ESE's works engine tuner

[wobbly]

So what did you do with the manifold after the reduced size duct ?

[tdc211]

So what did you do with the manifold after the reduced size duct ?


I duct was still short. I did not lengthen it.
Didn't want to reinvent a pipe. Sim showed a solid 1.5 or 2hp gain (cant remember) the outlet matched my header opening.tapered up to 32mm . Engine did change tone. Sounded a little better. Probably from less burnt gases I am guessing. But it didn't help or hurt it .
Was a pretty big gain in cfm

[dutchpower]

Can you explain this more tdc211

I was already at 29ish hp. Up from 23. So I flowed the cylinder on my flowbench and redid the exhaust tunnel with clay to find the optimum shape.then welded it and it is pretty much right on size to eng mods rules in sim and I found the cfm as well on the bench. But yet no more power

[wobbly]

I would only guess that if you were at 29 Hp then added the 75% duct exit geometry with an oval to round transition into the header ( that always works in a sim ) but did not gain
any power from this - then it would have to be that another element of the system has become the limiting factor.
Blowdown capability is usually the first mismatch to look at - if that or another STA number isnt capable of going over 29 , then no matter what efficiencies you can generate in other areas, the bottleneck still exists.

[tdc211]

I would only guess that if you were at 29 Hp then added the 75% duct exit geometry with an oval to round transition into the header ( that always works in a sim ) but did not gain
any power from this - then it would have to be that another element of the system has become the limiting factor.
Blowdown capability is usually the first mismatch to look at - if that or another STA number isnt capable of going over 29 , then no matter what efficiencies you can generate in other areas, the bottleneck still exists.

I agree. I think I know where it is.

[tdc211]

[QUOTE=dutchpower;1131161343]Can you explain this more tdc211

Not sure what you want me to explain. Think I gained 4 or 5 cfm . Would have to look at my excel sheet for exact #. But that is a decent gain. I been playing with car heads for the last few years and have a nice flowbench. So I used it on this.

[tdc211]

Stock chart has a 142 main 100% stock . Pump gas.
Jet it how you want. It wont go over 23 from ktm . I have a eng dyno. But its turned down to whp. Less mass in software.
My chart still on pump gas as well.

[dutchpower]

Exhaust duration around 195 deg.

[tdc211]

Exhaust duration around 195 deg.

close, but transfer stagger and there timings/area, are probably more important

[dutchpower]

Do you have the stock CDI grafiek tdc 211

[tdc211]

Do you have the stock CDI grafiek tdc 211

The stock curve is with a oem cdi 2018.
When I say it would hardley hit 23. I mean 23.0
Usually was in the high 22s. Corse change the pipe and
Ign. gets you in the 24s. Pipe in 29hp chart is 800mm long.

[dutchpower]

I meant from the CDI

[tdc211]

I meant from the CDI


i know what you meant and if i remember right the oem 19 box is different.
i had a hpi programable,so wasnt a issue

[tdc211]

i will add, if your wondering if my timing curve curve started out and ended correclty, yes it did. i tried changing the heat with ign.
i tried it all over the place. no free lunch, it just didnt care.

[wobbly]

Seen that before many times. If an engine is insensitive to ignition changes then there is some element that is overpowering EVERY attempt to make more.
When you find the issue , then even changing static advance by only 0.2mm will have an instant effect , usually pumping up the mid , and killing overev.

[dutchpower]

Nearly all the ktm's have that issue (2 stroke )

[koenich]

did you do any changes besides ignition and exhaust to get to ~29 hp? friend of mine has a standard 85SX and dynoed it at ~20 rwhp (which was quite disappointing) but ran out of time to jet it down...

[tdc211]

did you do any changes besides ignition and exhaust to get to ~29 hp? friend of mine has a standard 85SX and dynoed it at ~20 rwhp (which was quite disappointing) but ran out of time to jet it down...

I've been modifying these sense 2010. 0r 09
I changed just about everything mentioned in these 2500pages. Pipe and ign will get you little over 24hp.
If you didnt have time to lean it. 21hp is normal. Evertime i.put one on the dyno I tried to improve over the last one

[Flettner]

piston ring, what would one make it from, nitrided P20?
Or high speed steel, hard chrome wear surface. Or would just 4140 be suitable? Nitrided.

[Brett S]

piston ring, what would one make it from, nitrided P20?
Or high speed steel, hard chrome wear surface. Or would just 4140 be suitable? Nitrided.

What dimensions do you need?
Going by past history i'm guessing this isn't going to be a conventional ring..
Can you modify an existing ring?

[Flettner]

77mm larger dia. I see I've made the ring groove 2mm wide, not sure what I was thinking here. Could be I was thinking two 1mm rings side by side. Although It doesn't get the same acceleration / deceleration as a normal ring, mass not so important so probably a single ring will fit the bill.

[Brett S]

77mm larger dia. I see I've made the ring groove 2mm wide, not sure what I was thinking here. Could be I was thinking two 1mm rings side by side. Although It doesn't get the same acceleration / deceleration as a normal ring, mass not so important so probably a single ring will fit the bill.

Some of the foulstroke 250 mx bikes are 77mm, but have a 0.8mm ring. KXF, RMZ and YZF.
Honda has 78mm and 79mm but i assume also 0.8mm.

[Brett S]

After a quick google there is other options:

Honda GX270 is 77mm and 2mm.
also a VW engine is 77mm.

[Flettner]

what are they made of? Cast iron I'd assume.

[husaberg]

77mm larger dia. I see I've made the ring groove 2mm wide, not sure what I was thinking here. Could be I was thinking two 1mm rings side by side. Although It doesn't get the same acceleration / deceleration as a normal ring, mass not so important so probably a single ring will fit the bill.


Some of the foulstroke 250 mx bikes are 77mm, but have a 0.8mm ring. KXF, RMZ and YZF.
Honda has 78mm and 79mm but i assume also 0.8mm.


After a quick google there is other options:

Honda GX270 is 77mm and 2mm.
also a VW engine is 77mm.
old mitzi colts are 76.9mm and 2 mill
citreon as well
fiat 1500
Honda 76.9
mazda 1500 "323 1490 i think"
some mercs have 2.5mm

https://www.hastingspistonrings.com/assets/files/9/hastings_catalog_master.pdf
http://www.mingyang-group.2u.com.tw/pdf/CAPT-Piston.pdf

[Flettner]

No matter what I use Im going to have to re manufacture it anyway, so why no start fresh. Surface has to be curved / spherical and it needs to be hard, like a nitrided surface. So I'd guess steel, not cast iron. It will run against a cast iron 'sleeve' as it were. Nitride surface is in the order of 70R surface hardness and slippery but only microns deep.

[dutchpower]

Working on the tunnel on stock cil.

[tdc211]

Working on the tunnel on stock cil.

how much blowdown sta did you start with? stock amount?

[tdc211]

work the subs, theres more cfm there, not much, but some

[dutchpower]

Copy and scale the bidalot 50 cc exh. tunnel
Later 193 deg exh.duration ( Green on the dyno grafiek )

[peewee]

did you guys see this? supposedly a sucessful way to weld 7075. now where the hell do i buy the filler rods :2thumbsup

https://www.repairerdrivennews.com/2019/02/26/ucla-team-develops-new-wire-to-weld-7075-aluminum/

[ken seeber]

How things change with time.

Central spark plugs....gone. :msn-wink:

Tight squish....gone :msn-wink:

345861

[koenich]

Copy and scale the bidalot 50 cc exh. tunnel
Later 193 deg exh.duration ( Green on the dyno grafiek )

the Bidalot does a lot of things right...great cylinder out of the box.

[dutchpower]

Got that cil.from 19 hp to 22.7 hp changing exh.tunnel and new pipe

[Flettner]

How things change with time.

Central spark plugs....gone. :msn-wink:

Tight squish....gone :msn-wink:

345861

Ok, there is a bit missing.

[tdc211]

i figured results be different with a stock cylinder.
19 to 22.7 ? i thought you started at 23.3 or something.

[koenich]

he's likely talking about the Bidalot 50cc cylinder (at least that one has ~19 HP stock).

[dutchpower]

tdc211 ( Got that cil.from 19 hp to 22.7 hp changing exh.tunnel and new pipe )


Last post is from Bidalot 50cc cil.

[WilDun]

Ok, there is a bit missing.

Yes Ken, some info missing!

[tdc211]

tdc211 ( Got that cil.from 19 hp to 22.7 hp changing exh.tunnel and new pipe )


Last post is from Bidalot 50cc cil.

22.7 out of a 50? At what rpm?

[koenich]

Standard (incl. their exhaust) they make ~18-19 HP peak at ~13.500 1/min.

I'll start dynoing mine on Saturday, also testing a much shorter exhaust since I think the layout must have massive reserves reg power if it makes 19 HP at such "low" revs.

[dutchpower]

Kreidler Rotary

[tdc211]

Kreidler Rotary

i see, that is some power

[F5 Dave]

And some revs. Sheesh, I spent so much time with clearly a false rev ceiling based on RG50 in the 90s much past 12,000 killing cranks. I thought 13-14 was getting up there.

[koenich]

The modern cranks will last 40-50h on a 50cc with roughly 18 HP with overrev up to 14.000 1/min under racing condition...

We won that race with a 20h old crank 😁 https://youtu.be/KR-R6G76_i4

@dutchpower: care to share the changes in detail (exhaust channel and exhaust measurements)?

[dutchpower]

Ign. 1000 30

6500 30

17500 26

14500 19

16000 10

17000 9

[dutchpower]

Exhaust latest test 22.7

[wobbly]

I have never been able to understand why people in general ( tuners ) seem to think that spinning any under 125cc engine to 12,000 is " thrashing " it do death.
The 125 Aprilia GP engines were reved to 14,000 all day , and today we apin the 125 kart engines to 15,000 on a regular basis to delete gerchanges between corners.
Having a 50 or 85 making max power at 15500 , in terms of piston speed and inertial forces on the crank/rod/bearings is simply using the ( very ) safe rpm available.
If you can hold the torque up , having peak power 3000 rpm above that 12,000 level will effectively add 25% more Hp , and have no deleterious effect on power "range " or reliability.

And that Bidalot pipe is so last century , with many design features that could be dramatically improved with a days work on a computer screen.

[dutchpower]

And that Bidalot pipe is so last century , with many design features that could be dramatically improved with a days work on a computer screen

2 days is that oke for you to post pipe that give more !!!


https://www.youtube.com/watch?v=qi37ziNab_g&list=RDqi37ziNab_g&start_radio=1

[koenich]

Thanks for sharing! 23 HP is impressive...

Absolutely agree with you Wob, however the aftermarket cranks (even the most expensive ones) for the Derbi engines are usually crap and for the endurance races (main race 8h) I tend to want to keep the revs down.

[wobbly]

Hey Dutch , you send me the .pack file ( PM me and I will send email ) and I will spend a day on the pipe and post the results.
All the time listening to Mr Zappa , as I do regularily.
Yellow snow is quite inspiring , except when its in your eye.

[F5 Dave]

My reservations were based on archaic Suzuki engine that would die at 13,000. Rebuilt them every season to ward off mishap.

Fed Yamaha parts (non competition as per intent, 's' or otherwise on 'motors') I figured 13000 peak with sharp cut off should be ok. First engine did a billion miles and still had the same crank in it after 10 years. Clearly no where near limit. By then the Derbi engine had same TZR rodkit fitted but I never got around to increasing the revs as I wanted to see how a Spanish engine held up otherwise.

It's gone now, but clearly if I'd been paying attention to what was going on overseas it would have gotten me over my false fear.

[polcat88]

What they said before me - except to add that having the Aux at the same height as the main is never a good plan.

Can you expand on this statement, Wobbly? Specifically what are the negatives and how much difference in height would you recommend?

[wobbly]

Sure I love expanding.With a 3 port you have several elements interacting.
Firstly , is that when you stagger the Aux below the main port the initial wave front exiting into the duct has a high amplitude.
This has the effect of recovering the maximum energy from the remnant Blowdown pressure above the piston when the port cracks open.
Thus a high energy " pulse " travels down the duct and into the header , then eventually into the diffuser.

Once this wave front has been formed , and on its way , the lower positioned Aux then rapidly bleed down any remaining pressure into the duct.
BUT , be aware that the path length from the Aux ports , often around to bore center , is way longer than that of the main port - as they are effectively in a perpindicular relationship.

Open all three ports together , and you have two downsides.
First is that the initial opening area is much larger - thus the wave amplitude is reduced.
And secondly the two largely differing path lengths effectively " smears " the wave formation in time.
These two effects combine to reduce the wave fronts energy available to be used for scavenging by the diffuser , or plugging by the tailcone.

Timing variation of the port set varies according to the actual setup.
First case would be the obvious Aprilia.This had reverse stagger transfers , so the Aux ports floor were able to be very low - achieving a ton of area , without causing drastic short circuiting from the A port roof.
This , along with the main ports powervalve action , meant that the Aux ports were optimally positioned at around 9* of duration lower. This height still achieving sufficient Blowdown STA to match the transfers capability.

Then we have a TM125 R1. With slightly less power capability , matching the Blowdown STA needed results in an optimum of near 5* duration split - some what affected also by the factory refusing to use pin plugs ,that
would allow the Aux timing width to be increased, as well as the duct entries to be less tangential to the bore.
This translates to just over 1mm of height difference on the 54.5 stroke , and reducing the height difference immediately kills front side and peak power , with a gain of some overev power right at the very topend limit.
Way less total area under the curve.

[tdc211]

quote
These two effects combine to reduce the wave fronts energy available to be used for scavenging by the diffuser.

i was sort thinking along this line above. idk, been i definitely thinking something like that.

every time i have gotten greedy for a little more blowdown (when power is good) and raising subs just a tic higher , it just goes to hell in a hurry.
seen that quit few times.

[dutchpower]

Hey Dutch , you send me the .pack file ( PM me and I will send email ) and I will spend a day on the pipe and post the results.
All the time listening to Mr Zappa , as I do regularily.
Yellow snow is quite inspiring , except when its in your eye.
Think i get 2 answers

[tdc211]

Like 5 years ago. Guy that helped me time to time iced races a 3 port cr250. I stripped the plating. Welded up the sub roofs alot lower. Reported, Cant remember timings. Just used the sim. That and thin reed custom block made way more power . I have the chart on a old laptop. He won alot that season. Next season 1/2 thru it cracked on a bridge. Was junk unfortunately.

[polcat88]

[QUOTE=wobbly;1131161616]Sure I love expanding.....


A thorough and logical expansion! Thanks Wobbly.

[ceci]

Hi Katinas.
I want to ask you if this may be one of the reasons why you get a better result in the 1st model than in the 2nd model.
The Zhukowski pulse that I think occurs when passing point B to point A, creating the pressure pulse which when reaching the end of its path is returned to a positive pressure pulse which coincides with the opening of the transfer (point D exceeds point C) obtained supercharginghttps://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=344909&d=1583950655

[katinas]

Hi Ceci
Yes, the pressure fluctuation in trans tunnels at closed phase period (aprox 10 degree duration) helps to charge at higher revs.
But maybe your words, nicely confirms test that did not work. Most interesting and informative was 4 scheme test, when engine completely stop at 5000 rpm. as positive pressure blocked intake process when arrive at wrong time.

3 and 4 types is very similar, except that 3 type, with extended transfers deeper in the crankcase and with relatively higher position of intake tunnels, works in normal way.

I am still testing on the road, but finally tested things on my friend,s dyno, so many tests.
This is rear wheel dyno graphs of 1 and 2 types.
PS. 1 type now with slightly opened crankcase to trans, about 1/4 of original 2 type area, for better transition from mid to high range.
PS. Engine Honda NS 250 modified for only one horizontal cylinder, vertical blocked, 57 mm bore and 50.6 mm stroke 129 cc

[ceci]

3 and 4 types is very similar, except that 3 type, with extended transfers deeper in the crankcase and with relatively higher position of intake tunnels, works in normal way.


The normal operation is that of scheme 2, it seems a standard configuration.
The operation of scheme 3 is much lower than scheme 2, I think this is due to the fact that a percentage of the charge gets trapped in the crankcase (in scheme 1 this percentage of charge if it is used and transferred to the cylinder).
You are doing a great job of research, which is revealing important questions for a better engine development.

[katinas]

Ceci, 2 scheme is not normal std cylinder. The main central intake windows are closed with epoxy and all intake goes through enlarged side tunnels directly to transfer ports, partly to trans window partly through cylinder side cutouts as they are standard, not closed.
Add two dyno graphs for comparison
RED- 2 type with closed main intake ports
GREEN- Same cylinder, just main intakes ports are opened ( brake out epoxy ) say 2.1 type.
30 minutes between tests. Piston is the same with side pockets.

[Norman]

Ceci, 2 scheme is not normal std cylinder. The main central intake windows are closed with epoxy and all intake goes through enlarged side tunnels directly to transfer ports, partly to trans window partly through cylinder side cutouts as they are standard, not closed.
Add two dyno graphs for comparison
RED- 2 type with closed main intake ports
GREEN- Same cylinder, just main intakes ports are opened ( brake out epoxy ) say 2.1 type.
30 minutes between tests. Piston is the same with side pockets.

Thanks for information. It would also have been interesting to see the 1 type without the 1/4 opening and also sensitivity to a bit of changing on the transfer channel volumes..But, a lot of work to do all this. What would you say is the "baseline" power level of the engine?

[katinas]

Norman, yes transfers ports volume, with fully blocked freeway communication between crankcase and transfers ports (just one way from crankcase to transfers ports through side reeds), very important maybe critical for 1 type schematic performance. With ¼ open free way to crankcase add little torque at mid rpm, but top end not changed as tested on the road.
Cylinder bottom wall area must be fully exploited for side reed valve with 1 type. Still tested only with two side reed petals, but still left free places on the wall to add another pair. With 1 type schematic on the road engine feels much stronger than 2 type in upper gears, maybe because of cooler charge that goes directly from carb.

Honda NS cylinders designed for 9.800-10000 rpm max power and the biggest restriction is small reed house. Reed cage is even little smaller, than usually used on MX 85 cc engines, and testing on dyno shows big improvement with CR 85 reed cage and even more with Husqvarna/KTM 85 v force3 all the way from bottom to over rev.( later add graphs )
Now start adapt Honda CR 125 1981 cylinder with so much bigger transfers ports ( that maybe wrongly left from last air cooled CR 125 and not needed for new water cooling engine) , two exhaust ports, and normal for 125 size of reed house.

[Norman]

Norman, yes transfers ports volume, with fully blocked freeway communication between crankcase and transfers ports (just one way from crankcase to transfers ports through side reeds), very important maybe critical for 1 type schematic performance. With ¼ open free way to crankcase add little torque at mid rpm, but top end not changed as tested on the road.
Cylinder bottom wall area must be fully exploited for side reed valve with 1 type. Still tested only with two side reed petals, but still left free places on the wall to add another pair. With 1 type schematic on the road engine feels much stronger than 2 type in upper gears, maybe because of cooler charge that goes directly from carb.

Honda NS cylinders designed for 9.800-10000 rpm max power and the biggest restriction is small reed house. Reed cage is even little smaller, than usually used on MX 85 cc engines, and testing on dyno shows big improvement with CR 85 reed cage and even more with Husqvarna/KTM 85 v force3 all the way from bottom to over rev.( later add graphs )
Now start adapt Honda CR 125 1981 cylinder with so much bigger transfers ports ( that maybe wrongly left from last air cooled CR 125 and not needed for new water cooling engine) , two exhaust ports, and normal for 125 size of reed house.

A big improvement over STD which should be around 21-23? It will be interesting to follow your continued work.

[katinas]

With all std stuff, stock engine 1 cylinder rear wheel power is about 16-18 at 9500 rpm.
Add video ( youtube- ESE NS https://www.youtube.com/watch?v=BbZwRLXAmIY) from dyno tests , I cant remember what was tried in this video, so many tests, but power started to drop as temperature rise more than 70 c.

[Tim Ey]

If I recall correctly, here were som folks that needed a 60mm piston?

Well, turns out I did too.

345925
345926
345927

Overrev 60mm piston (by Wössner)
A specialitiy about this piston: The delivery scope contains two wristpins. A light and short pin and a longer, heavier version. The piston has two clip grooves each side - for the short pin, you are using the inner grooves, for the longer pin you will use the outer grooves. The idea is, to change the balancing factor of the crankshaft with very little measure. (And also to have an additional groove on the outside, for a Torlon Plug whilst using the shorter pin :Police:)

Ring position: 90° to the piston pin (central over the inlet)
Piston pin: 15mm
Compression height: 29mm
Piston dome height: 3mm
Piston length (without dome height): 64.5mm
Exact diameter: 59.94mm
Piston pin length: 45mm and 50mm
Weight, with the short pin: 199g
Weight, with the longer pin: 205g


If you need one, write me a PM.
Regards
Tim

[ceci]

But maybe your words, nicely confirms test that did not work. Most interesting and informative was 4 scheme test, when engine completely stop at 5000 rpm. as positive pressure blocked intake process when arrive at wrong time.

3 and 4 types is very similar, except that 3 type, with extended transfers deeper in the crankcase and with relatively higher position of intake tunnels, works in normal way.



Type 2, the crankcase, transfer tunnels and intake port is a single plenum.
Type 3, the solid barrier creates two plenums, to be less the% of the crankcase, this has better suction power.
Type 4, the reeds become a solid barrier creates two plenums, as the% of the crankcase is greater, it loses suction power

345929345930345931

[katinas]

Yes, maybe this is one of the reason why 4 type capitulate, but maybe not one. When 3 type firstly tested two years ago on NS engine, did not feel any big changes at low and mid range from normal scavenging, but engine revs higher.
Then tested same on the Suzuki RGV (add photo), but actually this was not 3 type, as intake was placed at the bottom of transfers ports, so we can call it 3.1 type. And engine reaction was not like on NS with 3 type. At 8000 rpm in the first gear engine nearly stopped, but if overcome this, engine revs again. Then made two 16 mm holes on separator sides to add pressure from crankcase and this immediately eliminate dip. So only the location of intake to transfers differs for 3 and 3.1 types.
Maybe in theme, add engine reaction with different, intake through transfers, timing duration.
Thank you for good point.

[ken seeber]

UHV 6 180520

So, after some thought (and being tied up on other work related stuff) I thought it’d be easier to do the Jante style flow tests, not on a motored engine, but on a simple steady state arrangement. Fortunately our shop vac, blowing thru the setup created approx the same tip lift when being motored at around 3800 rpm. Printed up a simple base plate and gantry to carry a hypodermic syringe pick up needle which is then connected to a U tube manometer. The base plate has a grid of holes on a 4 * 4 pattern that small pins in the gantry locate into, the manometer height being recorded at each position.

Then conducted 3 tests. After reading the mm H2O heights at each grid point, these were put into Excel and subsequently converted to velocity points. For each test there is a pic of the valve and head. Must point out that there could be quite some differences between these steady state flows and that of a running engine at various loads and speeds.

345952345953

Could be a bit flaky and dodginess in some instances, but the general flow characteristics can be seen:

A couple of quick comments could be:
3 petal. Very high flow in outer circumference plus a high central reverse flow. Not indicated in the test is the very high swirl nature, around 30 deg helical angle.
Annular. Very high central flow with a strong reverse flow down the outer circumference.
Convoluted. Similar to annular, but with a much lower, but universal downward flow and almost no reverse flow.


345951345954345955

Overall, I think none of these is suitable, something that I will confirm soon when I can conduct a shootout of all these plus a standard (Schnurle) engine.

[SwePatrick]

Me again with all these questions ;)

Is there any engine that shares the same Reedcage boltpattern as TZR250 (2ma) engine?

Rgds

[F5 Dave]

I'm going to say TDR250. But you knew that.

[SwePatrick]

I'm going to say TDR250. But you knew that.

Yeah,, 1kt(tdr engine) and 2ma (tzr engine) is almost the same ones ;)

[husaberg]

Me again with all these questions ;)

Is there any engine that shares the same Reedcage boltpattern as TZR250 (2ma) engine?

Rgds




I'm going to say TDR250. But you knew that.
boyseen 721
Fits
YAMAHA R1-Z 90-99

YAMAHA TDR250 88-

YAMAHA TZR250 85-87

Personally i woul be surprised if a few other YZ125 or DT200 ones dont fit.
One the back old old reed packets boyseen used to have a list by part number of what fitted what.
I have an old one but it buried somewhere.

[jbiplane]

Need advice.

I used on my 2-cylinder boxer crankshaft hardened to 48..52 hrc press fit of conrod pin 0.115 mm at diameter 24mm
Am I correct or it too much? Getting hesitated. Pin hardened to 60hrc and have internal 10.8mm hole...

[wobbly]

The crank press fit at 0.115mm is getting tight for a pin with a big hole thru it.
Reason , the pin will cone downward as it approaches the crank wheels , due to the softer material of the interior , plus the big hole - if you use much more press fit than that.
Best solution is to assemble it , true it , then press in small plugs on each side with the same press fit , un assembled.
This helps to tighten up the press fit grip , and stops the pin ends from crushing inwards and causing the rollers to skid over the curved ( ie not flat ) surface.
Saw this first on old KT100 Yamaha kart engines.

[jbiplane]

The crank press fit at 0.115mm is getting tight...
Thanks for comment. Finally will use press fit 0.075+- 0.005

Any advice related allembly process. Is there any special greases or some other mixture chemicals to simplify assembly and make contact stronger?
Some kind of CRANKSHAFT LOCTITE
I heard zinc coating can improve strength of press connection in times. May be grease with zinc powder will make a job?

[wobbly]

Loctite 620 makes assembly easyer , and it acts as a surface lube long enough to make truing quicker - before it sets anerobically.
I have used it for years after alot of tests to see what effect it actually had , for assembly , then truing , finally seeing how much extra press pressure was needed later to split it apart.

[Pursang]

Loctite 620 makes assembly easyer , and it acts as a surface lube long enough to make truing quicker - before it sets anerobically.
I have used it for years after alot of tests to see what effect it actually had , for assembly , then truing , finally seeing how much extra press pressure was needed later to split it apart.

That's a handy tip, Thanks wobbly.

Cheers! Daryl.

[jbiplane]

Loctite 620 makes assembly easyer...
Hi Wobbly. Thanks, will follow your advice.

[TZ350]

.
.
Paris 1976 https://youtu.be/YeEeyOCJ1OA
.
.

[katinas]

Type 2, the crankcase, transfer tunnels and intake port is a single plenum.
Type 3, the solid barrier creates two plenums, to be less the% of the crankcase, this has better suction power.
Type 4, the reeds become a solid barrier creates two plenums, as the% of the crankcase is greater, it loses suction power

345929345930345931

Hi,
Just played a little with crank space separators and tried another variation, with smaller volume under piston , call it Type 4.3.
Tried to ride again with Type 3, Type 4 and Type 4.3. Engine response to Type 4 and 4.3 very similar- impossible to overcome 5000 rpm in any way in the 1 st gear. Without loading, torque drop very clear seen in the video https://www.youtube.com/watch?v=PsiKnYLnGaE, but both 4 and 4.3 types, can jump over dip.
With Type 3 can ride in normal way, but clearly heard sharp noise, from airbox, just at 4000-6000 rpm interval and leaner mix needed at higher rpm, in comparison with Type 1 and 2.

Add comparison graphs, from Type1 tests with different B port opening time, from 136 to 140, A left unchanged 142. Time between tests 40 min.

[katinas]

https://www.youtube.com/watch?v=4SkyAnVIChE
16.15

21.20 I remember, really like camshaft gear train position on Yamaha M1, but from where it comes .....

[lodgernz]

Husa, do you have any idea of a 6-speed box that would fit a GT100?
Asking for a friend...

[ceci]

Hi,
call it Type 4.3.
Tried to ride again with Type 3, Type 4 and Type 4.3. Engine response to Type 4 and 4.3 very similar- impossible to overcome 5000 rpm in any way in the 1 st gear.

Hi Katinas
That fact of not exceeding 5000 rpm is what attracted me to know his research work, to discover if the TZ350 theory of pressure in the crankcase are true.
He has a huge job with so many types and variations on each type.
Type 1 various opening times port B.
Type 2 and type 2.1
Type 3 and type 3.1
Type 4 and type 4.3
Much and very good work, it is appreciated because it helps a lot to understand what happens inside the 2S engine

[mr bucketracer]

Husa, do you have any idea of a 6-speed box that would fit a GT100?
Asking for a friend...are you not thinking gt125 twin starting its life as (-;

[lodgernz]

are you not thinking gt125 twin starting its life as (-;

Sorry, I thought you said it was a GT100

[husaberg]

husa, do you have any idea of a 6-speed box that would fit a gt100?
Asking for a friend...

gt100?.............

[mr bucketracer]

Sorry, I thought you said it was a GT100it is now but as that's no such thing . It started as a gt125 twin

[F5 Dave]

Don't mention the watercooled MB50 barrels.


It's been so long ago I cant remember rightly who built that. Red leathers perhaps. I'm getting Phill Bird on the ouiji board, but I'm not even sure I can remember such a person so that's likely wrong.

[mr bucketracer]

Don't mention the watercooled MB50 barrels.


It's been so long ago I cant remember rightly who built that. Red leathers perhaps. I'm getting Phill Bird on the ouiji board, but I'm not even sure I can remember such a person so that's likely wrong.it was phil bird

[mr bucketracer]

Yes mb50 barrels . I remade the heads and ported the inlets think its got rg250 readvalves cut of and welded on the crankcase of the engine running the smaller nsr250 carbs. Still the best looking bucket engine built but the gearbox is not good

[husaberg]

Gt125 or X4 otherwise known as in japan RG125E gear ratios are
3.00 1.812 1.250 1.000 0.875.



the Gt125 had quite a long production run i would look at the parts fiches for gear ratio changes during its production run
I know the GT250 and GT380 shared gearboxs so it not out of the realms of reality that the Gt gearbox was used in other models

edit
there is quite a few asumptions here but if the gt185 shares ratios with the 125 you have some gearing options so maybe close up the ratios
The X5 version of the GT200 has very similar ratios it might be a co-incidence but
2.91
1.75
1.25
1.00
0.875

The Gt185 ratios are
346003
https://www.oldjapanesebikes.com/mraxl_GT_Resource/manuals/gt185man/index.php

Funny Enough the exact same ratios and more importantly primary drive ratio is on a TS185N
Transmission gear ratios:

1st: 2.75:1 (33/12)
2nd 1.81:1 (29/16)
3rd 1.25:1 (25/20)
4th 1.00:1 (23/23)
5th 0.80:1 (20/25)
Primary reduction ratio: 3.21:1 (61/19) (clutch and crankshaft)

also going through the parts fiche on the GT185 shows the same gears part numbers were also used on other models
from the DS 185to the TS125 and the RV125
345999

now some of these used different ratios for other gears
plus the rv itself has many ratios
https://www.partsfish.com/oemparts/a/suz/50d3a2d8f8700229982f4fa0/transmission-rv125m
https://www.partsfish.com/oemparts/a/suz/50d3a2d7f8700229982f4f9f/transmission-rv125k

if you look through the parts fiches most will tell you the teeth for each main and countershaft gear.


i also know at least one model of the TS125 ie the C and the N https://www.partzilla.com/product/suzuki/24231-48001?ref=ce826edfaa189916d70e7ae8f1e290cd2b7c79d4
was available in 5 and 6 with the same cases. although this might be the later ones ( iam not a suzuki dude)
there are a lot of ifs and asumptions in this info but its worth a poke around.
i had a look but there is little to find for the GT125 itself.

if 185 and x5 gears fit you can close up first and top for better ratios.

Here are the dimensions for th gear shafts on the ts125 5 speed and the 5 speed TS185.
346018346019346020
http://84.22.143.158/files/%D0%A0%D1%83%D0%BA%D0%BE%D0%B2%D0%BE%D0%B4%D1%81%D 1%82%D0%B2%D0%B0/Moto/Suzuki/Suzuki_TS_185_TS_185_A_1980_Manual_de_reparatie.pd f


here is the later TS125ER style gear widths made for 6 speed i belive
from memory Rob used the 6 speed in one version of the GP didnt he so maybe they are all the same gear shaft spacing
346021

[lodgernz]

Gt125 or X4 otherwise known as in japan RG125E gear ratios are
3.00 1.812 1.250 1.000 0.875.

the Gt125 had quite a long production run i would look at the parts fiches for gear ratio changes during its production run
I know the GT250 and GT380 shared gearboxs so it not out of the realms of reality that the Gt gearbox was used in other models

Thanks Husa, good info, as always.

[F5 Dave]

If you take out the kickstart and idler gears you could probably fit a sixth gear pair in there. You might not be able to select or use them, but it could be comforting to know they are there.

[ken seeber]

FYI

https://www.roadandtrack.com/new-cars/car-technology/a32612802/entry-ignition-two-stroke-engine-design-explained/

[lohring]

It sounds like a very complex engine. The piped, crankcase compression two stroke engine is very simple, light, and inexpensive. With current fuel costs I can't see how improved efficiency would lower costs enough to be worthwhile. As a former owner of 3 different diesel cars in the 1980s, the improved mileage was nice, but not enough to justify the extra cost and hassle. An electric power plant should kill it in maintenance, and longevity.

Lohring Miller

[peewee]

hey guys maybe somebody could find use in this. ive tried several ways to remove piston ring pegs but today ive found the best so far. just clamp the piston in a drill press and drill out the pin with a small carbide end mill. i used 1.58mm diam as that was very close to the peg diam but they make some down to .8mm diam. also it was 2flute center cutting that can make plunge cuts. i did four pegs in no time with one bit and it could still do many more pegs as it plenty sharp. theyre only $10 and high qaulity usa made. i got it here https://www.kodiakcuttingtools.com/

[TZ350]

hey guys maybe somebody could find use in this. https://www.kodiakcuttingtools.com/

Thanks. that is a great find.

[husaberg]

Thanks Husa, good info, as always.

I found out a lot more stuff and added it above as well
let me know what the GT125 primary ratio is and if the gear shafts are the same spacings

okay here is the parts fiches for the Gt125 and the later X4
https://www.npm.fi/fi/varaosa-luettelot/suzuki/125-cc/gt-125-1973-1977/10-vaihteisto
https://www.npm.fi/fi/varaosa-luettelot/suzuki/125-cc/gt-125-x4/10-vaihteisto


There are part numbers that are clearly TS125 and TS185's in both.
So i would be quite confident in saying you have some other parts that are compatible from the series of TS125 nd TS185 and GT185 right up until the TS125er and 185ER.
somewhere in these you will find some better ratios
As i said earlier a GT185 first and second are higher.
if i was you, i'd go through the parts fiches for all the models i have mentions and put the number of teeth for each gear into a spreadsheet then check for gear changes in other years, in those same models as well.
then find the best ratios to suit.
You might even find you have the room to fit the 6 speed of the later TSER based models if you have the width.

346027346028346031


Yes mb50 barrels . I remade the heads and ported the inlets think its got rg250 readvalves cut of and welded on the crankcase of the engine running the smaller nsr250 carbs. Still the best looking bucket engine built but the gearbox is not good

https://www.kiwibiker.co.nz/forums/showthread.php/124128-Bucket-development-A-few-questions-for-the-wise-ones?p=1130333983#post1130333983

[JanBros]

built some straight test pipes, and than made a curved version of the best one (the front one), but sadly lost some 13% power from straight to curved.

from re-reading a lot of posts about pipes : still too sharp edged between cones I suppose ? the angles in the drawing are the cut-angles per cone, so the angle between cones is double. What would be the maximum angle between cones ?
my problem is that I do not have a lot of space so the pipe is 1 big curve. the dash-dot lines are the boundaries in which the pipe needs to stay.

would it be better if I devide the pipe in 3 parts : straight beginning (+/- up to difuser), a tight 180° curve with a lot of sections to keep angles between cones low containing+/- the difuser and than straight back with the belly/baffle , so that the 2 straights are paralel next to each other ? or is a tight 180° curve not good for power ?

[wobbly]

Several issues are apparent.The max 1/2 angle you can use is around 7* ie 14% when rotated 180* and this max applies well into the diffuser only.
The straighter , for longer , you can make the header , the better. Also having the header turn sideways on the horizontal plane , causes a asymetric return wave shape at the port , upsetting the trapping efficiency big time.
Most power is lost when having sudden angle cuts in the header , but every cut in the rear cone looses power as well.
Also every weld should be hammered flat ( planished is the correct term I believe ), you can only get away with not doing this if you are back purging a SS or Ti pipe with lots of small angles , and max craftmanship welds.
If you have the right software then one thing many people dont realise is that every join of two differing cones can be made as a cut/turn as well.
This makes a big difference to how the pipe shape looks visually appealing , and can also help reduce the number of cuts made in each cone section.
Having a U bend leading up to and including the mid section , and then angle cutting the rear cone join line is the best ( leaving the actual rear cone dead straight ), having tested all this in the very tight confines of multi cylinder Jetskis.
Lastly , if the seagull shite welds are so bad on the outside you feel the need to grind them off , just imagine what sort of shit is happening on the inside.

[TZ350]

here is the later TS125ER style gear widths made for 6 speed I believe from memory Rob used the 6 speed in one version of the GP didn't he so maybe they are all the same gear shaft spacing.

I originally replaced the GP 5 speed with a TS 5 speed. It required some modification to the input shaft and selectors.

346030

Then I fitted a TS 6 speed gearbox which is about 12mm wider than the 5 speed. It required a spacer between the crankcase halves and re location of the spring plunger thing that holds the selector drum in position after a gear has been selected.


346029

[husaberg]

I originally replaced the GP 5 speed with a TS 5 speed. It required some modification to the input shaft and selectors.

346030

Then I fitted a TS 6 speed gearbox which is about 12mm wider than the 5 speed. It required a spacer between the crankcase halves and re location of the spring plunger thing that holds the selector drum in position after a gear has been selected.


346029

https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1131032881#post1131032881


https://www.kiwibiker.co.nz/forums/showthread.php/145142-For-Kel-B-Grades-bucket-build?p=1130510314#post1130510314

i guess that means the GP has the same shaft spacings as well........

[JanBros]

tnx wobbly.
I have a TIG but suck at welding thin plates. So I use a MIG. I don't care what it looks on the outside - it's just for moped-MX - but after connecting a new section I did gring it all down. the insides of the turn's are super smooth, the outsides maybe not visualy but you can hardly feel it.

[JanBros]

new provisional design, all angles 14°
I know there is still a curve in the horizontal plane in the header , but that is only after +/- 20cm straight. and all MX pipes need to make a turn like that.

another thing I've been wondering : how to chose your angles and diameters in the cuts. I've drawn an example to show what I mean. above is a straight cone with angle and diameters.
below is the same cone on the left and right angled at a straight section.
If I keep the angle and end-diameter of the cone the same (on the left, 7.13 and 40), than the diameter of the next section becomes smaller (only 38.8)
If - on the right- I connect the "outside-lines" of the cone to the 7° angled line at the 40mm diameter circle which seems the proper way to me, the end-diameter of the cone hardly changes (39.7), but the angle of the cone is different (7.36°)

How do you guys do it ?

[koenich]

Recently stumbled above the same topic JanBros...

In CAD you can sketch a circle with the desired dia on an angled plane and connect that to another circle on an offseted (length of cone) also angled plane. I double checked with ConeLayout (thats how I previously did developed shapes) and if you add an angle to the diameter in ConeLayout it cuts the cone at an angle leaving you with an elliptical shape instead of a circle.

IMO the in-/outlet dia should be a circle with the desired dia to give the right hydraulic diameter, elliptical shapes or other projections will result in a different hydraulic diameter. This way you can also connect the cones to each other no matter which angle you asigned per cone or twist relative to each other you want to use.

[Wos]

Dear jan,

Used your great Excel to calulate an exhaust for a 75 cc classic enduro named hrd with minarelli engine :) to run it in german championship :) fantastic job Jan!
Thanks! !!!!!

And we have same Problem as you when using Programm cone layout. ..:(

Circumfence and diameter changes with angeling the cone ...found no solution too. ..but i think to use a more professional Tool will solf this... ;)... cone layout is free...not very advanced...;) craftsmenship is still necessary to make the cones fit ;)

Greets. ..grüße. ..wolfgang

[JanBros]

I also use cone layout.
previously I did it cone by cone, but then sometimes halfway the pipe I came to the conclusion it wasn't gonna work and needed to cut of several cones again, so this time I wanted to design the whole pipe first and stumbled on this problem.

[wobbly]

Sorry , I wouldnt have thrown so much shit if I had realised you were polishing off the inside welds.
Here is your cone , angle cut in 1/2 , in SolidWorks.
First is a thin revolve 359.8*, then the cut keeping one 1/2 , then copy the part and keep the other 1/2.
Then using the cut sketches , assemble the two.
Then is SKUSA CR125 Pipe assembly using this technique.

[Niels Abildgaard]

Time for a quantum leap in pipe manufacture and design.
During the all important blowdown phase exhaust leaves as a say 4 to 5mm high and 30 to 40mm wide flat jet.
All these round pipe design is maybe not optimum.
If it was of vital importance to me(it is not) to win bucket races, i would weld a straigth exhaust pipe of four strips,edge-welded going from rectangular at cylinder to square profile at exit.If I possesed a good straigth round pipe I would keep the same crosssection area as function of way from port and test both and compare.
When that gives a 10% improvement to the four strip thing it will be mathematical interesting to plot the four strips cutting form for practical pipes going round corners.

[wobbly]

I have dyno tested a header that matched the oval shape at the flange face on the cylinder , by simply crushing a round cone in the press.
It matched perfectly at the cylinder and transitioned to round over 1/2 its length ( about 90mm ).
This made between 1 to 1.5 Hp better thruout the used powerband - 10,000 to 15000.
Then I tested thye oval to round transition within the length of the slip fit spigot only ( 28.5mm )
This made near 1/2 Hp more everywhere.
Jan had told me he had tested this idea on a header with the big Aux duct ears shape as used by Aprilia , with sucsess.
EngMod agrees with the result , and now I need to revisit the idea with my even smaller 75% duct exit geometry ( including ears now ).

[F5 Dave]

Sorry? From reading that it isn't clear if the just in the spigot was 2hp better than the original setup or 1hp worse than the 90mm transition in the header.

[JanBros]

Dear jan,

Used your great Excel to calulate an exhaust for a 75 cc classic enduro named hrd with minarelli engine :) to run it in german championship :) fantastic job Jan!
Thanks! !!!!!


Tnx, but don't forget to thank Frits and Wobbly. The last thing I want to do is take credit for all their hard work .

[koenich]

So what you do Wob looks the same as Cone Layout, my issue was fitment cone to cone if you want to turn the next cone lets say 45° to the previous one. Always left gaps (especially in the header if you use the 7° angle). Troublesome for my sub par welding skills :facepalm:

Other issues I found with Cone Layout was that the developed shapes always were longer than the ones out of CAD.

d1 = 33,4 mm, Angle1 = 10°, d2 = 34,3 mm, Angle2 = -10°, l = 20 mm => Green Cone Layout Flat Pattern Export, Black CAD Development:
346048
The bigger circumference will give a bigger diameter (think thats why a lot of people are using correction factors).

[JanBros]

was about to say the same as you Koenich.

cutting an excisting cone is not the problem, it arises when you want to angle 2 different cones. I don't think there is a solution for it. just don't angle 2 different cones ?


I've exagerated everything in the drawing below : the dash-dotted lines show where it goes wrong : the angles change in this case

[Wos]

Tnx, but don't forget to thank Frits and Wobbly. The last thing I want to do is take credit for all their hard work .

Jan...i am fully aware that frits and Wobbly had taken part...jan thiel indirectly too ...isnt he ;) thanks to all :) even the other members here!! :)

Pleasure for me to listen and learn so much! :)

Wolfgang

[Wos]

Hard for me to explain the issue in english...hope dont tell bullshit ;)

There is a missmatch if you want to fit a flat bottom cone to a cone with angled top...even when both cones have same general angle. ..solution...avoid that...angle top and bottom same way...then the elips should be the same Circumfence ...

[koenich]

If you asign the same angle to the next cone it will have the same elliptical shape in Cone Layout, a perfect joint will be possible in 2 positions and the actual hydraulic dia will vary with the angle. The more you think about the cone stuff the more complicated it gets :wacko:

CAD with circles as in-/outlet should give a more repeatable solution IMO but as always - it's a 2stroke so who knows...

[dutchpower]

So what you do Wob looks the same as Cone Layout, my issue was fitment cone to cone if you want to turn the next cone lets say 45° to the previous one. Always left gaps (especially in the header if you use the 7° angle). Troublesome for my sub par welding skills :facepalm:

Other issues I found with Cone Layout was that the developed shapes always were longer than the ones out of CAD.

d1 = 33,4 mm, Angle1 = 10°, d2 = 34,3 mm, Angle2 = -10°, l = 20 mm => Green Cone Layout Flat Pattern Export, Black CAD Development:
346048
The bigger circumference will give a bigger diameter (think thats why a lot of people are using correction factors).

Difference

[koenich]

nope, both use the neutral fiber. the circumference difference only occurs when entering an angle in Cone Layout and automatically an ellipse is created.

[JanBros]

I'm not bothered about the ellipse at the end, that is unavoidable.
it can not create a circle at the end, and have a circular form across it's total length.
join any circular tubes together under an angle, and the joint will always be eliptical.

[JanBros]

pfff, 33 cones ...
they'd better give me back my 13 % or :bash:

[wobbly]

So here is the cut setup for joining the square ends of two cones at an angle.
Extend the revolve , then cut it off on the angle needed at the end point on center.
Two different cones will then join at an angle , making 2 less angle cuts if you do both ends.

[Frits Overmars]

All the best mate!
346059

[TZ350]

All the best mate!
346059

Plus +1.......

[ken seeber]

80 years old and still thinking about 2 strokes....what a legend

Happy birthday Jan.

[Peter1962]

Happy birthday Jan !

[teriks]

80 years old and still thinking about 2 strokes....what a legend

Happy birthday Jan.
For sure a legend, happy birthday Jan!

[Haufen]

Cheers Jan!

[katinas]

Happy birthday Jan.

[husaberg]

Lang zal hij leven
Lang zal hij leven
Lang zal hij leven in de gloria
In de gloria, in de gloria

[JanBros]

Lang zal ze leven
Lang zal ze leven
Lang zal ze leven in de gloria
In de gloria, in de gloria

"ze" = she
"hij" = he
... :psst:

[husaberg]

"ze" = she
"hij" = he
... :psst:

bloody google
346068346069346070

[peewee]

i had question about studs that hold the cyl to the block and ones that hold the head to the cyl. theres two ways to prevent the stud from turning while the nut is tightened and wonder if one methos is better than the other. either the stud goes to the bottom of the hole and cant turn any more or theres a small piece of unthreaded shaft in the middle of the stud that prevents it from turning any further and presumably keeps it away from the bottom of the hole. whats the better way to use studs ?

[wobbly]

There are two answers , the first is if hollow dowels are used to locate the head or cylinder.
In this case having the thread bottom , and "lockup " is fine.
Without dowels , many companies use the unthreaded portion that locks in the top of the thread , to also locate the sliding component.
In my book a pair of hollow dowels is mandatory good practice.
Honda have used an extra pair of small solid dowels as well , but I believe in KISS like Frits.

[F5 Dave]

RIP Auckland track. Just read on Stuff the appeal failed in court.
Axe has fallen.

Sorry to hear you Auckland guys.

[lohring]

I don't know about engines, but I often used shoulder bolts to locate components in tooling. The precision shoulder portion locates the components. It's a lot quicker and easier than separate holes for dowels.

Lohring Miller

[mantonakakis]

Not sure if this has been shared yet, but figured it might be interesting to some of you guys... I've been on the Megasquirt forums lately, and someone there has been working on EFI for his 2-stroke converted EX500. He couldn't share details until he applied for a patent (patents?), but he recently submitted the application(s), so he is now free to share some details.
He just released this video that shows things pretty clearly:

https://www.youtube.com/watch?v=LRfyIBiJgZs

[Frits Overmars]

...He couldn't share details until he applied for a patent (patents?), but he recently submitted the application(s), so he is now free to share some details.I wonder what he hopes to patent. In the video I haven't seen anything that has not been done before.

[Norman]

I wonder what he hopes to patent. In the video I haven't seen anything that has not been done before.

It will take about 18 months until the application is public to see what of the engine that he claims. Respect to all of the work and thought put into it. I wonder if it is (yet) sort of "balanced" from the inlet to outlet to be a really high performer?

BTW, KTM is still working on to have their patent applications on the TPI granted. Not always so easy..

[Flettner]

Yes, its hard to patent something that has already been done.

[mantonakakis]

I wonder what he hopes to patent. In the video I haven't seen anything that has not been done before.

I currently work in the freight railroad industry, but not with locomotives. I work at a large test track, so I although I don't work with those big diesel engines directly, I've seen enough components laying around the place to see quite a few similarities... although the cylinder liners I see at the test center are the size of my torso!

EDIT: Here's the thread on the Megasquirt forums, there's a little bit of discussion/description going on later in the thread:
https://www.msextra.com/forums/viewtopic.php?f=101&t=72623

[TZ350]

346124 346125

Kawasaki EX500 55 RWHP @ 9500 RPM in 4T trim. I am not sure why you would want to convert it to a modest performance 2T.

Great bit of work though, impressive devotion to the mission. It is exciting to see these new engines and I would love to know more about any real advantages the constructor has found with his prototype.

[ken seeber]

I wonder what he hopes to patent. In the video I haven't seen anything that has not been done before.

Have to agree Frits, lots of design features seen elsewhere, even one starting with an R. Mind he put in a great effort, both in the detail design, manufacture and recording. Quite complex compared to either a 4 or 2 stroke. Interesting the primary header lengths are different from front to back.

The thing runs & idles, sounds smooth. However, it did have the characteristic failing: 4 stroking at low speeds = unburnt fuel = unburnt HCs = emissions = sadness. Still, this could be a simple mapping thing.

[husaberg]

Have to agree Frits, lots of design features seen elsewhere, even one starting with an R. Mind he put in a great effort, both in the detail design, manufacture and recording. Quite complex compared to either a 4 or 2 stroke. Interesting the primary header lengths are different from front to back.

The thing runs & idles, sounds smooth. However, it did have the characteristic failing: 4 stroking at low speeds = unburnt fuel = unburnt HCs = emissions = sadness. Still, this could be a simple mapping thing.

i had a quick look and the valve timing is also (from what was in one post before i got distracted by work)different front to back.
i noticed that as well the the 4 stroking (too rich on the pilot electronics:whistle:)different note though 4 stroke then and falling to a two stoke down low or on overrun with the normal off idle woollynesss

[Vannik]

Have to agree Frits, lots of design features seen elsewhere, even one starting with an R. Mind he put in a great effort, both in the detail design, manufacture and recording. Quite complex compared to either a 4 or 2 stroke. Interesting the primary header lengths are different from front to back.

The thing runs & idles, sounds smooth. However, it did have the characteristic failing: 4 stroking at low speeds = unburnt fuel = unburnt HCs = emissions = sadness. Still, this could be a simple mapping thing.

I asked him what is different from the Ryger concept but did not get a real answer.

[ceci]

346124 346125

Kawasaki EX500 55 RWHP @ 9500 RPM in 4T trim. I am not sure why you would want to convert it to a modest performance 2T.

Great bit of work though, impressive devotion to the mission. It is exciting to see these new engines and I would love to know more about any real advantages the constructor has found with his prototype.

What is missing
https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=345335&d=1586527919

[husaberg]

I asked him what is different from the Ryger concept but did not get a real answer.

funny, sounds exactly like what answers we got from Ryger and his sidekick luc fornicathimself.
Does the rev counter go to 30,000 rpm and make 70hp .:whistle:

but seriously his HP figures seam to be realistic.
dDd you ever map out the potential of the other engine if it actually defied physics and managed to hold together to 30,000rpm

[Vannik]

dDd you ever map out the potential of the other engine if it actually defied physics and managed to hold together to 30,000rpm

Yes, from the homologation papers it seems that its pumping chamber has only 55% of the engine displacement, so unless they discovered a way to more than double the suction of the pipe it was only good for mid 30s hp. Which seems to correspond to dyno figures Jan has heard. I think we will not hear any more from the Ryger crowd.

[F5 Dave]

But wait. A new Ryger 4 stroke. They removed the valves and are turning the camshaft at double speed to invoke the mixture in. It's pretty hush hush but send money to. . .

[WilDun]

I think many of us would have liked to see something sensational happen with the Ryger, but I don't think that many people actually believed it would happen at the time, most of all, some people like Jan who had already developed successful engines! - (and I took notice of that), but at the same time didn't like to see someone's dreams shattered - however that's life I guess!

From the look of things, this guy has approached it from a different angle and gone on and done it all first and is now talking!
As Frits says, nothing really new or sensational, so whether it will go anywhere or not, is the question!

I feel that all the sensational breakthroughs were made in the 20th century and all that's left now is to decide whether full on development is going to keep the two stroke alive - or let it die and surrender to electricity! ...... it's all in the balance at the moment!

[Vannik]

Here is his idea, just with the "mushroom" piston the other way round and loop scavenging in place of Uniflow scavenging:

http://www.ac-aero.com/technologies/

[husaberg]

it apparently runs on small balls.


Dunlet piston and engine pre ww2

346127346128346129346130
pre loop scavenged of course

[lohring]

As noted, stepped pistons have been around a long time. It really comes down to what is the most efficient pump in the size range we are talking about. In small engines it's hard to beat the crankcase pump/tuned pipe combination. It gives starting flow with some supercharge and good piston cooling. Piston pumps are most efficient in small sizes where clearances make other pumps leak. Screw compressors are good in moderate sizes where lower friction and wear makes them superior to piston pumps. it's hard to beat centrifugal and axial compressors in large sizes for the same reasons as well as compactness.

However, none of these pumps can add serious power without a system to recover energy, apply back pressure and cool the piston. Scroll expanders (https://patents.google.com/patent/US801182?oq=801182) may be suitable in small sizes, but turbines are proven in large sizes. Piston cooling is usually done with oil flow to the piston under side in large engines.

Lohring Miller

[Vannik]

The difference between the traditional stepped piston and the new generation versions is that they no longer use the crankcase but the "scavenging" chamber between the piston and the seal to the crankcase.

[katinas]

Interesting solution for oil supply to crank big end main on Honda test NR 125 engine.

[husaberg]

i was trying to find a pic of the gm non supercharged engine i thought they had but i found out ,Detroit and GM consider the Detroit series supercharged diesel to be normally aspirated as it only uses the roots blower to scavenge.
only the turbo are considered blown.

Sorry Vannik i wasn't trying to suggest they were the same, only the stepped pistons were nothing novel.
I suspect none of the older designs up until the late 60's-early 70's were that worried about emissions other then an impolite smokey haze that concerned the flash harry rather portly cigar smoking Daimlers driving 55 year old marketing executive.
346132346133

[katinas]

http://www.jicef.org/japanese/cimac/pdf/Dragsted_History_Booklet_2013.pdf

Torpedo boat Uni Flow https://glanze.sakura.ne.jp/24wz_diesel.html

[katinas]

Hi Katinas
That fact of not exceeding 5000 rpm is what attracted me

Last attempt with 4 type variation. This time, with opened under exhaust space to add trans volume. Results is the same, zero torque from 5000 to 8000 rpm.

[TZ350]

346137 Flettner 2013 https://youtu.be/hOGZ5llowoU



Yes, its hard to patent something that has already been done.

346138 KTM 2017 https://youtu.be/e8LgPoCQVCk

KTM tried to pinch Flettners idea. Their patent application was declined ..... :laugh:

[pete376403]

Interesting solution for oil supply to crank big end main on Honda test NR 125 engine.
If that arrow is pointing to some sort of "scoop" on the end of the pin to pickup oil thrown from the main bearings, that's pretty common among two strokes. My 72 F9 Kawasaki bighorn had a ring on the side of the flywheel that did the same thing

[katinas]

My 72 F9 Kawasaki bighorn had a ring on the side of the flywheel that did the same thing

Thanks, never noticed this before.

[ken seeber]

[QUOTE =KTM tried to pinch Flettners idea. Their patent application was declined ..... :laugh:[/QUOTE]

Lots of good stuff happening out there and it's not always the big companies....

346141

[ceci]

Last attempt with 4 type variation. This time, with opened under exhaust space to add trans volume. Results is the same, zero torque from 5000 to 8000 rpm.

Excellent work done, I hope it helps to develop new more efficient engines

[Flettner]

Thanks, never noticed this before.

Actually its not right to do it this way, too slow on the delivery vers load.
My 360 engine has a hollow crankshaft, a wee seal in the outside case. Hollow all the way to the inside of the crank pin, with a small hole in it, direct to the bigend rollers. Out side of this wee seal is open to air filter air via a small one way valve, one way valve for low speed operation and starting. Air is contantly being injested through this crankshaft cavity, oil is introduced to this inflow of air from the autolube pump.
Oil (and filtered air) is being contantly directed straight to the inside of the bigend rollers, instantly with load. Does not upset carburation, because there is none.

Opps, better patent it.

[F5 Dave]

Mate. glad to have met you. You're a star.

[Frits Overmars]

Interesting solution for oil supply to crank big end main on Honda test NR 125 engine.BMW used this system for decades on their roller-bearing boxers. The oil catch rings #10 feed oil into the hollow big end pins #12.
346146

[katinas]

Opps ...... Neil, indeed you words under a magnifying glass.

Frits, it was only today that I noticed all this in the Beckman's book, I had had all my life. Probably, because I never looked closely at the four-stroke. Add pic of Jawa 350 cc and Vostok C/364 350cc engines.

Add chart of race fuels composition/compression from this old book, maybe it will be useful for someone.

[katinas]

If, two years ago I started testing not from 3 type, but from type 4, it is very likely that I mistakenly stated that this cannot work. It is a coincidence.

The results of all current the tests merged into this concept ( with Neil's FI ), but with two stroke very easy to go wrong.

[Flettner]

Finaly getting the time to finish a gear for a special road race / twostroke / development Kiwibiker celebrity.
Code for, sorry TZ its taken so long but its being done as I wright.
Its the internal grinding that takes the time. Gear material is EN39B case hardened to 60R.

[TZ350]

.

Finaly getting the time to finish a gear for a special road race / twostroke / development .

346160346161346162

Pre 72 Classic replica Kawasaki F81M based road racer. Very Excited.

[pete376403]

.


346160346161346162

Pre 72 Classic replica Kawasaki F81M based road racer. Very Excited.
Harry Klemms website has lots of great info about the F9 that would probably apply to this

[husaberg]

Finaly getting the time to finish a gear for a special road race / twostroke / development Kiwibiker celebrity.
Code for, sorry TZ its taken so long but its being done as I wright.
Its the internal grinding that takes the time. Gear material is EN39B case hardened to 60R.

i remember reading something that the some of the gears or the cluster were the same as the H1.
that might have been on the site mentioned above. Which Rob has posted about before.
i think someone in the Waikato with knobbly knees might have made a head for one previously or maybe for them as well is that right?

okay its likely what you are doing anyway..
346163

[Peter1962]

Actually its not right to do it this way, too slow on the delivery vers load.
My 360 engine has a hollow crankshaft, a wee seal in the outside case. Hollow all the way to the inside of the crank pin, with a small hole in it, direct to the bigend rollers. Out side of this wee seal is open to air filter air via a small one way valve, one way valve for low speed operation and starting. Air is contantly being injested through this crankshaft cavity, oil is introduced to this inflow of air from the autolube pump.
Oil (and filtered air) is being contantly directed straight to the inside of the bigend rollers, instantly with load. Does not upset carburation, because there is none.

Opps, better patent it.

Neil, what is the reason that you chose to use a forced lubrication system combined with an influx of air ? Wouldn't it be logic to only use an oilpump ? (be it mechanical like in the old days, or an electronic mikuni esops-04 pump like on the ktm TPI models ? )
The aim is to get oil to the bigend rollers, i do not quite see what the additional air could be off benefit ?
What made you choose this approach ?

[Flettner]

I do use an Autolube pump to deliver to the crankshaft. The crankshaft is hollow with some volume. As the oil pump suddenly delivers more oil as required by load the pump may take time to fill this cavity to a point where oil is flung out via internal drilling to the bigend pin. So I figured if air was continuously flowing it would help carry this oil much quicker to where its needed.
Much like delivering oil to the air inlet stream as almost all normal Autolube systems.
Thats my story and Im sticking to it.

[Frits Overmars]

I do use an Autolube pump to deliver to the crankshaft. The crankshaft is hollow with some volume. As the oil pump suddenly delivers more oil as required by load the pump may take time to fill this cavity to a point where oil is flung out via internal drilling to the bigend pin. So I figured if air was continuously flowing it would help carry this oil much quicker to where its needed. Much like delivering oil to the air inlet stream as almost all normal Autolube systems.
Thats my story and Im sticking to it.An aircooled big end!:2thumbsup

[Niels Abildgaard]

Opps ......
Add pic of Jawa 350 cc and Vostok C/364 350cc engines.

.

The drawings shows crankshafts that are assembled by Hirth method I think.That was a very expensive way to do it but enabled rolling element bearings even in fourstrokes.
Those socialist countries took racing very seriously indeed.

[husaberg]

The drawings shows crankshafts that are assembled by Hirth method I think.That was a very expensive way to do it but enabled rolling element bearings even in fourstrokes.
Those socialist countries took racing very seriously indeed.

As did those West Germans.
Adler
346170346171346172


then the Swiss
with the Swissauto/roc/MUZ/Pulse
346169

[katinas]

As did those West Germans.
Adler




And the same on the soviets Bихрь outboard engine that was copied from Konig and modified through years.
For me it is still most nostalgic engine. As a child in the seventies, when my dad was a rowing coach, I spent my summers in the motorboat 4 hours a day and always sat in the back at this engine, which my dad didn't cover with a hood.
I later installed this std engine on my first motorcycle. Not impressive 30 hp at 5000 rpm from 488cc two cylinders 72x60mm. But after working with file on exhaust 195, disc vale 40 open after bottom, 74 closing after top, steel pistons rings and bigger 36 mm Ikov carb from CZ cross engine runs in the 10000 rpm zone. Std Jawa 350 clutch retaining rivets were cut off after the first ride.
Even a monument was built for this engine, with an inscription "Motor Bихрь - with love and hate"

[Frits Overmars]

I see a clear similarity between your engine with its central carburettor and two rotary inlet discs, and the East German Trabant.
I wonder which of the two came first.
346182 346181 346180

[katinas]

This engine was definitely a copy of Konig, perhaps pre war technology. Konig stop produce this engine in 1963 in West Germany, Bихрь started in 1966.
Just last week I saw working Trabant engine on an small wing plane and helped to adapt scooter 28 mm carb. With propeller engine revs to 3900 rpm.

The best and most racing-oriented Soviet two-stroke mass-produced engine, was the outboard Privet ( Hello) 350. Two cylinder 62x58mm, two disc valve, steel piston rings, separate cylinders ( at factory tried chrome or nicasil ) small end roller bearing . When the fist time see this engine, cant believed how race look all things was (photo with red flywheel and scheme)
Engine was produced from 1973 to 1982. Before mass production, five years engine was tested in boat race from 1969.

[Condyn]

Hi, new to the forum and if IÂ’m posting in the wrong thread, off with my head I guess.

I have a question about pipe design. IÂ’ve designed and built about a dozen pipes at this point and am starting to get a grasp on things. I recently had an idea... From what IÂ’ve gathered raising the compression ratio will make a given pipe act longer due to more of the energy being taken by the engine and the speed of sound travels slower through a colder gas.
I’ll be using this engine/pipes for 660 foot (in the fortnighthunderweight system or whatever Frits calls it, that we use in the states) drag racing on frozen lakes, with a cvt drive. Ice is readily available, and no ignition retards are allowed for pipe heating. I’m using very large D-max FOS based pipes and “everyone” seems to think they will take ages to build heat. I know they work well at sucking what’s left on higher compression engines, but “everyone’s” concerns got me thinking about doing things a little differently.


My question is:
Since itÂ’s a short drag run and ignition retard devices arenÂ’t allowed, what are your thoughts about icing down the pipes to a baseline temp before each pass and dropping the speed of sound (effectively shortening the pipe) until I make peak power at the same rpm as if I were preheating the pipe? I usually like testing things in real life instead of standing around munching on regular Cheetos, whilst thinking about trying the flamin hot version when I become brave enough. Is this a pipe dream (pun not intended) or could it work?

[Frits Overmars]

]From what IÂ’ve gathered raising the compression ratio will make a given pipe act longer due to more of the energy being taken by the engine and the speed of sound travels slower through a colder gas.
I’ll be using this engine/pipes for 660 foot (in the fortnighthunderweight system or whatever Frits calls it, that we use in the states) drag racing on frozen lakes, with a cvt drive. Ice is readily available, and no ignition retards are allowed for pipe heating. I’m using very large D-max FOS based pipes and “everyone” seems to think they will take ages to build heat. I know they work well at sucking what’s left on higher compression engines, but “everyone’s” concerns got me thinking about doing things a little differently.
My question is:
Since itÂ’s a short drag run and ignition retard devices arenÂ’t allowed, what are your thoughts about icing down the pipes to a baseline temp before each pass and dropping the speed of sound (effectively shortening the pipe) until I make peak power at the same rpm as if I were preheating the pipe?.... Is this a pipe dream (pun not intended) or could it work?Hi Condyn, icing down the pipes to a baseline temp before each pass and dropping the speed of sound would effectively lengthen, not shorten the pipe.
What would it bring? During your run the pipe temp would rise and the pipe would behave as if it was tromboning from long to short, shifting the complete power curve from low to high revs. But a pipe that wasn't pre-iced would do that too, only with higher initial and final temperatures.
Please note that the colder a pipe, the more energy it will steal from the exhaust gases inside, which is not desirable.

I have heard people say before that fat pipes will take ages to build heat. That is true for two reasons. First, there simply is more steel to be heated (which could be a reason for using stainless or titanium sheet that have lower specific heats).
The second reason is more interesting: fat pipes have a bigger volume to wall surface ratio, which means that less of the exhaust gas comes into contact with the pipe walls. And that's fine: the pipe will not heat up so quickly, but it will also steal less heat from the gas, so while the pipe may be colder, the gas will be hotter. At the end of the day it may be colder because of the larger expansion factor in the fat diffuser, but this awards us with more suction.
Finally, I wonder: with a good clutch and CVT setup you will always want maximum power at the same revs, from start to finish, so you don't really want the pipe temperature to climb during a run, do you?
PS: never say a good pun was not intended. If people get the impression that you're brilliant, don't take that away from them :msn-wink:

[Vannik]

For those interested in turbocharging a 2T:

https://www.snowmobile.com/trails/polaris-working-on-turbocharged-2-stroke-snowmobile-engine-65385

It seems Polaris has filed for 9 patents.

[Condyn]

Edited due to double post, sorry ��

[Condyn]

Hi Condyn, icing down the pipes to a baseline temp before each pass and dropping the speed of sound would effectively lengthen, not shorten the pipe.
What would it bring? During your run the pipe temp would rise and the pipe would behave as if it was tromboning from long to short, shifting the complete power curve from low to high revs. But a pipe that wasn't pre-iced would do that too, only with higher initial and final temperatures.
Please note that the colder a pipe, the more energy it will steal from the exhaust gases inside, which is not desirable.

I have heard people say before that fat pipes will take ages to build heat. That is true for two reasons. First, there simply is more steel to be heated (which could be a reason for using stainless or titanium sheet that have lower specific heats).
The second reason is more interesting: fat pipes have a bigger volume to wall surface ratio, which means that less of the exhaust gas comes into contact with the pipe walls. And that's fine: the pipe will not heat up so quickly, but it will also steal less heat from the gas, so while the pipe may be colder, the gas will be hotter. At the end of the day it may be colder because of the larger expansion factor in the fat diffuser, but this awards us with more suction.
Finally, I wonder: with a good clutch and CVT setup you will always want maximum power at the same revs, from start to finish, so you don't really want the pipe temperature to climb during a run, do you?
PS: never say a good pun was not intended. If people get the impression that you're brilliant, don't take that away from them :msn-wink:

Thank you for the insight Frits. When I said drop the speed of sound, I meant in the design process with anticipation of icing down the pipes. Since the sound travels slower through a slow gas, we would need to shorten the TL to compensate for the temp drop right? But you say the cold pipe will rob energy, and that makes sense. Maybe I should stick to conventional methods. As for the CVT, we run a primary and a secondary clutch that operate on Low ratio/high ratio curves. Shift speed is set to say 9,000 rpm and belt engagement is
say 6,000 rpm. Once we are at shiftout speed the goal is to maintain this speed as a straight shift. This transition takes time, so if done properly, I am curious if the tromboning effect could be beneficial as the pipe heats.

[Frits Overmars]

Thank you for the insight Frits. When I said drop the speed of sound, I meant in the design process with anticipation of icing down the pipes. Since the sound travels slower through a slow gas, we would need to shorten the TL to compensate for the temp drop right? But you say the cold pipe will rob energy, and that makes sense. Maybe I should stick to conventional methods. As for the CVT, we run a primary and a secondary clutch that operate on Low ratio/high ratio curves. Shift speed is set to say 9,000 rpm and belt engagement is say 6,000 rpm. Once we are at shiftout speed the goal is to maintain this speed as a straight shift. This transition takes time, so if done properly, I am curious if the tromboning effect could be beneficial as the pipe heats.I see what you meant by shortening the tuned length in the design proces.
Why are the engagements revs of the belt and the clutch so far apart, with the second rpm at 150% of the first rpm? Such a wide spread is asking a lot of the engine.
Surely a decent CVT can do better than that?
I would ask you to enlighten me with a sketch of your transmission layout but as you're new here, I'm afraid that you have not yet acquired the privilege to post pictures;
that seems to take some time on this forum.

[polcat88]

https://youtu.be/uCEvBGT8twM

I will give it a shot Frits. The video shows the conventional snowmobile clutching setup being driven by an electric motor for demonstration purposes. In a snowmobile, the secondary clutch drives a jackshaft connected to a chaincase on the opposite end. In Condyn's example the drive clutch would engage the belt at 6000 RPM. In drag racing, this engine's RPM would be held around 5600 to 5800 RPM while staged and waiting for the light to change. When the light changes and full throttle is applied, if the clutches are tuned correctly, the engine RPM will flash very quickly to the desired power peak of 9000 RPM and hold that RPM for the complete length of the run, be it 500, 660 or 1320 feet.

[wobbly]

Two points re pipe design and CVT.
Firstly is that " fat " pipes are only effective on porting layouts that have good transfer duct geometry , and good radial port geometry.
If the ducts are not " teacup " and the most important A port front wall is not pointing back to just in front of the boost port , then the efficient diffuser section easily overcomes
the transfer stream coherency , giving huge short circuiting directly out the Exhaust duct.
This makes the jetting appear rich , but in actuality the mixture within the cylinder may be burning at near optimum temperature.Lean this scenario down at your peril.
A good example being a TZ350 that will simply refuse to make more power with anything past 110mm belly diameter

Secondly , the clutching setup.
As Frits alluded to , the clutching setup seems at odds with keeping the engine at peak power continuously.
My experience with CVT is nill , but for many years we raced KT100 Yamaha with centrifical clutches and specially designed pipes to make alot of power over a narrow range.
In this scenario the fastest setup was to have the clutch springs and weights " just lockup ", and allow the engine to sit at peak torque rpm under full load.
Then from this start point , the gearing was selected to give peak speed just as it dropped over peak Hp.
The clutch lockup rpm was critical to within 100rpm and was typically 10400 rpm , and the pipe was over the top at just past 14,000.

[Condyn]

I see what you meant by shortening the tuned length in the design proces.
Why are the engagements revs of the belt and the clutch so far apart, with the second rpm at 150% of the first rpm? Such a wide spread is asking a lot of the engine.
Surely a decent CVT can do better than that?
I would ask you to enlighten me with a sketch of your transmission layout but as you're new here, I'm afraid that you have not yet acquired the privilege to post pictures;
that seems to take some time on this forum.

I hope my photo attachments work. I am still learning how to use this highly resourceful forum. The engine does reach shift speed or (peak power rpm) relatively quick, so I somewhat amend my original statement. However, there is a period where the engine speed climbs in low ratio ratio before this occurs.

[Frits Overmars]

I will give it a shot Frits. The video shows the conventional snowmobile clutching setup being driven by an electric motor for demonstration purposes. In a snowmobile, the secondary clutch drives a jackshaft connected to a chaincase on the opposite end. In Condyn's example the drive clutch would engage the belt at 6000 RPM. In drag racing, this engine's RPM would be held around 5600 to 5800 RPM while staged and waiting for the light to change. When the light changes and full throttle is applied, if the clutches are tuned correctly, the engine RPM will flash very quickly to the desired power peak of 9000 RPM and hold that RPM for the complete length of the run, be it 500, 660 or 1320 feet.Thanks Polcat. The CVT systems I am familiar with, have only one clutch, and I could not imagine a system with a primary and a secondary clutch.
Your video made it all clear: there still is only one clutch, and a crude one at that: nothing more than the primary pulley sheaves pinching the belt.
The secondary clutch is not a clutch at all; it's just another pulley, pinching the belt via an axial spring and a torque ramp. The torque ramp has the effect of reducing its pinching force when torque is reduced, which results in the CVT "shifting up" and reducing engine rpm when you go off the throttle, just what the average user expects.

I used to advise scooter tuners to fit a stronger spring and omit the torque ramp for racing, so engine rpm remains constant all the time and throttle response is more direct.
It worked fine, but it took some getting used to: scooter riders tend to open the throttle quite early on corner exit, to compensate for the fact that it will take a few tenths of a second for the CVT to "shift down" and start feeding power to the tire. With my mod they tended to open the throttle a few tenths of a second too early :D.
346222
(https://www.youtube.com/watch?v=EFjakgypqSs)
The video below shows a 125cc scooter (not mine) bantering a fleet of 1000cc superbikes with proper throttle response out of corners. Granted, it's hardly a superbike track, but it will make you understand why I would have applied CVT to GP-bikes ages ago, but for the rule that they are not allowed to have more than six gears.
https://www.youtube.com/watch?v=EFjakgypqSs

[Condyn]

Two points re pipe design and CVT.
Firstly is that " fat " pipes are only effective on porting layouts that have good transfer duct geometry , and good radial port geometry.
If the ducts are not " teacup " and the most important A port front wall is not pointing back to just in front of the boost port , then the efficient diffuser section easily overcomes
the transfer stream coherency , giving huge short circuiting directly out the Exhaust duct.
This makes the jetting appear rich , but in actuality the mixture within the cylinder may be burning at near optimum temperature.Lean this scenario down at your peril.
A good example being a TZ350 that will simply refuse to make more power with anything past 110mm belly diameter

Secondly , the clutching setup.
As Frits alluded to , the clutching setup seems at odds with keeping the engine at peak power continuously.
My experience with CVT is nill , but for many years we raced KT100 Yamaha with centrifical clutches and specially designed pipes to make alot of power over a narrow range.
In this scenario the fastest setup was to have the clutch springs and weights " just lockup ", and allow the engine to sit at peak torque rpm under full load.
Then from this start point , the gearing was selected to give peak speed just as it dropped over peak Hp.
The clutch lockup rpm was critical to within 100rpm and was typically 10400 rpm , and the pipe was over the top at just past 14,000.

Thank you for your time wobbly. Firstly I want to acknowledge that fact that I know what the FOS pipe design was targeted for. I know it is not a one size fits all design template. This pipe has a 150mm belly diameter, and since it’s a parallel twin engine with tight bore spacing you can guess what the transfer ducts look like. As for the false positive rich condition, I thank you for making that aware as I would not have picked that up quick. These engines run a large single exhaust port and no rear boost port. Another issue that comes to mind is the exhaust duration is 200°. With a large diffuser pulling on the transfer stream with a high duration exhaust port, what’s being trapped? I am starting to see the picture... since the pipes are already built, I think it’s only fair to test them anyway. Although probably not ideal, could I just scale the diameters down and give that a go? I really should give ENGmod2t a go. The cvt design is similar to what you talk about. It is held on its power peak shift speed almost the entire run, besides the point where the engine speed is accelerating in low ratio after engagement. I included a photo of the fat pipes built. The team I donated them to for testing insisted the baffle and stinger be the same diameter. I also included some attachments in my comment back to Frits on the cvt. Thank you again for your time.

[Frits Overmars]

The engine does reach shift speed or (peak power rpm) relatively quick, so I somewhat amend my original statement. However, there is a period where the engine speed climbs in low ratio ratio before this occurs.Condyn, I see that the "clutch" starts closing between 5000 and 6000 rpm. Seeing the way the CVT is set up, we may assume that maximum power is produced at 9000 rpm. Then the torque dip at 2/3 of max. power will be around 6000 rpm, right where the clutch closes, and by the looks of it your engine has no exhaust power valves, so the sled has to build up speed from zero to around 20 mph, starting with nearly zero power. That will take forever! Not the best way to start a drag race...
Why not lighten the centrifugal weights on the clutch a bit, so it bites later? It may reduce belt life, but it will also reduce your 0-to-660 ft time, won't it?
346217

[jonny quest]

It's not just the mass of the weights in the primary clutch. They are swinging weights with a ramp design. The placement of the mass in the weights along with the ramp profile are huge tuning tools. Not to mention roller diameter and roller orientation to the weights.

Traction is a problem, and the reason you can't just engage clutch at 9000 rpm and go. It needs the highest engagement possible without breaking traction.

[Condyn]

Condyn, I see that the "clutch" starts closing between 5000 and 6000 rpm. Seeing the way the CVT is set up, we may assume that maximum power is produced at 9000 rpm. Then the torque dip at 2/3 of max. power will be around 6000 rpm, right where the clutch closes. So the sled has to build up speed from zero to around 20 mph, starting with nearly zero power. That will take forever! Not the best way to start a drag race...
Why not lighten the centrifugal weights on the clutch a bit, so it bites later? It may reduce belt life, but it will also reduce your 0-to-660 feet time, won't it?
346217

If we engage later we spin. A good racer examines the track multiple times throughout the day and determines where his clutch should come in. As noted by Jonny Quest there is a multitude of tuning variables that come into play with the cvt that we use. Ice is brittle so we don’t just hook up and go all the time. I have changed engagement speed several times throughout a day as the top layer of ice deteriorates. Note the ice roost in photo. Many of these engines are well over 200hp

[Frits Overmars]

Ice is brittle so we don’t just hook up and go all the time. I have changed engagement speed several times throughout a day as the top layer of ice deteriorates.That is where I went wrong. I have some experience with ice speedway (I helped design the chassis in the picture below left) and their grip coefficient is phenomenal:
over twice the grip of a MotoGP bike, as is demonstrated by their lean angles.
I assumed that you would have the same amount of grip on your sled. But you seem to use tracks without spikes, or at least without the vicious toothpicks of the bikes.
346220 346219 346221

[wobbly]

The 200* Ex Duration is common for many twins with a single pipe.This allows the single pipe to work much more effectively.
But swapping to twin pipes I would urge you to have a go at re arranging the port layout to reduce the Ex height.
This worked very well in SeaDoo World Champ class engines when swapping to big twin pipes , but the transfers needed a heap of grinding to get a match to the diffuser efficiency.
Maybe the high port works in your favour though, stopping the big rush of torque from spinning up the drive too quickly ( early ) and loosing traction.

[jonny quest]

Snowmobiles do use ice picks, but the traction is just not the same as a motorcycle.

I believe a wheel drives spikes into ice. A snowmobile track flexes and because ice gets so chewed up the rubber track is sitting on ice and prevents full bite of picks, where a motorcycle is solely riding on picks


That is where I went wrong. I have some experience with ice speedway (I helped design the chassis in the picture below left) and their grip coefficient is phenomenal:
over twice the grip of a MotoGP bike, as is demonstrated by their lean angles.
I assumed that you would have the same amount of grip on your sled. But you seem to use tracks without spikes, or at least without the vicious toothpicks of the bikes.
346220 346219 346221

[F5 Dave]

Golly its a whole new world this icey stuff. I was going to ask if you can tap the back door, so to speak, and connect a boost port. But I think there will be some crazy reasons I can't fathom.

[lodgernz]

Jamathi !!

https://www.facebook.com/rtvdrenthe/videos/196777741631980/?t=186

[katinas]

I have some experience with ice speedway (I helped design the chassis in the picture below left) and their grip coefficient is phenomenal:
over twice the grip of a MotoGP bike, as is demonstrated by their lean angles.



Frits, what a lubrication system is used these days on the speedway engines (Jawa , GM). Stihl 4-mix use total loss oil scheme on 4t.
https://www.youtube.com/watch?v=NhprB_OOrLQ

I finally found that the Aaen engine was designed for speedway
https://cybermotorcycle.com/archives/speedwaybikes/aaen.htm

[Peter1962]

Frits, what a lubrication system is used these days on the speedway engines (Jawa , GM). Stihl 4-mix use total loss oil scheme on 4t.
https://www.youtube.com/watch?v=NhprB_OOrLQ

I finally found that the Aaen engine was designed for speedway
https://cybermotorcycle.com/archives/speedwaybikes/aaen.htm

AAEN : http://www.aaenperformance.com/V4_racing_engine.asp

I see that back then in 1967 he was using forced lubrication (very clever ) and disc valve induction (extremely clever).

Now they use piston controlled intake, no disc valve and not even a reed valve... :confused: And no forced lubrication anymore. :facepalm:

But they do have something special : a crankcase design like Jean Bertrand Bruneau was using in his JBB 250 http://www.pit-lane.biz/t117p560-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-1-locked

[Condyn]

Frits, what a lubrication system is used these days on the speedway engines (Jawa , GM). Stihl 4-mix use total loss oil scheme on 4t.
https://www.youtube.com/watch?v=NhprB_OOrLQ

I finally found that the Aaen engine was designed for speedway
https://cybermotorcycle.com/archives/speedwaybikes/aaen.htm

Olav Aaen is probably best known for his development in the very CVT’s that was mentioned just a few posts back. He is still in the shop after all these years.

[Frits Overmars]

Frits, what a lubrication system is used these days on the speedway engines (Jawa , GM).Katinas, I do not know anything about speedway engines, other than that they contain cylinder heads full of valves. They are called four-strokes.
For the ice speedway bike that I mentioned, I limited myself to the chassis. The Jawa frames, below left, with their flat front fork angle and without rear suspension, which were commonly used at the time, reminded me of Harley-Davidson choppers. But because of the incredibly high grip coefficient of the spiked tires, I thought we should go to the other extreme: a very stiff three-dimensional frame with a steep front fork angle, a twist-resistant upside-down front fork, the center of gravity shifted as far forward as possible, and a very progressive rear suspension. I'll be the first to admit that my contribution consisted mainly of talking; the only 'real' work I did was designing the suspension system.
The rider was Tjitte Bootsma, a Dutchman who ranked just below the world top, but with this frame he suddenly placed himself in the world top ten. Subsequently, the top riders also wanted to buy such a chassis and Tjitte was willing to meet their request, so that the entire world top now rides on similar frames and Tjitte himself was pushed out of the top ten again :p.

(https://www.facebook.com/pages/category/Motorsports-Store/Tibo-Motorparts-Tjitte-Bootsma-frames-471857229540070/)https://www.facebook.com/pg/Tibo-Motorparts-Tjitte-Bootsma-frames-471857229540070/posts/
346248 346247

To be honest, I did take a look at the engine as well. These 500cc four-stroke singles can offer a fair amount of engine braking when you close the throttle, which is just as well, because Ice speedway bikes have no brakes at all. But I thought I could do better. The braking on these engines is done during the compression stroke. But even without combustion, the piston is pushed down again by the cylinder pressure during the following expansion stroke, so the nett power absorbtion is not all that great.
But if we lift the exhaust valve a little, say one millimeter, the compression pressure still provides braking, but around TDC this pressure leaks away and will not push the piston down anymore after TDC, almost doubling the total amount of engine braking.
I used a Honda throttle grip with two bowden cables: the usual cable that opens the throttle, and a second cable that was there to pull the carburetor shut. But I did not attach that second cable to the carb, but to an exhaust valve lifter. So if you close the throttle, the carb is closed and you have normal engine braking. But if you force that throttle grip a bit further past 'normal closed', the exhaust valve is fractionally opened and engine braking is about doubled.
If worked beautifully, but it was considered too dangerous to use it in a field of bikes with killer spikes, who could not brake like that.

[lodgernz]

NFIG]346247[/ATTACH]

To be honest, I did take a look at the engine as well. These 500cc four-stroke singles can offer a fair amount of engine braking when you close the throttle, which is just as well, because Ice speedway bikes have no brakes at all. But I thought I could do better. The braking on these engines is done during the compression stroke. But even without combustion, the piston is pushed down again by the cylinder pressure during the following expansion stroke, so the nett power absorbtion is not all that great.
But if we lift the exhaust valve a little, say one millimeter, the compression pressure still provides braking, but around TDC this pressure leaks away and will not push the piston down anymore after TDC, almost doubling the total amount of engine braking.
I used a Honda throttle grip with two bowden cables: the usual cable that opens the throttle, and a second cable that was there to pull the carburetor shut. But I did not attach that second cable to the carb, but to an exhaust valve lifter. So if you close the throttle, the carb is closed and you have normal engine braking. But if you force that throttle grip a bit further past 'normal closed', the exhaust valve is fractionally opened and engine braking is about doubled.
If worked beautifully, but it was considered too dangerous to use it in a field of bikes with killer spikes, who could not brake like that.

2-stroke trials bikes back in the old days usually employed a decompressor for massive engine braking. Same theory.

[Condyn]

Back again for another question. I do the majority of my experimenting with limited port geometry, tight bore spacing twin cylinder engines. Many only have 4 transfer ports with elevator style ducts. Also used is a large single exhaust port.
I was doing a little poking around on old posts within this thread, and stumbled across an interesting topic about how the first transfer to open flows last because of the flow reversal effect, due to higher cylinder to case pressure differential.

This leads me to my question.
What prevents us from opening the B ports a couple degrees before the A ports to promote flow through the A’s first in a situation like this? Would this allow for better loop scavenging and less short circuiting? Or do we just rely on the proper angles and axial flow to keep things in check?

[wobbly]

Your situation is an odd one , thus will need an odd solution I am betting.
4 transfer ports is super wierd , is this a reed engine , or more likely a piston port.
I know that in the old screamer 100cc rotary valve kart engines they used a 3 port layout , with the boost port way higher - and this proved to be the best solution given the powerband required.
In a 4 port scenario , just maybe it would operate somewhat like the usual 5 ports - depends alot on the relative size / area of the A and B ports.
For a wider powerband ( and no PV ) normal stagger is used ie A port opens first.
For max power ( and with a PV ) reverse stagger ie B & C are highest , as this gives you the max transfer STA for the same timings - in both scenarios the Blowdown STA wont change.
This cant be modelled in 1 dimensional simulation , so grinding and dyno tests are the only option.
Maybe a good CFD analysis would give you the right direction to go , but hey , I would happily sacrifice a cylinder to find out what doesnt work - done it plenty of times before.
But I would bet the house on the fact that opening all 4 together , wont be the best solution.

[jbiplane]

Any idea how make simple and robust connection of 2 existing crankshafts to inline layout with minimal rework of original parts?
https://www.rrd-preparation.com/en/vilebrequin-maxi-scooter-2t-125cc-et-plus/22616-crankshaft-parmakit-race-origin-reinforced-rumi-125cc-bi-cylinder-2t.html

[katinas]

a very stiff three-dimensional frame with a steep front fork angle, a twist-resistant upside-down front fork, the center of gravity shifted as far forward as possible, and a very progressive rear suspension. I'll be the first to admit that my contribution consisted mainly of talking; the only 'real' work I did was designing the suspension system.




Thank you Frits, very interesting story and sudden evolution.
Steeper fork geometry really helps to go faster through the first part of the corner, but at full lean angle, with shorter front wheel twisting shoulder, its harder to hold tight line and the rear shock greatly helps to stay on the way, as front fork angle not changed too much through the corner.

[katinas]

Any idea how make simple and robust connection of 2 existing crankshafts to inline layout with minimal rework of original parts?
https://www.rrd-preparation.com/en/vilebrequin-maxi-scooter-2t-125cc-et-plus/22616-crankshaft-parmakit-race-origin-reinforced-rumi-125cc-bi-cylinder-2t.html

Hi, most easily dismantled construction was used on outboard Privet 350 engine.

[F5 Dave]

So if snow engine is piston port can you copy a Suzuki RM barrel circa 1980s and feed a pair of boosts from the Bs? Cut water jacket hole, then inner to make trenches, bore ports, glue back ally with Devcon/JB, then Water jacket. Must be bliss working on huge cylinders.

Or cut off inlet, graft on huge Reed and drill proper boost port? Done that before more than once.

[Niels Abildgaard]

Hi, most easily dismantled construction was used on outboard Privet 350 engine.

Do You have a clearer picture of how the screw position 8 clamps the counterweights around the shaft?
If it works well (do not loose grip) it is an elegant and cheap solution .

[Condyn]

Thank you for the replys. The specific cylinders that I am referring to are air cooled and indeed piston port. Experimenting with staggered openings may be in the future. The rules state that intake concept must be maintained. In other words, no reed conversion allowed. Feeding boost ports via the B ports is impractical in this application as I have already slightly blown thru the rear stud bores. Also already have a lot of devcon on the transfer short side radii as without it you can see the cylinder head from the bottom of the transfer ducts. They will call me Dr. Devcon if I keep it up!

[katinas]

Do You have a clearer picture of how the screw position 8 clamps the counterweights around the shaft?
If it works well (do not loose grip) it is an elegant and cheap solution .

Niels, I did not find clear picture, but found video https://www.youtube.com/watch?v=kVBOgW-o4CE from 17.47 to 22 min well visible.

[Frits Overmars]

Niels, I did not find clear picture, but found video https://www.youtube.com/watch?v=kVBOgW-o4CENice engine, nice video. It left me with two questions.
1: Why the threaded plug in the crankcase wall for access to the crankshaft pinch bolt, if that bolt is readily accessible from above?
2: Why are both piston ring slots right above each other instead of spread over the piston circumference? Just because it was convenient to use one long stift, fitted from above, for both ring slots? I will admit it's KISS, but I don't think it's the best way to reduce leakage.
346262 346261 346260

[Niels Abildgaard]

Niels, I did not find clear picture, but found video https://www.youtube.com/watch?v=kVBOgW-o4CE from 17.47 to 22 min well visible.

Thank You.Very clear and interesting even if I do not understand rusian.

[jbiplane]

Hi, most easily dismantled construction was used on outboard Privet 350 engine.

Thank Katinas. Yes clamping solution is elegant, but I thinking how correctly connect 2 existing crankshafts like AM6 using cylindrical shafts ;)

[Niels Abildgaard]

Nice engine, nice video. It left me with two questions.
1: Why the threaded plug in the crankcase wall for access to the crankshaft pinch bolt, if that bolt is readily accessible from above?
2: Why are both piston ring slots right above each other instead of spread over the piston circumference? Just because it was convenient to use one long stift, fitted from above, for both ring slots? I will admit it's KISS, but I don't think it's the best way to reduce leakage.
346262 346261 346260

I have no explanation for the plug hole in crankcasebut it does not cost much
Many two stroke pistons work their whole life with only one piston ring.
Maybe the second ring gives more friction than gain in power.
Worth a try by someone with a dyno and a two ring pison engine

[jonny quest]

Just put a hole in each inner crank webs, press a straight shaft between the 2


Thank Katinas. Yes clamping solution is elegant, but I thinking how correctly connect 2 existing crankshafts like AM6 using cylindrical shafts ;)

[wobbly]

My KISS take would be to have a single , central , female sleeve that both cranks press into.
This can be any suitable diameter than the stock main bearing surfaces , as you will then need to make a central labarinth seal fitting over this sleeve to suit.

Just be aware of the problems involved with pressing a shaft directly into the middle of any crank wheel.
This internal press fit will plastic deform the big end bearing hole directly above the shaft bore, and change the stroke slightly comparred to a non pressed wheel.
Makes truing the crank impossible , unless the wheel with the inner press fit has the stroke centerline moved inwards to compensate.

[Pursang]

Thank Katinas. Yes clamping solution is elegant, but I thinking how correctly connect 2 existing crankshafts like AM6 using cylindrical shafts ;)

By "Existing" cranks do you mean unmodified? If so, here is something dodgy, that could be done in a small workshop.

346263

Internal thread is only intended to pull the tapers tight. Secured with loctite, vent hole to prevent pressure lock.

Countersunk screws to provide visual & mechanical access to the key-ways for indexing. (Psychological security too, maybe!)

Final indexing will require selective fit or hand finishing on one taper.

One thread will be anti rotational??, if this is a concern, shim the coupler to the main bearing on that side. (fit a bigger ID crank seal)

If reversing one crank is not an option, it might be possible to machine one internal end of the coupler flat, to lock against the drive side shaft. Engine rotation will be more critical.

cheers Daryl.

[husaberg]

Ariel arrow
as there is more than one version i guess one is better /cheaper/easier than the other.
346264346265346266346267

Another option is what Aermacchi HD used.
346268346269

or good old RD200
https://www.aircooledrdclub.com/smf/attachments1/5018/Images/7_RD200_crankshaft_separated_s.JPG

There is maybe enough material to do any three but the HD/macchi solution looks to be the easiest

[WilDun]

The Ariel Arrow taper and woodruff key was the last straw, a great example of going too far with the budget thing! - no doubt meant to be a cheap alternative to a Hirth arrangement! :facepalm: - the bloody thing slipped slightly (just after you set the timing!! :angry2:
Also the splined shaft on the RD 200 is good of course, but how could that be cheaper than the Hirth design? - can't see it!

[jbiplane]

Thanks all comunity for advices :)


By "Existing" cranks do you mean unmodified? .
Very small modification like cut off shafts


My KISS take would be to have a single , central , female sleeve that both cranks press into.
Yes, I want to have conical shafts at left and right, and cylindrical crank parts fitted together. Probably thermal fit should work OK.
Or maybe loctite will make a job. May be I will need make groove in sleeve for keyhole.

Other company, my competitor make connection like this https://sibaero.ru/wp-content/uploads/2019/01/inside-1.jpg
Press fit and labyrinth sealing. But engine dont produce declared power and cranks often shift by some angle in connection.

Me making opposites with 2 main strokes 43mm+- and 52mm+-, but want try V90 and inline.
It is important to make cranks as cheap as possible and easy reparable by customer in any country using easy to get parts.
At moment I produce cranks by myself, but in small butch each crank for twin have internal cost ~250USD.
I quoted production in China on my drawings and got even bigger prices if order below 300 units.
Noone want make 10...25 custom cranks.

Contrary the price serial cranks, says:
BWS 90 42mm stroke
Simson s70 44mm stroke
Gilera Runner 51mm stroke
is just 46 USD for small numbers and 25USD in a quantity.

One strange idea - is it possible use "spline" side of crank to connect shafts using connector made of variator parts?
Or may be exist standards or drawings for splines shape? Will this connection compensate some imperfecties in aligment?

[eldog]

Just

This word should be removed from anyone who works with machinery:brick:

its caused grief every time it’s used.


note: it’s not a comment on what you proposed, only the word.




Alignment for timing seems problematic

[katinas]

Nice engine, nice video. It left me with two questions.
1: Why the threaded plug in the crankcase wall for access to the crankshaft pinch bolt, if that bolt is readily accessible from above?
2: Why are both piston ring slots right above each other instead of spread over the piston circumference? Just because it was convenient to use one long stift, fitted from above, for both ring slots? I will admit it's KISS, but I don't think it's the best way to reduce leakage.
346262 346261 346260

Plug in the crankcase wall, allows to check the tightening of the bolt without removing the cylinder.
In this video is simplified mass production version engine, but before, from 1969 they four years tried prototype engine in the boat race. And it was unique in the Soviet Union that the racing engine was adapted for mass production, always in reverse. Maybe they use only 1 piston ring on first race version, but I dont know.
Add again two schemes with arrows, full engine-is race version, only power part-is mass production.
Race version- rounded intake tunnel, different transfers tunnels shape, plated aluminium cylinders, cdi ignition, carb position on crankcase side, central crankcase part with fully opened tunnels for less weight and maybe for air circulation.
And finally on this engine was used centrifugal water pump, not usual outboard rubber high friction type. And sometimes, air in cooling system, caused exhaust side piston seize.

[katinas]

A
Another option is what Aermacchi HD used.
346268346269

t

Huge Central clamping flywheel was used on Иж Юпи́тер 350 parallel twin.
There was a race version of this motorcycle Иж Юпитер Ш-11 Ш-12, that was used in soviet championship and technical commission firstly checked (through a window in the crankcase) if the heavy steel flywheel was not replaced with light aluminum. The smartest used titanium, the color is similar to steel and similar for scratching

[katinas]

A
Another option is what Aermacchi HD used.
346268346269

t

Huge Central clamping flywheel was used on Иж Юпи́тер 350 parallel twin.
There was a race version of this motorcycle Иж Юпитер Ш-11 Ш-12, that was used in soviet championship and technical commission firstly checked (through a small box in the crankcase) if the heavy steel flywheel was not replaced with light aluminum. The smartest used titanium, the color is similar to steel and similar for scratching.
If only small clamping piece like on Aermacchi HD was allowed......

[Ocean1]

Probably thermal fit should work OK.


A self-locking taper (under 3 degrees, inclusive) can take a hell of a lot of torque. Morse tapers support massive loads driving drills.

A sleeve incorporating external seal grooves with an accurately ground internal Morse taper and lightly shrink fitted with a little heat would not move. A key or pin as a backup just reduces the capacity of the taper, introduces stress risers and won't help if the taper does let go.

The only problem I see with the general concept is the lack of a purely mechanical axial location and the requirement to time the cranks at assembly. So maybe you'd need to either use open roller bearings or a floating fit. And you'd have to make an assembly clamp/jig to hold the cranks halves correctly timed and apply the right force after the sleeve is warmed up.

Edit: you'd also have to make provision for a grease port at the center of the sleeve, for disassembly.

[WilDun]

In my experience the conical (tapered ) shaft arrangement as in the Ariel Arrow was not really satisfactory, as a key will move if the taper is not holding 100%!

Perhaps nowadays that isn't important I dunno, but way back then, when trying to race the thing, the ignition timing for both cylinders was taken from one crankshaft and caused constant headaches.

So (in hindsight), the timing constantly altering and causing big problems suggests that things were moving! - that can only get worse! The cranks (being pulled together by a central bolt) would then depend on that bolt and the key only ...... a key would not be adequate to keep things accurate and stood no chance of holding it alone!

J B - All this may not be relevant in your case of course (with less acceleration and deceleration) but thought that in the interest of safety in the air, I should point out the possibility of things failing!

....... only my opinion of course, but I would go for a spline first, or maybe a Hirth coupling! - then, the costing of it all has to be considered I guess!

[Muciek]

https://www.jordan-anwar.com/product/jordan-anwar/others/bea-19x50-bk95-locking-assembly/ maybe look for something like this and cut lab rings on the outside (or press a liner with them) ? They are used in CNC machines so they can't slip , there is also a version that looks like ER collet but can't find it online now.

[wobbly]

JB the central sleeve idea is for sure the KISS solution, but would also need the inner wheels/stub to be hollow to enable the sleeve ( with a thin solid center section ) to be pressed off easily.
If the sleeve was thick enough then small woodruff keys could be used for axial positioning at 180*, but as you will be doing a few then building a die set with setup holes to locate on the opposing
crank pins is an easy solution - this is how I do many RD/TZ/LC twin cranks , and then press on the outer wheels last.

[ken seeber]

EXHAUST AIR INLET

The idea is to fit a reed valve(s) into the inside of the exhaust cylinder passage or header or divergent cone. The reed valve being arranged such that it could admit & cool fresh air into the exhaust system. The reed valve being opened & closed by the cyclic pressure pulses in the system. When there is a negative wave adjacent to the valve, it could open and admit fresh air into the exhaust.

346275

This fresh cool air could possible displace some of the charge from the cylinder that passes into the exhaust prior to being plugged back. Potential benefit being that there could be a cooler charge in the cylinder at the time of EPC. Cooler = greater mass = more power.

Usual practical issues: mixture control, durability, noise, fitment etc.

So, if you think it is a dumb idea etc, then I’ll just say it was a friend’s idea.

[husaberg]

JB the central sleeve idea is for sure the KISS solution, but would also need the inner wheels/stub to be hollow to enable the sleeve ( with a thin solid center section ) to be pressed off easily.
If the sleeve was thick enough then small woodruff keys could be used for axial positioning at 180*, but as you will be doing a few then building a die set with setup holes to locate on the opposing
crank pins is an easy solution - this is how I do many RD/TZ/LC twin cranks , and then press on the outer wheels last.

Its not the world's best example but the TZ750 only uses a separate keyed gear doesn't it.
i have never seen on but i assume its a taper fit. but it has a bolt on much like a shitty old pommy cranknut.
pretty sure it gave trouble back in the day, i remember reading something about it from Cameron
346277346278346279

The NSR500 uses similar
but i suspect it used splineed shafts
346276




EXHAUST AIR INLET

The idea is to fit a reed valve(s) into the inside of the exhaust cylinder passage or header or divergent cone. The reed valve being arranged such that it could admit & cool fresh air into the exhaust system. The reed valve being opened & closed by the cyclic pressure pulses in the system. When there is a negative wave adjacent to the valve, it could open and admit fresh air into the exhaust.

346275

This fresh cool air could possible displace some of the charge from the cylinder that passes into the exhaust prior to being plugged back. Potential benefit being that there could be a cooler charge in the cylinder at the time of EPC. Cooler = greater mass = more power.

Usual practical issues: mixture control, durability, noise, fitment etc.

So, if you think it is a dumb idea etc, then I’ll just say it was a friend’s idea.

if you were adding air in wouldn't that oxidise the unburnt fuel and burn it in the exhaust.
my initial thoughts would be i think for off throttle emissions it would be good, but not while on the pipe.

[F5 Dave]

How did the RD400F US emmisions system work?

[Frits Overmars]

EXHAUST AIR INLET
The idea is to fit a reed valve(s) into the inside of the exhaust cylinder passage or header or divergent cone. The reed valve being arranged such that it could admit & cool fresh air into the exhaust system. The reed valve being opened & closed by the cyclic pressure pulses in the system. When there is a negative wave adjacent to the valve, it could open and admit fresh air into the exhaust.
This fresh cool air could possible displace some of the charge from the cylinder that passes into the exhaust prior to being plugged back. Potential benefit being that there could be a cooler charge in the cylinder at the time of EPC. Cooler = greater mass = more power.
Usual practical issues: mixture control, durability, noise, fitment etc.Practical issue # 1: there is only so much suction available from the pipe. Adding an air entrance to the pipe will steal from the suction that is supposed to move the mixture from the crankcase to the cylinder.
Plugging cool air from the pipe back into the cylinder will not add any power because air will not burn. You might compensate for it by enrichening the mixture that does get sucked from the crankcase, but even then there would hardly be enough time and turbulence to create a homogeneous air-fuel mixture.
Maybe you could put a carburetor on your pipe air inlet, add a spark plug to the pipe and create a pulse jet.
More power? I don't know. More noise? Absolutely! :rolleyes:



if you were adding air in wouldn't that oxidise the unburnt fuel and burn it in the exhaust.Any unburnt fuel in the exhaust pipe had already been mixed with air before it got there. Adding cold air would reduce rather than enhance the risk of burning this fuel.

[husaberg]

Any unburnt fuel in the exhaust pipe had already been mixed with air before got there. Adding cold air would reduce rather than enhance the risk of burning this fuel.

okay but why does it burn when you do this with the 4ts and the rotaries?
Is it because the exhaust temps are hotter?


How did the RD400F US emissions system work?
i will post the pics but it had butterflys in the ex pipe and they stopped the evil unburnt hydrocarbons from escaping until later where they kill the other flying butterflys.
346280346281346282346283346284346285
http://www.yeoldecycleshoppe.com/roadtestlibrary/2017/3/30/1979-yamaha-rd400f-daytona-special-road-test

They put cats in the RZ but that still wasn't enough to get them legal in California which accounted for over 1/2 the bikes sold then for the US

[WilDun]

This word should be removed from anyone who works with machinery:brick:

its caused grief every time it’s used.



Don't be daft! - That would then totally screw up the word "J.A.F.A" .... J*** think about it! :msn-wink:

[ceci]

Any unburnt fuel in the exhaust pipe had already been mixed with air before it got there. Adding cold air would reduce rather than enhance the risk of burning this fuel.


What you say is what happens in 99.99% of 2S engines, there is a 2S engine that the fuel can reach liquid ( spray) and not gaseous (steam) in the exhaust, which is it?

[jbiplane]

JB the central sleeve idea is for sure the KISS solution
Thank, Wobbly I experiencing now with a bit modified central sleeve.
Katinas seems as well have answers for all possible variants.


This word should be removed from anyone who works with machinery
its caused grief every time it’s used.
90% of stuff ariving from China should be carefully reworked and in wrong case dropped in garbidge immediatelly.
But it cheap and fast way save some money at ground experiments or use this parts as blanks for further machining.

Muciek, this is interesting idea which kept size and weight of coupling and allow easy detaching.

https://www.jordan-anwar.com/product/jordan-anwar/others/bea-19x50-bk95-locking-assembly/ maybe look for something like this and cut lab rings on the outside (or press a liner with them)...

[Frits Overmars]

if you were adding air in wouldn't that oxidise the unburnt fuel and burn it in the exhaust. my initial thoughts would be i think for off throttle emissions it would be good, but not while on the pipe.
Any unburnt fuel in the exhaust pipe had already been mixed with air before it got there. Adding cold air would reduce rather than enhance the risk of burning this fuel.
okay but why does it burn when you do this with the 4ts and the rotaries? Is it because the exhaust temps are hotter?If there is unburned fuel-air mixture in the pipe, it may ignite if the pipe wall temperature is high enough. Adding cold air won't help.
If there is unburned fuel without oxygen in the pipe, adding air wil make it combustible and depending on the pipe wall temperature it can indeed ignite.
I do not think pipes of naturally-aspirated four-strokes are hotter than two-stroke pipes. Wankel pipes definitely are.

How does unburned fuel without oxygen get into the pipe? Not from short-circuiting, scavenging losses or misfiring, because in all those cases the fuel was already mixed with air.
The only cause I can imagine is an overly rich mixture, whereby all of the oxygen but not all of the fuel was consumed during combustion.
In this case letting air into the pipe would be good for emissions, but getting the mixture correct would be even better.
<of the="" xygen="" but="" not="" all="" of="" fuel="" was="" consumed="" during="" combustion.="" in="" those="" cases="" adding="" air="" pipe="" would="" be="" good="" for="" emissions,="" getting="" mixture="" correct="" even="" better.


What you say is what happens in 99.99% of 2S engines, there is a 2S engine that the fuel can reach liquid ( spray) and not gaseous (steam) in the exhaust, which is it?I'm not sure that I understand what you are saying Ceci.</of>

[ceci]

How does unburned fuel without oxygen get into the pipe? Not from short-circuiting, scavenging losses or misfiring, because in all those cases the fuel was already mixed with air.
The only cause I can imagine is an overly rich mixture, whereby all of the oxygen but not all of the fuel was consumed during combustion.
In this case letting air into the pipe would be good for emissions, but getting the mixture correct would be even better.
<of the="" xygen="" but="" not="" all="" of="" fuel="" was="" consumed="" during="" combustion.="" in="" those="" cases="" adding="" air="" pipe="" would="" be="" good="" for="" emissions,="" getting="" mixture="" correct="" even="" better.

I'm not sure that I understand what you are saying Ceci.</of>



This is the only way for this to happen.
The Ski-Doo Rotax 2-TEC engine, its injection system can lead to this loss of liquid fuel.
The simulations were carried out in 2005 to demonstrate the losses of the 2-TEC system.

[ceci]

In addition to the Rotax 2-TEC (indirect injection) engine.
In direct injection engines it is also possible, a study by the UPV showed that the Derbi "TSI" injection prototype has loss of spray to the exhaust.

[Flettner]

In addition to the Rotax 2-TEC (indirect injection) engine.
In direct injection engines it is also possible, a study by the UPV showed that the Derbi "TSI" injection prototype has loss of spray to the exhaust.

TPI seems to work ok.
But you are right, we need to put the exhaust out of halms way, sling it down the other end of the cylinder, aye.

[Frits Overmars]

Afraid that your transfer ducts will catch cold, Neil? :msn-wink:

[ceci]

TPI seems to work ok.
.


Its TPI injection system has the advantage of injecting into the crankcase and not into the cylinder as is the 2-TEC, which prevents loss of spray in the exhaust.
Of all the indirect injections, the TPI is the most efficient for 2 reasons: 1st the spray cannot come out directly through the exhaust.
2nd when the spray is against the current, the fuel evaporates before

[WilDun]

Afraid that your transfer ducts will catch cold, Neil? :msn-wink:

Yes Frits, and they would normally sneeze straight into the exhaust which then would cough most of it back in and fart the remainder out at the other end - disgusting! (and we all thought that it was ok!! - surely not now?) ..... so as he said, he moved them well out of harm's way!
(Herr Schneurle?) would turn in his grave if he saw that we were still using his system today - he would have moved on!

[Flettner]

Afraid that your transfer ducts will catch cold, Neil? :msn-wink:

Frits, I LOLed, it is mid winter here after all.

[jbiplane]

Its TPI injection system ...
Our company www.flame-power.com made new REAL TIME engine management units with ARM processor based on Open Sourse RUSEFI.
It so fast that can calculate ammount of fuel and ignition advance angle each RPM for 1...4 cylinder engines

CAPABILITIES

Primary VR or Hall input (configurable with few resistor changes)
Secondary Hall input
x4 analog thermistor (temperature) inputs
x10 analog voltage inputs (0-5v)
x4 high-Z injector outputs
x2 high-current low side outputs for IAC/VVT/other solenoids
Dedicated main relay control output
x4 low-current low side outputs for relays or warning lights
x4 5v logic-level ignition outputs
x2 5v/12v configurable logic level outputs (requires resistor changes)
Electronic throttle body (drive by wire)
CAN connectivity on the plug
USB connectivity on the plug
https://www.homebuiltairplanes.com/forums/attachments/iso-jpg.98807/
https://www.homebuiltairplanes.com/forums/attachments/top-jpg.98808/