ESE's works engine tuner

[SwePatrick]

This epoxy you mention, is good for transfer ducts and what not? I've used Hagmans for this usually but if you find the loctite name I'd like to try it.

I can look it up this afternoon, i´m at work now, and yes it works fine modifying transferducts. :niceone:

[andreas]

I can look it up this afternoon, i´m at work now, and yes it works fine modifying transferducts. :niceone:

Ok, great..

[SwePatrick]

Ok, great..

https://www.henkel-adhesives.com/us/en/product/electrically-conductive-adhesives/loctite_ea_9497.html

I mix it up with some 'aluminiumdust' from grinding a part of the same quality.

[andreas]

https://www.henkel-adhesives.com/us/en/product/electrically-conductive-adhesives/loctite_ea_9497.html

I mix it up with some 'aluminiumdust' from grinding a part of the same quality.

Like "engine concrete" then, Thanks man.

[wobbly]

I want to fill a piston cavity exactly like the sample shown to test the effects of short circuiting.
Anyone found a supplier of 9497 in NZ.

[lohring]

On dyno correction factors; I've raced model boats from sea level to 5000' (1500 meters) and up to 40* C at that altitude. The nitro engines (60% nitro) lost a little power, but could pull the same diameter propellers thanks to the oxygen in the fuel. Gasoline engines lost a lot of power and needed to run much smaller props. We always dynoed and test ran at around 450' (140 meters) and in cool weather. Los Angeles was only a little lower, but warmer. We always could count on 2 or 3 mph (around 2%) more speed. Since boat speed is related to power cubed, that's a bigger difference than I would expect. Gasoline engines wouldn't pull sea level props starting around 2,500' (750 meters). Of course we couldn't change pipe length much or ignition timing. However, it seems that two strokes loose or gain power more drastically than conventional correction factors would suggest.

Lohring Miller

[husaberg]

I want to fill a piston cavity exactly like the sample shown to test the effects of short circuiting.
Anyone found a supplier of 9497 in NZ.

This is the NZ distributer and they don't list it.
https://www.shuk.co.nz/major-products/loctite-products/

they list

CTITE® EA 9017 (known as FIXMASTER® FAST CURE POXY PAK™ EPOXY) is a 2-part, room temperature curing epoxy adhesive used for high strength, permanent bonding of metals, ceramics, concrete, wood, glass and most plastics. This product can withstand temperatures up to +300 °F (+149 °C).
Premeasured resin and hardener for easy application, consistent strength and time savings - no waste, no mess, no clumping
Bonds virtually any material
Repair, fill and seal holes, cracks and worn surfaces
May be drilled, tapped, sanded, or machined and painted after cure
Reaches handling strength in 4 to 6 mins, fully cures in 45 to 60 mins
Easy to use in a syringe applicator
VS

9497
2-part, medium viscosity, high performance epoxy adhesive offering heat resistant bonding and filling characteristics.
LOCTITE® EA 9497 is a 2-part, grey epoxy adhesive for structural bonding that offers high technical performance. The product provides a high temperature resistance up to +180°C for heat resistant bonding and filling. It is thermally conductive and delivers high compression strength. It is ideal for bonding metal components.
High temperature resistance
Ideal for heat dissipation
Ideal for metal parts
High compression strength

Blackwoods have

Loctite Epoxy Adhesive 3805
Term Description
Steel and aluminium epoxy filler in dual tubes. High strength, fast cure. Ideal for fitting shaft repair sleeves and surface filling. Resistant to fuel, oil, anti-freeze, water etc. May be drilled, filed, tapped, etc. Temperature range
-55°;C to +150°;C, +175°;C (intermittent).

[AndreasL]

The adhesive/filler with the highest peek temperature (if it matters much I don’t know) from Loctite I could find was 3479.
Filled a crank case with it an it’s very hard and seems to adhere really well. Haven’t used it in anger though yet so no real prof.

9497 sounds really interesting though.

343301

[yatasaki]

Same stuff here, tested on aircooled cast iron

[AndreasL]

Same stuff here, tested on aircooled cast iron

Good results? No issues?

[yatasaki]

Nope, for modifying transfers , which became brownish (ie exhaust gases backflow) after approx. 15 hours of racing no any issue. Even 3450 for iron/steel parts was tested on CZ175 exhaust pipe header and aux exhaust port (but from outside of cylinder)
For conversion from reed to piston port cylinder by filling intake and reed flange with broken cooling fins and loctite mixture with grey iron dust..
No issues again, loctite gotta have some good heat transfer/conductivity

[AndreasL]

Nope, for modifying transfers , which became brownish (ie exhaust gases backflow) after approx. 15 hours of racing no any issue.

Great information as modifying transfers with 3479 is one of my future plan’s to try.

[lodgernz]

Great information as modifying transfers with 3479 is one of my future plan’s to try.

I've had no problems with DevCon in transfer ports.

[SwePatrick]

I've had no problems with DevCon in transfer ports.

Devcon JB-Weld and Belzona are all good ones.
I just have been using what´s on my shelf from porting 4stroke heads, And Loctite 9497 has been free for me.
I cant say how good it is with alcohol fuel thou.

I did a test and it worked fine when bathing in methanol, but as soon as i tested with oilmixture things altered colour, never used in real life with alcohol.
9497 is quite expensive as i can see here in sweden.

[husaberg]

Devcon JB-Weld and Belzona are all good ones.
I just have been using what´s on my shelf from porting 4stroke heads, And Loctite 9497 has been free for me.
I cant say how good it is with alcohol fuel thou.

I did a test and it worked fine when bathing in methanol, but as soon as i tested with oilmixture things altered colour, never used in real life with alcohol.
9497 is quite expensive as i can see here in sweden.

Jan has mentioned another one they used at Aprilia it was green and it even survived the cylinders being replated.
its mentioned on either the first of the second edition of the pitlane thread.

[yatasaki]

I've had no problems with DevCon in transfer ports.

Devcon steel putty was first to try and worked excellent, belzona 1111 same thing . Loctite is easiest to get around here

[Frits Overmars]

Jan has mentioned another one they used at Aprilia it was green and it even survived the cylinders being replated. It's mentioned on either the first of the second edition of the pitlane thread.The stuff was called Stucca Verde (green grout) but I don't know if that really was the product name, or just the description used in the racing department. In any case it was quite expensive and if I remember correctly, it had a limited shelf life.

[husaberg]

The stuff was called Stucca Verde (green grout) but I don't know if that really was the product name, or just the description used in the racing department. In any case it was quite expensive and if I remember correctly, it had a limited shelf life.
Cheers Frits. I am not sutre about europe but those words make sense even here.
We have stucco rendered houses and walls over here, plus the corrosion patina that gives aged copper its pretty colours is known as verdigris here, so those Latin types might be onto something with their words.:innocent:

[Muciek]

Isn't it Army Painter ARM05007? It's 2 piece stuff turns green when mixed...

[jato]

Ecobond (104?) used on alloy / magnesium castings on jet engines ... haven't seen it for years but i recall it being practically indestructable once its set. something like 4 or 5 hours at 200 degrees cure time. it was green. any current aircraft engineers on here?

[lodgernz]

For adjusting the roof angle of transfer ports, I always use Devcon Plastic Steel Liquid (B) 110210 because it flows enough to self-level.
I set the cylinder upside down and tilt it so that the top of the port is at the angle I want, then drop the Devcon in and it (slowly) settles to a level surface.
If I got the setup angle right, the roof is now at the correct angle to the horizontal.

I don't know if any of the other steel putties have a "liquid" version.

[katinas]

Ecobond (104?) used on alloy / magnesium castings on jet engines

Hysol ECCOBOND 104, short term up to 280C

http://media.oem.se/Archive/FilesArchive/106826.pdf

[husaberg]

pyro putty

Pyro-Putty 2400 is a ceramic and stainless steel filled, high temperature, thermally conductive paste used to bond, seal and repair defects up to 3/8" in cross-section in cast iron, steel and stainless steel components and structures used in automotive, truck, marine, and industrial applications to 2000°F (1093°C).

http://www.graphitestore.com/pyro-putty-2400-paste

[Haufen]

If I had to choose between several kinds of epoxy, I'd select the one with a thermal expansion closest to aluminium and the lowest specific weight. The piston expands quite fast in contrast to more usual areas of application like for example crankcases.

[adegnes]

Jan has mentioned another one they used at Aprilia it was green and it even survived the cylinders being replated.
its mentioned on either the first of the second edition of the pitlane thread.

First up, sorry for it being sooo long since my last post.
My YouTube channel kinda blew up and I'm having a hard time keeping up with just the mails, messages etc.
I know there's a few pm's I haven't gotten to here also.

With my limited experience in diy plating most epoxies, suitable for cylinder work or not, would survive a strip+replate pretty well.

Anyways.
Currently at the airport in Denver Colorado, on my way back from my first attempt at racing at Bonneville Speedway(event got canceled, rain)
We had a great time regardless, and now I have time to build a proper engine with my 100% width exhaust port cylinder on it.
Going to run on nitromethanol, efi, throttle slide part of the rotary valve cover.
Variator transmission electronically controlled.
Need to read up on the do's and don'ts with fuel injection.

[breezy]

First up, sorry for it being sooo long since my last post.
My YouTube channel kinda blew up and I'm having a hard time keeping up with just the mails, messages etc.
I know there's a few pm's I haven't gotten to here also.

With my limited experience in diy plating most epoxies, suitable for cylinder work or not, would survive a strip+replate pretty well.

Anyways.
Currently at the airport in Denver Colorado, on my way back from my first attempt at racing at Bonneville Speedway(event got canceled, rain)
We had a great time regardless, and now I have time to build a proper engine with my 100% width exhaust port cylinder on it.
Going to run on nitromethanol, efi, throttle slide part of the rotary valve cover.
Variator transmission electronically controlled.
Need to read up on the do's and don'ts with fuel injection.

what a shame "rain stopped play", seems like you were having to rush with the build i thought, but with a longer period to build again i would have more confidence that you could come away with something... :2thumbsup

[Flettner]

Mmmmm, throttle slide on the RV housing, EFI, good choices.

[jbiplane]

Want your advice.
Is there any recomendations or simplified calculator to design reed valve and its housing size?
Says what best to use for big bore Yamaha YZ85?

[husaberg]

Want your advice.
Is there any recomendations or simplified calculator to design reed valve and its housing size?
Says what best to use for big bore Yamaha YZ85?

A cadge designed for a RZ350 is bigger area with same bolt holes.
But YZ85 cadges are rather nice. They are also not ribbed for your pleasure
the engmod sim likely allows you do trial reed valves. People use the YZ85 reed valves on RD400's

[andreas]

Want your advice.
Is there any recomendations or simplified calculator to design reed valve and its housing size?
Says what best to use for big bore Yamaha YZ85?

Rd 125 lc fits with aminimum of work, tzr 125 require more grinding. Yz 85 reeds ought to stay in their itty bitty engines.

[SwePatrick]

As we speak..
Pipe is in progress.
Since my crankfailure i have modified some things.
I turned the cylinder 180 degrees just to open up some possibilities, easier pipe build, and easier forcing air from the front to an airbox i´ll build later, it might help topspeed some mph.

Later on i also plan to convert the engine to rotating disc inlet placed in front above the engine mount, i´ll just make a drivesystem a lot like the RSA from the balanceshaft.
I will also make the aerodynamics somewhat better when not having the pipe hanging on the side.
And more protected from airflow will help it keep the heat.

343309

[TZ350]

First up, sorry for it being sooo long since my last post.
My YouTube channel kinda blew up and I'm having a hard time keeping up with just the mails, messages etc.

Currently at the airport in Denver Colorado, on my way back from my first attempt at racing at Bonneville Speedway(event got canceled, rain)

I am sorry rain spoiled play. I have been following your two stroke stuffing thread with interest........ next time. .. :2thumbsup

Check out YouTube channel! - 2STROKE STUFFING -
https://www.youtube.com/2STROKESTUFFING
Two strokes & rum!

[JanBros]

Jan, Frits, or anyone else who would know :

Jan once said 1.5mm was the minimum bridge width between transfer ports in the RSA, what would be the safe minimum bridge between exhaust ports ?
between main and auxiliary
and
the bridge in the middle of a double main ? I suppose this has to be even wider than main-aux ?

[peewee]

Want your advice.
Is there any recomendations or simplified calculator to design reed valve and its housing size?
Says what best to use for big bore Yamaha YZ85?

you might contact vannik. with engmod it always tells me the reed block is insufficient, even with vf4. so there must be some calculator. perhaps its how much air the engine needs for a given amount of power

[andreas]

Jan, Frits, or anyone else who would know :

Jan once said 1.5mm was the minimum bridge width between transfer ports in the RSA, what would be the safe minimum bridge between exhaust ports ?
between main and auxiliary
and
the bridge in the middle of a double main ? I suppose this has to be even wider than main-aux ?

3 mm aux-main according to this.

[sonic_v]

First up, sorry for it being sooo long since my last post.
My YouTube channel kinda blew up and I'm having a hard time keeping up with just the mails, messages etc.
I know there's a few pm's I haven't gotten to here also.

With my limited experience in diy plating most epoxies, suitable for cylinder work or not, would survive a strip+replate pretty well.

Anyways.
Currently at the airport in Denver Colorado, on my way back from my first attempt at racing at Bonneville Speedway(event got canceled, rain)
We had a great time regardless, and now I have time to build a proper engine with my 100% width exhaust port cylinder on it.
Going to run on nitromethanol, efi, throttle slide part of the rotary valve cover.
Variator transmission electronically controlled.
Need to read up on the do's and don'ts with fuel injection.

For next year it might be worth looking at the FIM sanctioned event at Elvington in the North of England.

http://www.fim-live.com/en/sport/sport/world-records-attempts/

This event is held late September every year and has FIM and AMA classes just like Bonneville.

The runway is 3 km long.

These are the FIM records you can enter.

- the quarter mile with a standing start;
- the quarter mile with a flying start;
- the 1 kilometer with a standing start;
- the 1 kilometer with a flying start
- the 1 mile with a standing start

[wobbly]

The latest VeeForce 4 for the Banshee fits all the Yamaha variants such as LC , YPVS etc as well as Blaster with the same bolt pattern..
It has as much area as can be jammed in , flows more than all the previous versions ( not always the case with newer VF versions ) and has an integral stopper plate.
What you are being told by EngMod about the port and petal curtain areas is simply the dimensions you have entered.
In many cases bigger does not translate into better power.


An example is the CPI cylinders for the Banshee .One version has reed boxes to fit the 68mm wide CR250 cages , but to fit these in the box is offset 8mm outward - giving
tons of port area but asymmetric flow into the case.
Fitting 60mm CR125 reeds back on the cylinder center line with a spacer down the side ,according to the numbers should have made less power.
But in fact made far more mid range and equal top end.
Smaller reeds ( especially VeeForce ) simply stay open longer at high rpm, and the increased velocity in the mid makes better power in many cases.
This setup was modeled very well in EngMod , but the extra power gained by the symmetric inlet could not be factored in.

[TZ350]

now I have time to build a proper engine with my 100% width exhaust port cylinder on it.
Going to run on nitromethanol, efi, throttle slide part of the rotary valve cover.
Variator transmission electronically controlled. Need to read up on the do's and don'ts with fuel injection.

From my experience with two stroke fuel injection. For a high reeving 2T, staged injection into the B ports and Alpha-N mapping (TPS vis RPM) would be the ticket for drag racing and all out speed events on full throttle. Running Alcohol rich sure helps smooth out mixture requirements. But you could run into trouble trying to feather the throttle like you would Road Racing. Due to unstable pipe resonance/air flow at part throttle.

A thread I started about my 2T EFI adventures:- https://www.kiwibiker.co.nz/forums/showthread.php/185773-Speeduino-2T-EFI-Project

My pick is that EFI with Alcohol (need proper Alcohol injectors other wise the rust and internal short circuiting will kill the injector) and Nitro is eminently doable and EFI is much easier to get right for max power at WOT than a carb.

[adegnes]

what a shame "rain stopped play", seems like you were having to rush with the build i thought, but with a longer period to build again i would have more confidence that you could come away with something... :2thumbsup

Yep, was a bummer. Had a great time regardless though.
Absolutely, was really pressed for time this year.


Mmmmm, throttle slide on the RV housing, EFI, good choices.
Wonder where I got the idea from...


For next year it might be worth looking at the FIM sanctioned event at Elvington in the North of England.

http://www.fim-live.com/en/sport/sport/world-records-attempts/

This event is held late September every year and has FIM and AMA classes just like Bonneville.

The runway is 3 km long.

These are the FIM records you can enter.

- the quarter mile with a standing start;
- the quarter mile with a flying start;
- the 1 kilometer with a standing start;
- the 1 kilometer with a flying start
- the 1 mile with a standing start

Cool!


From my experience with two stroke fuel injection. For a high reeving 2T, staged injection into the B ports and Alpha-N mapping (TPS vis RPM) would be the ticket for drag racing and all out speed events on full throttle. Running Alcohol rich sure helps smooth out mixture requirements. But you could run into trouble trying to feather the throttle like you would Road Racing. Due to unstable pipe resonance/air flow at part throttle.

A thread I started about my 2T EFI adventures:- https://www.kiwibiker.co.nz/forums/showthread.php/185773-Speeduino-2T-EFI-Project

My pick is that EFI with Alcohol (need proper Alcohol injectors other wise the rust and internal short circuiting will kill the injector) and Nitro is eminently doable and EFI is much easier to get right for max power at WOT than a carb.

Thanks, been reading up.
My variator setup should make things even "easier" as I only need to
worry about one rpm point at a pretty much constant load.

Question, is there a 16krpm hard limit in the ecotron efi unit?
Someone sent me a complete kit a few years ago.

[JanBros]

My variator setup should make things even "easier" as I only need to
worry about one rpm point at a pretty much constant load.


a bit simplistic no ?

clutch engages and vario does noting until you reach the rpm of max torque
vario goes open and keeps the engine at rpm of max torque until the vario is at the end of it's range
then the rpm rises again to max power rpm.

a very small power-band will cost you a lot of speed. or a lot of clutches :msn-wink:

[41juergen]

3 mm aux-main according to this.

Andreas, would you have also the rest of the manual?
cheers
Juergen

[adegnes]

a bit simplistic no ?

clutch engages and vario does noting until you reach the rpm of max torque
vario goes open and keeps the engine at rpm of max torque until the vario is at the end of it's range
then the rpm rises again to max power rpm.

a very small power-band will cost you a lot of speed. or a lot of clutches :msn-wink:

Try this:
1. Clutch engages, variator does nothing until peak power rpm.
2. Electronically controlled linear actuator(of some kind) continuously adjusts spring tension to make variator stay at peak power rpm regardless of heat, belt stretch, etc. while it's climbing through the "gears".
3. Variator stays at peak power rpm indefinitely cause final ratio is higher than what can be reached with available power.

What I'm hoping to achieve anyway.

Completely off topic:
At 18000rpm with 145/90 timing the intake is closed for about 1.16ms during one revolution - that's a very small window of time for the intake charge to slow down, stop, then start accelerating in the opposite direction.
I think you know where I'm going with this...

[andreas]

Andreas, would you have also the rest of the manual?
cheers
Juergen

Sorry, just have this image.

[TZ350]

Question, is there a 16krpm hard limit in the Ecotron efi unit?
Someone sent me a complete kit a few years ago.

Yes, there seems to be some sort of limit. Speedpros turbo twin (18,000 rpm) four stroke would never go over 16,000 rpm with his Ecotrons unit.

Ecotrons turn off the VE table of their four stroke EFI firmware so that only the Alpa-N table is active and sell that as their two stroke EFI version.

My single cylinder two stroke was naturally limited to less than 13,000 rpm so I never found out if that 16k limit applied to two strokes.

My opinion, for what it is worth:-

I found Ecotrons help dept unable to help very much with experimental two stroke tuning and is the main reason I moved onto another EFI system that I could modify for myself.

At 16k two stroke rpm you are running into serious “Time” issues as you have only 3,75mS to get everything done and just opening/closing the injector takes up most of this time without delivering any fuel.

Assuming “B” port or case injection. The good news is, that because there is always carry over fuel from one cycle to another and it takes six or so crank revolutions to completely consume the cloud from any particular crankcase injection event it is possible to get away with averaging the fuel required over two cycles.

KTM take advantage of this cloud averaging for their staged injection by alternating their “B” port injectors side to side and when they need more injector capacity to cover the reduced time available at higher rpm they fire both “B” port injectors together.

I think that due to cloud averaging it would be possible at 16,000 rpm to fire twice the fuel required and spread it over two cycles and still have pretty much the correct air/fuel ratio in the cylinder all the time.

Staged injection. Roughly. The volume of fuel required each cycle at Idle is not much different to the volume required at peak torque. Just at peak torque less fuel is wasted. You don’t need the bigger injector at peak torque because you need more fuel than at idle. You need the bigger injector so you can deliver the same amount of fuel in the reduced amount of time available at higher RPM. Staged injection allows you to use a small injector at idle and reduced throttle and engine loads for refined fuel tuning and a bigger injector to get the job done at higher engine loads and rpm.

Because Methanol is so forgiving of rich mixtures and your going to basically run at WOT and high rpm I would consider using an Arduino Nano and write my own fuel injection firmware. You don’t need a lot of the refinements found in regular EFI systems.

Nitro carries slightly more fuel than oxygen. So if a motor is already jetted to run correctly and then you add Nitro through another jet, like a solenoid power jet the air/fuel ratio automatically gets richer. Nitro could be switched in/out as desired.

The inputs required for a basic EFI are fairly simple.

TPS … throttle position.
RPM … revs.
IAT … inlet air temperature.
Baro … barometric pressure.
LCT… liquid coolant temperature.

TPS and RPM for the Alpha-N fueling table that is used to predict engine load (air being consumed).
IAT and Baro for Air density.
LCT for fuel enrichment. Both when cold starting and enriching again when the engine starts operating in the golden zone and controlling the water pump for consistent engine temperature.

The Arduino Nano with some MosFet add on boards could easily handle all of this.

A Nano can easily count in steps of 4 millionths of a second without tricky coding. Not that you will require very accurate injection positioning. As with cloud averaging you will completely inject for the first cycle and part of the second so accurate positioning becomes a bit moot. But if you have a choice, the end point of injection is more important than the beginning. Making the end point at BDC or just before the transfers close seems to be best. Unlike a four stroke you don't need a complicated multi tooth wheel because you don't need to know which cylinder is up or down and who is next for a squirt of juice.

The EFI algorithm for Methanol can be quite simple. Fuel load is a math calculation based on air density and fuel required for the air consumed at the engine load as predicted in the Alpha-N table.

A simple fuel injection setup like this could easily compensate for changes in air temperature and elevation making tuning at home for all out WOT runs at Bonneville easy. No mucking about with carbs and jetting when you get there as the EFI system will have automatically adjusted for changes in environmental conditions with the on board IAT and Baro measurements.

As an aside, instead of being able to just predict air flow (Alpha-N) for a good drag at WOT. For road racing, due to changes in the pipe resonance effect at low throttle settings. To get good throttle response you have to actually measure changes in the air flow through the motor to keep the air/fuel ratio correct when trailing the throttle through a corner.

[wobbly]

One small point not to ignore - running Meth you need more than twice the fuel flow per injector on cycle.
So every part of the delivery system has to be sized to deliver this extra amount over petrol injection.

[peewee]

One small point not to ignore - running Meth you need more than twice the fuel flow per injector on cycle.
So every part of the delivery system has to be sized to deliver this extra amount over petrol injection.

then add in more than about 15% nitro and fuel demand starts to increase quit alot. with just meth i had one pj basically fully open. with 35% nitro i tried four pj fully open and it was just barely starting to get to rich.

there wasnt much trouble getting full throttle sorted out. was just a matter of turning all the pj full open then close them little by little until it ran good. but closed throttle and idle was a different story. i grinded my own needle in increments until it was rich enough at idle but when the throttle shut after full throttle ,the rpm would run away for several seconds, althought it sounded scary, it never seized. . all the while i was fighting a flooding crankcase at idle so im not sure if richening the needle further would of helped the run on. perhaps it would of helped but the crankcase flooding would of been even worse im sure. i did find a simple solution to the run on, after throttle closes just wait a few seconds before pulling in the clutch. this prevented the piston from running away, while giving the crankcase time to refill with fuel. for a standard gearbox it worked great but that method likely wont work if you have a clutchless gear box that cant tolerate a load on the coast side of the gear dogs. which is going to be my main problem with nitro in this yami twin. how will i stop the run on, without back loading the trans. but i love a good challenge so we'll see what happens when i get to that point

i wanted to try a hilborn mechanical injector but that requires a large pump, driven by the crankshaft or some other meens. alot of money and time to figure it out. special made pulleys and brackets. in the end, would it even work. fuck it. i didnt even want to try. ill keep the shitter lectron instead

i hope adegnes gets his idea working good

[flyonly]

Not sure if anyone has had a good look at this as an option or not. https://www.nanoefi.com


Sent from my iPhone using Tapatalk

[peewee]

forgot to mention fuel consumption of that particular engine [527cc single] was around 2.3L for 370meters with %35 mix. so yes the fuel system needs to be free flowing

[diesel62]

Not sure if anyone has had a good look at this as an option or not. https://www.nanoefi.com


Sent from my iPhone using TapatalkHere is an example
http://mdac.com.au/

And another

https://speeduino.com/wiki/index.php/Speeduino

[TZ350]

.
Of those three, the Speeduino is my pick because the firmware code is open source which means you can modify it to suit two stroke applications.

The other two are not as far as I can see open source and being aimed at four strokes you might have trouble adapting them to two stroke service.

If they tell you it is two stroke suitable the key is to ask "how do you measure air flow through the two stroke motor at part throttle?". Hint, it is not the same way as you would for a four stroke.

[TZ350]

then add in more than about 15% nitro and fuel demand starts to increase quit a lot. with just meth i had one pj basically fully open. with 35% nitro i tried four pj fully open and it was just barely starting to get to rich.


There is a big difference between nitro mixed into the methanol and nitro inducted separately to the methanol.

It might be worth trying the motor setup for methanol only and using a separate system for dropping nitro into the inlet when you need it. It could be as simple as a gravity feed system from a header tank with a valve that is opened by a re purposed auto lube oil pump cable at WOT. And if you want to go richer when the nitro is dropped in then mix a little extra meth with the nitro.

[peewee]

other than avoiding the crankcase flooding, what could be the benefits of introducing nitro seperate ? seems like it would be a bit more tricky to tune the full throttle aswell, since there would be a jet for the meth and perhaps multiple jets for nitro. and how do you know how much nitro your feeding the engine ? im going with frits old saying, kiss :laugh:

[husaberg]

Bell said something like the comp ratio for Meth vs comp ratio for Nitrometh mix needs to be dropped a couple of whole numbers for what it could run on Meth alone.

[TZ350]

other than avoiding the crankcase flooding, what could be the benefits of introducing nitro separate ? seems like it would be a bit more tricky to tune the full throttle aswell, since there would be a jet for the meth and perhaps multiple jets for nitro. and how do you know how much nitro your feeding the engine ? im going with frits old saying, kiss :laugh:

Yes Kiss and Simple Benefits ..... totally agree. Introducing the nitro separate makes tuning simpler.

After you have got the methanol air/fuel mixture right adding nitro separately is simple because the extra nitro makes the in cylinder mixture slightly richer and meth likes rich. You can just keep adding nitro separately to your hearts content without having to adjust the previously correct methanol jetting. Because the methanol was adjusted to use up all the normally inducted oxygen and the nitro brings its own fuel and sufficient oxygen to burn most of it.

First you get a good Methanol party going then Nitro is like the perfect surprise "life of the party" guest who brings their own booze and food with a little extra for the table.

[pete376403]

i wanted to try a hilborn mechanical injector but that requires a large pump, driven by the crankshaft or some other meens. alot of money and time to figure it out. special made pulleys and brackets. in the end, would it even work. fuck it. i didnt even want to try. ill keep the shitter lectron instead

i hope adegnes gets his idea working good
The Hillborn and similar systems (Crower, there may be others) are pretty crude. Big pump as you say, and the fuel regulator is basically a variable restrictor on the tank return line. What doesn't go back to the tank goes into the engine. (the systems I have experience with, anyway - V8 speedway motors running methanol, and possibly "additives" if no-one is looking) WOT was the only parameter they cared about.

[husaberg]

The Hillborn and similar systems (Crower, there may be others) are pretty crude. Big pump as you say, and the fuel regulator is basically a variable restrictor on the tank return line. What doesn't go back to the tank goes into the engine. (the systems I have experience with, anyway - V8 speedway motors running methanol, and possibly "additives" if no-one is looking) WOT was the only parameter they cared about.

the BMS 1000 851 Steve Roberts framed bike bike ran a hilborn injection system not because it was great but because no one could tech the webber injection back then.
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[adegnes]

Yes, there seems to be some sort of limit. Speedpros turbo twin (18,000 rpm) four stroke would never go over 16,000 rpm with his Ecotrons unit.

Ecotrons turn off the VE table of their four stroke EFI firmware so that only the Alpa-N table is active and sell that as their two stroke EFI version.

My single cylinder two stroke was naturally limited to less than 13,000 rpm so I never found out if that 16k limit applied to two strokes.

My opinion, for what it is worth:-

I found Ecotrons help dept unable to help very much with experimental two stroke tuning and is the main reason I moved onto another EFI system that I could modify for myself.

At 16k two stroke rpm you are running into serious “Time” issues as you have only 3,75mS to get everything done and just opening/closing the injector takes up most of this time without delivering any fuel.

Assuming “B” port or case injection. The good news is, that because there is always carry over fuel from one cycle to another and it takes six or so crank revolutions to completely consume the cloud from any particular crankcase injection event it is possible to get away with averaging the fuel required over two cycles.

KTM take advantage of this cloud averaging for their staged injection by alternating their “B” port injectors side to side and when they need more injector capacity to cover the reduced time available at higher rpm they fire both “B” port injectors together.

I think that due to cloud averaging it would be possible at 16,000 rpm to fire twice the fuel required and spread it over two cycles and still have pretty much the correct air/fuel ratio in the cylinder all the time.

Staged injection. Roughly. The volume of fuel required each cycle at Idle is not much different to the volume required at peak torque. Just at peak torque less fuel is wasted. You don’t need the bigger injector at peak torque because you need more fuel than at idle. You need the bigger injector so you can deliver the same amount of fuel in the reduced amount of time available at higher RPM. Staged injection allows you to use a small injector at idle and reduced throttle and engine loads for refined fuel tuning and a bigger injector to get the job done at higher engine loads and rpm.

Because Methanol is so forgiving of rich mixtures and your going to basically run at WOT and high rpm I would consider using an Arduino Nano and write my own fuel injection firmware. You don’t need a lot of the refinements found in regular EFI systems.

Nitro carries slightly more fuel than oxygen. So if a motor is already jetted to run correctly and then you add Nitro through another jet, like a solenoid power jet the air/fuel ratio automatically gets richer. Nitro could be switched in/out as desired.

The inputs required for a basic EFI are fairly simple.

TPS … throttle position.
RPM … revs.
IAT … inlet air temperature.
Baro … barometric pressure.
LCT… liquid coolant temperature.

TPS and RPM for the Alpha-N fueling table that is used to predict engine load (air being consumed).
IAT and Baro for Air density.
LCT for fuel enrichment. Both when cold starting and enriching again when the engine starts operating in the golden zone and controlling the water pump for consistent engine temperature.

The Arduino Nano with some MosFet add on boards could easily handle all of this.

A Nano can easily count in steps of 4 millionths of a second without tricky coding. Not that you will require very accurate injection positioning. As with cloud averaging you will completely inject for the first cycle and part of the second so accurate positioning becomes a bit moot. But if you have a choice, the end point of injection is more important than the beginning. Making the end point at BDC or just before the transfers close seems to be best. Unlike a four stroke you don't need a complicated multi tooth wheel because you don't need to know which cylinder is up or down and who is next for a squirt of juice.

The EFI algorithm for Methanol can be quite simple. Fuel load is a math calculation based on air density and fuel required for the air consumed at the engine load as predicted in the Alpha-N table.

A simple fuel injection setup like this could easily compensate for changes in air temperature and elevation making tuning at home for all out WOT runs at Bonneville easy. No mucking about with carbs and jetting when you get there as the EFI system will have automatically adjusted for changes in environmental conditions with the on board IAT and Baro measurements.

As an aside, instead of being able to just predict air flow (Alpha-N) for a good drag at WOT. For road racing, due to changes in the pipe resonance effect at low throttle settings. To get good throttle response you have to actually measure changes in the air flow through the motor to keep the air/fuel ratio correct when trailing the throttle through a corner.

Thanks for the the advice!
I might try to make/modify something arduino based to suit my needs.
My constant load transmission should make for a really simple AlphaN map.

There's a few reasons I want to go EFI.

- As you stated it will self adjust to elevation/temp changes.

- I won't need a carb body hanging off the side of the engine - slide valve in the rotary valve cover.

- No vibration induced fuel foaming at higher rpm(float carbs)

- "ram air" should be possible/easier to do.





One small point not to ignore - running Meth you need more than twice the fuel flow per injector on cycle.
So every part of the delivery system has to be sized to deliver this extra amount over petrol injection.


then add in more than about 15% nitro and fuel demand starts to increase quit alot. with just meth i had one pj basically fully open. with 35% nitro i tried four pj fully open and it was just barely starting to get to rich.

there wasnt much trouble getting full throttle sorted out. was just a matter of turning all the pj full open then close them little by little until it ran good. but closed throttle and idle was a different story. i grinded my own needle in increments until it was rich enough at idle but when the throttle shut after full throttle ,the rpm would run away for several seconds, althought it sounded scary, it never seized. . all the while i was fighting a flooding crankcase at idle so im not sure if richening the needle further would of helped the run on. perhaps it would of helped but the crankcase flooding would of been even worse im sure. i did find a simple solution to the run on, after throttle closes just wait a few seconds before pulling in the clutch. this prevented the piston from running away, while giving the crankcase time to refill with fuel. for a standard gearbox it worked great but that method likely wont work if you have a clutchless gear box that cant tolerate a load on the coast side of the gear dogs. which is going to be my main problem with nitro in this yami twin. how will i stop the run on, without back loading the trans. but i love a good challenge so we'll see what happens when i get to that point

i wanted to try a hilborn mechanical injector but that requires a large pump, driven by the crankshaft or some other meens. alot of money and time to figure it out. special made pulleys and brackets. in the end, would it even work. fuck it. i didnt even want to try. ill keep the shitter lectron instead

i hope adegnes gets his idea working good


forgot to mention fuel consumption of that particular engine [527cc single] was around 2.3L for 370meters with %35 mix. so yes the fuel system needs to be free flowing


Yeah, I remember when I was experimenting with 30% nitro RC fuel.
On gas I ran a 110 main and 55 pilot, on RC fuel I ran 2.5mm main, 1.5mm pilot, drille out the pilot circuit, and a 1mm powerjet fully open.
Unburnt fuel was dripping out the exhaust at peak power.
Consumed about 1l in two dyno pulls.


There is a big difference between nitro mixed into the methanol and nitro inducted separately to the methanol.

It might be worth trying the motor setup for methanol only and using a separate system for dropping nitro into the inlet when you need it. It could be as simple as a gravity feed system from a header tank with a valve that is opened by a re purposed auto lube oil pump cable at WOT. And if you want to go richer when the nitro is dropped in then mix a little extra meth with the nitro.

I really like this solution but can't get pure nitro in Norway.
Fractional distillation of RC fuel is a possibility, but probably quite hard as the boiling point of nitro is very close to methanol.
Also Norwegian authorities wouldn't be too happy about it...

My break at work is over, I'll be back

[peewee]

Bell said something like the comp ratio for Meth vs comp ratio for Nitrometh mix needs to be dropped a couple of whole numbers for what it could run on Meth alone.

i believe its common practice to drop com ratio. ive no idea what the perfect com ratio is for a given nitro percent [i guess it would depend on many factors] but i droped mine from 16 to 12.5:1 just to be on the safe side. perhaps i went to far. i dont know

[adegnes]

i believe its common practice to drop com ratio. ive no idea what the perfect com ratio is for a given nitro percent [i guess it would depend on many factors] but i droped mine from 16 to 12.5:1 just to be on the safe side. perhaps i went to far. i dont know

I remember doing calculations(with numbers I can't remember) and ending up with 30/70 nitro/methanol roughly needing the same comp as pump gas.

Probably something crude like this:
(70%methanol x 18:1 compression) + (30%nitro x 6:1 compression) = 14.4:1

[adegnes]

Just thinking out loud here.

I might go no-intake-valve with this engine.
It's ment to run at a very narrow rpm range, should be possible to tune the intake duct to suit. Probably needs to be quite long - a good thing. Isolating the carburetor from vibration would be easy with a long softish rubber spigot.
Intake could be typical reed style behind the Cport pointing forward.(upside down engine)
Maybe I won't have to dive into Efi after all.
Could use a super simple flat reed block that pulls out of the way when on the pipe. Like a flat slide with reeds.

I would have room for a magneto ignition once again, something fierce that can cope with the alcohol/nitro, wouldn't have to be programmable either.

Like that one speed no intake old engine, going forward by going backwards...

Have to get this modeled up and see what intake length would work.

[Flettner]

or run vairable rotary valve housing on one side of the crank case, and just a butterfly valve ditect into the other side, only opens at full throttle. A straight in hole, when the butterfly valve is open. Both sides of the crankcase get feed.

[adegnes]

or run vairable rotary valve housing on one side of the crank case, and just a butterfly valve ditect into the other side, only opens at full throttle. A straight in hole, when the butterfly valve is open. Both sides of the crankcase get feed.

Yeah!
Only problem is it would make for a wider engine than with the "central" intake.
How about a small reed intake on the exaust side + a huge slide valve on the opposite side?
Would require injection or two carbs, but actually less complicated than the sliding reed thing. The big carb could be without a slide, no throttle control.
The small carb could be fed gasoline to get things going, then the big carb/injection would switch over to nitromethanol at wot.
Maybe not so good for cooling... Would make purging a breeze.

[SwePatrick]

Respect Adegnes,, you sure pick a lot of fights to fight.
Almost that i wonder if you have a fetish to get beaten again and again. =)

[adegnes]

With my one rpm constant load engine and a small carb taking care of of everything except WOT, efi could be REALLY simple couldn't it?
Just one injector in the intake duct, duty cycle controlled by temperature and air density.
No timing or anything.

[adegnes]

Respect Adegnes,, you sure pick a lot of fights to fight.
Almost that i wonder if you have a fetish to get beaten again and again. =)

Haha, thanks! I think I do.
Learnt a lesson this year at Bonneville though, even if the event was canceled
- Win the fights before you get there!

[yatasaki]

Yeah!
Only problem is it would make for a wider engine than with the "central" intake.
How about a small reed intake on the exaust side + a huge slide valve on the opposite side?
Would require injection or two carbs, but actually less complicated than the sliding reed thing. The big carb could be without a slide, no throttle control.
The small carb could be fed gasoline to get things going, then the big carb/injection would switch over to nitromethanol at wot.
Maybe not so good for cooling... Would make purging a breeze.
Reminds me on this engine
Hope you'll go step by step. Personal would go for100% exhaust working. Rest issues are more or less fixable.

[TZ350]

With my one rpm constant load engine and a small carb taking care of of everything except WOT, efi could be REALLY simple couldn't it?
Just one injector in the intake duct, duty cycle controlled by temperature and air density. No timing or anything.

Good idea Adegnes, I like it.

The carb could be a small but suitable size to get the engine up to speed and at the right RPM and WOT you could open a 24/7 inlet and have an injector squirt a predetermined amount of extra fuel. At 15,000 rpm the fuel might have to be delivered over two crank cycles to give the injector enough time to open, deliver a measured amount of fuel and close again.

The injector could be running a different fuel (say 30% nitro/methanol) to the carb which could be running plain Av gas.

A simple Arduino Nano could easily be trained to watch the rpm and throttle and open a 24/7 inlet at the right time and squirt a fixed amount of extra fuel.

343324

I am building a F5 50cc road race engine that is just begging for a down draft resonant tuned length 24/7 inlet.

You have got me thinking about how I could apply your idea to my bike ..... :yes: ... it would solve a few EFI problems and with a tuned inlet length, add a bunch of power.

[adegnes]

Good idea Adegnes, I like it.

The carb could be a small but suitable size to get the engine up to speed and at the right RPM and WOT you could open a 24/7 inlet and have an injector squirt a predetermined amount of extra fuel. At 15,000 rpm the fuel might have to be delivered over two crank cycles to give the injector enough time to open, deliver a measured amount of fuel and close again.

The injector could be running a different fuel (say 30% nitro/methanol) to the carb which could be running plain Av gas.

A simple Arduino Nano could easily be trained to watch the rpm and throttle and open a 24/7 inlet at the right time and squirt a fixed amount of extra fuel.

You have got me thinking about how I could apply your idea to my bike ..... :yes: ... it would solve a few problems and with a tuned inlet, add a bunch of power.

Thanks!
Exactly, and in my case that nano could take care of variator control(tensioning the belt) with a linear actuator too.

Got to clean up the garage and start working!

[speedpro]

Or you could simply open the injector, and run it at 100% duty cycle, at the same time as the inlet and have the fuel flow controlled by an adjustable rising rate fuel pressure regulator. In other words the injector would be an on/off tap and the adjustable fuel pressure used to control fuel flow.

[F5 Dave]

Or create a pool of petrol and resting in it a wick you could raise or lower in the airstream.

Whoops, wrong century.

[adegnes]

Or create a pool of petrol and resting in it a wick you could raise or lower in the airstream.

Whoops, wrong century.


:killingme

[andreas]

First up, sorry for it being sooo long since my last post.
My YouTube channel kinda blew up and I'm having a hard time keeping up with just the mails, messages etc.
I know there's a few pm's I haven't gotten to here also.

With my limited experience in diy plating most epoxies, suitable for cylinder work or not, would survive a strip+replate pretty well.

Anyways.
Currently at the airport in Denver Colorado, on my way back from my first attempt at racing at Bonneville Speedway(event got canceled, rain)
We had a great time regardless, and now I have time to build a proper engine with my 100% width exhaust port cylinder on it.
Going to run on nitromethanol, efi, throttle slide part of the rotary valve cover.
Variator transmission electronically controlled.
Need to read up on the do's and don'ts with fuel injection.

A747 is genius on piston wear but I have some concerns about it's bearing properties. Might be nonsense, but to see your big end give in I thought I'd mention it.

[ken seeber]

With my one rpm constant load engine and a small carb taking care of of everything except WOT, efi could be REALLY simple couldn't it?
Just one injector in the intake duct, duty cycle controlled by temperature and air density.
No timing or anything.

Here's what some guy in Oz did (with success ?) ages ago. It is a 125 cc BSA Bantam. From memory, the 2 carbs opened simultaneously rather than being staged.

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[lohring]

Model engines running high nitro fuels have run a simple "injection"system for years. Pipe pressure is fed to a sealed tank. Often we run a hopper tank that's always full to offset the effects of fuel sloshing, especially in high G turns and rough water. The output from the tank runs through a flow valve. This valve can be radio controlled to adjust the mixture on the fly. We mostly run either at idle or wide open so subtle flow control isn't needed. Some "carbs" have a low speed adjustment to help. As the power goes up the pipe pressure rises, delivering more fuel. The methanol based fuels aren't very mixture sensitive, especially on the rich side.

Lohring Miller

Tank & pressure line
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Remote flow valve
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[Frits Overmars]

Model engines running high nitro fuels have run a simple "injection"system for years. Pipe pressure is fed to a sealed tank. Often we run a hopper tank that's always full to offset the effects of fuel sloshing, especially in high G turns and rough water. The output from the tank runs through a flow valve. This valve can be radio controlled to adjust the mixture on the fly.We use the same system for F3D model pylon race planes. These don't use nitro at all (forbidden), just 80% methanol and 20% (yes, that greasy!) oil.
The fuel is contained in a bladder in the tank. Exhaust pipe pressure administered between the tank and bladder walls squeezes the fuel from the bladder to the inlet.

There have been experiments with radio-controlled needle jets, but more than one pilot had to regret his greed when he tried to squeeze the last couple of revs out of the engine and was punished with detonation that blew his glow plug away.

This system is quite sensitive to the tank position, as the centrifugal force in the corners can strongly influence the fuel flow. Measuring the magnitude of this centrifugal force failed because the g-force sensors that we used, couldn't register more than 36 g...

[Flettner]

This system is quite sensitive to the tank position, as the centrifugal force in the corners can strongly influence the fuel flow. Measuring the magnitude of this centrifugal force failed because the g-force sensors that we used, couldn't register more than 36 g...[/QUOTE]

Hahaha Wow.

[Frits Overmars]

This system is quite sensitive to the tank position, as the centrifugal force in the corners can strongly influence the fuel flow. Measuring the magnitude of this centrifugal force failed because the g-force sensors that we used, couldn't register more than 36 g...
Hahaha Wow.Which makes me wonder: what kind of g-forces can an autogiro generate? I suppose you won't need to wear a g-suit..

[lohring]

Even slower model boats I've data logged can pull close to 4 Gs in the turns with +- 1 G vertical accelerations even in smooth water. I bet high performance model boats pull closer to double that from my experiences with bent turn fins. Frits, you hit on the problem with radio controlled valves. However, unlike airplanes, boats don't run under load until they're launched. That makes it harder to find the right needle setting.

Lohring Miller

[Frits Overmars]

... unlike airplanes, boats don't run under load until they're launched.That would call for something like a tuning bucket, wouldn't it?
However, I'm not sure that immersing the boat propeller in some basin would sufficiently imitate track conditions, as playing with airplanes taught me that the propeller is somewhat unloaded when the plane comes up to speed. You can hear it in the video below: the engine is running WOT all the time, but the plane needs about a full lap for the revs to build up and stabilize.
http://www.youtube.com/watch?v=5aBCQGq5Al4

[F5 Dave]

Geez they don't rev very high do they? :lol:

It also strikes me as um, potentially somewhat dangerous?
:clap:

[adegnes]

You wouldn't want the pilot suddenly realizing you slept with his wife!

[teriks]

Geez they don't rev very high do they? :lol:

It also strikes me as um, potentially somewhat dangerous?
:clap:
Saw 34krpm on the logger at the wc this year. Surprised the rod stayed in one piece.
Prefer to peak close to 33krpm so "geared up" with a heavier prop.

[husaberg]

Saw 34krpm on the logger at the wc this year. Surprised the rod stayed in one piece.
Prefer to peak close to 33krpm so "geared up" with a heavier prop.

I assume they just run plain bronze bushed big and little ends, is that right?

[peewee]

343016 343017 343018

These are hardened steel washers from a Suzuki RGV250. 0,010" side clearance (0,254mm). Very close slip fit on the pin and no appreciable grooving of the pin after hours of service. These washers are used to centralize the rod when no big end washers are being used. I have seen steel and hard anodized aluminium in Yamaha KT100 cart engines. I was not that impressed with the life of the alloy KT100 ones. I would think washers made out of any good quality steel would be fine. I don't think hardening would be all that necessary for a short run competition engine.

eh mate i got around to making the washers. ctankshaft and lower rod still have a bit of side float but atleast the small bearing wont be able to walk around off center as much.

[Frits Overmars]

Geez they don't rev very high do they? It also strikes me as um, potentially somewhat dangerous?
You wouldn't want the pilot suddenly realizing you slept with his wife!Dave, you're right: they don't rev very high. Maximum power comes at around 32.000 rpm and maximum revs are around 35.000 rpm, which, with a 19 mm stroke, works out at a mean piston speed of 22,2 m/s. If these little screamers were to equal the piston speed of an Aprilia RSA with 54,5 mm stroke and 14.500 max.rpm, they ought to rev to 41.600 rpm. Imagine what that would sound like.

Dangerous? Noticed the guy wearing the white ear protectors in the video? That's me, staying close to the pilot, which is definitely the safest place.
Those F3D pilots are supposed to fly around three pylons and they don't want to lose time making detours, so sometimes they cut corners, literally.
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[teriks]

I assume they just run plain bronze bushed big and little ends, is that right?
On the big end yes, the small end run directly in the aluminium rod, no bushing.

[Frits Overmars]

I assume they just run plain bronze bushed big and little ends, is that right?Yep. There have been attempts to make caged big end bearings, but no joy there yet. On the other hand, the main bearings are hybrid.
Cages and outer races from conventional ball bearings are being used, the inner bearing races are ground directly on the crankshaft, and ceramic balls are fitted.
Expensive? Nea. The nine balls cost one Euro a piece and these bearings have eternal life.
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[lohring]

Jim Allen has experimented with rod big end bearings in high rpm model engines. The rod big end is the weak link in all high power engines. My article on the subject is Big End Blues (http://namba.com/content/library/propwash/2012/April/#/11/). Below are some pictures of Jim's bearing. It uses a very high strength cage with two rollers per slot.

Lohring Miller

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[husaberg]

On the big end yes, the small end run directly in the aluminium rod, no bushing.


Yep. There have been attempts to make caged big end bearings, but no joy there yet. On the other hand, the main bearings are hybrid.
Cages and outer races from conventional ball bearings are being used, the inner bearing races are ground directly on the crankshaft, and ceramic balls are fitted.
Expensive? Nea. The nine balls cost one Euro a piece and these bearings have eternal life.


cheers

Jim Allen has experimented with rod big end bearings in high rpm model engines. The rod big end is the weak link in all high power engines. My article on the subject is Big End Blues (http://namba.com/content/library/propwash/2012/April/#/11/). Below are some pictures of Jim's bearing. It uses a very high strength cage with two rollers per slot.

Lohring Miller
L]

Nice
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[andreas]

70 bore 64.7 stroke 7mm squish width. What clearence will I want in standard MX form, and does it change with a higher bmep and rpm?

[TZ350]

What clearence will I want in standard MX form

You might have to dig through it to find what you want. I used the Google "site:" search term to find a whole lot of references to bore and squish on the ESE thread.

Bore Squish site:https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner

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[andreas]

Thanks TZ. p1805 seems to cover it.

[marsheng]

70 bore 64.7 stroke 7mm squish width. What clearence will I want in standard MX form, and does it change with a higher bmep and rpm?

I think the general rule is 1% of the stroke. This would be .65 to .7 mm. I run 0.8 on my Maico 250 with a 70 mm stroke. Added a bit for safety. If the piston is clean around the squish area, then its roughly right.

[Michael Moore]

On GrabCAD I found a model of an Aprilia RSA cylinder

https://grabcad.com/library/cilindro-aprilia-rsa-1

It seems very detailed, to a point where I suspect the modeler had a cylinder on hand to work with, rather than just making something that looked reasonably close to photos. Has anyone else looked at this model and been able to check it for validity/accuracy?

There's also an assembly with crankshaft/cylinder head/piston and exhaust that can be downloaded with the cylinder model.

cheers,
Michael

[monkeyfumi]

Unless it has been updated, there is an error in that model, the aux ex ducts break through.

(Edit: having a closer look, that may have been fixed)

[Michael Moore]

The ex ports seem pretty contiguous surfaces to me other than what I presume is the hole for the power valve in the main port.

[Frits Overmars]

On GrabCAD I found a model of an Aprilia RSA cylinder
https://grabcad.com/library/cilindro-aprilia-rsa-1
It seems very detailed, to a point where I suspect the modeler had a cylinder on hand to work withNever mind the details Michael, it's not an Aprilia RSA cylinder at all, no matter what it says on that site.
It's an RSW cylinder (left), very different from an RSA cylinder (right, by GighenZz Marco).
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[Frits Overmars]

The ex ports seem pretty contiguous surfaces to me other than what I presume is the hole for the power valve in the main port.Some more GighenZz Marco-pictures:
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[Michael Moore]

Frits, is it known how accurate the RSW cylinder model is? If it is only a "looks sorta like this" cosmetic model then I won't put a lot of time into trying to glean any information from it.

[Frits Overmars]

Frits, is it known how accurate the RSW cylinder model is? If it is only a "looks sorta like this" cosmetic model then I won't put a lot of time into trying to glean any information from it.I haven't got a clue Michael. I don't know who made it and I would have to "put a lot of time into trying to glean any information from it", as you describe so aptly, before I could say anything about it.

[lohring]

Could this be the model used by VD Jimenez at the University of Valencia To produce this CFD movie of the Aprilia cylinder?

Lohring Miller

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[koenich]

Does anyone have or can find the full thesis? Tried to google it but no luck...

[jamathi]

Does anyone have or can find the full thesis? Tried to google it but no luck...

The actual cylinders were made without any such studies.
So it is only backward engineering......
A whole LOT easier!!!
And not very useful when making a cylinder.
Fairly useless, but that is how you get a Doctor's title….

[Frits Overmars]

Could this be the model used by VD Jimenez at the University of Valencia To produce this CFD movie of the Aprilia cylinder?
Does anyone have or can find the full thesis? Tried to google it but no luck...Yep, but it's too big to upload here. Try googling for Tesis Doctoral VDJiménezInPress_Version3.pdf

[jbiplane]

Not sure if anyone has had a good look at this as an option or not. https://www.nanoefi.com


This guy in apha stage for years and years...
The open project https://rusefi.com/forum/
much better and based on ARM processor. Many Speeduino contributors moving to RusEFI


Could this be the model used by VD Jimenez at the University of Valencia To produce this CFD movie of the Aprilia cylinder?
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Ansys Fluent have tutorial how setup CFD for scavenging. Very detailed. But it is very time consuming.

[lohring]

That article is the only study I have found that gives a clue about flow in a tuned pipe engine. It's helpful for visualization, but there's nothing like an inertial dyno for studying scavenging's effects. Power is a very sensitive measure of scavenging efficiency. Blair used 3D printed cylinders in a single revolution test engine to study scavenging. Is this still more useful than CFD? It just takes a lot of time to study small cylinder changes in real, running engines. I'm interested in any ideas.

Lohring Miller

PS I can't find the paper by googling Tesis Doctoral VDJiménezInPress_Version3.pdf or various variations.

[Frits Overmars]

I can't find the paper by googling Tesis Doctoral VDJiménezInPress_Version3.pdf or various variations.This is the best I can do at the moment Lohring.
343415

[Michael Moore]

try this

https://riunet.upv.es/bitstream/handle/10251/30773/TesisDoctoralVDJim%C3%A9nezInPress_Version3.pdf

[TZ350]

This guy in apha stage for years and years...
The open project https://rusefi.com/forum/
much better and based on ARM processor. Many Speeduino contributors moving to RusEFI


Thanks. I will check it out....:niceone:

[jbiplane]

Hi guys. I asked here a lot and always got good ideas. At the moment I looking for my projects lightweight 85...180cc liquid cooled cylinders kits (cylinder, piston, pin rings) which are nicasil or coated, nonexpensive and easy to buy in quantity. Without power valve, and better without intake on cylinder. It should not be too powerfull.

I want to have from this cylinder 20 hp+ at about 9500 rpm with rather small exhaust. At moment found only Yamaha Yz85 and Gilera Runner 180. BTW YZ85 cylinder weiight more than 180cc pf Runner! Both possible buy in China for below 100 USD. Nicasil is not a must, weight should be minimal. May be exists intermediate variants? If no good variant I'll produce by myself if will got good reference.

[katinas]

Hi guys. I asked here a lot and always got good ideas. At the moment I looking for my projects lightweight 85...180cc liquid cooled cylinders kits (cylinder, piston, pin rings) which are nicasil or coated, nonexpensive and easy to buy in quantity. Without power valve, and better without intake on cylinder. It should not be too powerfull.

I want to have from this cylinder 20 hp+ at about 9500 rpm with rather small exhaust. At moment found only Yamaha Yz85 and Gilera Runner 180. BTW YZ85 cylinder weiight more than 180cc pf Runner! Both possible buy in China for below 100 USD. Nicasil is not a must, weight should be minimal. May be exists intermediate variants? If no good variant I'll produce by myself if will got good reference.

Hi,
Rotax max junior 125 cc cylinder with intake on cylinder, but with friendly to piston small center intake window and two big passages directly to B trans. One exhaust window without power valve. For testing you can find many cheap used cylinders in good conditions.

https://www.ebay.co.uk/itm/Rotax-max-junior-mini-max-barrel-head-and-head-cover-year-2002-Go-kart/163909285654?_trkparms=aid%3D1110001%26algo%3DSPLI CE.SIM%26ao%3D1%26asc%3D20131231084308%26meid%3D5c 58ce6638a54d4c91dcda993e3cb0e5%26pid%3D100010%26rk %3D1%26rkt%3D12%26sd%3D323942711221%26itm%3D163909 285654%26pmt%3D0%26noa%3D1%26pg%3D2047675&_trksid=p2047675.c100010.m2109

https://www.rotax-kart.com/upload/files/5370.pdf

[andreas]

try this

https://riunet.upv.es/bitstream/handle/10251/30773/TesisDoctoralVDJim%C3%A9nezInPress_Version3.pdf

Sagrado cabrón

[SwePatrick]

I just had to test the 3d printer at work =)

343423

[flyincat]

By looking at the piston.

343420

Hi Jan, I apologize for digging up an old post, but the picture of the piston you posted had me wondering. Your reply, and picture, were in regards to how you can tell if flow is attaching to transfer walls. My question is on the piston pattern. The piston you posted doesn't have a clean band around the outer diameter. The clean outer band seems to be common with super tight squish. Does the pattern you posted come from a tight squish motor? Similar to reading a spark plug, how much can we ACTUALLY tell about an engine by looking at the piston burn pattern? Example: BLACK = HOT. Can we tell much more than that if we start factoring all the variables (Jetting, fuel type, port radial, port axial, piston shape, head shape, etc....) and interactions?

Here are a couple of google searched piston wash charts. Clearly these scales are 'characteristic' of different engine configurations. Is there anything we can tell about these engines?

343421 343422

[Frits Overmars]

BLACK = HOTOr not. I've seen pistons that developed a clean spot in the center of the dome, where apparently the soot had been burned off.
The more power the engine produced, the bigger the diameter of that clean center spot.

[flyincat]

I just had to test the 3d printer at work =)



That is awesome! What material was that printed with? Did you have to use supports? If so, do you have any pictures with supports?

[SwePatrick]

That is awesome! What material was that printed with? Did you have to use supports? If so, do you have any pictures with supports?

I used something called 'tough pla' and used an Ultimaker printer with 'cura' software.
It generates the supports it self if clicked.

343424343425

[katinas]

And 3D pistons

https://additivemanufacturingtoday.com/frustum-announces-release-of-truesolid-3d-volumetric-kernel-for-generative-design

[jbiplane]

Rotax max junior 125 cc cylinder
https://www.rotax-kart.com/upload/files/5370.pdf
Thanks for an idea extend search and estimate cart engine cylinders!

[jamathi]

343420

Hi Jan, I apologize for digging up an old post, but the picture of the piston you posted had me wondering. Your reply, and picture, were in regards to how you can tell if flow is attaching to transfer walls. My question is on the piston pattern. The piston you posted doesn't have a clean band around the outer diameter. The clean outer band seems to be common with super tight squish. Does the pattern you posted come from a tight squish motor? Similar to reading a spark plug, how much can we ACTUALLY tell about an engine by looking at the piston burn pattern? Example: BLACK = HOT. Can we tell much more than that if we start factoring all the variables (Jetting, fuel type, port radial, port axial, piston shape, head shape, etc....) and interactions?

Here are a couple of google searched piston wash charts. Clearly these scales are 'characteristic' of different engine configurations. Is there anything we can tell about these engines?

343421 343422

Squish was 0,75mm
Less gave much more power until 12500, but did not rev any further.
The 'clean' spots is were detonation usually begins....
They are a sign of turbulence I think
We succeeded to keep them to a minimum!!
There was no detonation on the dyno, never.
But severe detonation occurred at high rpm and small throttle openings, like 30%.
Due to insufficient piston cooling!

[katinas]

Thanks for an idea extend search and estimate cart engine cylinders!

Forget to write that this cylinder weight is 1349 g. maybe this is important.

[jasonu]

I just had to test the 3d printer at work =)

343423

Nice Knipex!!!

[ceci]

The actual cylinders were made without any such studies.
So it is only backward engineering......
A whole LOT easier!!!
And not very useful when making a cylinder.
Fairly useless, but that is how you get a Doctor's title….



If this type of study was used to create real cylinders (at least Derbi itself)
In those years of backward engineering, it wasn't
were used to improve performance

https://upcommons.upc.edu/bitstream/handle/2099.1/2737/36813-3.pdf?sequence=3&isAllowed=y

[SwePatrick]

Nice Knipex!!!

Only the best ;)

Used it to pull out the support from the 3dprint.

[ceci]

If this type of study was used to create real cylinders (at least Derbi itself)
In those years of backward engineering, it wasn't
were used to improve performance

https://upcommons.upc.edu/bitstream/handle/2099.1/2737/36813-3.pdf?sequence=3&isAllowed=y




This is the study I was referring to


https://upcommons.upc.edu/bitstream/handle/2099.1/2737/36813-1.pdf?sequence=1&isAllowed=y

[jamathi]

This is the study I was referring to


https://upcommons.upc.edu/bitstream/handle/2099.1/2737/36813-1.pdf?sequence=1&isAllowed=y

Nothing new.
A description with scientific words about copying a Honda cylinder.....
Nothing else was ever done!!!!!
And they NEVER improved performance
They needed the help of a university for this shit.
The reality was that some Honda-team mechanic brought the latest Honda cylinder each year.
Against payment of course.....
A model maker was then flown in from Italy to copy the cylinder as quick as possible!
And the university of Valencia made their scientific explanation after the season....
In order to make someone a 'Doctor', without having done something useful.
The reality is that the university of Valencia NEVER contributed ANYTHING to engine development.


The Honda-500-4 instruction book was made in a way that it could not be foto copied.

[teriks]

Squish was 0,75mm
Less gave much more power until 12500, but did not rev any further.
The 'clean' spots is were detonation usually begins....
They are a sign of turbulence I think
We succeeded to keep them to a minimum!!
There was no detonation on the dyno, never.
But severe detonation occurred at high rpm and small throttle openings, like 30%.
Due to insufficient piston cooling!
Now this is bloody interesting.
I have always believed that those "clean" spots is where the transfer streams provide plenty of cooling.
After reading this, its easy to understand that there for sure could be lots of turbulence around the piston edge..

So, what keeps those areas clean looking then? More heat burning the deposits, like Frits more or less described? Very light deto?

Might have been better to shut up to avoid proving my stupidity ;)
Lucky me, have no throttle so at least don't have to worry about part throttle deto..

[Frits Overmars]

I have always believed that those "clean" spots is where the transfer streams provide plenty of cooling.... So, what keeps those areas clean looking then? More heat burning the deposits, like Frits more or less described? Very light deto?Deto will certainly remove the deposits off a piston crown, not unlike sandblasting. It's a pity that it will also remove the aluminium....

[lohring]

You can see color variation on this piston before detonation burned a hole in it. I think the black area was the hottest and the brown area was cooler. The black area was the exhaust side. It was running a high nitro methanol based fuel with around 20% oil. I think the oil was mostly synthetic, but could have had some castor oil.

Lohring Miller

343446

[katinas]

Maps on pistons from Honda RS 250 2002 manual.

[ceci]

Nothing new.
A description with scientific words about copying a Honda cylinder.....

The reality is that the university of Valencia NEVER contributed ANYTHING to engine development.


.


I thought the copy was from yamaha (by the exhaust valve)
It is not from the University of Valencia, it is from the University of Barcelona (greater connection with the factory because it is from the same city)

[TZ350]

.

Interesting bit of chat with the developer of the first successful TPi fuel injected two stroke:- https://www.drd.co.nz/2-stroke-tpi-conspiracy-theory/

This is the earliest reference that I could find to the original fuel injected Kawasaki BigHorn:- http://www.twostrokemotocross.com/forum/index.php?PHPSESSID=poltrhrtlirj5npjbl8bhb9nt0&topic=4884.15

A successful fuel injected YZ250 in 2012 and a VMX Kawasaki two stroke. They sure pre date KTM.

[Frits Overmars]

It is not from the University of Valencia, it is from the University of Barcelona (greater connection with the factory because it is from the same city)Really?
343451

[ceci]

Really?
343451

They are two studies:
The one you indicate, the first one, is from Valencia and is CFD in an aprilia cylinder.
The one that indicated, is from Barcelona and is FEM of a derbi cylinder, and was made in the middle of the competition season to improve the union with the cylinder head.

https://upcommons.upc.edu/handle/2099.1/2737

[peewee]

for anyone thats cut in boyesen ports on the yami twin. do you bother welding on any reinforcement to the rear outboard cyl ear to prevent cracking ? or its not a concearn ? maybe i should have reinforced that ear when doing all the other welding but i over looked it. now the final machining is done on the top and bottom decks, gasket thickness and cyl height position is sorted out. . even with bolting the cyl to a heat sink im not confident i could weld any reinforcement and not end up with alittle bottom deck distortion. part of me says go for it and it will be fine

[andreas]

Maybe someone can give some pointers cause I'm an electrical analfabet. in this Motoplat ignition where is the cdi, does it have a curve? Can I use this coil/cdi with a pick up rotor? Lastly will it work to rotate a pick up ignition the opposite way?

[Haufen]

They are two studies:
The one you indicate, the first one, is from Valencia and is CFD in an aprilia cylinder.
The one that indicated, is from Barcelona and is FEM of a derbi cylinder, and was made in the middle of the competition season to improve the union with the cylinder head.

https://upcommons.upc.edu/handle/2099.1/2737

PhD Thesis (Valencia) (https://riunet.upv.es/bitstream/id/79807/TesisDoctoralVDJiménezInPress_Version3.pdf)
Is there an english version, too?

[wobbly]

Motoplat ignitions are a nightmare to sort out.
All the early versions were straight line , but later they built in an analogue curve like PVL do by varying the source coil winding number.
The actual CDI is in the stator plate , unlike a PVL where its in the coil.
They have an arrow on the stator and only run one direction.
The coil/stator are a matched pair , for the straight line or retard stator.
I did have the serial numbers that identified a retard curve setup years ago, but sorry long gone.
Easy to distinguish though , as only two were made ,dead straight line and a retard curve - so can be strobed .

[andreas]

Many thank Wobbly.

[Muciek]

Here in eastern eu, back in the day (pre 1989) many ppl did swap motoplats to their racers and they can be run both sides (did that few years ago with two engines), You just need to time the ignition using strobe light . And the "cdi module " is in coil . Some ppl nowadays used coils with cdi from scooters (as spare part since finding original was hard) and it did worked , although there are differences in cdi schematics comparing motoplat and "ordinary cdi's" (thyristor is reversed the cathode is on current/voltage supply side ).
Coil inside photo.
343470

[breezy]

.

Interesting bit of chat with the developer of the first successful TPi fuel injected two stroke:- https://www.drd.co.nz/2-stroke-tpi-conspiracy-theory/

This is the earliest reference that I could find to the original fuel injected Kawasaki BigHorn:- http://www.twostrokemotocross.com/forum/index.php?PHPSESSID=poltrhrtlirj5npjbl8bhb9nt0&topic=4884.15

A successful fuel injected YZ250 in 2012 and a VMX Kawasaki two stroke. They sure pre date KTM.

ive just been surfing the net and it seems theirs a lot of 2 strokes making a come back with euro4 compliant engines.. inspired by the excellent development of fuel injection by you know who back in 2012....:2thumbsup:2thumbsup

[andreas]

Here in eastern eu, back in the day (pre 1989) many ppl did swap motoplats to their racers and they can be run both sides (did that few years ago with two engines), You just need to time the ignition using strobe light . And the "cdi module " is in coil . Some ppl nowadays used coils with cdi from scooters (as spare part since finding original was hard) and it did worked , although there are differences in cdi schematics comparing motoplat and "ordinary cdi's" (thyristor is reversed the cathode is on current/voltage supply side ).
Coil inside photo.
343470

Haha, you had me lost at "the thyristor is reversed". well the plan was to buy a swedish made SEM rotor/stator (outer) that has a light source, and I believe will fit my engine physically, then use my spark coil wich is -91. You think it will be worth a try? The coil looks like the one I posted so it might not be the same.

[Flettner]

ive just been surfing the net and it seems theirs a lot of 2 strokes making a come back with euro4 compliant engines.. inspired by the excellent development of fuel injection by you know who back in 2012....:2thumbsup:2thumbsup

Yes, GasGas are next.

[Muciek]

Haha, you had me lost at "the thyristor is reversed". well the plan was to buy a swedish made SEM rotor/stator (outer) that has a light source, and I believe will fit my engine physically, then use my spark coil wich is -91. You think it will be worth a try? The coil looks like the one I posted so it might not be the same.
I think it should work , the foto I posted is the same as yours, just different lighting on photo. If You have any questions about cdi You can pm me , will try to help with it.

[husaberg]

Many thank Wobbly.

pretty sure bells book shows the curve of the motoplat from a Rotax.
The look cool on a kawa three

[andreas]

I appreciate that Muciek.

[41juergen]

for anyone thats cut in boyesen ports on the yami twin. do you bother welding on any reinforcement to the rear outboard cyl ear to prevent cracking ? or its not a concearn ? maybe i should have reinforced that ear when doing all the other welding but i over looked it. now the final machining is done on the top and bottom decks, gasket thickness and cyl height position is sorted out. . even with bolting the cyl to a heat sink im not confident i could weld any reinforcement and not end up with alittle bottom deck distortion. part of me says go for it and it will be fine

I only added some JB weld were I came through the wall, but no welding and it holds since years now...

343472343473

[ceci]

PhD Thesis (Valencia) (https://riunet.upv.es/bitstream/id/79807/TesisDoctoralVDJiménezInPress_Version3.pdf)
Is there an english version, too?



I have no knowledge of whether it is in English.
Google translate translate pdf

[ceci]

Yes, GasGas are next.




The enduro model will be the same as Husqvarna.
The trial model how will it be?

[AndreasL]

KTM buys 60% of GasGas.

All ideas of why surfs the www at the moment.
Wonder what effect it will have in the end?
GasGas, with only 2 strokes in their lineup :headbang:, seems to offer quite a descent bike with a really good suspension as stock.
Don’t expect GG to keep the KYB if owned by KTM/WP. :no:

[JanBros]

Frits, here in your FOS data it says the squish angle in the RSA head is 8.17°

if I draw that in solidworks, that's the angle of the tangent line to the piston radius. but wasn't the squish paralel to the piston crown radius ?

and shouldn't the squish radius be 190.7 mm ?

[peewee]

I only added some JB weld were I came through the wall, but no welding and it holds since years now...

343472343473

im sure it would be ok. i filled in the void with weld so it doesnt break through but i overlooked any type of reinforcement . i suppose maybe it isnt needed

[peewee]

has you guys seen this engine before ? says its aussie invention but i never heard of it

https://motorbikewriter.com/aussie-two-stroke-invention/

[husaberg]

has you guys seen this engine before ? says its aussie invention but i never heard of it

https://motorbikewriter.com/aussie-two-stroke-invention/

its posted in the odballs thread its been on this one too i think.
https://www.kiwibiker.co.nz/forums/showthread.php/171300-Oddball-engines-and-prototypes

[SwePatrick]

Jan Theil, Frits Overmars, Wobbly.

A question, as i got spaceproblems, is it a big loss shaping a pipe somewhat oval?
I need clearance so i can have some suspensiontravel left.

343480

[jamathi]

Jan Theil, Frits Overmars, Wobbly.

A question, as i got spaceproblems, is it a big loss shaping a pipe somewhat oval?
I need clearance so i can have some suspensiontravel left.

343480

MZ once used them, but they cracked....

[guyhockley]

Or you could simply open the injector, and run it at 100% duty cycle, at the same time as the inlet and have the fuel flow controlled by an adjustable rising rate fuel pressure regulator. In other words the injector would be an on/off tap and the adjustable fuel pressure used to control fuel flow.

This bloke has hacked a pressure regulator to give a larger range of adjustment for alternative fuels.
It is one of those weird engines with unported cylinder liners, sorry...

https://courseware.ee.calpoly.edu/~amaccarl/MyMethanolMotorcycle/

[lodgernz]

Jan Theil, Frits Overmars, Wobbly.

A question, as i got spaceproblems, is it a big loss shaping a pipe somewhat oval?
I need clearance so i can have some suspensiontravel left.

343480

http://www.pit-lane.biz/t6246p550-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-5

Go to the bottom of page 23. You'll have to login to see the images

[husaberg]

http://www.pit-lane.biz/t6246p550-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-5

Go to the bottom of page 23. You'll have to login to see the images

He could also see what happened with the std ovalised TZ750 pipes.

[Niels Abildgaard]

http://www.pit-lane.biz/t6246p550-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-5

Go to the bottom of page 23. You'll have to login to see the images

Iam wondering why exhaust pipes are round or sligthly oval.
The exhust jet during blowdown is some kind of rectangular and it will not be more difficult to edge weld four funny looking strips(methinks)?

[SwePatrick]

MZ once used them, but they cracked....

Thanks for the answer, i guess it´s no problem for me then, i´m just racing 201m at the time ;)
Is the function still nearly as good as a round one?

[SwePatrick]

http://www.pit-lane.biz/t6246p550-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-5

Go to the bottom of page 23. You'll have to login to see the images

I have no login on that site :(
any chance of posting the pics here?

However, i read what Frits wrote, my pipe is almost 100% straight at the point where i need to make it a little bit oval.
No curve at that point of the pipe.

[lodgernz]

I have no login on that site :(
any chance of posting the pics here?

However, i read what Frits wrote, my pipe is almost 100% straight at the point where i need to make it a little bit oval.
No curve at that point of the pipe.

Frits, would you be happy to post those pics here? I can do it if you're busy.

[philou]

The header seem to be in aluminum. What is the interest?

343486

[teriks]

Iam wondering why exhaust pipes are round or sligthly oval.
The exhust jet during blowdown is some kind of rectangular and it will not be more difficult to edge weld four funny looking strips(methinks)?
Mecanical strength for one, round is simply the strongest cross section available (when pressurized).

Look at what happen when hydroforming a pipe for example.

Now, the exhasust pulses are of lower magnitude, but a pipe with "squarish" walls will behave lot more like a speaker membrane than a round pipe with the same wall thickness would.

[cotswold]

Pinky has been given a new heart and it's not too far off ready to make a blue haze. Wiring and ignition is next on the list.

[F5 Dave]

That will be great.

So, white bodywork and flowers?

[Frits Overmars]

Frits, here in your FOS data it says the squish angle in the RSA head is 8.17°. if I draw that in solidworks, that's the angle of the tangent line to the piston radius. but wasn't the squish paralel to the piston crown radius ?Yes, they are; both the piston dome and the squish band have a 190 mm radius.


shouldn't the squish radius be 190.7 mm ?If you want parallelity at 0,7 mm gap, then yes. But when the engine is running, that 0,7 mm gap has vanished :rolleyes:.
343490

[Frits Overmars]

Jan Theil, Frits Overmars, Wobbly.
A question, as i got spaceproblems, is it a big loss shaping a pipe somewhat oval? I need clearance so i can have some suspensiontravel left.
MZ once used them, but they cracked....Yamaha did that with their first version of the TZ750. Those pipes were not just oval, they really had flat-sided bellies (don't we wish we had too?)
Those TZ750-pipes cracked like mad. One temporary cure was to drill a small hole through the middle of each flat, poke a bicycle spoke through the holes and butt-weld it to the flat sheet areas, so these could no longer vibrate in- and outward quite so much.

Changing the pipe from round to oval can be done in several ways. If you keep the circumference constant, the cross flow area will decrease. Just imagine pushing the pipe flat: the circumference will still be the same but the cross flow area and the pipe volume will become zero.
You'll want to keep the cross flow area and the pipe volume equal to that of the round pipe, so initially you will have to give it a bigger circumference at the place where you are going to flatten it afterwards. And then the power loss should be minimal.

[JanBros]

Yes, they are; both the piston dome and the squish band have a 190 mm radius.If you want parallelity at 0,7 mm gap, then yes. But when the engine is running, that 0,7 mm gap has vanished :rolleyes:.


Once again, Im outsmarted by you, but I have absolutly no problem with that :niceone:

But I still don’t understand the squish angle of 8,17 :(

[Frits Overmars]

Once again, Im outsmarted by you, but I have absolutly no problem with that :niceone:
But I still don’t understand the squish angle of 8,17 :(That's not the squish angle; it's the squish edge angle; the squish angle is variable because of the spheric squish band.
Imagine the vertical line through the center of the piston dome radius. Then imagine a line through the center of the piston dome radius and the upper timing edge of the piston. The angle between those two lines is 8,17° for a piston with a 54 mm bore and a 190 mm dome radius.

[Frits Overmars]

I have no login on that site :(. any chance of posting the pics here?
Frits, would you be happy to post those pics here? I can do it if you're busy.Thank you for the offer Lodgernz. But I think those two pictures are not relevant here; they deal with the cross flow area shape of a curved pipe, not with a straight pipe that is pushed out of round.
Besides, those pictures are available for all to see; there is no need to register here or anywhere else. You'll find them at https://drive.google.com/drive/folders/18l2ShH-MzrnTO0uEk9rNTk89_KgwgWof in the folder FOS Tips & Concepts

[yatasaki]

The header seem to be in aluminum. What is the interest?

343486
That's casting but of iron or steel, no way that could be aluminium as exh. temp. on that bike is around Al melting point.
Only if double walled water cooled

[JanBros]

[QUOTE=Frits Overmars;1131144091]That's not the squish angle; it's the squish edge angle; the squish angle is variable because of the spheric squish band.
Imagine the vertical line through the center of the piston dome radius. Then imagine a line through the center of the piston dome radius and the upper timing edge of the piston. The angle between those two lines is 8,17° for a piston with a 54 mm bore and a 190 mm dome radius.

yes, that I know. that's what I draw in Solidworks. I just didn't understand why you used that angle. but I think I get it now. I use a "parralel angle" which corresponds with the straight line from the outer edge to the inner edge of the squish band, and also cut my squish in the head straight which off course gives a small deviation, but in my world my tolerances are a lot bigger than in Aprillia's GP-world .

I was entering all the RSA data into my spreadsheet to test it but that angle didn't work and now I know why.
So you use the tangent angle because it is the only angle you can mathematicaly true define, ;)

[husaberg]

That's casting but of iron or steel, no way that could be aluminium as exh. temp. on that bike is around Al melting point.
Only if double walled water cooled

You mean like the piston or the Exhaust port does?:innocent:

https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=316037&d=1443001389https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=312297&d=1432629123https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=301291&d=1411294677

not to mention hundreds of thousands of CR125's
https://p.vitalmx.com/photos/forums/2016/12/13/164014/s1200_DSC_0443.jpg

[yatasaki]

Husa, on Philous picture isn't aluminium, can say by colour.
ATAC, SAEC, KIPS, APTS etc all enough close to water space.
Or- enough thick/short piece would stand temperature as long as there is metal to metal connection to flange.
Why not complete pipe from Aluminium? We know that

[wobbly]

Two of the three cylinders on Freddie's triple 500GP had ATAC as per the pic.

[husaberg]

Husa, on Philous picture isn't aluminium, can say by colour.
ATAC, SAEC, KIPS, APTS etc all enough close to water space.
Or- enough thick/short piece would stand temperature as long as there is metal to metal connection to flange.
Why not complete pipe from Aluminium? We know that

That's casting but of iron or steel, no way that could be aluminium as exh. temp. on that bike is around Al melting point.
Only if double walled water cooled

your quote as i pointed out was incorrect to say aluminium would melt is incorrect.

https://www.dealsanimg.com/d/l400/pict/303265680982_/1984-cr125-atac-exhaust-manifold-with-butterfly-valve.jpg
The pipe doesn't get as hot as the exhaust gas does, as it gets washed by a fuel air mixture as well as being able to conduct heat away to the atmosphere and to the other parts. plus its not exposed to a constant heat.
if you used your logic you could not have aluminium pistons. Or air cooled heads or cylinders. as combustion and exhaust gas would melt both.
I don't wish to debate it as your assumption is simply incorrect. Or else the world would be full of melted atac vavles that have ZERO water cooling.



Two of the three cylinders on Freddie's triple 500GP had ATAC as per the pic.
I thought freddie had all three and the mortal plebs only got 2?
I was reading something on Freddie the other day with the first transatlantic match race he rode in he was lowering the lap record on the same bikes as the locals were running by over a second on tracks he only had done a few laps on.

[Frits Overmars]

That's not the squish angle; it's the squish edge angle; the squish angle is variable because of the spheric squish band.
Imagine the vertical line through the center of the piston dome radius. Then imagine a line through the center of the piston dome radius and the upper timing edge of the piston.
The angle between those two lines is 8,17° for a piston with a 54 mm bore and a 190 mm dome radius.

I was entering all the RSA data into my spreadsheet to test it but that angle didn't work and now I know why. So you use the tangent angle because it is the only angle you can mathematicaly true define.My combustion chamber program needs to know the piston crown shape, but directly determining a piston dome radius is quite difficult, so the program offers two more options to answer that question. If you answer the radius question by entering a zero, the program will ask for the piston dome edge angle which is easier to measure,
and if you enter a zero again, it asks for the dome height. That is the true reason for mentioning the edge angle at all in the case of a radiused piston dome; it only serves to determine the dome radius.
Of course, if the piston has a flat or conical crown instead of a domed crown, the edge angle value is meaningful in itself for the squish area calculation.



Two of the three cylinders on Freddie's triple 500GP had ATAC as per the pic.
I thought Freddie had all three and the mortal plebs only got 2?You're right Husa. The NS500 works bike had ATACs on al three cylinders; the RS500 production racer only had them on the two upper cylinders.
343495343494

[yatasaki]

Looks like vespa 50 was going gp:dodge:

[katinas]

Husa, on Philous picture isn't aluminium, can say by colour.
ATAC, SAEC, KIPS, APTS etc all enough close to water space.
Or- enough thick/short piece would stand temperature as long as there is metal to metal connection to flange.
Why not complete pipe from Aluminium? We know that

Like Husa write, headers on Philous picture (Honda NSR 500 98 or 99) is definitely made from light alloy and maybe even from magnesium (color is the same like on HRC magnesium cover and header as long as the engine and very close to gearbox in first picture)
When Honda stick to 112 angle configuration for NSR 500 engine from 1987 (Gardner) , they use long headers from light alloy on rear 1,3 cylinders until 2000. From 2001 (Rossi) and 2002 (Katoh) engines rear cylinders used with short headers, like on the front cylinders.

[F5 Dave]

I knew a chick who had a vespa. We went to a rally . She was a vegetarian. That's a non starter.

[TZ350]

343503 343504 343505

Barn Find, or re discovery by the original builder. A 1972 Kawasaki F9 350cc BigHorn racer. https://www.cycleworld.com/custom-built-race-winner/

I am not looking to build a monocoque but I am looking to build a pre 72 racer using a Kawasaki 350/250 rotary valve motor. I want to race my friends who ride pre 76 Beneli 250 two strokes and pre 72 Yamaha twins. The plan is to get a rotary valve BigHorn 350 and sleeve the cylinder back to 250. Sleeving the big cylinder back should allow room for some modern porting trickery like axillary side exhaust ports and staggered large radius sweeping transfer ducts. A decent combustion chamber shape and modern pipe design with digital ignition. Running methanol which is allowed in pre 72 here. It should hopefully keep things cool enough so I don't have thermal problems with the plated alloy sleeve.

Anyway, if you can help. I am looking for Kawasaki rotary valve 350cc BigHorn F9 or F5 and/or 250cc Bison F8 engine/gear box parts and any info on the early BigHorn 350cc racers. If we can do a deal and the items are packed and addressed I can arrange collection from pretty much anywhere in the world.

[pete376403]

343503 343504 343505

A 1972 Kawasaki F9 350cc BigHorn racer. https://www.cycleworld.com/custom-built-race-winner/

I am not looking to build a monocoque but I am looking to build a pre 72 racer using a F9 motor. I want to race my friends who ride pre 76 Beneli 250 two strokes. The plan is to get a rotary valve BigHorn 350 and sleeve the cylinder back to 250. Sleeving the big cylinder back should allow room for some modern porting trickery like axillary side exhaust ports and staggered large radius sweeping transfer ducts. A decent combustion chamber shape and modern pipe design with digital ignition. Running methanol which is allowed in pre 72 here should hopefully keep things cool enough so I don't have thermal problems with the plated alloy sleeve.

Anyway, if you can help. I am looking for Kawasaki F9 and F5 engine/gear box parts and any info on the early BigHorn 350cc racers.\

Kevin Cameron built a 350 Bighorn at a time when the AMA allowed 350 singles to run against 250 twins. Ridden by Cliff Carr, it was featured in Cycle magazine. If you have back issues, it was in October 1971. Or get one here https://www.ebay.com/itm/Cycle-Magazines-Lot-October-1971-December-1973-March-1975-August-1975-/254393627276

These days Harry Klemm is the goto guy for bighorns now, and of course Flettner right here.

I had a 72 F9 from new If I hadn't been a 18 year old who thought he knew more than the factory it probably would have served me a lot better

[husaberg]

\

Kevin Cameron built a 350 Bighorn at a time when the AMA allowed 350 singles to run against 250 twins. Ridden by Cliff Carr, it was featured in Cycle magazine. If you have back issues, it was in October 1971. Or get one here https://www.ebay.com/itm/Cycle-Magazines-Lot-October-1971-December-1973-March-1975-August-1975-/254393627276

These days Harry Klemm is the goto guy for bighorns now, and of course Flettner right here.

I had a 72 F9 from new If I hadn't been a 18 year old who thought he knew more than the factory it probably would have served me a lot better

I have it saved somewhere ..........
343506
Okay they are to big i will convert to smaller tomorrow
343509343510343511343512

[Frits Overmars]

I have it saved somewhere ..........Okay they are to big i will convert to smaller tomorrowWill these do?
343508 343507

[husaberg]

Will these do?
343508 343507

For Starters you are going to make me do it tonight
343513343514343515343516

[andreas]

343503 343504 343505

Barn Find, or re discovery by the original builder. A 1972 Kawasaki F9 350cc BigHorn racer. https://www.cycleworld.com/custom-built-race-winner/

I am not looking to build a monocoque but I am looking to build a pre 72 racer using a Kawasaki 350/250 rotary valve motor. I want to race my friends who ride pre 76 Beneli 250 two strokes and pre 72 Yamaha twins. The plan is to get a rotary valve BigHorn 350 and sleeve the cylinder back to 250. Sleeving the big cylinder back should allow room for some modern porting trickery like axillary side exhaust ports and staggered large radius sweeping transfer ducts. A decent combustion chamber shape and modern pipe design with digital ignition. Running methanol which is allowed in pre 72 here should hopefully keep things cool enough so I don't have thermal problems with the plated alloy sleeve.

Anyway, if you can help. I am looking for Kawasaki rotary valve 350cc BigHorn F9 or F5 and/or 250cc Bison F8 engine/gear box parts and any info on the early BigHorn 350cc racers. If we can do a deal and the items are packed and addressed I can arrange collection from pretty much anywhere in the world.

https://www.klemmvintage.com/bighorntech.htm Maybe some is useful.

[jbiplane]

https://patentimages.storage.googleapis.com/c4/d0/be/d6835653ad8410/US20050062177A1.pdf
http://www.eta-engine.com/downloads/CWI

Seems simple solution from chainsaw world

[JanBros]

Frits, don't know if I have to congratulate you or ask you, looking at this graph :

is from my excel, entered all the RSA data (cylinder and head, and than calculated your FOS pipe. Red is standard FOS as by your fomula's with 57.5 BHP at crank and a speed of sound of 587m/s to get the same length as the tubo102.
green is a copy as good as I could get it within the limitations of my sheet (read : max half a milimeter here and there, and whitout the last baffle) with a Wobbly-duct at the front.

so : did you derive your FOS from the RSA pipe ? if, so, you did an excellent job https://www.cosgan.de/images/midi/froehlich/b015.gif
or is it an everlasting fine-tuning of your exhaust concept from the seventies, and than it is a outstanding-out-of-this-world job https://img.smileys.nl/406/worshippy.gif

[andreas]

Re the cooling of the spigot.
As we already know that wrapping a header will instantly cause deto from overheating the slug, then the heat uptake in that area for sure
has enough time to wreak havoc.
So by inference a cool duct would also have time to cause a positive effect.
But I well know assumptions are errors waiting to be revealed, so hard evidence is needed.
I just happen to have that, as I have been drilling holes and cutting slots into the flange faces of KZ2 castings the results are easily seen and repeatable.
On track the simple mod reduced the egt by around 30*C - a jet size spot on.
So now we run 1 jet leaner over the original dyno baseline weather corrected RAD, and can run all day at 640C with no deto.
Absolutely impossible previously.
The bulk cylinder water temp is the same as before at 45*C exit, but on the dyno it is now possible to touch the flange bolted to the cylinder,after a hard all
gear run up.
Previously it was way too hot to do this.
At the time I didnt recognise that I could have leaned it down on the dyno - and make more power, but on track the data log was immediately conclusive.

I am sceptical about cooling the header with heat radiating plate fins or whatever, as this would be detracting from the pipe heat energy available - BUT, it may be a workable
compromise if the duct cannot be kept cool enough - for whatever reason.
Maybe a thermal barrier, like a gasket where possible, to the spigot/header? A volume/port size reducing contraption bolted to the floor will do more harm than good , because of it's insulating effect?

[pete376403]

I have it saved somewhere ........

Thanks for posting that. I used to subscribe to Cycle, from about 1969. Sometime ago, in a fit of madness I traded all the boxes of back copies for some space in the attic, save for the very last issue they published.

Reading that bought back memories of all the things I wanted to do to my F9, but ignorance, life, etc., got in the way.

Good luck with your search for an f5/f9 - or, if you are determined for it to be a 250, find an F8 Bison

[husaberg]

Thanks for posting that. I used to subscribe to Cycle, from about 1969. Sometime ago, in a fit of madness I traded all the boxes of back copies for some space in the attic, save for the very last issue they published.

Reading that bought back memories of all the things I wanted to do to my F9, but ignorance, life, etc., got in the way.

Good luck with your search for an f5/f9 - or, if you are determined for it to be a 250, find an F8 Bison

Two Stroke Fridge

https://www.youtube.com/watch?v=qmYpLlBWHp4
Flet i think made a mold for the heads already.
I think i remember from somewhere the gearbox is the same as some other Kawasaki.
So he really only needs a bottom end as i are assuming hes making a cylinder.
Flet even has a period Lake injector he made

[Flettner]

F9 stuff, reporting for duty TZ.😆

[breezy]

hope its good game:bleh::bleh::bleh:

[F5 Dave]

Please. Not here. Team sports are for school kids.

[Frits Overmars]

Frits, don't know if I have to congratulate you or ask you, looking at this graph: 343525
is from my excel, entered all the RSA data (cylinder and head, and then calculated your FOS pipe.
Red is standard FOS as by your fomulas with 57.5 BHP at crank and a speed of sound of 587 m/s to get the same length as the tubo102.
Green is a copy as good as I could get it within the limitations of my sheet (max half a milimeter here and there, and without the last baffle) with a Wobbly-duct at the front.
So: did you derive your FOS from the RSA pipe ? If, so, you did an excellent job
Or is it an everlasting fine-tuning of your exhaust concept from the seventies, and than it is a outstanding-out-of-this-world job Thanks for the flowers Jan :D.
The development of my pipe concept has been a continuous process, from the seventies, as you noticed, until now.
I tried to understand what happens in an exhaust pipe and I tried to develop a theoretical pipe shape that would promote the desired physical events. This resulted in equations that gave fairly good shapes, which however were quite complicated to produce in sheet metal.
Next, I tried to distinguish between fundamental details and details that, though theoretically correct, had little influence on the end result, which allowed me to simplify the pipe concept into what it is today.
Most of the recent work went into making the concept universally applicable, from a 2cc model engine to a 700cc MX single.

Of course there have been interactions between the physical theories and the measured results, like you did, when you juggled the speed of sound in order to match the pipe length to your chosen RSA example. Incidentally, that is exactly the recommended way of using the concept.
343524

[KKT]

I apologize if this is the wrong place to ask, i have been a member on here for quite some time and have been working my way through this thread, but this is only my second post.

I love twostrokes, and i am in many ways stuck in the late 70's - 1980, i'm old enough (51) to remember watching the 50cc and 80cc GP races on TV and they still amaze me.

The 50cc bikes are coming back strong in the Freetech class, and in classic 50 racing, but otherwise they seem like a forgotten era, many bikes are retired to museums and private collections.

I've spent many hours looking for more info, especially about the Garelli 50gp from the last years they raced ( I believe they all had Jan Thiel's engine design) Kreidlers, Minarellis, Derbi 50 and so on, google does come up with nice photos of the bikes, but that's about it. It looks like it's a deep secret of how the cylinders looks like inside, what the portmap looks like, and all the technicall stuff like disc valve timing, port sizes and durations i would love to see and read about and learn what made them so incredible fast.

Can anyone help directing me to where to look ?

Thank you.

[JanBros]

Thanks for the flowers Jan :D.


Frits, but can you share some of the flowers with Wobbly :clap: ?

perhaps I should have expalined it more : not only is FOS very very close, also Wobbly's exhaust duct is spot on with it's length and starting diameter of the pipe !

just wanted to show this graph to everyone, that with some simple calculations like Wobbly's duct and your FOS pipe, how close you can get to a factory pipe when you have enough correct data :wings:

[TZ350]

F9 stuff, reporting for duty TZ.��

I am off to see Flettner today for a frame and engine. He is about an hour and a half's drive away, so pretty handy.

I would still like another spare Kawasaki Bighorne or Bison engine and I am not kidding, I can pick it up easily from anywhere especially the USA.

I once won five good Suzuki T500 engines and spares on Ebay. A half tones worth and the price was reasonable. They were picked up and shipped out of Ohio no problem. They are now doing duty in three Senior post classic racers. Not ours, after a bit of thought. Chambers and I sensibly decided that we did not need to ride bikes that frighteningly fast so we passed the engines on at cost. Junior post classic looks more our level. If anyone in the US has a Kawasaki 350/250 F9, F8 or F5 engine or two they might sell I would be very interested.

[wobbly]

I too must thank Jan for the flowers , but as I have just reread some posts I must apologize to Andreas if i gave incorrect info about the Motoplat - its been 30 years
is my excuse.

[adegnes]

Mockup of my new engine in the frame.
Green is small carb with reed intake, blue is big 24/7 intake with a slide valve for opening at WOT.
The case is pretty much ready for machining.

343526

Constant rpm/load/throttle opening(WOT, no throttle)

Questions:
- Anything wrong with mounting injectors where I've marked in the drawing?

- Been thinking I should use two and have one open as the other closes to minimize "gaps" in delivery - necessary? One would be preferable, less parts.

- Injector size? (19k rpm, 70/30 methanol/nitro by weight, 30ish hp}
Here's my crude calculation

(50cc x air mass 0.00129gcm3) x 20000rpm = 1290g Air
1290g / 3:1AFR = 430g fuel

(0.7 x methanol 0.792gcm3) + (0.3 x nitromethane 1.14gcm3) = 0.896gcm3

430 / 0.896 = 480cc

480 / 0.8 duty cycle = 600cc

600 x 50% safety factor = 900cc

Does one 900cc/two 450cc injectors sound sensible? (two 900cc if I want them to alternate on/off)


Picture of Moped Dick Experimental Test Vehicle #1 in front of what should have been salt flats.
343527

[Frits Overmars]

I love twostrokes, and i am in many ways stuck in the late 70's - 1980, i'm old enough (51) to remember watching the 50cc and 80cc GP races on TV and they still amaze me.
The 50cc bikes are coming back strong in the Freetech class, and in classic 50 racing, but otherwise they seem like a forgotten era, many bikes are retired to museums and private collections.
I've spent many hours looking for more info, especially about the Garelli 50gp from the last years they raced ( I believe they all had Jan Thiel's engine design) Kreidlers, Minarellis, Derbi 50 and so on, google does come up with nice photos of the bikes, but that's about it. It looks like it's a deep secret of how the cylinders looks like inside, what the portmap looks like, and all the technicall stuff like disc valve timing, port sizes and durations i would love to see and read about and learn what made them so incredible fast. Can anyone help directing me to where to look ? Sure we can, KKT. Take a look here: https://drive.google.com/drive/folders/18l2ShH-MzrnTO0uEk9rNTk89_KgwgWof
(https://drive.google.com/drive/folders/18l2ShH-MzrnTO0uEk9rNTk89_KgwgWof)

Frits, but can you share some of the flowers with Wobbly :clap: ?
perhaps I should have expalined it more : not only is FOS very very close, also Wobbly's exhaust duct is spot on with it's length and starting diameter of the pipe !
just wanted to show this graph to everyone, that with some simple calculations like Wobbly's duct and your FOS pipe, how close you can get to a factory pipe when you have enough correct data :wings:I'll be glad to share, Jan. You may have noticed that my method of starting at the blowdown area and gradually expanding it, and Wobbly's method of starting at the total exhaust port area and gradually reducing it, can lead to identical exhaust duct shapes. Here you go Wob, although I suspect you would prefer a single malt :D.
343528

[andreas]

I too must thank Jan for the flowers , but as I have just reread some posts I must apologize to Andreas if i gave incorrect info about the Motoplat - its been 30 years
is my excuse.

No worries Wobbly, I havn't staked the route just yet.

[husaberg]

I apologize if this is the wrong place to ask, i have been a member on here for quite some time and have been working my way through this thread, but this is only my second post.

I love twostrokes, and i am in many ways stuck in the late 70's - 1980, i'm old enough (51) to remember watching the 50cc and 80cc GP races on TV and they still amaze me.

The 50cc bikes are coming back strong in the Freetech class, and in classic 50 racing, but otherwise they seem like a forgotten era, many bikes are retired to museums and private collections.

I've spent many hours looking for more info, especially about the Garelli 50gp from the last years they raced ( I believe they all had Jan Thiel's engine design) Kreidlers, Minarellis, Derbi 50 and so on, google does come up with nice photos of the bikes, but that's about it. It looks like it's a deep secret of how the cylinders looks like inside, what the portmap looks like, and all the technicall stuff like disc valve timing, port sizes and durations i would love to see and read about and learn what made them so incredible fast.

Can anyone help directing me to where to look ?

Thank you.

http://www.classic50racingclub.co.uk/mount-up---the-bikes.html

https://www.elsberg-tuning.dk/50ccroadracing.html

[TZ350]

343531

Spent a happy afternoon at Flettner's place digging through his surplus Kawasaki BigHorn parts. He found a stack of useful stuff and donated them to the cause. There are cases and cylinders plus cylinders from Yamaha and Suzuki. Gear box parts and side covers, plenty to sort through. And a frame modified to move the Kawasaki engine 50mm further forward to put more weight on the front wheel. Many thanks Flettner..... :niceone:

The plan is to check through as many likely cylinders as we can and select the one with the best outer transfer duct shape. Then sleeve it back to 250cc. And with a thick alloy sleeve we should be able to cut a triple exhaust port and the inner sweeping transfer shape into it.

The pre 72 Japanes pre 76 European 250cc light weight class I am looking at riding in has mostly Yamaha DS7's and Benelli 2C 250 twins. Typically they make mid 30's rear wheel horse power and the top ones, low 40's.

With everything that has been written on here by those that know and the use of Engmod to develop a plan. If I can't get mid 40's RWHP out of the much lighter rotary valve Kawasaki I should be ashamed of myself...... :rolleyes:

[adegnes]

I had the same plan, though not for the same reason.
I was working on 6.5 cc MB40-engines for F3D model airplanes. The fuel tank position in the fuselage of these little planes is critical as they pull a lot of g's in corners (we don't know how many g's exactly because the g-sensor's maximum is 'only' 36 g). When the fuel level drops, the mixture strength changes; not nice.
My plan was to replace the cruel fuel system (fuel in a bladder with exhaust pipe pressure squeezing the bladder from the outside) with a pump injection. It had to be constant flow because I could not find injectors capable of delivering the required tiny amounts of fuel to a 36,000 rpm engine.
I found suitable pumps here: http://shopping.netsuite.com/app/site/site.nl?alias=flightworks (http://shopping.netsuite.com/app/site/site.nl?alias=flightworks) . These pumps are designed for model jet turbines but the snag is that the DC pump motors cannot run slowly enough for a small piston engine; the pump would drown the engine at the first start attempt.
Stepper motors were considered but the problem with those would be that when rapid pump acceleration is required, the stepper motor may miss steps and the engine will lean out without any feedback other than a complete cut-out because of a molten glow plug.
Pulse width modulation for the original DC pump motor was considered next, but then other things took priority so the idea never got finished.

I like this approach a lot!

[peewee]

343503 343504 343505

Barn Find, or re discovery by the original builder. A 1972 Kawasaki F9 350cc BigHorn racer. https://www.cycleworld.com/custom-built-race-winner/

I am not looking to build a monocoque but I am looking to build a pre 72 racer using a Kawasaki 350/250 rotary valve motor. I want to race my friends who ride pre 76 Beneli 250 two strokes and pre 72 Yamaha twins. The plan is to get a rotary valve BigHorn 350 and sleeve the cylinder back to 250. Sleeving the big cylinder back should allow room for some modern porting trickery like axillary side exhaust ports and staggered large radius sweeping transfer ducts. A decent combustion chamber shape and modern pipe design with digital ignition. Running methanol which is allowed in pre 72 here. It should hopefully keep things cool enough so I don't have thermal problems with the plated alloy sleeve.

Anyway, if you can help. I am looking for Kawasaki rotary valve 350cc BigHorn F9 or F5 and/or 250cc Bison F8 engine/gear box parts and any info on the early BigHorn 350cc racers. If we can do a deal and the items are packed and addressed I can arrange collection from pretty much anywhere in the world.

seems heres a f4. never heard of it before
https://classifieds.ksl.com/listing/57946754

120 superlube ? never heard of it
https://classifieds.ksl.com/listing/57932093

f7. sorry never heard of it
https://classifieds.ksl.com/listing/57863583

bushwacker
https://classifieds.ksl.com/listing/57863543

[SwePatrick]

Here you can see my problem with clearance between tire and pipe.
i might just put a smaller tire on to gain some clearance as i also need to lower the rear some.

343534

Don´t mind the mess,,, professor at work! ;)

[wobbly]

Move the pipe center-line to one side up near the belly to clear the tire.
Same as a twin pipe out the back setup.

[SwePatrick]

I could do that, but i want it to be easy to build new pipes, easiest pipes must be a straight one ;)
If routing it a bit to the side i will get into new problems.

I can lift the pipe about 20mm.
and a smaller rear tire would also give me about 10-15mm
Then i think i´m home free.
I havent made the pipe oval yet ;)

[wobbly]

There is already a bend in the header.
Put a bend at the end of the header/start of diffuser join , then one at the end of the diffuser/start of the mid section.
No extra cuts or welds - easy.
Oval changes the area and thus the pipes efficiency - bad idea.

[TZ350]

Mockup of my new engine in the frame.
Green is small carb with reed intake, blue is big 24/7 intake with a slide valve for opening at WOT.
The case is pretty much ready for machining.

343540

Constant rpm/load/throttle opening(WOT, no throttle)

Questions:
- Anything wrong with mounting injectors where I've marked in the drawing?

- Been thinking I should use two and have one open as the other closes to minimize "gaps" in delivery - necessary? One would be preferable, less parts.

Does one 900cc/two 450cc injectors sound sensible? (two 900cc if I want them to alternate on/off)


I would pick two 900cc injectors fired alternately and overlapping each other as required when time gets to short for one injector to open-FireFuel-close, move the open-close part and some fueling if needs be to the alternate cycle.

I think for what you are trying to do, EFI will serve you well.

Timing of the injector closing point seems to make a difference to performance too. I aim for injector closing at BDC where the pipe is sucking its hardest. Flettner found aiming for injector closing at transfer closing worked best for him.

343541

This is Flettners two injectors. You can just see the injector nozzles at the back of the "C" port duct of the Kawasaki BigHorn crankcase. They fire horizontally across and above the flywheels. This worked well and looks a bit like the arrangement you have in mind.

343543

I had a lot of success by firing directly across the bottom of the transfers.

But this was not always possible and I tried a lot of different configurations like firing 4 stroke style with the wind going down the inlet tract, and that was the worst.

Nearly anything with two strokes and fuel injection behaves totally different to four strokes. The message is, to avoid disappointment, don't blindly copy any of the methods used with 4T EFI.

343542

"B" port injection against the wind seems to be the best practical arrangement and currently gives very good results.

Anyway for what its worth, that is my take on it.

[Flettner]

You saw it here on Kiwi Biker first, mk2 TPI.
This arrangement allows for better control and better homogenization. B port injectors first at low speed, then A and B port injectors once up on the pipe. B port TPI will supply fuel to the A ports at longer injector on times but not so controlled, not like this.
Anyway if I were you I'd inject like this.

[husaberg]

You saw it here on Kiwi Biker first, mk2 TPI.
This arrangement allows for better control and better homogenization. B port injectors first at low speed, then A and B port injectors once up on the pipe. B port TPI will supply fuel to the A ports at longer injector on times but not so controlled, not like this.
Anyway if I were you I'd inject like this.

Odd est ignition set up there Neil......:innocent:

[TZ350]

.
Kawasaki F81M Post Classic Racer Build.

Now that we have some parts to play with, the ideas can flow.

343549

The first step is to improve the transfers. The Suzuki has a much better looking duct shape than the Kawasaki.

343548

If I fitted the piston port Suzuki cylinder to the rotary valve Kawasaki. I could have two inlets and arrange one of them as a 24/7 when its up on the pipe. Open all hours, it's kinda crazy, but a very tempting idea..... :drool: . There have been racing single cylinder twin carburetor specials made before.

I am not sure if fitting a Suzuki cylinder to a Kawasaki will be regarded as an after market conversion or a tuning modification. Back in the day I was running Yamaha cylinders on my TR250 Suzuki so mix and match has certainly been done before.

These are the class rules:-

343553

[adegnes]

I would pick two 900cc injectors fired alternately and overlapping each other as required when time gets to short for one injector to open-FireFuel-close, move the open-close part and some fueling if needs be to the alternate cycle.

I think for what you are trying to do, EFI will serve you well.

Timing of the injector closing point seems to make a difference to performance too. I aim for injector closing at BDC where the pipe is sucking its hardest. Flettner found aiming for injector closing at transfer closing worked best for him.

343541

This is Flettners two injectors. You can just see the injector nozzles at the back of the "C" port duct of the Kawasaki BigHorn crankcase. They fire horizontally across and above the flywheels. This worked well and looks a bit like the arrangement you have in mind.

343543

I had a lot of success by firing directly across the bottom of the transfers.

But this was not always possible and I tried a lot of different configurations like firing 4 stroke style with the wind going down the inlet tract, and that was the worst.

Nearly anything with two strokes and fuel injection behaves totally different to four strokes. The message is, to avoid disappointment, don't blindly copy any of the methods used with 4T EFI.

343542

"B" port injection against the wind seems to be the best practical arrangement and currently gives very good results.

Anyway for what its worth, that is my take on it.


You saw it here on Kiwi Biker first, mk2 TPI.
This arrangement allows for better control and better homogenization. B port injectors first at low speed, then A and B port injectors once up on the pipe. B port TPI will supply fuel to the A ports at longer injector on times but not so controlled, not like this.
Anyway if I were you I'd inject like this.

Thanks a bunch to both of you!

The more I think about this, the more I lean towards setting it up like a wet nitrous system without nitrous.
Just one "fogger nozzle", a solenoid, and a pump.
Controlled by varying return flow to the tank.

[Frits Overmars]

You saw it here on Kiwi Biker first, mk2 TPI.This arrangement allows for better control and better homogenization. B port injectors first at low speed, then A and B port injectors once up on the pipe.
343554I love it Neil :2thumbsup.


Odd est ignition set up there Neil......:innocent:Never seen a high-tension cooler before Husa? Oh well, you're probably too young :p.

[andreas]

.
Kawasaki F81M Post Classic Racer Build.

Now that we have some parts to play with, the ideas can flow.

343549

The first step is to improve the transfers. The Suzuki has a much better looking duct shape than the Kawasaki.

343548

If I fitted the piston port Suzuki cylinder to the rotary valve Kawasaki. I could have two inlets and arrange one of them as a 24/7 when its up on the pipe. Open all hours, it's kinda crazy, but a very tempting idea..... :drool: . There have been racing single cylinder twin carburetor specials made before.

I am not sure if fitting a Suzuki cylinder to a Kawasaki will be regarded as an after market conversion or a tuning modification. Back in the day I was running Yamaha cylinders on my TR250 Suzuki so mix and match has certainly been done before.

These are the class rules:-

343553

Somewhere I read reed valves not permitted, that would make the 24/7 less atractive. A guess is that a well flowing c-port is worth more than superior induction, at least that is probably why Suzuki abandoned their otherwise excellent power reed system. Then again surely there is a solution...

[jbiplane]

Just curious if it is a good idea to try make engine with very exhaust small duration, but very wide exhaust port to minimize exhaust system size and weight. Anyone tryed to make it with volume about 125cc? Will engmod preduct behaviour of this?

[F5 Dave]

.
Kawasaki F81M Post Classic Racer Build.

Now that we have some parts to play with, the ideas can flow.

343549

The first step is to improve the transfers. The Suzuki has a much better looking duct shape than the Kawasaki.

343548

If I fitted the piston port Suzuki cylinder to the rotary valve Kawasaki. I could have two inlets and arrange one of them as a 24/7 when its up on the pipe. Open all hours, it's kinda crazy, but a very tempting idea..... :drool: . There have been racing single cylinder twin carburetor specials made before.

I am not sure if fitting a Suzuki cylinder to a Kawasaki will be regarded as an after market conversion or a tuning modification. Back in the day I was running Yamaha cylinders on my TR250 Suzuki so mix and match has certainly been done before.

These are the class rules:-

343553
And that's why rules are so hard to write.
One would have to read that paragraph wrt intake system, otherwise you couldn't put clipon bars on. But that while giving a freer hand on cylinder would make a target on inlet. Two carb bikes never seem to offer any real advantages. I'd be blocking inlet and Devon the area into a C port. I did just that with my MB when I full cased it.

[Brett S]

You saw it here on Kiwi Biker first, mk2 TPI.
This arrangement allows for better control and better homogenization. B port injectors first at low speed, then A and B port injectors once up on the pipe. B port TPI will supply fuel to the A ports at longer injector on times but not so controlled, not like this.
Anyway if I were you I'd inject like this.


Looks good Neil.
Can you explain what the plunger looking part is sticking out the end of the fuel rail?
Will the fuel system be dead headed or have a pressure reg with return line?
Is it just the picture or is that radiator very thick?

[husaberg]

.
Kawasaki F81M Post Classic Racer Build.

Now that we have some parts to play with, the ideas can flow.

343549

The first step is to improve the transfers. The Suzuki has a much better looking duct shape than the Kawasaki.

343548

If I fitted the piston port Suzuki cylinder to the rotary valve Kawasaki. I could have two inlets and arrange one of them as a 24/7 when its up on the pipe. Open all hours, it's kinda crazy, but a very tempting idea..... :drool: . There have been racing single cylinder twin carburetor specials made before.

I am not sure if fitting a Suzuki cylinder to a Kawasaki will be regarded as an after market conversion or a tuning modification. Back in the day I was running Yamaha cylinders on my TR250 Suzuki so mix and match has certainly been done before.

These are the class rules:-

343553

https://www.facebook.com/120511237959379/photos/kawasaki-f5-f8-f9-close-ratio-5th-gearthe-stock-5-speed-transmission-of-the-kawa/2105923856084764/

Kawasaki F5 / F8 / F9 Close Ratio 5th gear
The stock 5 speed transmission of the Kawasaki F5/F8/F9 is actually a close ratio 4 speed transmission with a very tall and distant 5th gear ratio. In the past, the best close ratio option was to install the F81M gearbox. As time has gone on, these F81M gearboxes have become very rare (and expensive). To attend to this problem, we have embarked on “fixing” the 5th gear issue of the stock gearbox…. And that fix is not complex.
The H1 triple 5th gear-set installs easily into the Bighorn gearbox, and it offers a ratio that turns the stock Bighorn gearbox into a “close-ratio” box. The problem is that the stock Bighorn 1st gear (driven-shaft) that engages this H1 5th gear has the wrong shift-dog pattern.
We are in the process of manufacturing a custom batch of the Bighorn 1st gear that will allow the use of the H1 5th gear. The ratios (compared to the F81M gearbox) are shown below.
GEAR F9-H1-5th F81m
1st 2.45 2.45
2nd 1.71 1.60
3rd 1.17 1.26
4th .90 1.09
5th .81 .95
As the chart shows, the 4th and 5th ratios of the H1 modified F9 box are “very” close to one another….. but that is ideal for high geared pavement engine arrangement.
The H1 5th gear set are all the same (among different years), and readily available worldwide. We will be offering the modified 1st driven-shaft gear to mesh the H1 5th gearset for $219. each (plus freight). There are a limited number available, so a $100 deposit will secure the gear until delivery around May 1st. If you change your mind after deposit, we will gladly refund you. At this time (3/13/18) only 4 are still available.

[Flettner]

Normal pressure system with return to tank, relief valve is removed in the picture. Valve is special in that the exhaust pressure changes it. Not finished yet.
Radiator is twin core, its a single radiator, othet side is now air cleaner.

[husaberg]

There is already a bend in the header.
Put a bend at the end of the header/start of diffuser join , then one at the end of the diffuser/start of the mid section.
No extra cuts or welds - easy.
Oval changes the area and thus the pipes efficiency - bad idea.

https://scontent.fchc2-1.fna.fbcdn.net/v/t1.0-9/54729847_2251596461773578_3165533842253545472_n.jp g?_nc_cat=110&_nc_oc=AQkuUH76yWPwidurYjG9EC-lUXlfS4Inbnp8CxwHG88cFY81kYokiL57wTIVlNBJxDw&_nc_ht=scontent.fchc2-1.fna&oh=b01da079392ead09fe63980043202719&oe=5E535C29

[TZ350]

343557

Pinky makes noise.......

[Brett S]

Normal pressure system with return to tank, relief valve is removed in the picture. Valve is special in that the exhaust pressure changes it. Not finished yet.
Radiator is twin core, its a single radiator, othet side is now air cleaner.

Ah on closer inspection i see now that is just a button head capscrew in the end.. I thought it was a spring over a plunger..

So its an adjustable fuel pressure reg like a turbo 4 stroke car's fuel pressure regulator referenced to manifold vacuum and boost.

[katinas]

I could do that, but i want it to be easy to build new pipes, easiest pipes must be a straight one ;)
If routing it a bit to the side i will get into new problems.

I can lift the pipe about 20mm.
and a smaller rear tire would also give me about 10-15mm
Then i think i´m home free.
I havent made the pipe oval yet ;)

Maybe its not good example, but to find place with the "straight" type swing arm, on 1987 NSR 500, Honda used the most flattened pipes on Gp racing scene. Power 163hp 12000 rpm together with normal shape upper pipes.
Add photo Elf bike with that 1987 NSR 500 engine and exhaust

[husaberg]

Of course, its not good example, but to find place with the "straight" type swing arm, on NSR 500, Honda used the most flattened pipes on Gp racing scene. Power 163hp 12000 rpm with two normal shape upper pipes.

I see your Honda GP500 and raise you F750 Plus AMA dirt track
http://i.imgur.com/sYSITB7.jpghttps://www.cyclechaos.com/images/d/d2/1974_Yamaha_TZ700.jpghttps://2yrh403fk8vd1hz9ro2n46dd-wpengine.netdna-ssl.com/wp-content/uploads/2014/11/2014-yamaha-tz-story-3.jpg
i have better photos in my TZ album but i are not allowed to access them at the moment.
BTW if anyone is interested in the albums you better take a look as i willl be deleting them off the site in a months time.

[katinas]

Nice pictures Husa.
For 1988 season Honda used round shape lower exhaust, but with cuts for rear tire and right side cut on swing arm for pipe. 162.8hp 12500 rpm.
Add Yamaha YZR 500 1985 left hand side exhaust with cut for chain and swing arm

[Muciek]

I was trying to find them few days ago but it does say that I don't have the access(using links from 1000 page). And the direct link from user profile to galleries is gone. Are they gone already ?

[husaberg]

I was trying to find them few days ago but it does say that I don't have the access(using links from 1000 page). And the direct link from user profile to galleries is gone. Are they gone already ?

No idea i are in the naughty corner atm so i cant see any of my attachments.
But if they are not gone already they will be deleted soon as iam able. Sme as there is over 10,000 pictures.
But as it seems the site moderators have decided they would rather have content from internet trolls rather than motorcycle stuff.

[Zrt1200]

Hello fellow 2 stroke tuners. My name is Al and I am a retired CNC Machinist with his own work shop at home. I have modified a lot of 2 strokes over the last 30 years mostly for drag race snowmobiles with a CVT transmission but dirt bikes and 4 wheeler's as well. I currently use TSR software and I have been looking into Engine mod2 as of late. I use to Drag race snowmobiles for years but once I got married and had kids the garage money went for toys so the kids could go riding and my racing was on hold. Our youngest is now 21 years old and out of the house so I am thinking about building a new drag race snowmobile for my self. I have been a member here for a few weeks now quietly reading in the background and using the search function. I have read all 5 chapters on Pit-lane biz on the Aprilia as I am trying to get my self up to speed for a new build. I am also on facebook and have read and posted in 2 Stroke research & development. Frits Overmars, Jan Thiel, & Wayne Wright are great minds and I would like to thank you gentleman for your post's and answering our question as we all are learning from you guys.

[Frits Overmars]

Hi Al, it's good to have you here, where we have all the facilities that we don't have on Farcebook, like proper chronology, and quote and search functions that really work :D.

[AndreasL]

No idea i are in the naughty corner atm so i cant see any of my attachments.
But if they are not gone already they will be deleted soon as iam able. Sme as there is over 10,000 pictures.
But as it seems the site moderators have decided they would rather have content from internet trolls rather than motorcycle stuff.

NO!!! Sad to hear that. Your pictures are a real treasure and would be a great loss not to have here to go through.

Wish there was something we could do to have “someone in charge” change their mind...or something.
Totally understand your decision though...without knowing the background.

[Frits Overmars]

No idea i are in the naughty corner atm so i cant see any of my attachments.
But if they are not gone already they will be deleted soon as iam able. Sme as there is over 10,000 pictures.
But as it seems the site moderators have decided they would rather have content from internet trolls rather than motorcycle stuff.I don't know what is going on, but in any case save your treasures by uploading them to Google Drive. Then nothing is irrevocably lost, and you can decide who you want to give access to the material.

[philou]

Husaberg fired?

what's this shit?

You express yourself correctly, participate in discussions.

Soon it's the topic that will disturb....

[Peter1962]

I don't know what is going on, but in any case save your treasures by uploading them to Google Drive. Then nothing is irrevocably lost, and you can decide who you want to give access to the material.

Husaberg is one of the most respected forummembers, I hope that whatever the source of dispute is, it will get sorted out.

[peewee]

Hi Al, it's good to have you here, where we have all the facilities that we don't have on Farcebook, like proper chronology, and quote and search functions that really work :D.

i looked at that facebook page some time ago but its a mess and plenty of the people havent a clue what theyre even talking about :laugh:

[Flettner]

Moderators, think about what you are doing, you will wreak this site, Glenn is a national treasure and should be treated as such, with some respect!

[AndreasL]

Moderators, think about what you are doing, you will wreak this site, Glenn is a national treasure and should be treated as such, with some respect!

+1

Listen to the community in this case.

[wobbly]

WTF did I miss , can I sign a " Bring Back Husa Petition "
Seriously , what went on ?

[lodgernz]

Moderators, think about what you are doing, you will wreak this site, Glenn is a national treasure and should be treated as such, with some respect!

+1 .

[katinas]

Cant believe Husa, so much nice material. Is it happen today after you posted image of TZ 750 exhaust or earlier?
On image history browser pictures are still visible.

[breezy]

+1 .

+15....:msn-wink:

[ken seeber]

He's fired ??????????????

That's total CRAP

We want Glenn, Husa or is it Hooser or, in fact, the whole three of them !!!!!!!!!!!!!!!!!!!.

[Pursang]

WTF did I miss ,
can I sign a " Bring Back Husa Petition "
Seriously , what went on ? :shit:

Ditto for Me

[2005bully]

:shit:

Ditto for Me


Where do I sign!!!

[TZ350]

Hi Husaburg
I love your pictures and posts on here, I hope we don't loose you.
Warmest Regards TZ

[Flettner]

Valve keepers, work of the devil. Slippry little buggers.
Another reason I dislike fourstrokes.