ESE's works engine tuner

[F5 Dave]

Yeah it was. Frame supposedly an RGV500 copy, I was very impressed at its handmade appearance. RG500 converted to V configuration, RGB dry clutch, wanky gearbox, reputably ex works bit suspension etc etc. He offered it to me about 3-4 years back when he realised he would never have time to finish it, & I was tempted. But had to be realistic, it needed some serious skills to finish things like inlet manifolds machined for V config, there was just too much to do custom made. So instead I opted for something simple like a CPI barreled RZ in a hybrid frame.:facepalm: Hey I rode it today.

[speedpro]

I worked for Nige a few years back. The bike was on a stand in his workshop/lounge. You had to appreciate the work that had gone into it. Nigel did say something about heat treating the frame before riding it and there was a mountain of other stuff to do. Niggly stuff like float bowls for the carbs. Nige had the skills and contacts to finish it but time was another matter. You only have to check out his bucket to know what he's capable of.

[TZ350]

The handmade V4 of Nigals, now that’s a very impressive effort, and truly a work of art …….

I feel I am starting to get my head around this software and developed the model as best I can then optimised it. It takes 1 hour and forty minuets to run a simulation in turbulent mode on my old computer. Once I had the combustion data it was much quicker in prescribed mode and I spent some serious time looking for ways of improving things.

251624 the best I can do with a 24mm carb and my old RS pipe.

The best arrangement with the 24mm carb and old RS125 pipe I have been able to come up with is.
For the Single exhaust port, Ex opening 79 ATDC, Trans 117 ATDC and inlet 145 BTDC / 85 ATDC.
For the Triple exhaust port, Ex opening 85 ATDC, Trans 116 ATDC and inlet 145 BTDC / 85 ATDC.

The triple even though it has STA’s good for 40+ hp its simulated curve is much the same as the single exhaust port with STA’s at 35ish confirming my thoughts that the 24mm carb has become the limiting factor.

As power is torque by rpm I could get more power by spinning increasingly less torque faster but I rather like my fatter torque curve, I think it has benefits that shear hp lacks.

So I have become convinced that there is not much future in making special triple ex port ally liners in the quest for more power although they could help with ring life.

251623 My 28.9hp bike compaired to Speedpros 30hp open carb 100.

With carfull work I might get another hp or two but It seems clear the future lies in developing a new pipe and extending the lower end of the torque curve.

From a comment by Wobbly earlier, I think the triple port might have its uses here as the lower Ex duration allows the pipe to stay in sink over a wider rpm range than it would with the single ports higher duration (peaker) timing.

Now I just have to figure out, how to use the pipe to spread the lower part of the torque curve out a bit, just like Wobbly has for Speedpro.

[koba]

As power is torque by rpm I could get more power by spinning increasingly less torque faster but I rather like my fatter torque curve, I think it has benefits.


Not to mention the reliability benefits of not spinning an old commuter bike crank so hard!

It will be interesting to see how further work on the pipe influences things.

[TZ350]

It will be interesting to see how further work on the pipe influences things.

EngMod2T, I think this is the software Wobbly used to develop Speedpros engine and pipe and that works pretty well.

[gamma500]

Do you guys have info and photos of The Steadman special 750?

Another amazing kiwi built 2t special!

Link to article I found from the internet:

http://img5.imageshack.us/gal.php?g=7500001.jpg

Faster than the superbikes at Taupo!!

[TZ350]

EngMod2T

The model assumes the combustion process stays the same as long as the basic combustion chamber and process stays the same but has to be re calculated if the compression ratio, fuel or other details like piston dome, squish clearance or area are changed.

The "Turbulent" combustion calculation (takes a lot of time) only has to be done once, then the details are entered by hand once and the program run in "Prescribed" combustion mode (much faster) while changes to other items like pipe, ports and port timing can be explored without affecting the combustion model.

From EngMod2T's help file.

Turbulent eddies are created from the bulk flow of the fluid. Kinetic energy is taken from the bulk flow and transformed into turbulent energy (the spinning of the turbulent eddy). The size of these eddies are in part determined by the size of the container or duct and in our engines are typically between 5 and 20mm diameter depending on the cylinder and transfer port sizes. (This size is known as the integral length scale) These eddies break down into progressively smaller eddies down to eddies of about 0.5 to 1mm.

It is at this size that combustion takes place.
To decrease the delay time we need to increase the strength and duration of the spark to ignite as much of this first eddy as good possible. The size of this spark also needs to be at least the size of a turbulent eddy. Bigger does not really help because one or two eddies burning at the laminar rate has no real effect on the delay time. Increasing the spark strength and duration past the point where the eddy has been fully ignited will also have no or a very small effect. This partially explains why some engines show a performance improvement with a bigger gap - they have larger turbulent eddies.


To increase combustion rate we have to spin these eddies faster to come into contact with non burning eddies at a faster rate. This is why faster spinning eddies (higher turbulent intensity) results in a faster combustion. It also implies that combustion happens at a specific rate. Uncontrolled combustion is where these eddies ignite because of a sharp temperature and pressure rise. This is an uncontrolled event and if enough eddies ignite we have detonation which is definitely uncontrolled!


Prescribed burn rate. This model goes one step further in that the shape of the mass fraction burn rate is described by the user. Mass fraction burnt is usually a curve that is S-shaped. To descibe this the model uses typically a Sine function or a Wiebe (Vibe) function to describe the S-shape. The user supplies the constants that describe the form of this function. The user also supplies the ignition timing, the delay period length and the duration of the combustion. The chamber geometry is ignored.

Turbulent eddy entrainment. The turbulent intensity is calculated by the simulation and from this and the mixture purity and AFR, the laminar and turbulent burn rates are determined. This is then used to calculate the burn rate. The user supplies the ignition timing. The major characteristics of the chamber is included and squish action is calculated. Blending radiuses are ignored but dome shape and piston crown shape are used to calculate the flame front characteristics.

To read more, buy a copy of EngMod2T, its worth every penny.

These graphs are from my single exhaust port GP125 with a flat top pistion with 0.6mm squish and 7.6:1 corrected comp ratio. They will change if I change any of the combustion chamber details and have to be recalculated.

Ignition Delay ... VibeM ... Burn Duration in Degrees ... VibeA once calculated these numbers can be hand feed into EngMod2Ts simulation model to speed the calculating process up when simulating changes to pipes and ports.

[TZ350]

you should use the "Supplied" option in X/Y-axis limits (it's on the window for choosing perf. data) to limit the range and get even more accurate values.
A small trick I use is this: say I see the value of delay at 10500 is between 10 and 12. I limit the Y-axis between these two, and set the X-axis to start at 10500. It says the exact value right on the Y-axis scale.

I can't seem to make the "Supplied" X/Y option work.....

251638

How accurate does one have to be? would line of best fit work here?

[wobbly]

I have some pics of Jimmys triple on an old hard drive somewhere, I will see if I can find them.
It was here for a while when I did the pipe/port/ignition specs for him.
Initially it used a special PVL setup I built.
Then a set of 3 poxy Oz built ignitions, but we just couldnt stop them from talking to each other.
Its as fast as hell, but even using the triple balance program from BSL days, it still vibrates your balls off after a few laps.
He is building a V6 now, with RS125 cylinders.

TeeZee, yes best fit curve is fine for combustion data, its the value trend that is important.
More especially when you are simply doing pipe performance tests, as the combustion characteristic will remain a constant.

I used Dynamation back when I did the specs for the MB100 and NoMates engine - EngMod 2T would now do a way better ( more detailed) job.
The data generated back then was accurate enough, but all credit to Mike and Nige for implementing the basic info into something that works.

[dinamik2t]

Now that we say about pipes.. what is your opinion on dual stage baffle cones?? What would be the limit to the angle of the steeper stage?

[F5 Dave]

Think we probably have some pics of the 750 earlier in the thread.

here's an early pic. Wood radiator didn't make the final cut.

[wobbly]

TeeZee, in your VibeM graphic, it doesnt need to start at 0 ( this is the default ).
The range in Y is 0.2 min to 1.2 max, put this in and it expands the Y axis within these limits.
Leave rpm ( X ) as is.
makes reading off the specific numbers much easier and accurate.

[husaberg]

I had a bit of a dig around on the net and came up with these I see what Wob was meaning when it came to the Chassis. A truly beautiful example of CNC.

[husaberg]

I had a bit of a dig around on the net and came up with these I see what Wob was meaning when it came to the Chassis. A truly beautiful example of CNC.

A few that wouldn't fit. Including the Britten maybe Wob would like to mention any inside detail he may know about it? The Supermono is there for no other reason than because it's pretty

Credit to most of the pic to this guy http://picasaweb.google.com/114821789113527181423/MotorcyclesUnleashed#5271321351539510098

[speedpro]

Do you guys have info and photos of The Steadman special 750?

Another amazing kiwi built 2t special!

Link to article I found from the internet:

http://img5.imageshack.us/gal.php?g=7500001.jpg

Faster than the superbikes at Taupo!!

I have heaps of photos including of bits getting machined plus a video of when they first fired it up. It isn't bad considering it was pretty well all done in a double garage with a pretty basic lathe and mill. Nige made the pipes and as usual are a work of art.

[F5 Dave]

Well I’ve managed to engineer myself into a corner with SE bearings again. I have a 50.75 barrel I am running in the interim on my MB so I ordered a ye olde YZ100 piston to check out. Good luck finding online info on a ‘76 piston.

Arrived on my desk this morning so yet to check it at home.

Single 1mm ring that is pegged looking like far enough away from boostport not to have to move. Bit heavy as 3rd oversize & suitable for single port only. But heck it will keep this interim cylinder working ok & is far & away better than the MB one.


Whoops, 16mm pin. 14 is std. rod is 19mm ID. Yams usually run thin SE bearings, but 16x20 is their size (same as RD250 apparently so don’t yell foul yet).

I forgot to order a pin, it was a mission enough to find rings & piston from same seller who would ship. But that should match up with something else easy enough or be shortened.

So can someone point me in the direction of a reasonable resource (can’t seem to find a decent site, maybe I should try PeteSalesbearingcatalogue.com?) for finding if a 16x19x## bearing is indeed made? 1.5mm rollers? Mammy!

[jasonu]

I had a bit of a dig around on the net and came up with these I see what Wob was meaning when it came to the Chassis. A truly beautiful example of CNC.

What is the bike in the background in the last pic?

[F5 Dave]

Last pic?, you'd have to be a forensic scientist to see that (or do you mean the reflection of the same bike?, heaps of mirrors in that show). I see both the Ally & Kevlar Roberts bikes in other pics though,.

[husaberg]

Last pic?, you'd have to be a forensic scientist to see that (or do you mean the reflection of the same bike?, heaps of mirrors in that show). I see both the Ally & Kevlar Roberts bikes in other pics though,.

My guess is jason means this one the Roberts one in the background of the first set of pics? he just confirmed this.

http://picasaweb.google.com/114821789113527181423/MotorcyclesUnleashed#5271322403647734418

(http://picasaweb.google.com/114821789113527181423/MotorcyclesUnleashed#5271322403647734418)

[jasonu]

Last pic?, you'd have to be a forensic scientist to see that (or do you mean the reflection of the same bike?, heaps of mirrors in that show). I see both the Ally & Kevlar Roberts bikes in other pics though,.

Hus pm'd me the answer and another pic. I was looking at the Roberts bike. It looked familar but I wasn't sure. Still looks the business.

[jasonu]

Who was it that did a fair amount of races on the BSL? IIRC it was an Aussie and he did a lot of bitching about it 'ruined my career' and such. But maybe I am thinking of something else.

[F5 Dave]

From my own pics from the show. + the ally one that was built earlier. Kevlar one is sitting about 2k from here.

[TZ350]

EngMod2T


A small trick I use is this: say I see the value of delay at 10500 is between 10 and 12. I limit the Y-axis between these two, and set the X-axis to start at 10500. It says the exact value right on the Y-axis scale. :)

Basically, now that I think about it, while you keep using Prediscribed, there is no need for too great an accuracy, since you are only looking for differences between modifications.


TeeZee, yes best fit curve is fine for combustion data, its the value trend that is important. More especially when you are simply doing pipe performance tests, as the combustion characteristic will remain a constant.

Thanks for the tips, got that part working now.... this is how I went about it.

251691

To select the file and range, I had to enter both Y (data range) and X (rpm) values or the screen screwed up.

251690

Selected the variable I wanted to graph.

251689

And there I have it, an expanded chart for more accuracy.

And I have finaly found the list of definitions.

RPM Simulated engine rpm
P-av Average engine power over the last three cycles (kW)
Torque The engine torque related to P-av. (Nm)
Tex-AvC Average temperature in center of exhaust (ºC)
Tex-AvT Average temperature at transducer position in exhaust header (ºC)
Power Power per cylinder (kW)
Imep Indicated mean effective pressure per cylinder (bar)
Bmep Brake mean effective pressure per cylinder (bar)
Fmep Friction mean effective pressure (bar)
Dratio Delivery ratio per cylinder
Purc Purity of the mixture in the cylinder at exhaust port closure
Seff Purity of the mixture in the cylinder at transfer port closure
Teff Trapping efficiency per cylinder
Ceff Charging efficiency per cylinder
BSFC Brake specific fuel consumption per cylinder (kg/kWh)
TC-av Average maximum cylinder temperature per cylinder (ºC)
TUBmax Maximum unburned mixture temperature per cylinder (ºC)
MaxDeg Degrees after TDC where maximum cylinder pressure occurs per cylinder
Timing Ignition timing (ºBTDC)
Delay The user prescribed delay period in degrees (deg)
Durat The user prescribed combustion duration (burn period) in degrees (deg)
TAF Trapped Air/fuel ratio
VibeDelay The calculated delay period for a turbulent combustion model (for the prescribed combustion model it is the same as "Delay")
VibeDurat The calculated burn period for a turbulent combustion model (for the prescribed combustion model it is the same as "Durat")
VibeA The calculated Vibe A value for a turbulent combustion model (for the prescribed combustion model it is the same as prescribed)
VibeM The calculated Vibe M value for a turbulent combustion model (for the prescribed combustion model it is the same as prescribed)

The units are standard SI units: kg, s, Nm, kW etc.

[husaberg]

Who was it that did a fair amount of races on the BSL? IIRC it was an Aussie and he did a lot of bitching about it 'ruined my career' and such. But maybe I am thinking of something else.

I know you don't mean this guy.
but I guess he may regret this decision to wear the misses undergarments on this occasion. Or maybe not.

[wobbly]

The Oz was Willis, but I fail to see how BSL ruined his career.
He got onto the Modenas team working for Kenny, when the BSL was stopped from racing by Dorna..
He was the quickest KR3 rider, so there were other reasons he didnt get to stay in 500GP.

[F5 Dave]

Well it looks like I'm schmozzled with a 16x19 small end bearing. All the ones I've found in my spares drawer have been 16x20 or 15x19. Might have to make some bushes which is a pain. Can't stretch to another rod with other bills atm.

[jasonu]

The Oz was Willis, but I fail to see how BSL ruined his career.
He got onto the Modenas team working for Kenny, when the BSL was stopped from racing by Dorna..
He was the quickest KR3 rider, so there were other reasons he didnt get to stay in 500GP.

Thanks for the reply.
The career ruining thing was something I vaguely remember reading some time ago. Maybe/probably thinking of someone else.

[Bert]

Well it looks like I'm schmozzled with a 16x19 small end bearing. All the ones I've found in my spares drawer have been 16x20 or 15x19. Might have to make some bushes which is a pain. Can't stretch to another rod with other bills atm.

you could always sell the piston to me to add to the collection for the future (took my a long time to sort out that YZ100's would fit my TZR project):brick:.

what about a crowded roller (as getting 1.5mm roller pins is easy enough) and packing washers (what was it: grown men cry.. Bell..)?
or could you pull a 15*19 apart and put in larger rollers (the cage maybe be slightly off centre as a result but...; just a thought don't shoot me down).

or machine up some small end - end caps (that act as spacers/bushings as well) (Woobly/Fits blow-by preventers) and taper/step the ends of the pin to match it all up nicely and provides some meat to the bushes??
again don't shoot me down; just some of the crazy ideas that came to me to resolve my issues.:facepalm:

[TZ350]

... what about a crowed roller (as getting 1.5mm roller pins is easy enough) and packing washers (what was it: grown men cry.. Bell) ...

1.5 mm crowded rollers with end washers and assembled up using a short dummy pin is my bet.

[wobbly]

16 by 19 isnt a standard size in any of my references.
But crowded rollers in a small end is going back to McCulloch chainsaw days, they all rub like hell on each other and die under any load
that a caged roller setup would live happily with all day.
Must be another way??

[F5 Dave]

Thanks for looking guys, I'll have to go down the bush path. There is a heap of room in between the pin bosses so I would have had to run some thrust washers in the Yam piston anyway (found out the hard way putting a RD piston in my MB50 back 1990). So there is room for bushes & I already have some scribbled pictures moments after the piston arrived. Bit of a pity to be doing some intricate engineering on what was hopefully going to be an interim solution & esp while I'm a bit broke atm. Taking my eye off doing new cases.

[F5 Dave]

quick question for the pipe builders: Stinger tube? Trying to think who would carry off cuts of thin wall steel tube with an ID of between 19-20mm. I kinda want to get it bent too. Too small for muffler shops to carry or bend.

[speedpro]

If I need thin light tube I make it myself from .8mm mild steel. I smash it into shape on a bar with the correct OD. I cut it on a guillotine so the edges are nice and straight, make it a good tight fit, and seam weld it while it's still on the bar. Quite often it needs a good hammering with a ball pein hammer to unjam it. Hammering it with a rubber mallet gives it a nice smooth finish. For stinger tube I've got some mandrel bends of 20mm ID from a custom motorcycle exhaust place here in Auckland. The walls aren't so thin but it's OK.

[koba]

Does anyone know the crankcase volume of an MB 100??

I will eventually measure mine but its a real prick to sort out and if anyone has an easy answer they are willing to share I'd be keen to know.

[koba]

quick question for the pipe builders: Stinger tube? Trying to think who would carry off cuts of thin wall steel tube with an ID of between 19-20mm. I kinda want to get it bent too. Too small for muffler shops to carry or bend.

I've seen handlebars used in a section of stinger by a respected local racer/tuner... ;) :shutup:

[husaberg]

I've seen handlebars used in a section of stinger by a respected local racer/tuner... ;) :shutup:

I have seen Furniture steel used at a pinch. Old school and children's chairs etc are thin wall steel. As are cheap gazebos, but I have never had problems obtaining small Dia tube from my local muffler shop.

The bend gas and very dry sand. It has to be dry or else it just creases.

Wednsday question for the panel
What was the piovaticcis?:innocent:

Who were the designers?
where did they work afterwards?

PS Google won't work.

[bucketracer]

Page 370 ....

[Sketchy_Racer]

Well it looks like I'm schmozzled with a 16x19 small end bearing. All the ones I've found in my spares drawer have been 16x20 or 15x19. Might have to make some bushes which is a pain. Can't stretch to another rod with other bills atm.

Hey Dave,

Sorry I've missed your calls, haven't paid the phone bill so cant call back, I'll give you a call from home tonight, I may have a solution to the piston pin problem, its so crazy it just might work!

[Frits Overmars]

Wednsday question for the panel What was the piovaticcis?:innocent: Who were the designers? where did they work afterwards?
PS Google won't work.My Google works just fine. And it will return even more results if you omit that last S.
As I am new to these panel questions: what's the first prize? (if it is attractive enough, I might even lure Jan Thiel into reacting :msn-wink:).

[kel]

Sorry Frits, Husabergs from the South :shutup:

251784

1974, the master with his creation

[F5 Dave]

Hey Dave,

Sorry I've missed your calls, haven't paid the phone bill so cant call back, I'll give you a call from home tonight, I may have a solution to the piston pin problem, its so crazy it just might work!
I got distracted making up an acetal version to get the juices flowing (obviously not to use). One would be closed at one end & T section inserted from the inside (which is too wide for he Honda rod so needs spacing anyways). But a simpler & better idea was forthcoming. Just harder to machine two with closed ends rather than straight through bush.

A plain bush solution may actually work ok if both ends are slightly shrouded (a 1mm step at the end so 14mm ID & then stepped down to 12) & the 14mm pin ground to the right length to push them apart so they retain the circlips & space the bearing properly without rubbing on it. This was the bit of the equation I was worried about.

Removal will still be possible by pushing the inner pin. I am considering using a 16mm pin as the bush, but it will be hardened so machining I'm not so sure about. Maybe Brass or SS will be easier. That's where you come in Sketchy.:yes: Hopefully.

I have ground circlip removal slots to I can use plain wire clips.

[jasonu]

Sorry Frits, Husabergs from the South :shutup:

251784

1974, the master with his creation

That looks like Bruno Lawrence from Smash Palace and The Crocodiles.

[husaberg]

Sorry Frits, Husabergs from the South :shutup:

251784

1974, the master with his creation


Number one Yes Husaberg is from the Tropical South and Special Dave considers me "Very attractive"
Not sure if that's a compliment or not.


Is that an old family snap? You're quite a handsome lad,


My Google works just fine. And it will return even more results if you omit that last S.
As I am new to these panel questions: what's the first prize? (if it is attractive enough, I might even lure Jan Thiel into reacting http://www.kiwibiker.co.nz/forums/images/smilies/msn-wink.gif).


So the T90 is still in a shed? I need a headlight surround & the chrome strip for the seat of my stinger resto that I'm quietly collecting bits for


Yes the google works a lot better with the correct spelling Removing the S at the end. It seemed to be auto correcting for me.I was getting a lot of hotels and resorts
I found reference to the bike in a Derbi article I will be posting soon.
I question was an subtle attempt to to lure at least one the creators into give some details on what was a rather advanced creation for the time and a bike I had never heard of. Had a rather unique story of evolution and yet today still appears modern.
The prize for the panel questions is a bit of a lucky dip.

The prizes are consisted mainly of adoration, respectful appreciation.

Because it is not likely that you have heard of Burno Lawerence here is a pic he was a NZ Character actor and entertainer/performer but probably not that well know outside of NZ and Aussie. A real Kiwi Icon.

http://www.elsberg-tuning.dk/piovaticci.html

[TZ350]

Kel sent me this link http://www.deraceheldenvanweleer.nl/index.php/topic,51.0.html on the lifes work of Jan Thiel all in Dutch but its worth a look for the pictures alone, lots of mouth watering stuff on Jamathi's and other 50cc racers of the 60's -70's.

[Frits Overmars]

Kel sent me this link http://www.deraceheldenvanweleer.nl/index.php/topic,51.0.html on the lifes work of Jan Thiel all in Dutch but its worth a look for the pictures alone, lots of mouth watering stuff on Jamathi's and other 50cc racers of the 60's -70's.Those pictures are all in English :msn-wink:. And in case you are interested in "Jamathi's and other 50cc racers of the 60's" I've got a lot more photo material. Not just Jamathi, but also (in alphabetical order) Bultaco, DKW, Jawa, KTM, Kreidler, MZ, Ossa, Rumi, Suzuki and Yamaha, from 50 cc triples to 750 cc fours, all two-strokes.
I've even got pictures of the works Hondas (both two- and foul-stroke).

Mental Trousers and yours truly just managed to work out a way to upload big files. Momentarily there is 37 MB of Aprilia information hovering in the cloud, waiting to be downloaded. Once you unzip it, it's over 70 MB.... And we could do the same with those other brands I just mentioned. Only if you are interested, of course....

The Aprilia stuff I uploaded, contains mostly drawings and photos; some works material, some made by myself, some made by others (so not all of it is copyright-free). It also contains manuals and parts lists of the works racers. They may give you some insight into the way these machines were built. They also offer a great opportunity to learn Italian; it's the way I started learning the lingo.

I keep saying Italian is easy. Just some examples: cilindro. pistone. carburatore. I bet you could decipher all of them.
Of course not all words are this obvious. Google will tell you for instance that an Albero is a tree. But what are all those trees doing in an engine?
Izze simple: Google forgot to tell that an albero is also a shaft. And with the help of the drawings in the manuals it's a doddle to figure out that an 'albero motore' is a crankshaft, that a cuscinetto is a bearing (a 'cushion' for the shaft) and that an ingranaggio is a gear.
Now I am anxious to see how Mental Trousers is going to make my ZIPs accessible :shifty:.

[dinamik2t]

and foul-stroke).

I keep saying Italian is easy. Just some examples: cilindro. pistone. carburatore. I bet you could decipher all of them.
Of course not all words are this obvious. Google will tell you for instance that an Albero is a tree. But what are all those trees doing in an engine?
Izze simple: Google forgot to tell that an albero is also a shaft. And with the help of the drawings in the manuals it's a doddle to figure out that an 'albero motore' is a crankshaft, that a cuscinetto is a bearing and that an ingranaggio is a gear.
Now I am anxious to see how Mental Trousers is going to make my ZIPs accessible :shifty:.

Haha now, wasn't that "oul" mistake on purpose??:sweatdrop

You have a great sense of humor, Frits! :D


I had found a interview of Jan Thiel in the past. If you use google translate it is ok understandable.
(Don't try your non-english native language, it will translate shafts to trees there too. I had the unfortunate idea to try greek.:crazy:)

http://forum.scooterforum.net/forum/f37/interview-jan-thiel-master-two-stroke-169193/

And there is another one on 50cc history: http://www.elsberg-tuning.dk/engineering.html

[TZ350]

Those pictures are all in English :msn-wink:. And in case you are interested in "Jamathi's and other 50cc racers of the 60's" I've got a lot more photo material. Not just Jamathi, but also (in alphabetical order) Bultaco, DKW, Jawa, KTM, Kreidler, MZ, Ossa, Rumi, Suzuki and Yamaha, from 50 cc triples to 750 cc fours, all two-strokes.
I've even got pictures of the works Hondas (both two- and foul-stroke).

Mental Trousers and yours truly just managed to work out a way to upload big files. Momentarily there is 37 MB of Aprilia information hovering in the cloud, waiting to be downloaded. Once you unzip it, it's over 70 MB.... And we could do the same with those other brands I just mentioned. Only if you are interested, of course....

A big thank you to you and Mental Trousers .... and yes yes very interested, Buckets is what we do, and in my case its because its what I can afford that allows me to get totaly involved tuning wise but all strokers interest us.

Yes please post it, here is ok and would be very welcome.

[koba]

Buckets is what we do, and in my case its because its what I can afford that allows me to get totaly involved tuning wise but all strokers interest us.


Not to mention the high level of competition, great people, great events, great :drinkup: and a whole pile of dirty diesels to mop up.

Oh, forgot the roller-skating.


A big thank you to you and Mental Trousers .... and yes yes very interested,

+1


Yes please post it, here is ok and would be very welcome.

+1 again.

[F5 Dave]

++ lots. Thank you for the chance to view material we would never otherwise have access to.

[F5 Dave]

Number one Yes Husaberg is from the Tropical South and Special Dave considers me "Very attractive"
Not sure if that's a compliment or not.

To put that in perspective you had just posted a picture of a pasty Asian guy with a monster mullet sitting on a scooter or something . So that was you!

[dmcca]

I might even lure Jan Thiel into reacting :msn-wink:.


Mental Trousers and yours truly just managed to work out a way to upload big files. Momentarily there is 37 MB of Aprilia information hovering in the cloud, waiting to be downloaded. Once you unzip it, it's over 70 MB.... And we could do the same with those other brands I just mentioned. Only if you are interested, of course....



:thud:

Thats me falling over with shock/excitement... if you could make either one or both of those things happen it would make me (and many others im guessing) very very happy.



A question for Frits (and Mr Jan Thiel is he's listening...) Can you give any updates on the ICRT?... is it still going ahead and are there any tips you can share on who might participate and what sort of engines we might see? I love the philosophy behind the series... free and open without restrictions... just what two strokes need to dominate again:first:

***EDIT... i just found this link http://continentalchampionshipracetech.weebly.com Should have searched harder first, sorry... still interested to hear anything you might wish to add...

[kel]

[/SIZE]Mental Trousers and yours truly just managed to work out a way to upload big files. Momentarily there is 37 MB of Aprilia information hovering in the cloud, waiting to be downloaded. Once you unzip it, it's over 70 MB.... And we could do the same with those other brands I just mentioned. Only if you are interested, of course....


Interested? :wings:
Frits your generosity is overwhelming. :drinknsin

[husaberg]

To put that in perspective you had just posted a picture of a pasty Asian guy with a monster mullet sitting on a scooter or something . So that was you!

Nah sorry, Husaberg would never be seen dead or alive on a scooter.:scooter:
but it does concern me that your tastes run to pasty Asian dudes with large er.. mullets on scooters:eek5: Bull-wee Wei Ciwus I guess?

Add some old Derbi stuff later.
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=251892&stc=1&thumb=1&d=1322894560 (http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=251892&d=1322894560)
Cheers to to Frits and Mental trousers?

[2T Institute]

I'm making lampshades out of these old things is anybody intersted in one?

[2T Institute]

The RSA was not the first behind-the-cylinder disc valve engine that honour might go to the CZ factory circa 1982

[2T Institute]

Sorry guys a bit off topic,but this thread has some very knowageable people, could i just ask what they think about this?
at the entrance to the transfers the rsa aprilla has very wide dividers between each one while most tuners would narrow these down, i wonder what people like frits think about this or does it not matter.
great thread by the way

Not meaning to pick on you pete but anyone who does knife edges isn't a tuner, the above and the old chesnut of the 'ported and polished' are 2 of the big no no's. The first as Frits explained as well as port velocity is sub sonic, no propellor engined aircraft have sharp leading edges on wings. Besides 'knife edging' that Aprilia cylinder just cost you 3000Euro :shit:
With port texture/finish the best analogy I ever heard was imagine 2 sheets of glass on top of each other, if you tried to move them around dry it would be quite difficult, but if you were to add a medium between the sheets of glass which would make the glass easier to move ? What medium would make it easier to move the glass? Oil or beach sand? The oil would make it more slippery (but viscous friction to over come) but a sprinkling of sand would allow the sheets of glass to 'roll' on each other

[Frits Overmars]

The RSA was not the first behind-the-cylinder disc valve engine that honour might go to the CZ factory circa 1982One should always be careful with such statements. I'm not claiming the MZ125 below was the first engine with such a disc, but it's at least 25 years older than the CZ.

[dmcca]

I'm making lampshades out of these old things is anybody intersted in one?

Heck, I'll take one if you're giving them away... Need a new lamp shade...

Seriously, looks like an RSA sand mould, or maybe a 3d printed model... Care to elaborate? It'd be very interesting to see the ducts in their true physical size.. Looking at cad models and sketches is one thing but seeing the real size would give a whole new understanding.

[2T Institute]

One should always be careful with such statements. I'm not claiming the MZ125 below was the first engine with such a disc, but it's at least 25 years older than the CZ.


I knew that I just wanted to see what else was in those Famous Frits Files :laugh:

[husaberg]

Derbi Stuff.
The first paragraph is what drew me to the piovaticci

Maybe Jan Could complete the yarn about the engine and how it came into being?

I really like the Layout of the Narrow angle 125 V twin shame about the air cooling and it wasn't developed further.

As per normal Kiwibiker. The attachment carefully loaded in sequence are in appearing in Random order pg1,6,2,3,4,5.

Ps My take on the earliest rear facing carburetor rotary valve 2 stroke would be the Scott in 1912....:woohoo:


Alfred Scotts engines were so good the authorities decided to handicap the 2 stroke by giving them a capacity multiplication of 1.32X

How times have changed :innocent:

150cc 4 strokes vs 113cc liquid cooled 2 strokes seems about right to me:whistle:

[husaberg]

More old stuff this is one of my favourite race bikes so simple, so cheap, shame it was a couple of years to late. Without a better gearbox and Disk valve.

Greeves Silverstone

Note the effects of the inlet tract length and the pre Teflon crank seals

[Frits Overmars]

I knew that I just wanted to see what else was in those Famous Frits Files :laugh:Yeah, right..... How about something to really wet your appetite: a works Honda with a rear disc :shit:.

[Grumph]

[QUOTE=husaberg;1130207683]More old stuff this is one of my favourite race bikes so simple, so cheap, shame it was a couple of years to late. Without a better gearbox and Disk valve.

Greeves Silverstone

In the period they were a real POS....biggest problem was the OE pistons - heavy/thick and very seize prone.
Ask Mike Sinclair...I came round at Wigram to see him on one side of the track and the Greeves the other - and he crossed the track on a broken ankle because the thing was screaming it's ring out with a stuck throttle - when stripped it showed the partial seizure which had tossed him off but it had kept running on it's side....go figure.

[gamma500]

That rsa cylinder sandcore looks interesting, do you guys have photos of the coreboxes used for casting 2t cylinder?

I have been dreaming of casting a 2t cylinder someday...

[Frits Overmars]

That rsa cylinder sandcore looks interesting, do you guys have photos of the coreboxes used for casting 2t cylinder? I have been dreaming of casting a 2t cylinder someday...The cores for the exhaust and transfer ducts are not the most difficult parts; it is the cooling waterjacket core that really complicates things when you are planning to cast your own cylinders. In my Aprilia-papers there are CT-scans of the ducts and the cooling void, available as soon as mental trousers has worked out a way to make those data accessible.

[Ocean1]

The cores for the exhaust and transfer ducts are not the most difficult parts; it is the cooling waterjacket core that really complicates things when you are planning to cast your own cylinders. In my Aprilia-papers there are CT-scans of the ducts and the cooling void, available as soon as mental trousers has worked out a way to make those data accessible.


You used a CTscan to reverse engineer a cylinder? That's brilliant! I assume it was a medical unit? Did you have any trouble booking time on it or was it a perk? What flavour files did you get?

[wobbly]

I have reverse engineered a couple of parts using CT scan.A place on Remuera Rd did the scans for free, as it was interesting to them.
The big issue is getting the scan data into a format that can be manipulated by a CAD program.
This in the first instance cost plenty to have done - then my son did a torrent download of a 30K USD program that can take the scan data and turn it into
a .xt solid for example.
There are even programs now that can create a constructional element tree that emulates how SolidWorks would have created the part.
Constructing a cylinder as a solid model from scratch stretches the limits of the system, the programs and the CAD engineers intellect.
Last one I did took 6 weeks full time.
Taiwanese companies can now do a one off cylinder casting using Rapid Prototyping with ceramic sand for around 1500USD, about a 1/4 of what the BSL cylinders cost to produce.

[speedpro]

Taiwanese companies can now do a one off cylinder casting using Rapid Prototyping with ceramic sand for around 1500USD, about a 1/4 of what the BSL cylinders cost to produce.

Only US$1,500. It's only a matter of time until they turn up at bucket racing. I can see it now - bridged exhaust port MB100s or even triple exhaust port MB100s, mmmm, blowdown.

Do you have a web page or address?

[bucketracer]

Those Wild Rocket Karts!

251970 ... a rocket powered Dart Kart from the mid-1960's.

There have been many wild and strange experiments throughout karting’s history. Perhaps the wildest of all were the rocket powered karts of the 1960’s, 70’s and 80’s.

Would you believe that in the mid-1960’s the rocket-powered kart pictured above turned the quarter mile at over 150 mph? 0 to 150 in 7.3 seconds! That was Jack McClure with his modified 1963 Rupp Dart Kart powered by a pair of Turbonique T-16 rocket motors.

251969

These motors, each producing 300 lbs of thrust, used a special kind of monopropellant which the company dubbed "Thermolene" (actually N-Propyl Nitrate). These engines powered the little kart to faster times than rail dragsters of its day.

These engines, however, were also very dangerous and killed many users because under certain conditions they could explode like bombs. Those disasters resulted in the Turbonique factory closing and its owner landing in jail.

Rocket Karts in the 1970's

In 1967, a company called Reaction Dynamics built a record-breaking dragster powered by a 90% hydrogen peroxide rocket motor. This car was the inspiration for many rocket powered vehicle builders in the 70’s, among them (back again!) Jack McClure with a hydrogen peroxide rocket-powered laydown kart. The kart, which resembled a Margay, was actually custom designed by Jack and built by Glenn Blakely of Tampa Florida. Jack fitted this kart with an engine built by Arvil Porter that produced 1000 lbs of thrust.

251971Jack McClure's kart with the 1000 lb thrust rocket.

Jack needed more speed (!!) however, and had Arvil build him a 1500 lb thrust version. This engine, crafted of stainless steel, was 10" long by 7" diameter. The hydrogen peroxide was forced through a catalyst pack made of silver and nickel screens. Superheated steam produced by the reaction at 300 PSI escaped through a 2 " diameter nozzle and produced enough thrust to push the little kart to over 215 mph in 6 seconds in the quarter mile.

For stopping, the kart featured disc brakes (for below 100 mph) and a drag chute. The driver’s suit was also fitted with its own parachute in case driver and kart became separated during one of those wild runs. The kart was later sold to Ramon Alvarez who raced the kart for a short time. The kart might still exist to this day.

The 1980's

In 1980, the karting speed envelope was pushed yet further by Australian Rosco McGlashan. Rosco, who at the time was living in the U.S., built and drove a hydrogen peroxide rocket kart that surpassed 253 mph!

251972

Taken from:- http://www.vintagekarts.com/Rockets/Rockets.htm

[bucketracer]

I found that bit on rocket Karts while trying to find out for TeeZee's alky Ariel Arrow project the earliest time hydraulic disk brakes appeared on Go Karts.

If anyone can help, TeeZee is working through the Classic Bike Racing Register registration process and he is particularly interested in brakes from the pre 63 and 76 eras, and would like to know more about the Air Hart brand as seen on Karts and Flat Trackers.

Any documented evidence like old sales brochures or dated photos of Karts/FlatTrackers with hydraulic brakes or Tillotson carbs would be much appreciated.

The plan is to use hydraulic disks and Tillotsons if they can be authenticated as being available in the pre 63 or 76 era.

[Kickaha]

I found that bit on rocket Karts while trying to find out for TeeZee Ariel Arrow project the earliest time hydraulic disk brakes appeared on Go Karts.

If anyone can help TeeZee is particularly in the pre 63 and 76 eras, and would like to know more about the Air Hart brand.

You mean Airheart?
Why don't you just email the company and ask them

[bucketracer]

You mean Airheart?

Yes, Airheart ... thanks.


Why don't you just email the company and ask them

Didn't do to well with Tillotson or the bigger Tilly retailers on the net, but will give it a go with Airheart.

Original sales brochures or dated photos would be interesting in their own right too.

[husaberg]

I found that bit on rocket Karts while trying to find out for TeeZee's alky Ariel Arrow project the earliest time hydraulic disk brakes appeared on Go Karts.

If anyone can help, TeeZee is working through the Classic Bike Racing Register registration process and he is particularly interested in brakes from the pre 63 and 76 eras, and would like to know more about the Air Hart brand as seen on Karts and Flat Trackers.

Any documented evidence like old sales brochures or dated photos of Karts/FlatTrackers with hydraulic brakes or Tillotson carbs would be much appreciated.

The plan is to use hydraulic disks and Tillotsons if they can be authenticated as being available in the pre 63 or 76 era.

http://www.nzcmrr.com/events/rules

Rules state they the brakes must be drum.For Pre 63 76 anything goes as long as they were available pre 76.

and not contrary to this rule


MAJOR COMPONENTS. These will determine age. These are frame and swingarm, engine, fork assembly, gearbox, hubs, brakes, carburettors. No major Japanese components will be accepted.



For the carbs Amal mk2 are not so bad. much much better than mk1's


<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman";} </style> <![endif]--> 1. FACTORY BUILT RACING CLASS. Machines built specifically for Grand Prix Racing.
1. Machines must have been produced and raced by a recognised factory in the period.
2. Fuel. Open (to MNZ rule) - Alcohol permitted.
3. Ceriani G.P. forks only permitted in pre 1963 classes if fitted as original factory equipment.
2. CLUBMANS CLASS PRE 1963. Machines with major components (as per rule 3) not built specifically for racing:
1. Lights and stands must be removed.
2. Exhausts. Road type silencers may be retained but if racing exhausts are used they must comply with MNZ rules.
3. Brakes. No twin leading shoe front brakes, or double-sided front brakes may be used unless fitted as original equipment.
4. Gear boxes shall have a maximum of four (4) speeds. Ratios may be varied.
5. Carburettors. Pre 1963 road or racing carburettors or Amal Mk 1 concentric if the original type is not available.
6. Fuel. Petrol only, up to 100 octane (R.O.N. rating) Avgas or No 1 Racing Fuel permitted.
7. Fairings are not permitted. A number plate with 'fly screen', of a type fitted as original equipment to a 7R or Manx, is the largest type of front screening allowed.
8. Capacity. Engines must retain the manufacturers bore and stroke. Maximum allowable overbore is 0.060" (1.5mm). Effective from 31st May 2004.
3. MODIFIED CLASS PRE 1963. A modified machine must conform to all the general requirements except:
1. Engine and gearbox to be the same silhouette as pre 1963 machines.
2. Frame and suspension components built after 1963 may be used provided they are similar in type and style to pre 1963 components.
3. Wheels must be of wire-spoked type. Maximum rim width 3.5" (inside width).
4. Brakes may be later model, provided that they are of drum type.
5. Carburettors. Amal Mk 1 and Mk ll concentric carburettors will be accepted in pre 1963 open and modified class.
6. Fuel. Open (to MNZ rule) - Alcohol permitted.


POST CLASSIC MODIFIED CLASS. A Post Classic machine must conform to all the general requirements except:

All models of British, European or American motorcycles of a type manufactured pre 1976 are eligible.
No Japanese machines. No Japanese major components (as defined in rule 3).
Carburettors. Must be of a type manufactured pre 1976. Post Classic Factory Built Racing machines may have Japanese carburettors only if fitted as original Factory equipment.
Ignition. Unrestricted.
Silencing as per MNZ rule.
Brakes. Disc brakes are allowed with a maximum of two pistons per calliper. All brake components must be of a type manufactured pre 1976.
Wheels. Maximum rim width 3.5" (inside width). Must be of a type manufactured pre 1976. Cast alloy wheels are permitted only if factory fitted as original equipment for the individual machine and must be of a type available pre 1976.
Fuel. Open (to MNZ rule) - Alcohol permitted.

[bucketracer]

Thanks for the info,

3. MODIFIED CLASS PRE 1963. A modified machine must conform to all the general requirements except:

4. Brakes may be later model, provided that they are of drum type.

Ok, so screwed with the disks here.

5. Carburettors. Amal Mk 1 and Mk ll concentric carburettors will be accepted in pre 1963 open and modified class.

I don’t think this excludes Tillotsons, just allows a later model British carb to be used for availability reasons.



POST CLASSIC MODIFIED CLASS. A Post Classic machine must conform to all the general requirements except:

* All models of British, European or American motorcycles of a type manufactured pre 1976 are eligible.

So by extrapolation, parts used on racing machines of the era are eligible too.

* Carburettors. Must be of a type manufactured pre 1976. Post Classic Factory Built Racing machines may have Japanese carburettors only if fitted as original Factory equipment.

Tillostson ?

* Ignition. Unrestricted.

IgniTech

* Brakes. Disc brakes are allowed with a maximum of two pistons per calliper. All brake components must be of a type manufactured pre 1976.

Airheart hydraulic

* Wheels. Maximum rim width 3.5" (inside width). Must be of a type manufactured pre 1976.

Flat Tracker spool hubs.

Looks like its going to be pre 76, Got to find those photos or sales brouchers.

[Kickaha]

* Brakes. Disc brakes are allowed with a maximum of two pistons per calliper. All brake components must be of a type manufactured pre 1976.

Airheart hydraulic

.

Why would you waste your time with Airheart when you can run Brembo 08 as fitted to numerous Ducati/Moto Guzzi/ Eurotrash of that era, calipers are still available new and there are good pad compound choices




* Wheels. Maximum rim width 3.5" (inside width). Must be of a type manufactured pre 1976.

Flat Tracker spool hubs.


I guess if you have more money than sense you could use them although I would have thought proper flat track hubs wouldn't even have mounts for front discs :whistle:
GN250 Wire wheel front hubs same as fitted to GT550/750/GS750 so they take twin discs and you can buy them for bugger all

[husaberg]

Why would you waste your time with Airheart when you can run Brembo 08 as fitted to numerous Ducati/Moto Guzzi/ Eurotrash of that era, calipers are still available new and there are good pad compound choices


I guess if you have more money than sense you could use them although I would have thought proper flat track hubs wouldn't even have mounts for front discs :whistle:
GN250 Wire wheel front hubs same as fitted to GT550/750/GS750 so they take twin discs and you can buy them for bugger all

Other than they are Japanese that is whoops

[Kickaha]

Other than they are Japanese that is whoops

Oh yeah I forgot about all that anti jap bias bullshit so their new replica pommy piles of crap dont get hammered

Of course they're quite happy to get Jap bikes of special interest over as a display drawcard though

[Ocean1]

I have reverse engineered a couple of parts using CT scan.A place on Remuera Rd did the scans for free, as it was interesting to them.
The big issue is getting the scan data into a format that can be manipulated by a CAD program.
This in the first instance cost plenty to have done - then my son did a torrent download of a 30K USD program that can take the scan data and turn it into
a .xt solid for example.
There are even programs now that can create a constructional element tree that emulates how SolidWorks would have created the part.

Last time I looked, (4-5 yrs ago?) they used a proprietary (of course :rolleyes: )mesh based format. I was reviewing a new RP printing system using Ti and Tool steel sintered by microwaves. The app for the system was also mesh based: http://www.materialise.com/Magics-e-Solution-Suite and in fact felt more CGI than CAD to use but worked OK once you got a feel for it.

I normally use Rhino, ( http://www.rhino3d.com/ ) which has some pretty solid translation routines, but I’d be interested in anything that could generate SW constraints / history for a given export...



Constructing a cylinder as a solid model from scratch stretches the limits of the system, the programs and the CAD engineers intellect.
Last one I did took 6 weeks full time.

I don’t doubt it. I’m constantly up against unrealistic expectations of clients about modelling complex shapes, and that's exactly what Rhino’s optimised for.

[bucketracer]

Why would you waste your time with Airheart when you can run Brembo 08 as fitted to numerous Ducati/Moto Guzzi/ Eurotrash of that era, calipers are still available new and there are good pad compound choices

TeeZee had hoped to squeeze into pre 63 with disks but yes your right, there are better calipers for pre 76, thanks for the heads up reminder.


I guess if you have more money than sense you could use them although I would have thought proper flat track hubs wouldn't even have mounts for front discs :whistle: GN250 Wire wheel front hubs same as fitted to GT550/750/GS750 so they take twin discs and you can buy them for bugger all

Nothing Japanese, TeeZee is probably not going to buy original Flat Track spools, under the rules he can make replicas ....

[bucketracer]

252011



Guazzoni 50 (http://www.eurospares.com/graphics/guazzoni.jpg) An Italian rotary valve two stroke - note the rearward facing exhaust.

252013

The top bike is a Tomos from Yugoslavia, with an Italian Moto Minarelli below. You can find pictures of a Minarelli that I took this past September in Italy elsewhere on the site.

252012



The top bike is an Italian Morbedelli . The middle bike might be a Kreidler - note the need of a big single crankshaft flywheel to bring the bike up to minimum weight! The bottom photos show the very successful Dutch Jamathi (though they spell it Yamathi, which is the phonetic pronunciation). The Jamathi was built by a small team of friends, and if I remember correctly, they found the dual SLS front brake (ex works Suzuki) at a swap meet.

Heaps of interesting classic bikes here:- http://www.eurospares.com/graphic2.htm#Vintage Japanese motorcycles

[Frits Overmars]

....Jack needed more speed (!!) however, and had Arvil build him a 1500 lb thrust version. This engine, crafted of stainless steel, was 10" long by 7" diameter. The hydrogen peroxide was forced through a catalyst pack made of silver and nickel screens. Superheated steam produced by the reaction at 300 PSI escaped through a 2 " diameter nozzlePlease tell me how to generate 1500 lb of thrust with 300 psi and a 2" nozzle, then I will contact Boeing, Lockheed, Airbus and NASA.


... The Jamathi was built by a small team of friendsA very small team: JAn THIel and MArtin Mijwaart, aided by rider Paul Lodewijkx who in 1968 rode the home-built Jamathi single to beat 50cc world champion Anscheidt on his 14-speed works Suzuki twin.

[2T Institute]

Good to see you look at mxworksbike website Frits, (that is the only disc valve Honda ever seen it's not even on display at the Collection Hall at Motegi ) :laugh:

13 ports is the most I have jammed into a H100/MB100 cylinder

How's everyones Italian? This is a overview on how to cast a cylinder the old fashioned way

http://www.youtube.com/watch?v=Lj4h9666d9s&feature=related

[Frits Overmars]

How's everyones Italian? This is a overview on how to cast a cylinder the old fashioned way
http://www.youtube.com/watch?v=Lj4h9666d9s&feature=relatedGreat video. But you better start here: it is a series of three videos, and very, very instructive:
http://www.youtube.com/watch?v=I-2rJtnkYq4&feature=related
By the way, the leading actor, Gabriele Gnani, is one of the founding fathers of the new Continental Championship Race Tech, CCRT.

[bucketracer]

Please tell me how to generate 1500 lb of thrust with 300 psi and a 2" nozzle, then I will contact Boeing, Lockheed, Airbus and NASA..

I didn't see that but too late ..... the jet Kart advertising copy writers have patented it already ....

[speedpro]

13 ports is the most I have jammed into a H100/MB100 cylinder

My new watercooled H100 is up to 11 ports but I'm seriously looking at 12 & 13. I'm gonna try adding them to another engine first just to see if there is any advantage.

[Frits Overmars]

My new watercooled H100 is up to 11 ports but I'm seriously looking at 12 & 13...That is like putting cooling fins inside the ducts. Think about it...

[bucketracer]

That is like putting cooling fins inside the ducts. Think about it...

Hmmm good idea, thats something for TeeZee to think about, he has already been looking at ice water cooling of the inlet side just before the carb with a CPU fan and heat sink inside a still air box.

[husaberg]

Interesting engine? An early crankcase reed 1958

http://www.rearenginekarts.com/clark engine.htm


Note the Exhaust port width
Also the interesting reed cadge brings a meaning to petal I suppose? it kind of looks like the reeds for the jet engine on Oceans webpage


With regards to Frits post I assumed he is inferring that the ports will serve to remove heat from the cylinder as they will be totally around the cylinder, Thus the cooling system will not be making contact with the cylinder but will be cooling the transfers. I could of course be well off the mark a bit there though.

Yes I too am not sure why the whole post is appearing to be a link as well.
(http://www.rearenginekarts.com/clark%20engine.htm)

[koba]

Good to see you look at mxworksbike website Frits, (that is the only disc valve Honda ever seen it's not even on display at the Collection Hall at Motegi ) :laugh:

13 ports is the most I have jammed into a H100/MB100 cylinder

How's everyones Italian? This is a overview on how to cast a cylinder the old fashioned way

http://www.youtube.com/watch?v=Lj4h9666d9s&feature=related


My new watercooled H100 is up to 11 ports but I'm seriously looking at 12 & 13. I'm gonna try adding them to another engine first just to see if there is any advantage.

Is that all ports, like 5 inlet, 5 transfer and 3 exhaust or something?

[TZ350]

EngMod2T

I have been looking at exhaust port nozzels, now I would have thought the best arrangement was to have the exhaust port gently opening up starting at the port window and flaring out to the expansion chambers header diameter which is 40mm on my bike(old RS125 chamber).

But EngMod2T and Wobbly tell me that a nozzel shape is what I need for top end and over rev.

252041

First step was to model the exhaust port then click on calc to find the predicted best nozzel diameter.

252044

You can see that it is less than the effective diameter of the port exhaust port window itself.

I tried nozzel diameters from the diameter of the expansion chamber header at 40mm, 38-36 and 34mm. All other aspects of the model were the same, just the nozzel was changed.

252040

A 34.5mm nozzel (green line) worked the best as the nozzel diameter increased top end and over rev dropped off.

The exhaust port outlet (nozzel) on my bike is currently 40mm, I guess I will be trying a 34.6mm one soon.

[koba]

That is like putting cooling fins inside the ducts. Think about it...

Perhaps because of the limited scope offered by the standard design?

Do you think the turbulence created, or the surface area would in some way (Heat transfer, drag effects?) negate the extra inlet/exhaust/transfer area then available?

[wobbly]

The calculator in EngMod was added by Neels after I had done dozens of tests with tripple and T port designs.
The calculator simply uses 75% of the total effective port area as a guide.
This always works and always makes alot more power and generally I found that the duct exit should be about the area of the main port alone.
This usually ends up around 75% of the total ( by taking away the extra area of tripple ports) needed for lots of blowdown - thus power.
It was never intended to be used with a single port only as I havnt tested that at all, apart from years ago on TD3s etc, and we always went bigger back then, not smaller.
Theory says that having a smaller duct volume changes the Helmholtz frequency ( higher ) , and reduces the amount of exhaust residuals able to be stored in that duct ( meaning more clean mixture sits close) , but im not sure this theory will apply to making more power with a single port.
Having said that, a 40mm pipe entry on an engine only making 30 Hp is way too big, so reducing the duct and or header area, or maybe both, will very likely work real well.
Did you model the nozzle as a short tapered section ( 30mm say) from the duct exit up to the header dia ( as the first section of the pipe) and this is made as an oval to round transition in the flange on T port and tripple port designs.
Be real interesting to see if the sim reflects reality on a dyno, in your single port scenario TeeZee.

[speedpro]

Is that all ports, like 5 inlet, 5 transfer and 3 exhaust or something?

3 exhaust, 5 transfer, 3 inlet. 2 extra exhausts and 2 extra piston port inlets. I'm considering adding "Boyensen ports" to the transfer passages from the reed block cavity. I'm still thinking about the "cooling fins in the ducts". I'm presuming that if the transfer ports were widened and then a divider devconned in that the divider would act like a fin dividing and directing the flow, and also providing a cool surface. I wasn't thinking of doing that. The basic software I'm using suggests that the transfer ports aren't actually a limiting factor. I've pressed solder onto the port inner radii and then very carefully removed it. The curve looks to be pretty good. The only thing I'm going to do is polish the transfer ports.

I just had an idea - What if the transfer ports were divided vertically into upper and lower sections. You could have the gas flow directed in one direction as the port opened and as the second lower portion opened it's gas flow could be in some other direction. There would not neccessarily be a reduction in gross flow as the port duct could be enlarged to allow for the divider. An advantage is that the upper portion of the port would open first and close last and the gas flow in that smaller duct could contain a lot of energy and maintain an ideal port outlet shape until the piston started closing it off keeping flow rate up. I know someone has already thought of it but I've never seen it. I envisage the divider following the curve of the port right to the duct entry so effectively you will have 2 seperate transfer ports stacked. You could even close off the outer duct leading to the upper portion of the port with a guillotine, if that was a benefit.

[koba]

3 exhaust, 5 transfer, 3 inlet. 2 extra exhausts and 2 extra piston port inlets. I'm considering adding "Boyensen ports" to the transfer passages from the reed block cavity. I'm still thinking about the "cooling fins in the ducts". I'm presuming that if the transfer ports were widened and then a divider devconned in that the divider would act like a fin dividing and directing the flow, and also providing a cool surface. I wasn't thinking of doing that. The basic software I'm using suggests that the transfer ports aren't actually a limiting factor. I've pressed solder onto the port inner radii and then very carefully removed it. The curve looks to be pretty good. The only thing I'm going to do is polish the transfer ports.

I just had an idea - What if the transfer ports were divided vertically into upper and lower sections. You could have the gas flow directed in one direction as the port opened and as the second lower portion opened it's gas flow could be in some other direction. There would not neccessarily be a reduction in gross flow as the port duct could be enlarged to allow for the divider. An advantage is that the upper portion of the port would open first and close last and the gas flow in that smaller duct could contain a lot of energy and maintain an ideal port outlet shape until the piston started closing it off keeping flow rate up. I know someone has already thought of it but I've never seen it. I envisage the divider following the curve of the port right to the duct entry so effectively you will have 2 seperate transfer ports stacked. You could even close off the outer duct leading to the upper portion of the port with a guillotine, if that was a benefit.

Gosh, my brain is going to be ticking over quite a bit tonight.

It's great to have so much input from smart bastards on this thread, I'm amazed at how lucky we all are to be exposed to top-notch knowledge.

One thought on the stacked transfer thing; Would the flow suffer really badly - I'm thinking like bridged ex port vs single. I think Bell mentioned for the same area a non-bridged port will flow significantly more. Dunno if that is still current thinking...

Frits - I'm also still thinking about the "cooling fin" comment. Not even sure if you meant it as a + or - now!

[TZ350]

I envisage the divider following the curve of the port right to the duct entry so effectively you will have 2 seperate transfer ports stacked. You could even close off the outer duct leading to the upper portion of the port with a guillotine.

Very clever ...... :yes:

[TZ350]

Did you model the nozzle as a short tapered section ( 30mm say) from the duct exit up to the header dia ( as the first section of the pipe) and this is made as an oval to round transition in the flange on T port and tripple port designs.

252070

I modelled the convergent half of the nozzel in the exhaust port port duct and the other half as a divergent cone at the start of the header.

I am not sure if this is the right thing to do but the simulator liked it. The pipe is my old Honda RS125 chamber.


... im not sure this theory will apply to making more power with a single port.

Having said that, a 40mm pipe entry on an engine only making 30 Hp is way too big, so reducing the duct and or header area, or maybe both, will very likely work real well.

Be real interesting to see if the sim reflects reality on a dyno, in your single port scenario TeeZee.

Yes dyno time will be interesting ......

[speedpro]

Interesting design at the end, 22mm dia for 3mm, then diverging to 25mm over 20mm length

[TZ350]

EngMod2T

Transfers openning 114 atdc vis 117 atdc, all other aspects of the engine model are the same.

In the early days I chose a transfer opening time of 114 atdc duration 132 for 12,000 rpm based on Jennings and Bells books. This involved skimming the top of the barrel and fitting a spacer plate. This must have been a popular thing to do as I saw many strokers with small spacer plates under their barrels.

I do remember Sonic-V saying that he has often been disapointed by tall transfer ports.

252071

The simulator works on STA or specific time area and it tells me that with the effective transfer port window that I have the transfers only need a duration of 126 degrees opening 117 atdc for a little more power and improved blowdown.

Low and wide just as Wobbly said.

[TZ350]

Interesting design at the end, 22mm dia for 3mm, then diverging to 25mm over 20mm length

Pinched that bit from the later RS example file that came with the simulator, I expect its a tail pipe venturie that controls the bleed down and that the rest of the tail pipe does not come into the equation.

[Frits Overmars]

That is like putting cooling fins inside the ducts. Think about it...
Hmmm good idea..
With regards to Frits post I assumed he is inferring that the ports will serve to remove heat from the cylinder.........Thus the cooling system will....be cooling the transfers.
Do you think the turbulence created, or the surface area would in some way (Heat transfer, drag effects?) negate the extra inlet/exhaust/transfer area then available?
Frits - I'm also still thinking about the "cooling fin" comment. Not even sure if you meant it as a + or - now!The good news is that y'all did think about it, and that is what I hoped to accomplish.
Husaberg is right: 'the ports will serve to remove heat from the cylinder'. But then he spoils it by saying: 'the cooling system will...be cooling the transfers'.
Koba seems more cautious. And he is right too. Heat transfer: yes. But from where to where?
'Cooling fins' is a misleading expression, deliberately in this case, because I tried to set you on the wrong foot. I should have called them by their scientific name: heat exchangers....
The cylinder material will always be hotter than the fresh charge in the transfer ducts. So these 'internal fins' will cool the cylinder to the detriment of the charge density. Not good for power....

[koba]

The good news is that y'all did think about it, and that is what I hoped to accomplish.
Husaberg is right: 'the ports will serve to remove heat from the cylinder'. But then he spoils it by saying: 'the cooling system will...be cooling the transfers'.
Koba seems more cautious. And he is right too. Heat transfer: yes. But from where to where?
'Cooling fins' is a misleading expression, deliberately in this case, because I tried to set you on the wrong foot. I should have called them by their scientific name: heat exchangers....
The cylinder material will always be hotter than the fresh charge in the transfer ducts. So these 'internal fins' will cool the cylinder to the detriment of the charge density. Not good for power....

Hmm, very smart. Makes me think twice, no already done that, (must be up to 36) about the "Boysen" type ports for my motor. I'm betting speedpro is thinking along the same lines as soon as he reads that.

[Frits Overmars]

I just had an idea - What if the transfer ports were divided vertically into upper and lower sections. You could have the gas flow directed in one direction as the port opened and as the second lower portion opened it's gas flow could be in some other direction. There would not neccessarily be a reduction in gross flow as the port duct could be enlarged to allow for the divider..... I envisage the divider following the curve of the port right to the duct entry so effectively you will have 2 seperate transfer ports stacked. You could even close off the outer duct leading to the upper portion of the port with a guillotine, if that was a benefit.The idea is good. But your logic is not always... "There would not neccessarily be a reduction in gross flow as the port duct could be enlarged to allow for the divider". Yeah, right. Then you could also enlarge the port without putting in the divider.That would give you even more flow area.

Then why is it still a good idea? Because you reduce the port height in the curve; the ratio of inner curve radius to outer curve radius becomes larger, and that is very good for the flow. Look at any air conditioner ceiling-outlet: they are all shaped like that.
To my knowledge the idea was first proposed by a german researcher, Ernst Ansorg, around 1965. I have seriously thought about applying it, but incorporating thin-walled curved guides in a cylinder casting proved too difficult at the time. It might still work though.
Yes, the guides will heat up the passing charge. But the net result will probably be positive; especially if the guides are kept short, only in the upper, curved part of the ducts.

I also like the idea of closing off the outer/ upper transfer ducts. It would prevent wrongly-timed exhaust pulses from shoving fresh charge from the cylinder back into the crankcase, and that would yield a very civilized power curve.

[bucketracer]

... good idea? Because you reduce the port height in the curve; the ratio of inner curve radius to outer curve radius becomes larger, and that is very good for the flow.

THis sounds like something TeeZee was doing with his curved inlet. I will see if I can find a picture.


Inlet Manifold Dyno Test

252089 252090

Red line is the original inlet manifold, Blue line is the manifold with the divider fitted.

[breezy]

teezee, i noticed on the exhaust print out there are values for the pipe volume cc and also a ratio of the pipe against the engine cc. what , if any , do these values play in the pipe design.. thanks

[wobbly]

The exhaust exit "nozzle" was used first by Helmut Fath ( my hero ) when tuning for Honda where their V twin 250 had one stinger 150 long the other 450 long.
I have tested all manner of variations and the best is around 10mm of parallel nozzle and then 10mm of divergence to a stinger around 1.5mm bigger.
This reduces the effect of the waves bouncing up and down the stinger off atmosphere disrupting the rear cone waves.

The pipe vol/engine cc field in the pipe screen was added by Neels to the program when Frits noted that he had calculated this for the RSA - maybe he can elaborate on the relationship.
Note also that there is two fields for the length to end of header and length to end of diffuser.
I got Neels to add this as so few pipe designs are "correct" and its a pain to calculate all the time.The header end should be 30 to 32% and the diffuser should be 64 to 68%

TeeZee - really glad that you are looking at the STA numbers and realising that the sim is telling you what is needed - or not in many cases.
Getting all the elements of a design in harmony is what makes big power numbers.
I would try making the divergent header nozzle longer - very short ones can create shock waves and reduce the energy available to do positive "work" in the pipe.

[F5 Dave]

The old RS pipe has a stinger join. for my 100 I have made up some interconnect bits of tube machined with different tapers & sizes that can be easily swapped. But with the pipe still out of whack in other areas I haven't had much conclusive results with these experiments.


For the transfer duct dividers I was imagining heated bent razor blades devconed in place.

[dinamik2t]

Hey, TZ, nice seeing you improving those results!
I noticed one thing in you ex.port data. Isn't 74% (chordal) of the bore too much?
I liked your idea on the inlet divider too! Yielded almost 1.5whp!


to a stinger around 1.5mm bigger.

That worked best for me too!:first:

A couple of days ago I tried modifying the pipe design a little (so far, I tried every other variable, except the pipe). I don't want to build a pipe from stratch and limited myself to modifications only after the mid section.
So I came up with this idea; seperating the baffle cone into two stages of different angles. I saw this design in a Rotax pipe. First stage was about 24 deg and the second one was 33 deg.
I did a lot of testing and managed to achieve a great power increase from 38 to 42 hp.
I am not sure about the small stinger diameter and the laaarge angle of the second baffle stage (40 deg). Both numbers though gave the best results among other variants :confused: ; at least in the simulator. Perhaps I'm missing something, like back then with the wall pipe temperature?

Here's the "old" pipe design:
252093

and here's the newer one. Mid section length reduced 20mm, stinger length increased 80mm, plus the alterations in baffle:
252094

No other parameter was altered.
252095

[bucketracer]

Hey, TZ, nice seeing you improving those results!
I noticed one thing in you ex.port data. Isn't 74% (chordal) of the bore too much?

Hi dinamik2t, TeeZee is impressed with your work and carfully reads your posts.

All the team ESE engine exhaust ports are 70+% chordal of the bore, TeeZee has been running about 75% with good 1mm rings.

[dinamik2t]

That compliments me, thank you! I don't think of myself to be that great though..

Have you ever measured ring life with such widths? In hours or km s perhaps? I'm very curious as I always though of ~85% arc width to be somewhat the limiting percentage for decent ring life. I believe that 85 arc must be around 69 chordal.
I really don't know; never tried anything above that...:dodge:

[NordieBoy]

For the transfer duct dividers I was imagining heated bent razor blades devconed in place.

As long as they don't have knife edges or you'll get a wobbly smack.

:D

Thin brass sheet?

[Frits Overmars]

There is a relationship between how wide you make a port, and how gradually it should widen in order to keep the ring healthy.
With a good ring, 70% chordal of the bore is the optimum width. If you make it any wider, the widening has to be so gradual that you loose surface area at the top, where it counts most, because that's the area that opens first and stays open the longest.
The drawing below shows that with too wide a port you have to sacrifice the yellow areas at the top. But sacrificing those areas costs blowdown angle.area. That red port may have more open area, but not where it counts, at the top; the blue port is better.

[Frits Overmars]

Unless you keep the revs really low, a single exhaust port with a 70% chordal width does not give sufficient blowdown time.area, but because of the reason I explained above, making the port wider will be even worse. You will either have to use a bridge, add auxiliary exhaust ports, or raise the timing of the single port to well above the 190° that is optimal for pipe resonance.

The Aprilia cylinder is extreme in that respect: the middle exhaust port is 38 mm wide (older versions were 40 mm wide) and there are huge auxiliaries but even so the middle port is raised to 196° and then it gets a large radius at the top. The radius makes it difficult to measure the timing but if you shove a piston ring in the bore until you can just see light between the ring and the bore, you will find an exhaust timing of 202°. Don't try this at home, unless you want your engine to produce its maximum power at a mean piston speed of 23.6 m/s. But then your transfer time.area will probably be insufficient. And you know: if you raise the transfers, that will eat into the blowdown time.area.

Why does Aprilia use an exhaust timing that is too high for optimum resonance? It is a compromise: any lower, and the maximum torque will rise, but the reduced blowdown time.area will cause an early torque collapse and the product of torque times revs (yes, that's power) will be lower.

[wobbly]

The Rotax 24/33 rear cone was dropped in Superkart racing when I discovered that a single 28* made more power on the dyno.
This led to the development of the so called Silverstone pipes that we made when I worked for JL when he was still in England.
These won dozens of World and Euro titles.
I have spent days of dyno time testing multi angle rear cones, and have always been able to achieve the same or better power with a single rear of the right angle.
In many cases the sim likes a sharp rear cone, but in reality its no better.
Seems to me that the main reasons you got better power with the modified pipe, was down to a gradual front nozzle, stinger nozzle, and a way shorter tuned length.

[TZ350]

The cylinder is extreme in that respect: the middle exhaust port is 38 mm wide (older versions were 40 mm wide) and there are huge auxiliaries but even so the middle port is raised to 196° and then it gets a large radius at the top. The radius makes it difficult to measure the timing but if you shove a piston ring in the bore until you can just see light between the ring and the bore, you will find an exhaust timing of 202°.

I would be very interested in the Aprilias port STA numbers.

[Yow Ling]

How does this gearbox work? It a 1968 Jamathi, looks like an 8 speed but doesnt have the usual selector drum, forks etc.
Is the method of operation similar to the new seamless hondas? Can you shine any light on this Frits?

252111

[husaberg]

The good news is that y'all did think about it, and that is what I hoped to accomplish.
Husaberg is right: 'the ports will serve to remove heat from the cylinder'. But then he spoils it by saying: 'the cooling system will...be cooling the transfers'.
Koba seems more cautious. And he is right too. Heat transfer: yes. But from where to where?
'Cooling fins' is a misleading expression, deliberately in this case, because I tried to set you on the wrong foot. I should have called them by their scientific name: heat exchangers....
The cylinder material will always be hotter than the fresh charge in the transfer ducts. So these 'internal fins' will cool the cylinder to the detriment of the charge density. Not good for power....

What did you think of the 1958 Clarke engine Frits.
Wob had seen one. In CHCH of all places.

I understood you were playing devils advocate a little bit there......... What i was attempting......
(more than a little clumsily no doubt English is my first language yet you write it better than I do. This speaks volumes about me, as it is, probably you third Language of a about 6!)
.....to say was with too many ports on an AC cylinder there would be so little contact area with the fins and cylinder bore and in effect the fins will be only cooling the transfers rather than the cylinder.
ergo the transfers will be then cooling the cylinder. Which as you infer is not that clever.
Isn't that what you were saying anyway or have i missed it again ? Don't worry
It wouldn't be the first time I have been extremely wrong. Just ask my lady She can supply a limitless array of examples.

I seem to remember something about how the crankcase should be cooled first (Prof Cramp i think) He also said F1 cars were far more advanced with their cooling systems too than GP bikes.

But how hot does a crankcase get on a racing two stroke? I must admit to never checking them, but my sons ktm50 is very hot. Too hot to touch comfortably.
Which I assumed was mostly a result of heat transfer from the slipper clutch? The oil is hot enough to burn you. Trust me I figured that the hard way.
This must be killing HP.

Remembering your pipe shielding pics awhile back. I realize it could have a large effect on power with inefficient cooling system.
Then why don't we see 2 stage cooling systems with a separate system for crankcases and one for the hotter bits Cylinder and Head.
Possibly with a kind of air gap or thermal barrier gap between to minimise heat transfer to the charge in the transfers maybe.
Or do we have them but I do not see them? inside the engine and all that? or are they there anyway because the modern two stokes transfers do seem to poke out
and i spent far to much time playing with old shitters.

Should the people that are using spacers beneath cylinders be using a plastic spacer (rather than an Alloy one to minimise heat transfer or are std gaskets on a AC cylinder an effective barrier?

What would be the optimum for efficient running of each part be?

Crankcase and charge (I guess just above icing) not really practical i guess as it will be heated as it compresses anyway.
Cylinder (another total guess 70-90 degrees C) it would have to be cool enough to minimise distortion and hot enough to minimise wear.
Even temps around the cylinder walls to I guess.Which your FOR cylinder would achieve.
The Head hotter as Wob said on one part and cooler on the other whoops i forget where I will have to look back and see?


The Starmaker shape was stolen from diesel tech, but as it shrouded the squish from the main body of mixture in the chamber, it was doomed from the onset.
The material is aluminium bronze, I would use beryllium bronze if cost wasn't an issue, the stock head itself I machined away to suit the insert.
In this case we attack all the relevant issues involved, with small detail tricks.
The squish band has a very highly heat conductive bronze surface that runs cool and keeps the end gases from overheating and thus forming radicals that lead to thermal runaway - deto.
Bronze inserted "rings" only do 1/2 the job as they have a heat joint barrier no matter how well fitted they are.
The one piece insert is far stronger than plain aluminium in such a big bore, thus the water can be run much closer to the places its needed, in the squish area , and around the plug threads, reducing thermal hysteresis.
And lastly, the chamber only is coated with a clear ceramic heat reflective, that retains the high temp in the chamber as the combustion gases are expanding.
Creating more gas expansion is the holy grail to pushing the piston down harder , with less wasted heat into the water - on the other side of the insert.
Same with the piston - only the chamber area is coated, if you coat the whole piston, the heat reflective surface becomes hotter than the raw piston underneath, again this will create deto in he squish band area.


I must admit that mid rant I started conjuring up some way to make use of the 50's sodium filled (Manx Norton amongst others) valve technology in another way.
They (the Sodium filled Valves) were superseded by better materials that could stand the thermal loads, but moving around the heat in a way like they did to increase in a way the area. To dissipate the heat i wonder..........?
Sorry if that is an overwhelming array of questions and probably more than a few gross generalizations there Fits

[Grumph]

How does this gearbox work? It a 1968 Jamathi, looks like an 8 speed but doesnt have the usual selector drum, forks etc.
Is the method of operation similar to the new seamless hondas? Can you shine any light on this Frits?

252111

Around that period there was a lot of interest in boxes with the gears on the mainshaft all fixed - usually splined - and the layshaft all free. Engagement was by a shaft up the center of the layshaft either with dogs on or pushing balls out to engage each free gear as required. The Lotus "queerbox" as used in F1 was of this type and at least one continental maker did a replacement box for things like Manx Nortons too. Saves space on the shafts but you still need to pull the engagement rod out the side....

[TZ350]

The squish band has a very highly heat conductive bronze surface that runs cool and keeps the end gases from overheating and thus forming radicals that lead to thermal runaway - deto.


Hmmmmm I just love that detonation supressing copper squish come head cooling fin on my air cooled.

252120252121252122

The copper head fin on my current engine comes right into the chamber and forms the squish band, copper being a much better conductor of heat than aluminium I expect the squish area runs cooler than it would have done with the std head.


And lastly, the chamber only is coated with a clear ceramic heat reflective, that retains the high temp in the chamber as the combustion gases are expanding.
Creating more gas expansion is the holy grail to pushing the piston down harder , with less wasted heat into the water - on the other side of the insert.
Same with the piston - only the chamber area is coated, if you coat the whole piston, the heat reflective surface becomes hotter than the raw piston underneath, again this will create deto in he squish band area.

I would very much like to know more about this clear ceramic and where I can get it, as I would like to try it on my all copper combustion chamber head (copper spray coated 1.5mm thick).

252118

The copper was for sheding wast heat from the combustion area and transporting it to the outer fins to be dissipated. As copper transfers heat quicker than alloy I hoped for a cooler running combustion chamber shell.

The problem was that the copper discolured, so instead of being a good heat reflector it became a heat absorber. I am hoping that the clear ceramic will reflect heat and protect the copper and keep it shiny.

I have also found that if I use a std GP125 composit head gasket between the barrel and copper head gasket fin thing the head runs much much cooler, maybe 60 deg near the plug, with the barrel at about 100-130 between the top fins and 200 near the exhaust port area (lazer heat gun).

[bucketracer]

Then why don't we see 2 stage cooling systems with a separate system for crankcases and one for the hotter bits Cylinder and Head. Possibly with a kind of air gap or thermal barrier gap between to minimise heat transfer to the charge .....?

This is not quite what your talking about but close, this is the way DKW did it with their air cooled engine, also notice the short exhaust port duct that minimizes heat take up from the hot exhaust gas.

Generous case finning, short exhaust tract, crank case separated from bottom end and the roots of the clyinder head fins are all centered on the combustion chamber, unlike the Suzuki head where the heat has to travel further before getting to a fin. Even if they both have the same fin area the Suzuki's combustion chamber will run hotter than the DKW for the same power output because of the Suzuki's longer thermal path. TeeZee posted about this before complete with graphs and pics.

[Frits Overmars]

I would be very interested in the Aprilias port STA numbers.STA stands for Specific Time.Area. STA depends on rpm: the higher the revs, the shorter the ports are open per revolution. So I can only give you STA numbers if you specify for what rpm you wish to know them.
It's like this: a cylinder has port windows with a certain width and certain distances from the cylinder top plane to port roof and port floor. You can only express the window dimensions in millimeters and square millimeters (or in other funny length and area units that english-speaking folk still use).
Put this cylinder on an engine with a crankshaft with a certain stroke and a certain conrod length. Now you can also express the window dimensions in crankshaft degrees.

Now we can look at the angle.area concept (the point between angle and area indicates a multiplication; I make a point of writing it like this :cool:)
Let us assume a port window is 1 mm wide. Turn the crankshaft until the window is on the verge of opening. Its open area is still zero.
Then turn the crankshaft 1° further. Let's say the piston descends 0.5 mm, so the open window area is 0.5 mm height * 1 mm width = 0.5 mm² , and it has been open for 1°; that yields an angle.area of 1° times 0.5 mm² = 0.5 °mm².
Then turn the crankshaft 1° further again. That first 0.5 mm² open area has now been open during 2°; and as the piston has descended some more, there is now some additional open window area that has been open for 1°. Multiply all those pieces of open window area with the number of crankshaft degrees they have been open, all the way from initial port opening till port closing, and you get the total angle.area of the port.
But for gas flow it does not matter during how many crank degrees an area has been open; what matters is the number of seconds it has been open. That is where engine rpm comes into play: twice the revs means half the time; angle.area divided by rpm is time.area. And if you divide time.area by the cubic capacity of the cylinder that has to be filled (or emptied), you have specific time.area.
You may have noticed that in previous posts I sometimes talked about angle.area, and sometimes about time.area. And hopefully now you understand why. When I talk about an engine, I use angle.area. When I talk about a running engine, I use time.area.
O, TZ350, before I forget: here is what you have been asking for:

[Frits Overmars]

How does this gearbox work? It a 1968 Jamathi, looks like an 8 speed but doesnt have the usual selector drum, forks etc. Is the method of operation similar to the new seamless hondas? Can you shine any light on this Frits?Counting to nine can't be that difficult... The selector mechanism is under the engine.

[husaberg]

Counting to nine can't be that difficult... The selector mechanism is under the engine.

The original 8 plus err.. 1 gearbox pic Yow Ling posted has what looks like a set of Bevel gears at the rear underneath is this an ancillary drive (IE Pump) or part of a earlier design? of the gear selector mechanism.

[Frits Overmars]

What did you think of the 1958 Clarke engine Frits.Doesn't ring a bell.
What i was attempting to say was with too many ports on an AC cylinder there would be so little contact area with the fins and cylinder bore and in effect the fins will be only cooling the transfers rather than the cylinder. ergo the transfers will be then cooling the cylinder. Which as you infer is not that clever. Isn't that what you were saying anyway or have i missed it again ? No, that is not what I was saying. But I missed your point too; only now do I understand it. I was not talking about the 'real' cooling fins but about all the separating material with the accordingly large total surface area that you get between 11 ports.
why don't we see 2 stage cooling systems with a separate system for crankcases and one for the hotter bits Cylinder and Head.You would have to find a place for a second radiator, about as big as the one we've already got.
Possibly with a kind of air gap or thermal barrier gap between to minimise heat transfer to the charge in the transfers maybe. Or do we have them but I do not see them? inside the engine and all that?You apparantly missed the inside view of the Aprilia 250-engine I showed recently.
Should the people that are using spacers beneath cylinders be using a plastic spacer (rather than an Alloy one to minimise heat transfer or are std gaskets on a AC cylinder an effective barrier?AC cylinders are not suited for racing; not since the 80's of the previous century. Sorry Bucketeers, but that's the way it is.
What would be the optimum for efficient running of each part be? Crankcase and charge (I guess just above icing) not really practical i guess as it will be heated as it compresses anyway.All the more reason to cool as much as you can. Just above icing would be great for power.
The Head hotter as Wob said on one part and cooler on the otherI usually agree with Wob, but not on this one: hot heads induce detonation.
Sorry if that is an overwhelming array of questionsSometimes it takes over an hour to answer one question. So I guess you've had your share of answers up until christmas 2016....:devil2:

[gamma500]

There is a relationship between how wide you make a port, and how gradually it should widen in order to keep the ring healthy.
With a good ring, 70% chordal of the bore is the optimum width. If you make it any wider, the widening has to be so gradual that you loose surface area at the top, where it counts most, because that's the area that opens first and stays open the longest.
The drawing below shows that with too wide a port you have to sacrifice the yellow areas at the top. But sacrificing those areas costs blowdown angle.area. That red port may have more open area, but not where it counts, at the top; the blue port is better.




In the pic you posted, would that blue port make engine peakier, because of the sharper exhaust pulse?

[husaberg]

Doesn't ring a bell.No, that is not what I was saying. But I missed your point too; only now do I understand it. I was not talking about the 'real' cooling fins but about all the separating material with the accordingly large total surface area that you get between 11 ports. You would have to find a place for a second radiator, about as big as the one we've already got.You apparantly missed the inside view of the Aprilia 250-engine I showed recently.AC cylinders are not suited for racing; not since the 80's of the previous century. Sorry Bucketeers, but that's the way it is.All the more reason to cool as much as you can. Just above icing would be great for power.I usually agree with Wob, but not on this one: hot heads induce detonation.Sometimes it takes over an hour to answer one question. So I guess you've had your share of answers up until christmas 2016....:devil2:

I see what you mean with the Aprilia engine cooling now:facepalm:

I hope that they won't have banned the 2 stroke before then.
Although my son would be able to ride it by then.

Wob informed me today that there is a new arrival from overseas currently being processed though in customs so maybe it will be ready by October i hope.
A baby Girl. Vanessa.

ps this err...liquid cooling you speak of. Do you think it will catch on.
Seems a bit high tech.
Oh well put me down for one of those to then Wob.

The Clarke engine is below 1959


.http://www.rearenginekarts.com/clark engine.htm


(http://www.rearenginekarts.com/clark engine.htm)

[Frits Overmars]

The original 8 plus err.. 1 gearbox pic Yow Ling posted has what looks like a set of Bevel gears at the rear underneath is this an ancillary drive (IE Pump) or part of a earlier design? of the gear selector mechanism.It is the water pump drive. But it's not underneath; in the picture showing the 9-speed gear box the engine was upside down.

@Mental Trousers:
Shane, I could upload the complete collection of Jamathi pictures like I did with the Aprilia-files. Then I would not have to post individual pictures all the time. What do you say?
Another matter: the last couple of days, when I try to attach an PNG-file, is does not seem to function. When I convert the file to JPG or GIF, there's no problem. Any suggestions?

[Frits Overmars]

In the pic you posted, would that blue port make engine peakier, because of the sharper exhaust pulse?In theory, maybe. But there are other, stronger effects. The sides of the wide red exhaust port are much closer to the A-transfers than is the case with the narrower blue port. That would provoke short-circuiting

[TZ350]

I could upload the complete collection of Jamathi pictures like I did with the Aprilia-files.

The Aprilia Files? .... where can I find the Aprilia files?

[TZ350]

STA stands for Specific Time.Area. STA depends on rpm: the higher the revs, the shorter the ports are open per revolution. So I can only give you STA numbers if you specify for what rpm you wish to know them.

12,500rpm would be good.

I thought STA was transportable, ie an STA for a certain rpm could be made the same at a different rpm by changing the port area. Ie half the time double the mean angle area, same STA.

[TZ350]

teezee, i noticed on the exhaust print out there are values for the pipe volume cc and also a ratio of the pipe against the engine cc. what , if any , do these values play in the pipe design.. thanks

Thank you for asking, I was wondering myself, I am just a newbee to this ...


The exhaust exit "nozzle" was used first by Helmut Fath ( my hero ) when tuning for Honda where their V twin 250 had one stinger 150 long the other 450 long.

I have tested all manner of variations and the best is around 10mm of parallel nozzle and then 10mm of divergence to a stinger around 1.5mm bigger.

This reduces the effect of the waves bouncing up and down the stinger off atmosphere disrupting the rear cone waves.

The pipe vol/engine cc field in the pipe screen was added by Neels to the program when Frits noted that he had calculated this for the RSA - maybe he can elaborate on the relationship.

Note also that there is two fields for the length to end of header and length to end of diffuser.
I got Neels to add this as so few pipe designs are "correct" and its a pain to calculate all the time.The header end should be 30 to 32% and the diffuser should be 64 to 68%

I would try making the divergent header nozzle longer - very short ones can create shock waves and reduce the energy available to do positive "work" in the pipe.

Thanks for the info and suggestion, I will try it.

[Frits Overmars]

12,500rpm would be good.I thought STA was transportable, ie an STA for a certain rpm could be made the same at a different rpm by changing the port area. Ie half the time double the mean angle area, same STA.With the angle.area values I posted, you should be able to work out the specific time.areas for 13.000 rpm. And these are universal; if you manage to get the same STA values for an engine with any cubic capacity and any rpm, you're doing fine.

But how did you come by the 'mean area' expression? Been reading Gordon Jennings, have you? That was a very coarse approximation of the time.area concept in an era where Gordon did not yet have a computer at his disposal. He certainly would have approached it differently nowadays.

[TZ350]

But how did you come by the 'mean area' expression? Been reading Gordon Jennings, have you?

That was a very coarse approximation of the time.area concept in an era where Gordon did not yet have a computer at his disposal. He certainly would have approached it differently nowadays.

Thank you for the time you put into this.

Yes ... after reading Gennings and his idea of measuring the port area uncoverd by 50% of the crank rotation between just opening and fully open that not all port shapes will amount to the same equivalent angle area, tall versis wide for instance.

My post might not have been a good use of the word "mean" maybe eqivalent effective area might have been better, ie wider at the bottom would not be as effective as wider at the top.

[koba]

But how did you come by the 'mean area' expression? Been reading Gordon Jennings, have you? That was a very coarse approximation of the time.area concept in an era where Gordon did not yet have a computer at his disposal. He certainly would have approached it differently nowadays.

Just because it is interesting:

...any study of port-time area would have to be based on number not readily available unless one has endless hours to devote to collecting information either locked away inside the engines themselves or the manufacturers archives. It is possible to work out time-area number on a purely theoretical basis, but this approach is even more time consuming, involving as it does some really nasty work with integral calculus equations. Also, this approach virtually demands that one make some fairly shakey assumptions in a number of areas - and that a computer be at hand if all the calculations are to be completed this century.

From "Two stroke tuners handbook" by Gordon Jennings c.1973

It seems the computer issue has been solved to some extent. They could always be faster though.

I bet you are still hoping someone sorts the endless hours problem though, eh Frits?

[wobbly]

TeeZee, the ceramic coating on the piston and the chamber is a secret weapon used for years on KT100 Yamaha engines.
Its not actually stated in the rules as being illegal, but the way the rules are worded they say that if it doesnt say you are allowed, then you are not.
The coating doesnt need to be clear, its only done that way so you cant see it.
HPC do all manner of coatings, but I know nothing at all about the clear version do I.

Also re STA - you have the perfect tool for calculating what the RSA must have to make 55Hp @ 13000.
Assuming that is at the sprocket ,add say 5% and put it into EngMod2T - it will spit out the target values, and I can tell you for sure that the end result will tell you
VERY close to what is needed in reality, to make that power.
Its been proven so many times now I never think to question the results - for example I wrote down the numbers ( yes ,with a pencil no less) for SpeedPro years ago on how to get 30 Hp from his MB100
and here we are, now that the mechanical version is starting to resemble the one I had in my computer,the thing makes 30 Hp.
Everyone said it was rubbish for years - and it just couldnt be done, but the dyno tells no lies, and I dare not as well - too many smart people about.

[Frits Overmars]

Just because it is interesting:
...any study of port-time area would have to be based on number not readily available unless one has endless hours to devote to collecting information either locked away inside the engines themselves or the manufacturers archives. It is possible to work out time-area number on a purely theoretical basis, but this approach is even more time consuming, involving as it does some really nasty work with integral calculus equations. Also, this approach virtually demands that one make some fairly shakey assumptions in a number of areas - and that a computer be at hand if all the calculations are to be completed this century.
From "Two stroke tuners handbook" by Gordon Jennings c.1973
It seems the computer issue has been solved to some extent. They could always be faster though.
I bet you are still hoping someone sorts the endless hours problem though, eh Frits?Which endless hours problem do you mean, Koba? The time I spend on this forum? Oh well, it keeps me out of the pub :p.

[bucketracer]

Its been proven so many times now I never think to question the results - for example I wrote down the numbers ( yes ,with a pencil no less) for SpeedPro years ago on how to get 30 Hp from his MB100
and here we are, now that the mechanical version is starting to resemble the one I had in my computer,the thing makes 30 Hp.
Everyone said it was rubbish for years - and it just couldnt be done, but the dyno tells no lies - about.

And it was the Team ESE dyno no less ... you can't imagine how much TeeZee vomited when he saw he was beaten to the first usefull 30hp Bucket, particuarly funny as TeeZee was recording the runs while Speedpro was spinning the bike up, talk about rubbing TeeZee's nose in it .... :laugh:

[Strokerhaus]

The idea is good. But your logic is not always... "There would not neccessarily be a reduction in gross flow as the port duct could be enlarged to allow for the divider". Yeah, right. Then you could also enlarge the port without putting in the divider.That would give you even more flow area.

Then why is it still a good idea? Because you reduce the port height in the curve; the ratio of inner curve radius to outer curve radius becomes larger, and that is very good for the flow. Look at any air conditioner ceiling-outlet: they are all shaped like that.
To my knowledge the idea was first proposed by a german researcher, Ernst Ansorg, around 1965. I have seriously thought about applying it, but incorporating thin-walled curved guides in a cylinder casting proved too difficult at the time. It might still work though.
Yes, the guides will heat up the passing charge. But the net result will probably be positive; especially if the guides are kept short, only in the upper, curved part of the ducts.

I also like the idea of closing off the outer/ upper transfer ducts. It would prevent wrongly-timed exhaust pulses from shoving fresh charge from the cylinder back into the crankcase, and that would yield a very civilized power curve.

Is there not another effect as well with "adding a divider" which is to change the resonance of the transfer port, yes you loose flow area but you could well gain by a shift in resonance frequency of the port. I suspect I have seen negative effects that appear in some wide transfer ports which I am beginning to think are an out of phase resonance. Which is why I suspect the TZ350 ended up with 6 transfer ports and an increase in power, instead of the larger ports that flowed better.

[Frits Overmars]

Is there not another effect as well with "adding a divider" which is to change the resonance of the transfer port, yes you loose flow area but you could well gain by a shift in resonance frequency of the port. I suspect I have seen negative effects that appear in some wide transfer ports which I am beginning to think are an out of phase resonance. Which is why I suspect the TZ350 ended up with 6 transfer ports and an increase in power, instead of the larger ports that flowed better.Thin (< 1 mm) dividers in the transfer ducts will hardly have any influence on the system's Helmholtz frequency. But I assume you are talking about radial dividers, not about the curved dividers we mentioned earlier.
The four large transfers of the old TZ350 did not flow better; they just flowed more, but not in the desired direction. Because the cylinders were so crowded, there was no room for sweeping ducts; they were squatted between the bores without any directional capabilities.
Adding the radial dividers that sub-divided the TZ350's B-ports, gave some more steering to the flow. That reduced short-circuiting, thus influencing the exhaust gas temperature and hence the pipe frequency.

[jasonu]

And it was the Team ESE dyno no less ... you can't imagine how much TeeZee vomited when he saw he was beaten to the first usefull 30hp Bucket,

But it has yet to be proven 'useful' and sorry to say the same goes for the rest of the big HP buckets and I include No Mates' bike because as far as I know it has yet to finish a GP on a big track.
Not trying to be a knocker but thems the facts as I see them and I am hopeing to be proven wrong as I am a 2 stroke guy too.

[wobbly]

You are dead right - but we are dealing with buckets here after all.
The dead set fact remains, that if and when a 100cc bucket is correctly made, and assembled, and tuned, then is ridden by a competent rider in a good chassis on good tyres,there will not be a 4T within site.
Its simply physics - not rampant bias or dreaming.
So that is the main reason I am here helping guys out - the end result is without question, its just finding a way to get there.

[jasonu]

You are dead right - but we are dealing with buckets here after all.
The dead set fact remains, that if and when a 100cc bucket is correctly made, and assembled, and tuned, then is ridden by a competent rider in a good chassis on good tyres,there will not be a 4T within site.
Its simply physics - not rampant bias or dreaming.
So that is the main reason I am here helping guys out - the end result is without question, its just finding a way to get there.

Mostly agreed mate. I don't think the above described bike will simply ride off into the distance as by the time it is finally built someone will no doubt have put a 4t into a GP chassis and will also have had time to further develop their motors.

[Moooools]

You are dead right - but we are dealing with buckets here after all.
The dead set fact remains, that if and when a 100cc bucket is correctly made, and assembled, and tuned, then is ridden by a competent rider in a good chassis on good tyres,there will not be a 4T within site.
Its simply physics - not rampant bias or dreaming.
So that is the main reason I am here helping guys out - the end result is without question, its just finding a way to get there.

See you in ten years.

[F5 Dave]

Learn some History Max. 2 stroke victories outweigh 4 stroke ones by more than 2:1 at a generous guestimation.

[bucketracer]

But it has yet to be proven 'useful' and sorry to say the same goes for the rest of the big HP buckets.

What I meant by usefull was that Speedpros engine designed by Wob could be easily ridden around the track, TeeZee's 30 wasn't so useable and he prefered to use a lessor engine at the Taupo GP.

[TZ350]

What I meant by usefull was that Speedpros engine could be easily ridden around the track, TeeZee's 30 wasn't so useable and he prefered to use a lessor engine at the Taupo GP.

Maybe there has been other 30rwhp 2-strokers in the past, mine was the first to record 30 on a dyno, Speedpros 30 was the first that I know of, thats power spread was good enough to be ridden succesfully in a race, he started 39th off the back of the grid and finished in the top 10 (8th??) and there were two other strokers that finished ahead of him.


The dead set fact remains, that if and when a 100cc bucket is correctly made, and assembled, and tuned, then is ridden by a competent rider in a good chassis on good tyres,there will not be a 4T within site.

Its simply physics -

So that is the main reason I am here helping guys out - the end result is without question, its just finding a way to get there.

Like Wobbly I think the end result is without question.

Its a numbers thing, currently the 4-strokers have more of the better riders but it is only a matter of time before a few realy good riders get hold of or build fast easy to ride strokers and the tide turns, the day is coming.

[jasonu]

Its a numbers thing, currently the 4-strokers have more of the better riders but it is only a matter of time before a few realy good riders get hold of or build fast easy to ride strokers and the tide turns, the day is coming.

I hope you are proven right.

[Moooools]

Learn some History Max. 2 stroke victories outweigh 4 stroke ones by more than 2:1 at a generous guestimation.

I appologise for not taking the time to ask an old timer for the exact break down of two stroke to four stroke wins. Like yourself.:innocent:

Just simply stating 2:1 is a not really good info. Is that including pre rule change results? Pre fxr results? Pre cbr results?

I would love to have a resonably comprehensive list of all winners - right from the early days - and a few hours with excell. If you could give me a list i will churn you out aome actual stats.

Would be very interesting despite being a pointless exercise.

[husaberg]

I appologise for not taking the time to ask an old timer for the exact break down of two stroke to four stroke wins. Like yourself.:innocent:

Just simply stating 2:1 is a not really good info. Is that including pre rule change results? Pre fxr results? Pre cbr results?

I would love to have a resonably comprehensive list of all winners - right from the early days - and a few hours with excell. If you could give me a list i will churn you out aome actual stats.

Would be very interesting despite being a pointless exercise.

Tell you what give me a copy of the results as well and I will show you just how easy it is to manipulate statistics to gain any desired outcome.:innocent:

Lies lies and damned statistics.

The simple fact is both 4 strokes and 2 stroke both have their on pro's and con's

Horse's for courses as it were.

Back to the thread. IE 2 stroke tuning.

I was informed last evening that my new engine had indeed arrived in New Zealand.
It will be case reed. If only, because there is no legal modern engine that is Rotary valve.
Which is a shame. It will also be 100cc 2 stroke. Square bore and stroke with an effective power valve.
It has a six speed gearbox with alternate ratios available if necessary.


It will please Fits. I guess, in that it will be liquid cooled.
It will please Wob in that it will provide him something to play with.
It will please me when it makes 35hp at the rear wheel as this is the target. With a wide power spread.
It will please the MNZ in that it will 100% legal.
It will please Dave in that it is a Honda.
It will please Rob in that it will be documented here.


I also hope it may piss off more than a few FXR's.:innocent:
As for some reason a few people, are under a delusion that they are some sort of racing engine.:wacko:

[TZ350]

It will please Rob in that it will be documented here. I also hope it may piss off some FXR's.

I look forward to following the progress ....


I include No Mates' bike because as far as I know it has yet to finish a GP on a big track.

Not sure why Nigals has had reliability issues, the team ESE bikes have finished plenty of long track races and proved quite reliable, some are making a few ponies now and still seem to hold together ok, they just need better riders, mine in particular.


But it has yet to be proven 'useful' and sorry to say the same goes for the rest of the big HP buckets

From a graph I have seen Adlams and Rich's bikes make plenty of mid 20's power, there are a few other over 20 hp FXR's and a 20+ CBR or two out there, see if you can pick them out at the next race meeting. One thing for sure, anything 4-stroke at the pointy end does not have a standard engine.

[Henk]

I also hope it may piss off some FXR's.:innocent:
As for some reason people are under a delusion that they are some sort of racing engine.:wacko:

OK I'll bite.
FXRs are popular not because they are a shit hot race bike but because they are the only bike at the moment that is available in reasonable numbers, for not much cash that isn't 20 years old. I love two strokes but there is a good reason we have a fleet of FXRs, i don't have the time and knowledge to build a similar number of strokers for a start.

[TZ350]

FXRs are popular not because they are a shit hot race bike but because they are the only bike at the moment that is available in reasonable numbers, for not much cash that isn't 20 years old. I love two strokes but there is a good reason we have a fleet of FXRs, i don't have the time and knowledge to build a similar number of strokers for a start.

+10 to that ... different strokes for different folks ... its what makes Buckets so great.

[husaberg]

OK I'll bite.
FXRs are popular not because they are a shit hot race bike but because they are the only bike at the moment that is available in reasonable numbers, for not much cash that isn't 20 years old. I love two strokes but there is a good reason we have a fleet of FXRs, i don't have the time and knowledge to build a similar number of strokers for a start.

Bite err....I wasn't fishing?:innocent:

Please note the first part of my post.




The simple fact is both 4 strokes and 2 stroke both have their on pro's and con's

Horse's for courses as it were.

Back to the thread. IE 2 stroke tuning.



I love buckets for their diversity engines designs, budgets and style.

[kel]

I also hope it may piss off more than a few FXR's.:innocent:
As for some reason a few people, are under a delusion that they are some sort of racing engine.:wacko:

Mate I partnered on a FXR for the 2hr a couple of weeks back, the bike was a well sorted kart track racer (yes a RACER!) that most 2 strokes would struggle to beat, on the short tracks that is. ;)

[gav]

Hmmm, Al Hoogies CBR150 has been dynoed at 27 rwhp, seems to go ok for a standard framed Thailand built commuter bike.
As others have stated the four strokes have hardly started yet.
Anyway if these pesky two strokes get too fast I guess we can always get the four stroke limit bumped up to 200cc? Sounds fair doesnt it?
MotoGP went from 500cc two strokes to 990cc four strokes, MX has 125 2 strokes racing with 250 four strokes ... :innocent: :corn:

[2T Institute]

It will please Fits. I guess, in that it will be liquid cooled.
It will please Wob in that it will provide him something to play with.
It will please me when it makes 35hp at the rear wheel as this is the target. With a wide power spread.
It will please the MNZ in that it will 100% legal.
It will please Dave in that it is a Honda.
It will please Rob in that it will be documented here.


I also hope it may piss off more than a few FXR's.:innocent:
As for some reason a few people, are under a delusion that they are some sort of racing engine.:wacko:

And it has a balance shaft.
Will look forward to see what happens with it.

A KH 125 can easily accomodate a water cooled cylinder, ,my own 'top secret' project for the Aussie Nats will be a YZ85 (in TZ125 frame) with a 'mini RSA' pv cylinder :shutup:

[husaberg]

And it has a balance shaft.
Will look forward to see what happens with it.

The balance shaft or the engine?:shit:


A KH 125 can easily accomodate a water cooled cylinder, ,my own 'top secret' project for the Aussie Nats will be a YZ85 (in TZ125 frame) with a 'mini RSA' pv cylinder :shutup:


My idea is to use as many std parts as possible so it can be easily replicated by all if they so desire and it is ok with wob.

But I love the way your thinking. How many other tuners are so freely giving advice for four stokes like we see here.

we are lucky and honored to have access to some of the best 2 stroke minds in the tuning world
It seems the Four stroke guys spend an awful lot of time here after all as well.

Wob has helped out the odd four stroke as well so he isn't that biased i seem to recall a blue red and pink one that did all right in the 90's

I have a few ideas floating around on how to bring the MB100 into at least the 90's rather than the 70's. In kind of a kit form.

But it would be nice to see some more info shared on this for the good of all the others about.

Rob is already basically doing it now with the GP125.

[wobbly]

Not wanting to make excuses but the reason Nigels bike was unreliable was that he rode it for a couple of years with no issues at all winning plenty of races..
Then it started seizing regularly.It was the fact that the bridge had 3 times the proper clearance,from ring wear.
He now has had the bore plated, the bridge ground and a new piston with oil holes.
It hasnt been fanged in anger since all that work, due to him having a back op and his work/time issues.

[2T Institute]

I'm not letting to much on at this point as Buckets here are quite different to NZ.
Oh also there IS a modern rotary valve engine that by a quirk of fate has a odd ball 51.8mm stroke the humble 1982 Kawasaki AR125. Water cooled, 6 sp rotary valve ticks all the boxes hoping to get it legal for Period 5 but would make an ideal bucket engine.
I see the scans are backwards and 6 is missing.

[koba]

I've always done alright in GP's considering having a huge power deficit.

When I sort some horsepower I'm keen to rack up a few more good placings on my two stroke.

[husaberg]

I'm not letting to much on at this point as Buckets here are quite different to NZ.
Oh also there IS a modern rotary valve engine that by a quirk of fate has a odd ball 51.8mm stroke the humble 1982 Kawasaki AR125. Water cooled, 6 sp rotary valve ticks all the boxes hoping to get it legal for Period 5 but would make an ideal bucket engine.
I see the scans are backwards and 6 is missing.

Glad to see i am not the only one who encounters problems with the order when posting attachment they seem to just go in random order no matter how they are loaded sometimes.

The quirky stroke is the same as the KH100 mmm....

They were tuned extensively in the UK for some racing class

I posted a link awhile back to a guy that specialized in them somewhere there was a crowd who used to specialize in tuning them and the later AR50 and 80's.
Peterborough? and BDK race engineering I think.

It also would qualify here for post classic racing.
I never knew they were rotary valve plus reed like a KR250 though Thanks for the info.
But it does tick pretty much all the boxes if it had a proper power valve.
The engine to be used for Vanessa is at least three generations more modern.


She looks a little like this below.:psst:

[F5 Dave]

. . .
It will please Dave in that it is a Honda. . .


Let it be widely known that I ground the letter H, O, N & a few others off the side of my MB engine case. Over 16 years ago.

[F5 Dave]

....

Not sure why Nigals has had reliability issues, the team ESE bikes have finished plenty of long track races and proved quite reliable, some are making a few ponies now and still seem to hold together ok, . . .

He'd said when he had an EGT running the bike on a long track the temp was shooting up to a silly level. He changed the needle jet & it stayed constant where he wanted it. Needle jet restricting the main. That's why it did fine on kart tracks & seized on long tracks.

[F5 Dave]

Just got back from Sketchys place. This is a YZ100 piston from Evilbay with two simple shrouded bushes. The pin is shortened so it is long enough to push them into the circlips retaining them & not rubbing on the bearing. They are made pretty tight but sliding. Far better than I could hope to turn up on my lathe. By a long shot. He can make some nice stuff.

Peg seems to be out of the way & ex covered at TDC. Deck is the same as MB, but you can't have everything.

I'll try put it in before the meet on sunday. Only drama is the piston crown is lower & a different profile from the MB one so com will be lower & squish will need adjusting. Not sure if I'll have the time.

Thanks Glen.

[husaberg]

Let it be widely known that I ground the letter H, O, N & a few others off the side of my MB engine case. Over 16 years ago.

Well Da......

Was it due to this
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こんにちは、特別なデイブ San あなたが我々がフルの音階と上塗り教育までそれから（彼・それ）らに送った写真の回転を提案して、そしてし た（とき・から・につれて・ように）、我々が正確に鈴木ピットの前（に・で） mr ガードナー Sans 移動住宅を駐車したという重量分配に関しての内報をありがとうございます我々の自転車フレーム我々が、あな たが我々がデイブ San であったと言ったのとちょうど同じ（ように・時に）、エンジンの下の燃料タンクとそれの上のパイプで重心を 下げようとしている間違った方向に入っていたように思われます。

Hello Special Dave San

Thanks for the heads up regarding the weight distribution. We parked MR Gardner Sans motor home in front of the Suzuki pit exactly as you suggested and took rolls of pictures. We then blew them up to full scale and overlay-ed our bike frame. It seems we were going in the wrong direction trying to lower the Center of gravity with the fuel tank below the engine and the pipes above it just as you said we were Dave San. We think with that info we should be able to reclaim the titles from that dastardly Yamahas We now look set to dominate the gp racing scene so thanks for the tip also thanks for the heads up on that young Doohan chap.Well he’s looking to be going rather well now don’t you think. If we can keep him in one piece and in a couple of years i think he will do OK.
On a sadder note that young chap Neil you recommended for the job in the design department has left on a rather sad note. After his initial success with the VF750 cams.the VT250 cam chain tensioners and the MVX rear cylinders we had a bit of bother with him and had to let him go we suggested the honorable thing was Hari Kari but I hear he is now tuning scooters in Europe so the punishment will fit the crime as you westerners say.ha ha
More bad news as well our people in the racing department are a little concerned to here you are intending to modify one of our commuter bikes into a race bike. I have suggest that you could remove the logo as it would be rather embarrassing for our corporate prestige if we were to be upstaging in the GP classes my one of our own creations especially a humble commuter bike. So could you remove the logo lastly thanks for the invite to Taupo for the world debut of your new creation but due to my frail health i will no longer be able to make it. Although i am keen to know how you get on. Keep me posted. I hope to see you in Suzuka in 92.
Soichiro H 1/4/91.

[TZ350]

EngMod2T

252240

I was trying to explore the effect of various nozzels at the exhaust port, thay are all 34mm and vary in the exit angle and length.

They started at 5mm long out to 30 mm and the angles varied from 61-33-22 degree to 11 for the 30mm one.

Now I am not sure if the change in overall tuned length was making the difference or the angle of the nozzel but food for thought.

[dinamik2t]

Hey, TZ!
I got better results at first with the shorter nozzles, but I ended up trusting Wobbly's experience and left it at 30mm L. Then I tried to accomodate the length added by removing some mm's from where it would seem to matter the least in this testing. I think those points where the straight pipe I have before the header and the exhaust duct length.
I shortened the former by 20mm and the later by 5mm (I do can actually dig 5mm in my duct, due to its shape (http://i736.photobucket.com/albums/xx5/Vag1-2/PSC02169.jpg?t=1315949002)). I ended up with pretty much the same results of the short nozzle. :)

[TZ350]

Hey, TZ! I got better results at first with the shorter nozzles ... I tried to accomodate the length added by removing some mm's from where it would seem to matter the least in this testing. I think those points where the straight pipe I have before the header and the exhaust duct length. I ended up with pretty much the same results of the short nozzle.

Thanks, I will try that ...

[wobbly]

Hey TeeZee, I think what you are seeing is related to the fact that the sim cannot replicate the flow regime that an oval to round transition creates in the spigot.
The wide oval shape, that keeps this width right thru to the header start,really promotes the flow from the top of a T or the tripples in that setup.
But as I said at the start of your experiments I have not tested the relationships or area changes in a single port engine.
My feeling is that just maybe a single port would "like"a small volume duct,and then a step at the header - as your short transitions seem to help top end, at the expense of some area under the curve leading up to peak though.
I have asked Neels about the ideal way to model this as part of replicating a sliding header project I am working on ( as this has a step at the end of the header).
You cant have a "zero length" step within the pipe, so I have asked him what to do.
Will let you know the result.

[Frits Overmars]

The Aprilia Files? .... where can I find the Aprilia files?Here.
Let's hear it for Mental Trousers: he created a way for me to upload BIG files.
I will be offline for a couple of days, but this might keep you busy:

http://www.kiwibiker.co.nz/manual/Aprilia-1.zip
http://www.kiwibiker.co.nz/manual/Aprilia-2.zip
http://www.kiwibiker.co.nz/manual/Aprilia-3.zip
http://www.kiwibiker.co.nz/manual/Aprilia-4.zip
http://www.kiwibiker.co.nz/manual/Aprilia-5.zip

One request:
Don't spread the contents all over the world wide web.
Then I might upload some collected data of other racing brands as well.

Enjoy.

[F5 Dave]

drooling,

but get this

Forbidden You don't have permission to access /manual/Aprilia-2.zip on this server.

[Frits Overmars]

drooling,but get this
Forbidden
You don't have permission to access /manual/Aprilia-2.zip on this server.Oops. I didn't test the above links; I only tested the first link Mental sent me, and it worked.
It was this one: http://www.kiwibiker.co.nz/manual/RSA_125.xls

This should give you the unzipped version of the Aprilia RSA125 manual & parts list. The zipped manual is 7 MB, but this unzipped version is 41 MB....

EDIT: and this doesn't work any more either. Mental, Help!

[F5 Dave]

. . .Mental, Help!

I wake screaming this as well, but when they arrive to take me away there is a short conversation about insurance cover & tangible assets. Then they leave again; care in the community I believe it is called:crazy:.

[wobbly]

Mental - Help ,Shit I love that - sarcasm is the lowest form of wit, but hell its effective.

[Mental Trousers]

ffs. It was working an hour ago :facepalm:

Hang on .....

Sorry about that. The permissions on the directory changed for some reason.

[Frits Overmars]

Thanks, Mental; everything seems to be fine now. So here they are again:

http://www.kiwibiker.co.nz/manual/Aprilia-1.zip (http://www.kiwibiker.co.nz/manual/Aprilia-1.zip) (6.8 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-2.zip (http://www.kiwibiker.co.nz/manual/Aprilia-2.zip) (8.3 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-3.zip (http://www.kiwibiker.co.nz/manual/Aprilia-3.zip) (9.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-4.zip (http://www.kiwibiker.co.nz/manual/Aprilia-4.zip) (7.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-5.zip (http://www.kiwibiker.co.nz/manual/Aprilia-5.zip) (5.6 MB)

[kel]

Works for me!
Big thanks to Frits and Mental :2thumbsup

[F5 Dave]

An me. A thousand thanks Frits & also Mental. Wow some interesting stuff with just a light skim. Enjoy your offline time Frits, hopefully a break, or at least some interesting project time.

[TZ350]

Works 4 me now 2 many thanks .....

[F5 Dave]

Wow there is some cool stuff in there. Subtle but very real differences in the 1980 256 barrel, but pretty advanced for its time. Seeing stuff I didn't see having spent a bit of time looking into one ages ago.

erm with Frits away, the first of the dumb questions; Why is the RSA(?) piston pin so incredibly complex?

[wobbly]

Where is the data on the piston pin - plenty on caps??

[husaberg]

Where is the data on the piston pin - plenty on caps??
Zip 3 aprilia piston pin

Question on Gudgeon pins. With the std 2 stroke type. How practical is it to attempt to machine the inside of a finished pin. Say a small groove in it?
I am not talking fiddly as i realize it will be. but as i have access to a model makers lathe? I am only taking hardness of the material inside.

It is just i was looking at a decorative stopper plug of some type and i had an idea.
What draws me to it is the way it positively locates at the base. It is a bit hard to pick in the pics though.
Sorry about the quality of the pics as they were done with my phone as my camera was "borrowed" today


Words can not express my gratitude for the open door policy you have shown here Fits

It may be a little odd considering the treasure trove here, That i am so drawn to how beautiful the inner gearbox casing is. Don't understand it myself.

[dinamik2t]

Many thanks to Frits from my part also!

Except all other impressive stuff in the files, there is some that tingled my curiosity.
It's in the last two photos of the 5th folder, named "workbench". What are those circular stuff on the wooden rectangle, between the pipes and the cylinders?? Remind me of those mirrors the dentists use.:sweatdrop


ps. Towards mr. Trousers :psst:: is it possible to add a quick reply window at the bottom of the page? Perhaps with some of the basic html tags. I think it will be a lot more convenient that the whole 'post reply' procedure. :)

[Grumph]

Zip 3 aprilia piston pin

Question on Gudgeon pins. With the std 2 stroke type. How practical is it to attempt to machine the inside of a finished pin. Say a small groove in it?
I am not talking fiddly as i realize it will be. but as i have access to a model makers lathe? I am only taking hardness of the material inside.

It is just i was looking at a decorative stopper plug of some type and i had an idea.
Sorry about the quality of the pics as they were done with my phone as my camera was "borrowed" today

Don't do it - any groove on the inside surface of a gudgeon pin is a perfect stress raiser.....

[Mental Trousers]

ps. Towards mr. Trousers :psst:: is it possible to add a quick reply window at the bottom of the page? Perhaps with some of the basic html tags. I think it will be a lot more convenient that the whole 'post reply' procedure. :)

You'd have to talk to Spank about that. But in the past it's caused some problems with double posts etc so it's much less irritating not having it.

[breezy]

thanks frits, going into hibernation for a while......hope my laptop doesnt sieze up:yes:

[husaberg]

Don't do it - any groove on the inside surface of a gudgeon pin is a perfect stress raiser.....
I should rephrase that to a shoulder with a generous radius at the transition.
Starting with a thick walled blank.

[2T Institute]

Even a couple of my 'GP spy pics' ended up in the 'Frirs Files' :laugh:

[dinamik2t]

You'd have to talk to Spank about that. But in the past it's caused some problems with double posts etc so it's much less irritating not having it.

Aha! Ok then, no prob :)

[bucketracer]

page 380, other link lists and interesting quotes on the decade pages 370-360-350 .... etc


Thanks, Mental; everything seems to be fine now. So here they are again:

http://www.kiwibiker.co.nz/manual/Aprilia-1.zip (http://www.kiwibiker.co.nz/manual/Aprilia-1.zip) (6.8 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-2.zip (http://www.kiwibiker.co.nz/manual/Aprilia-2.zip) (8.3 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-3.zip (http://www.kiwibiker.co.nz/manual/Aprilia-3.zip) (9.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-4.zip (http://www.kiwibiker.co.nz/manual/Aprilia-4.zip) (7.2 MB)
http://www.kiwibiker.co.nz/manual/Aprilia-5.zip (http://www.kiwibiker.co.nz/manual/Aprilia-5.zip) (5.6 MB)


Kel sent me this link http://www.deraceheldenvanweleer.nl/index.php/topic,51.0.html on the lifes work of Jan Thiel all in Dutch but its worth a look for the pictures alone, lots of mouth watering stuff on Jamathi's and other 50cc racers of the 60's -70's.


. http://www.elsberg-tuning.dk/piovaticci.html


And there is another one on 50cc history: http://www.elsberg-tuning.dk/engineering.html


Heaps of interesting classic bikes here:- http://www.eurospares.com/graphic2.htm#Vintage Japanese motorcycles


This is a overview on how to cast a cylinder the old fashioned way
http://www.youtube.com/watch?v=Lj4h9666d9s&feature=related


Great video. But you better start here: it is a series of three videos, and very, very instructive:
http://www.youtube.com/watch?v=I-2rJtnkYq4&feature=related
By the way, the leading actor, Gabriele Gnani, is one of the founding fathers of the new Continental Championship Race Tech, CCRT.


Interesting engine? An early crankcase reed 1958 http://www.rearenginekarts.com/clark%20engine.htm


The calculator in EngMod was added by Neels after I had done dozens of tests with tripple and T port designs. The calculator simply uses 75% of the total effective port area as a guide. This always works and always makes allot more power and generally I found that the duct exit should be about the area of the main port alone. This usually ends up around 75% of the total ( by taking away the extra area of triple ports) needed for lots of blowdown - thus power.

It was never intended to be used with a single port only as I haven’t tested that at all, apart from years ago on TD3s etc, and we always went bigger back then, not smaller.

Theory says that having a smaller duct volume changes the Helmholtz frequency ( higher ) , and reduces the amount of exhaust residuals able to be stored in that duct ( meaning more clean mixture sits close) , but im not sure this theory will apply to making more power with a single port.

Having said that, a 40mm pipe entry on an engine only making 30 Hp is way too big, so reducing the duct and or header area, or maybe both, will very likely work real well.


… you reduce the port height in the curve; the ratio of inner curve radius to outer curve radius becomes larger, and that is very good for the flow. Look at any air conditioner ceiling-outlet: they are all shaped like that.

I also like the idea of closing off the outer/ upper transfer ducts. It would prevent wrongly-timed exhaust pulses from shoving fresh charge from the cylinder back into the crankcase, and that would yield a very civilized power curve.


The exhaust exit "nozzle" was used first by Helmut Fath ( my hero ) when tuning for Honda where their V twin 250 had one stinger 150 long the other 450 long.

I have tested all manner of variations and the best is around 10mm of parallel nozzle and then 10mm of divergence to a stinger around 1.5mm bigger. This reduces the effect of the waves bouncing up and down the stinger off atmosphere disrupting the rear cone waves.

The length to end of header and length to end of diffuser. so few pipe designs are "correct" and its a pain to calculate all the time. But the header end should be 30 to 32% and the diffuser should be 64 to 68%


The Rotax 24/33 rear cone was dropped in Superkart racing when I discovered that a single 28* made more power on the dyno.

This led to the development of the so called Silverstone pipes that we made when I worked for JL when he was still in England. These won dozens of World and Euro titles.

I have spent days of dyno time testing multi angle rear cones, and have always been able to achieve the same or better power with a single rear of the right angle.
In many cases the sim likes a sharp rear cone, but in reality its no better.

Seems to me that the main reasons you got better power with the modified pipe, was down to a gradual front nozzle, stinger nozzle, and a way shorter tuned length.


There is a relationship between how wide you make a port, and how gradually it should widen in order to keep the ring healthy.
With a good ring, 70% chordal of the bore is the optimum width. If you make it any wider, the widening has to be so gradual that you loose surface area at the top, where it counts most, because that's the area that opens first and stays open the longest.

252375

The drawing shows that with too wide a port you have to sacrifice the yellow areas at the top. But sacrificing those areas costs blowdown angle.area. That red port may have more open area, but not where it counts, at the top; the blue port is better.


Unless you keep the revs really low, a single exhaust port with a 70% chordal width does not give sufficient blowdown time.area, but because of the reason I explained above, making the port wider will be even worse. You will either have to use a bridge, add auxiliary exhaust ports, or raise the timing of the single port to well above the 190° that is optimal for pipe resonance.

The Aprilia cylinder is extreme in that respect: the middle exhaust port is 38 mm wide (older versions were 40 mm wide) and there are huge auxiliaries but even so the middle port is raised to 196° and then it gets a large radius at the top. The radius makes it difficult to measure the timing but if you shove a piston ring in the bore until you can just see light between the ring and the bore, you will find an exhaust timing of 202°.

Don't try this at home, unless you want your engine to produce its maximum power at a mean piston speed of 23.6 m/s. But then your transfer time.area will probably be insufficient. And you know: if you raise the transfers, that will eat into the blowdown time.area.

Why does Aprilia use an exhaust timing that is too high for optimum resonance? It is a compromise: any lower, and the maximum torque will rise, but the reduced blowdown time.area will cause an early torque collapse and the product of torque times revs (yes, that's power) will be lower.


STA stands for Specific Time.Area. STA depends on rpm: the higher the revs, the shorter the ports are open per revolution. So I can only give you STA numbers if you specify for what rpm you wish to know them.

252376

It's like this: a cylinder has port windows with a certain width and certain distances from the cylinder top plane to port roof and port floor. You can only express the window dimensions in millimeters and square millimeters (or in other funny length and area units that english-speaking folk still use).

Put this cylinder on an engine with a crankshaft with a certain stroke and a certain conrod length. Now you can also express the window dimensions in crankshaft degrees.

Now we can look at the angle.area concept (the point between angle and area indicates a multiplication; I make a point of writing it like this )

Let us assume a port window is 1 mm wide. Turn the crankshaft until the window is on the verge of opening. Its open area is still zero.
Then turn the crankshaft 1° further. Let's say the piston descends 0.5 mm, so the open window area is 0.5 mm height * 1 mm width = 0.5 mm² , and it has been open for 1°; that yields an angle.area of 1° times 0.5 mm² = 0.5 °mm².

Then turn the crankshaft 1° further again. That first 0.5 mm² open area has now been open during 2°; and as the piston has descended some more, there is now some additional open window area that has been open for 1°. Multiply all those pieces of open window area with the number of crankshaft degrees they have been open, all the way from initial port opening till port closing, and you get the total angle.area of the port.
But for gas flow it does not matter during how many crank degrees an area has been open; what matters is the number of seconds it has been open.

That is where engine rpm comes into play: twice the revs means half the time; angle.area divided by rpm is time.area. And if you divide time.area by the cubic capacity of the cylinder that has to be filled (or emptied), you have specific time.area.

You may have noticed that in previous posts I sometimes talked about angle.area, and sometimes about time.area. And hopefully now you understand why. When I talk about an engine, I use angle.area. When I talk about a running engine, I use time.area.


With the angle.area values I posted, you should be able to work out the specific time.areas for 13.000 rpm. And these are universal; if you manage to get the same STA values for an engine with any cubic capacity and any rpm, you're doing fine.

But how did you come by the 'mean area' expression? Been reading Gordon Jennings? That was a very coarse approximation of the time.area concept in an era where Gordon did not yet have a computer at his disposal. He certainly would have approached it differently nowadays.


Yes ... after reading Gennings and his idea of measuring the port area uncovered by 50% of the crank rotation between just opening and fully open that not all port shapes will amount to the same equivalent angle area, tall versus wide for instance. My post might not have been a good use of the word "mean" maybe equivalent effective area might have been better.


EngMod2T … the perfect tool for calculating what the RSA must have to make 55Hp @ 13000.
Assuming that is at the sprocket ,add say 5% and put it into EngMod2T - it will spit out the target values, and I can tell you for sure that the end result will tell you VERY close to what is needed in reality, to make that power.


… the ceramic coating on the piston and the chamber is a secret weapon used for years on KT100 Yamaha engines. Its not actually stated in the rules as being illegal, but the way the rules are worded they say that if it doesn’t say you are allowed, then you are not. The coating doesn’t need to be clear, its only done that way so you cant see it. HPC do all manner of coatings, but I know nothing at all about the clear version do I.

[wobbly]

Why put the plug inside the pin with a "new"" groove,there is already a groove available and also there is a chamfer on the end of the pin that can be used - as it was previously - to force outward, the retainer
into this groove.
Wont say any more as this stuff is Frits intellectual property , but with all the pics flying about its quickly becoming public property.
I made these plastic plugs several years ago using glass reinforced Peek,and tested them with no positive results at all.
But now we have tripple ports reaching around to 1/2 bore, and yes they do work a treat.

[F5 Dave]

yeah that 3rd pic Hus posted of the complex pin. can't work it out.

[Yow Ling]

Would it be to stop the pin flexing and maintain a better contact area with the SE bearing?

[husaberg]

Why put the plug inside the pin with a "new"" groove,there is already a groove available and also there is a chamfer on the end of the pin that can be used - as it was previously - to force outward, the retainer
into this groove.


Oh I get it. Some times I guess the obvious solution is well..... just too bloody obvious for me really.:facepalm:

Any news on Vanessa. Is she still in the delivery room. I can't wait to meet her.

[wobbly]

The baby girl is lost in customs somewhere - not a good feeling as this usually means the feckers are assessing for gst charges before release.
Anything the deemed valued over 500 including freight, is chargeable, but depends if the NZC agent had a good rogering the night before..

[husaberg]

The baby girl is lost in customs somewhere - not a good feeling as this usually means the feckers are assessing for gst charges before release.
Anything the deemed valued over 500 including freight, is chargeable, but depends if the NZC agent had a good rogering the night before..

Rogering ......er...the Handler or the Beagle?

Or if they know who Mick Doohan is.

When they said under 500 they could have meant cc's. So it should just scape in.

Those Nsr$500 common as muck. Honda must have made a couple of hundred thousand of them. The grids used to be full of them after-all. So they would hardly a collectors item and are second hand to boot :innocent:

Did Benson ever get around to replying about the Rad?

[dinamik2t]

Hey, Wobbly, I have an EngMod question. It's more about performance boundaries actually.
You mentioned that one should try and increase the TuBmax, which is a performance "indicator". EngMod warns for Deto at around 950.
Say someone reaches this value, then that's it? Is there another way of getting more performance out of that engine combo, without changing the RPM of max power?

What I have in mind, is perhaps a way of decreasing TuBmax without losing performance, thus gaining some room to increase it again, in another way, that gives performance. :sweatdrop Is that even possible?
I guess one way would certainly be cooling, but let's assume that is left aside.


Also, have you ever encountered this error?

252354

[k14]

The baby girl is lost in customs somewhere - not a good feeling as this usually means the feckers are assessing for gst charges before release.
Anything the deemed valued over 500 including freight, is chargeable, but depends if the NZC agent had a good rogering the night before..
Just FYI, it's actually $400 (if there is no duty, which there isn't on motorbike parts). From here (http://www.customs.govt.nz/features/internetshopping/privateimportsbypost/Pages/default.aspx)


When duty and GST are not payable:

Customs does not collect duty and GST where the total revenue payable on any one importation is less than $60.​

Also if you get stung then they will charge you another $38 on top of the GST, so if you goods are $400 you will end up paying another $100. Makes buying something under $400NZD a lot higher value when it is arrived. I have however bought bike parts/gear that has been over $1000 and not been charged, but have been charged on stuff in the $500-800 range, it's just pot luck!

[jasonu]

I've sent all sorts of mc stuff to NZ. I labeled it as used and vintage and so far have avoided any import charges.

[NordieBoy]

I've sent all sorts of mc stuff to NZ. I labeled it as used and vintage and so far have avoided any import charges.

Motorcycle stuff is generally duty exempt.
Not GST however...

[wobbly]

Re TuBMax, this is the temp of the unburnt end gases in the squish.
It is affected only by a few factors.The main ones being ignition advance and effective compression.
Effective com is composed of the static com as set by the cc in the head.Then you add dynamic com to this.
The dynamic com increases with charging efficiency ie more air/fuel in the cylinder per stroke - better trapping efficiency ie more air fuel kept in the cylinder per stroke, and lastly scavenging efficiency - less exhaust residuals left behind per stroke.
As you increase the last three mentioned, then the effective compression within the cylinder, as the piston approaches TDC, becomes greater, and more fuel is burnt - creating more pressure and heat, thus power.
Then you will reach a stage where the end gasses detonate, due to radicals forming,from excess heat and or uncontrolled pressure rise.
The only way to reduce this , is to drop the static com or reduce the ignition lead.
As you approach the theoretical limits of charging,trapping and scavenging efficiency,then you have to balance this with a static com and or ignition advance that will keep the piston alive.
This is exactly what happens on the dyno during development - its a juggling act to balance the com and advance to get the highest cylinder pressure you can, to release as much heat into the gas as is possible ,at the right time to suit the engine characteristics needed.
Com and advance put more of the finite fuel "energy" into the piston and cylinder and then eventually into the water - thus this energy is lost, and cannot be used in the external sense ie to heat up the pipe and generate
more overev .
But pushing the limits of all the factors ,in some form of synergy, is the black art we are only just beginning to be able to reliably juggle with in a good sim - without locking up a piston and a rod coming at you thru the screen.

Hope I never see that error on my screen - looks bad.

[dinamik2t]

Thanks for the time you took to analyze! That's really great info! :Punk:

It's not like in reality things will be near the 'limit' as in the sim, but ok. I guess there are a lot of stuff concerning proper engine assembly & clearences to achieve those results. And then there is carb tuning ofcourse!
But.. in stroke we trust.

[husaberg]

Question why is the optimum configuration for a 2 stroke seemingly square bore and stroke. ie 54x54mm or 50x50mm.

What got me thinking about it was Wobs insistence that Vanessa be a Square motor around 50mmx50mm and the Final configuration of the Cagive V4 which was converted to 54x54.5mm in to improve midrange power.

Is it just the best trade off? ie port width vs height Combustion chamber dimensions.etc force area on piston heat loss etc.
Or is there more to it.

If someone was to modify say TZ's 56x50.6mmm 125 engine to 54x54mm and assuming all the port widths were kept in proportion to bore sizes was retained would there be the same top end power and more mid range? Theoretically speaking. I am assuming the engine is still within its mechanical limits with rpms of course.

Found this from Wob i knew it was somewhere. It answers a lot of my questions.



Scaling ports in a 2T is a complete waste of time, the STA numbers are different for every bore/stroke ratio, rpm and swept volume.
In general you want to keep as close to square as you can, as this maximizes the angle area available, and maximizes the safe rpm for the swept volume.
ie a 74 bore on a 58 stroke for 250cc will never make as much power as a 68 square 250 as the angle area of the ports is reduced way more than the short strokes ability to rev ( piston weight notwithstanding) and make power.
The roof angles for A,B,C were reversed years ago from your convention ie 25,8 ,55 , and the floor angles depend upon the inner turn radius size.
Scavenging patterns will be similar for similar bore/stroke ratios ie a 50 square, will be similar to a 75 square, IF the STA numbers are equalized for the max rpm achievable.
ie reving a 50 stroke 100 to only 12500 is nothing like reving a 125 Gp engine to 14500.
Bottom line is that to maximize power, the transfers will need to occupy ALL of the wall area not taken by the Exhaust, and once this is achieved then blowdown STA will ultimately set the power achievable.

Found this today Replica TZ anyone.
http://www.fondseca.com/index.php?main_page=index&cPath=141&zenid=23bc30cdcb149a6b238743f63a4d4772
http://www.fondseca.com/index.php?main_page=index&cPath=96


Here is below a couple of not so well known 3 cylinder 2 strokes.
No Honda's here. A ADM and not your normal Laverda triple either 1985
The pages look unreadable but they are clear when zoomed.

[wobbly]

As I said in the previous post we need to address two important factors in a 2T engine design.
Torque and rpm
It all comes down to Hp = Tq*RPM/5252.
Keep the torque constant and increase rpm by 10% and you get 10% more power.
Hard part is holding up the torque at the higher rpm level.
A short stroke will allow greater safe rpm, but the bore area needed to create the angle area needed, is limited more and more as you increase the piston size at the expense of stroke length.
The piston gets heavier as well, so ultimately the engine may not physically be able to rev to anything like what the stroke may allow.
Yamaha tried for years to fight Honda with a 56 bore size.The 250s failed miserably from Haradas win in 93 all the way up to 2000 when Jaques won easily on the new square engine derived from the 500.
The 125s won in 74 then never again.The short stroke 500s were useless except for the Rainey years, where he rode the wheels off the thing and Kennys bench was real deep.
The bottom line to all this is that the square engine has the best compromises of rpm capability Vs useful bore area.
Go short stroke and though you may be able to rev it, the scavenging is compromised by the bore availability.
With long stroke - the reverse happens.
This all assumes we are talking max power capability - 250cc MX is all longer stroke now as this favours torque production from low rpms,and the extra rpm capability of a square engine isnt needed to create peak power numbers.

[F5 Dave]

Wob, just looking at the hand drawn pipe in this list Frits posted (pijp 21) & looking at the stinger venturi; -it would tend to follow your rule of parallel section diffused out ~1.5mm larger, - the only thing I am confused about is the smallest diameter is ~23mm which is what I’d expect a conventional 125 stinger to be.

I thought the idea was to run a very short section at a smaller di than you’d run a conventional stinger mimicking the restriction of a longer pipe? So even though the drawing is exaggerated the diameter isn’t that small. I was expecting 21mm or something like that. Is it because the last baffle stage is steep? Or the requirement to get heat into the pipe can be produced by other means of ign & powerjet so stinger sizes have increased? It still seems odd. Or am I just wrong about the smaller than conventional size part?

[dmcca]

a question for Mental Trousers...

Is there any way to download or copy this entire thread in one go, attachments and all? Or possibly a way to make the printable version more than 40 pages per page and include the image thumbnails not just the URL?

Im heading away on holidays soon without net access and would love to take a copy of the whole thing to re-read

[F5 Dave]

Won't someone think of the children, cough I mean trees, Won't someone think of the trees.

either way most of the first 200 pages is lather & engine specific, although no one has accused anyone of being like Hitler (although maybe that did occur & I've forgotten). Mental won't read all threads so won't answer, perhaps a post in 'Site Stuff' thread.

[edit]
Ha, just for giggles I read the first page back in 2008. Post 5 for me & I'm probably still spouting nonsense.

[dmcca]

Won't someone think of the children, cough I mean trees, Won't someone think of the trees.

either way most of the first 200 pages is lather & engine specific, although no one has accused anyone of being like Hitler (although maybe that did occur & I've forgotten). Mental won't read all threads so won't answer, perhaps a post in 'Site Stuff' thread.

[edit]
Ha, just for giggles I read the first page back in 2008. Post 5 for me & I'm probably still spouting nonsense.

Thanks... dont worry the tree are safe... just want a copy in in word or pdf or whatever to go on the mini laptop

[Grumph]

from what i can see only the last couple of hundred pages are worth printing.
Out of curiosity I looked backatsome early pages and there's TZ wallowing in angst about air cooling a 125...justike a couple of pages back.

Fercrissake TZ - beg borrow or steal a copy of Irvings "Two stroke power units" and read wha he says about fan cooling....

As holiday reading though it beats Mills andBoon hands down.

[Buckets4Me]

Out of curiosity I looked backatsome early pages and there's TZ wallowing in angst about air cooling a 125...justike a couple of pages back.

.

the only difference seems to be the first time he was only making 19 h/p
and now he has nearly 30 h/p


<iframe src="http://www.youtube.com/embed/egiqzJ5MPmc" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

They would make good bucket racers if they wanted to step up

[ac3_snow]

Quick question for all you wise ones out there. Should be a little more simple than what has been going on for the last month. Finally got around to trying to tap out the head studs which i ripped out two months ago. No worries except I also ripped out the one which I had previously tapped out to 10mm. Which is a slight delima as there is buggah all room left to go much bigger. So could I get it welded up and then re-drill it? or should I just devcon it back in.... :whistle:

as You can see in the pic I had a channel machined around the liner, to fit the head gasket/o-ring. This means there's not a whole lot of room around the studs.

252550

[Henk]

Devon will likely go up in smoke. Main options are probably weld or helicoil.

[wobbly]

The stinger config in pipe 21 is exactly what is needed for a 125 making anything like 50 Hp.
I have been using CNC nozzles I had made over 10 years ago that are 23.2 at the smallest section specifically for the pipes I have built for karts that make around 50.
For a 125 down at 40 Hp then 22 is about right, as is used by the CR125 engines in SKUSA stock class,down at 30 Hp I would say 20 or 21 ( never built one, sorry)
It all comes down to the amount of air that is dumped into the pipe, and this is totally reflected in the Hp numbers - empirically these sizes work every time to generate the correct back pressure, without causing deto or finicky tuning issues..

[speedpro]

Which is why my pipe has a removeable end piece sandwiched between the end of the cone and the tailpipe. It is just a little piece of cone with a precise diameter nozzle. I tried one size then went up one and made more power on the dyno. Funny enough it felt better initially on the track with the smaller one.

[Frits Overmars]

Like below? Red is the exchangeable restrictor. Blue is its container, welded to the yellow endcone at the left. The yellow pipe at the right is the tailpipe (held in place by a spring) with a bigger diameter than the restrictor.

[speedpro]

Not as fancy. Mine has no venturi and is made from .8mm sheet. The two sizes I have were formed very tightly around the required size rod, welded, and then hammered with a rubber mallet. The end result is a perfect fit with a nice smooth finish. I might look at doing one with the venturi.

[gamma500]

Hi Frits, could you explain those numbers at bottom of the A-102Fos pipe drawing

from your Aprilia files?


Lsz=0.427? Vol=32.6(pipe volume/cylinder volume?)/46?

iso=1? nL=13036, nD=13035 and nT=13035 must mean max power rpm?


Btw is there any power difference between A-102Fos pipe and Aprilia pipe 102?

[F5 Dave]

Thanks for the thoughts about restrictions relating to power output Wob.

Thanks for the pics again Frits.
I have been using an old RS pipe & there is a connecting area so I have machined up a few shapes pretty much as above. Only issue that had me thinking was that my stinger tube was 23mm & for a 100cc my restriction was 18mm so it was diffusing 5mm instead of suggested 1.5. I wasn't having much joy with the 18 & really didn't see much change between 19 & 23 straight pipe, but I really need to get my next pipe on the dyno & retry but I'll start with 19 & go from there & try match a stinger pipe closer to 1.5. Clearly as power levels make steps up (I'm on interim get-me-going arrangements) I'll need to retrial.

Changing the stinger to match is the hardest part though. Pity you can't just buy different size thin wall tube by the foot.

[speedpro]

Changing the stinger to match is the hardest part though. Pity you can't just buy different size thin wall tube by the foot.

Make your own from say .8mm sheet. If you cut it nice and straight on a guillotine it comes out very nice. I have a good selection of different size axles which I form it on. Once welded it typically jams on the axle but a bit of smashing it with a rubber mallet soon frees it up and leaves it looking good. I form a lot of stuff from .8mm sheet - exhaust mounting brackets, brake stay arms, engine mounts. I have a couple of lumps of steel for beating it over and getting it flat so it welds up nicely.

[Gigglebutton]

Quick question for all you wise ones out there. Should be a little more simple than what has been going on for the last month. Finally got around to trying to tap out the head studs which i ripped out two months ago. No worries except I also ripped out the one which I had previously tapped out to 10mm. Which is a slight delima as there is buggah all room left to go much bigger. So could I get it welded up and then re-drill it? or should I just devcon it back in.... :whistle:

as You can see in the pic I had a channel machined around the liner, to fit the head gasket/o-ring. This means there's not a whole lot of room around the studs.

252550


I have Helicoils if you want to bring it in

[Bert]

Quick question for all you wise ones out there. Should be a little more simple than what has been going on for the last month. Finally got around to trying to tap out the head studs which i ripped out two months ago. No worries except I also ripped out the one which I had previously tapped out to 10mm. Which is a slight delima as there is buggah all room left to go much bigger. So could I get it welded up and then re-drill it? or should I just devcon it back in.... :whistle:

as You can see in the pic I had a channel machined around the liner, to fit the head gasket/o-ring. This means there's not a whole lot of room around the studs.

252550


I have Helicoils if you want to bring it in

Get it correctly welded up (this may require drilling it out larger to give a better welding surface) and re-cut the o-ring channel and plain everything true; the poor old barrel is suffering from age and crap alloy.

i chased all sorts of "fix's" on my TF head and at the end of the day I wished I'd fixed the bloody thing correctly in the first place. nothing worse than having your day ended by a popped helicoil or duraweld coming apart.
but when you do sort it out; 24hr Araldite in the studs (I think that came from speedpro??) never had that issue again (if you are running an o-ring then you shouldn't need to torque the ass out of the head anyway)...

[speedpro]

Buy a good torque wrench and use it. Welding is going to cause all sorts of distortion and maybe even seperate the aluminium from the liner. A helicoil inserted using a drill press to get it dead straight and square should be fine.

[Gigglebutton]

We use loctite retaining compound on the helicoils to help retain them.

We have welded barrels in containers filled with water to help minimize the heat affected area

[TZ350]

Just add another nut to the end of flywheel, then you can add a bolt that secures the degree wheel. Pointer must be secure (I use a clamped on scriber) & degree wheel should be as big as possible.

Barrel must be bolted down well or gives incorrect readings, this can be a problem if engine has thru bolts & a few gaskets used. Use feeler gauge to determine if port is closed by piston, doing it by eye is imprecise.

When starting with another carb just pull the mainjet out, no point putting a big one in. If the engine doesn’t bog past ½ way then the needle is too fat.


Ha, just for giggles I re-read the first page back in 2008. Post 5 for me & I'm probably still spouting nonsense.

I thought you were offering good advice, still do ...

[husaberg]

although no one has accused anyone of being like Hitler (although maybe that did occur & I've forgotten).

[edit]
Ha, just for giggles

Found this TZ quotes Hitler in engine development kind of anyway. Note he was on to the exhaust venturi as well. All on PG 8


From Koba,s post, and Goggle I have found some interesting info on air cooled motors. Before the "War" in some circles water cooling was considered inefficient, unreliable and expensive. This is the era V-Dubs come from.

Before the "War" Hitler had the Autobahns built, this was before there were fast cars. Then he encouraged the car makers to build Autobahn cars. They were often air cooled and very aerodynamic. There was an air cooled 3.8l V8.

In the 80's when large wind tunnels became available some of these old cars were tested and their drag coefficients (and fuel consumption) were lower than modern cars.

A quick intro to Mackerle. Julius Mackerle was the chief engineer at Tatra motorworks for many years. Tatra make a lot of air cooled vehicles and trucks. Mackerle published a huge amount of interesting air cooled engine information in a book of his called Air-Cooled Engines.

The interesting thing is that the air cooling was effected in different ways.

There was the V-Dub style cooling fan

Another device like a turbo charger that was spun by the exhaust gas and the fan compressor sucked or blew the air through the cooling fin ducts.

And a ventuire ejector system that also used the energy of the exhaust gas to sucke the air through the cooling fin ducts.

I am not sure about the difference between a venturie and a venturie ejector. But I think a venturie is like a motorcycle carb's needle-jet/choke arrangement. Where a small pipe leads into the middle of the venturie's choke and a venturie ejector is more like the old vaccume cleaner spray paint gun?

A venturie ejector is used where shifting bulk is the aim.

Here is an abstract from a US Patent.

Venturi exhaust cooler Document Type and Number: United States Patent 3875745

"The kinetic energy of the exhaust gas from an internal combustion engine is utilized as a driving fluid to aspirate a large volume of quiescent ambient air as a driven fluid for cooling the exhaust gas quickly in a very short path of travel. This mode of operation is to be distinguished from conventional injector and ejector devices utilizing a current of air as the driving fluid. The present device utilizes the Coanda effect to introduce the exhaust gas around a lip on one end of a venturi tube, causing the gas to flow in a high velocity film adherent to the inner surface of the tube. This laminar flow draws in a large volume flow of air through the center of the venturi, cooling 1000°F. exhaust gas down almost to ambient temperature in a distance of a few inches."

I have seen on some modern expansion chamber designs, that the stinger has changed to a restricter that looks like a venture with a tail pipe, makes me think this could be made into a venture ejector.

The good thing about using the energy in the exhaust gas to do some work, is that it quietens it like a muffler does.

A ventuire ejector might have possibilities.

.

[Farmaken]

Hey Tz, having used both these sims, do you reckon they give similar outputs for the same data input? Seems that Engmod is alot more involved and requires far more data input from what you have posted so far, but having ordered Mota the day before you listed your copy for sale :doh: was curious about your results so far.
Cheers Ken

[wobbly]

Problem with Mota is that in many cases the data cant be entered correctly,and there is now no backup or updates.
Engmod is way ahead in accuracy due to the extra work needed on data entry, but also is way ahead now due to the constant updates and refining that Neels has
been doing.

[TZ350]

Hey Tz, having used both these sims, do you reckon they give similar outputs for the same data input? Seems that Engmod is alot more involved and requires far more data input from what you have posted so far, but having ordered Mota the day before you listed your copy for sale :doh: was curious about your results so far.
Cheers Ken

Mota's good I learnt a lot from using it, you won't be disappointed.

My opinion of Mota vis EngMod2T

I couldn't get Mota to mimic my engines real dyno curve as well as EngMod2T does but Mota did show the general shape and rpm range although it over stated the power.

Mota was good at showing what effect a change was going to have and it did allow me to find the port timing and shape and pipe dimensions that best suited my engine. With Mota's help we got an old Suzuki GP125 into the high 20's (28.9 rwhp which must be over 30 at the crank) so it can't be all bad.

Mota also has some nifty side applications for developing curved multi section pipe cone templates that we found very usefull.

Being an integrated package I found Mota very easy to get started with where EngMod2T is spread over three main applications and two sub apps like a Mota to EngMod data file converta. EngMod took a little getting used to, but now I am starting to know my way around it I find its very easy to use too.

Mota vis EngMod2T is like comparing Jennings port-time-area work with Blairs work at Belfast University, Blair and Neels EngMod2T are a generation or two ahead and incorporate a much more developed understanding of 2 stroke behaviour, but Jennings and Motoa are still very useful for a basic understanding of tuning 2-strokes.

On the negative Mota only deals with a single exhaust port EngMod2T can handle a triple port and has other refinements like a convergent cone stinger nozzle, a rpm dependent variable pipe temperature, much more sophisticated combustion modelling amongst other better developed features. Also the range of information available from EngMod2T's output like the STA values and detailed graphs are streets ahead.

Yes I think EngMod2T is more accurate (by a mile) and produces much more information than Mota but Mota got me to where I am and EngMod2T tells me I am about as far as I can get, with a little EngMod polish there may be another hp or two but with the 24mm carb 30 rwhp is about it for my engine.

[Farmaken]

Thanks Wobbly and TZ for your thoughts, good to know Mota will give a fair idea of the expected HP amd torque curves even if they are a little optimistic !!

Have been playing with numbers for my TF engine - hoping for 20+Hp from 9000 to 12500 with peak power of 26.5 at 11500

Plugged numbers in as I had it running at Taupo and got data output which seemed to correspond with how it felt on track - peak power 17 Hp at 9000 then nothing from there on.

No wonder it was easy to ride on slicks in the wet:no:

[TZ350]

Thanks Wobbly and TZ for your thoughts, good to know Mota will give a fair idea of the expected HP amd torque curves even if they are a little optimistic !!

I probably could have got Mota closer to the real thing by playing with the combustion efficency and other variables more but it was the shape of the curve and how it was affected by changes to the engine/pipe/inlet that mattered more than the displayed hp numbers.

[TZ350]

if these pesky two strokes get too fast I guess we can always get the four stroke limit bumped up to 200cc? Sounds fair doesnt it?
MotoGP went from 500cc two strokes to 990cc four strokes, MX has 125 2 strokes racing with 250 four strokes ... :innocent: :corn:

Yes 125 2-stroke vis 200 4 with a 24mm carb restriction and air cooling only, same rules for both, sounds fair to me. :laugh:

[koba]

Quallman1234 and I wen't halves in your (TZ- I think) old copy of MOTA.

I'm having a play with it first as I'm currently needing more power from my engine. The TF Quallman has isn't going to be going for quite some time.

It took me quite a while to get everything working right. I feel I have a basic model (Could be slightly better) of my engine sussed.

I was very surprised to see the power curve look exactly how it feels on the bike.
It may be a different story against a dyno.
The dip I can feel is there, the revs are about what I think they feel like.

The power does seem over-stated at 16 rather than an arse-dyno 14-at-best.
I know arse-dyno is terribly inaccurate but this IS in an environment I'm quite familiar with and directly compared to bikes of a known quantity.

I do think it hasn't really changed my planned modification strategy at all.
This is possibly because I'm dealing with a well known platform with access to the experience of many others.
EDIT: I do feel it has validated my plans, I'm less worried about cocking it up.

I think it would be quite valuable if dealing with a less well known motor or if less access to information was available.


Right, Time to run another sim... (number 82)

[Bert]

Yes 125 2-stroke vis 200 4 with a 24mm carb restriction and air cooling only, same rules for both, sounds fair to me. :laugh:

and only 2 valves...:weird: isn't that the BRA rules (http://www.ozbucketracing.com/rules.html) (well 185cc at least)....

[husaberg]

Itailian Friday

Few could deny it is still a beautiful bike.

It was on the cusp of finally living up to its potential.
Finally being developed in a more methodical manner.
A great shame the plug was pulled.
as a side note Foggerty said the FI was a piece of poo.

[wobbly]

Just goes to show even supposedly "good " reporters know jack - calling EGT probes Lambdas and then not spelling them correctly.

[NordieBoy]

Colin Lyster didn't have many good words to say about Sir Al either :D

[F5 Dave]

. .. Have been playing with numbers for my TF engine - hoping for 20+Hp from 9000 to 12500 with peak power of 26.5 at 11500. . .

I'd be looking at some fairly serious re-engineering before you ask a Suzuki TS/TF crank to spin that fast.

[2T Institute]

I'd be looking at some fairly serious re-engineering before you ask a Suzuki TS/TF crank to spin that fast.

Crank is no problem, same crank in the RM 100/125 air cooled , early water cooled and the RG 125 with the 54mm stroke , power reed and the 19mm crankpin.
What IS diabolical is the TS/TF gearbox ratios which are wide enough to drive a semi through. If you were being sneaky fitting a air cooled RM 125/100 gearbox would be ideal.

[speedpro]

I'd be looking at some fairly serious re-engineering before you ask a Suzuki TS/TF crank to spin that fast.

I have to agree with Dave. Based on a few years experience the cranks don't like much more than 11,000rpm regularly. I used phenolic resin caged mains which were OK but the thrust washers were a problem. It's not really an issue as the pistons won't handle those revs anyway. Even the RG400 pistons don't last and crack. I was replacing them every two meetings and that was after I polished the regions where the cracks originated. All rods were superceded to the RM rods which was nice - silver plated big end bearing.

[wobbly]

Unless the part number from Suzuki is the same for the later superseded rod/bearing ie both models then use the same parts from the factory - then of course an RM rod is illegal.
No different than sneaking in a RM gear set - im watching you buggers.

[Farmaken]

I have to agree with Dave. Based on a few years experience the cranks don't like much more than 11,000rpm regularly. I used phenolic resin caged mains which were OK but the thrust washers were a problem. It's not really an issue as the pistons won't handle those revs anyway. Even the RG400 pistons don't last and crack. I was replacing them every two meetings and that was after I polished the regions where the cracks originated. All rods were superceded to the RM rods which was nice - silver plated big end bearing.

I have not opened the inlet ports at all, in fact they are sealed and now have crankcase reed fitted to barrel with boost port at rear machined to exit thru std rear transfer ports ( actually now one port with roof angle of 55*. Hoping this will extend piston life somewhat.

RM/TF rod will have to do for now but that gear set sounds tasty !!

[F5 Dave]

You're following Mikes lead with the CC induction, although he by then wasn't using TS top end.

[speedpro]

I'm pretty sure if you order a TS/TF rod you will be told they have been superceded. The only genuine rod you can get that fits is what used to be the RM rod. You have to wonder why they even bothered making two rods with different material specs.

Don't listen to me though. I have a reputation for using illegal rods.

[husaberg]

Don't listen to me though. I have a reputation for using illegal rods.

Shh ......its a secret:psst:
You may find something "legal" here http://www.pro-x.com/downloads/Technical.pdf

More Italians to follow. ......

Not as cool as the Frits files though. 88

[husaberg]

Italian Friday Aprilia RSV400
The thing I found most interesting about this article is what Jan (Jan Witteveen) says and how it comes err..across........

Maybe Fits could be kind enough to add some insights into the RSV400 project.

[Frits Overmars]

Italian Friday Aprilia RSV400. The thing I found most interesting about this article is what Jan (Jan Witteveen) says and how it comes err..across........
Maybe Fits could be kind enough to add some insights into the RSV400 project.You have no idea what you're asking of me. I refrained from reading the above articles because I want to keep my good mood. But OK....
The 400 cc twin was entirely Witteveen's idea. He built it in cooperation with Franco Moro (the same glorious cooperation that produced the Maxtra / Haojue 125...). When they realized that 400cc wasn't enough to beat the 500 cc fours after all, they made the pistons bigger and bigger, resulting in a more and more oversquare engine with more and more thermal problems.

[Grumph]

A few years back Kevin Grant (well known Britten owner) apparently had all the 400's here in NZ - I don't know if he still has them.
Talking to him he was quite keen to get one running and bring it South for the Sound Of Thunder meeting but it hasn't happened.

Frits - you should be happy they're as far away from you on the planet as they can go....

[husaberg]

You have no idea what you're asking of me. I refrained from reading the above articles because I want to keep my good mood. But OK....
The 400 cc twin was entirely Witteveen's idea. He built it in cooperation with Franco Moro (the same glorious cooperation that produced the Maxtra / Haojue 125...). When they realized that 400cc wasn't enough to beat the 500 cc fours after all, they made the pistons bigger and bigger, resulting in a more and more oversquare engine with more and more thermal problems.

Sorry Frits it wasn't intended to be a mood killer. I had only just read the article and sensed some stuff in it relation to either a lacking of confidence or competence. I had never got the same feeling from other articles relating to the 250. So I will be assuming the later?
Googled those bikes you mentioned. a few teething problems and a rider revolt and a sacking http://www.crash.net/motogp/picturearchive/147765/1/photos

Upside down engine i am assuming the Rumi layout (I am sure you are a little familar with that as well I guess see pic 5)i had posted earlier i thought it was quite trick until i looked at a 1988 YZR500 or for that matter a 1988 Aprilia v twin naked and realised the upside down engine was just so plain logical.The beauty of hindsight for me, Genius for the designers. Who did the Chassis for it?
oh ok Nico Bakker.http://2stroker.createforumhosting.com/rumi-project-hans-spaan-jan-thiel-t2652.html

Grumphs bit. I shouldn't be that surprised knowing of Kevins collection of exotica. But i was about the Aprilia.

[Kickaha]

Upside down engine i am assuming the Rumi layout i had posted earlier i thought it was quite trick until i looked at a 1988 YZR500 naked and realised the upside down engine wasn't innovative after all.
I hadn't seen them before but I helped a friend build an upside down NSR250 in a Kart with the gearbox cut off driving through a fluid coupling although that was late nineties

[wobbly]

As an indicator of the relative genius of the design team, look at the intake on the Rumi - an FCR carb with dead straight manifold.
Then look at the Maxtra, balls up par excellence.
I had a job interview with Mr Witteveen at P.I when McWilliams put the Aprilia on pole,short of the story was I didnt take the job, wish Frits had done the interview and then I would maybe have got to meet Jan.

[Frits Overmars]

A few years back Kevin Grant (well known Britten owner) apparently had all the 400's here in NZ - I don't know if he still has them. Talking to him he was quite keen to get one running and bring it South for the Sound Of Thunder meeting but it hasn't happened.
Frits - you should be happy they're as far away from you on the planet as they can go....Maybe you could bring them just a little bit closer - isn't there a deep spot in the ocean somewhere?