically and computer controlled to give it the option of also having fixed gear positions based on how its being driven........not simple but intersting

skip forward to 3 minutes....

[wobbly]

Once you generate the other 10 Hp thats hidden in the engine you havnt even thought about - then a small body plug may help to
give you maybe another 1/2 Hp.