ESE's works engine tuner [Archive] - Page 125

Matt@TYGA

30th November 2018, 21:59

For an engine without a power valve I would not hesitate to say yes, but I don't think we'll find a single MX-bike without a power valve these days.
The restrictor bypass will no doubt counteract high-rpm part-throttle deto on any engine, but those MX-bikes are not that highly strung: a 250 cc MX-engine makes less power than a 125 cc GP-roadracer, so maybe they haven't got that deto problem. You'd have to try it, Peter. And let us know what you find :msn-wink:.

So maybe a redesign of the pipe biased towards the top rpm range, with a smaller restrictor, and then the bypass system to reduce the chance of deto (if this now becomes an issue), and also bring the midrange back up. Just a thought.

husaberg

1st December 2018, 08:46

So maybe a redesign of the pipe biased towards the top rpm range, with a smaller restrictor, and then the bypass system to reduce the chance of deto (if this now becomes an issue), and also bring the midrange back up. Just a thought.
Matt could you give us a run through on how to tell NSR model cylinders apart and what the differences are?

katinas

1st December 2018, 23:21

Some interesting graph about mix burning speed. This is general information, but maybe can help.

1. Percentages - residual EX gas in fresh mix
2. Lambda from 0.6 to 1.2

With 43 % residual Ex only at 0.8 burning speed still usable.
Maybe this can explain why sometimes is very difficult adjust carburation at some rpm.

jbiplane

2nd December 2018, 01:33

Want to be adviced:
Where to get cheap lightweight aircooled cylinder kits (nikasil or very thin liners) 70, 85, 110, 125 and 172cc.

They should be
- available in different countries and fitted to widelly spread moto and scooters
- small and lightweight
- dont want reed valve on cylinders
- be symmetrical shaped
- work nicelly at 8500...11500 rpm
- be nicelly ported and powerfull for its sizes
- not have too thin piston finger

Pro and contra
Honda (oversize Dio 50 and Lead 100) ???
Yamaha (oversize Jog 50, Jog 90, address 100 and 110)???
Suzuki (address 50, address 100, LT 80)???

Want to try on my 2-cylinder engines instead of chainsaw cylinders. May be I am wrong and chainsaw cylinders are light and powerfull enough or can be easily ported and give good power with correct resonator??? Says 120cc Husqvarna 3120XP have 8.5hp and with tuned pipe have 14hp. Cylinder weight just 1kg.

koenich

3rd December 2018, 22:18

Airsal has a massive range of cylinders for all sorts of mopeds, scooters, bikes and so on...

TerraRoot

3rd December 2018, 22:21

piaggio hexagon/NRG 125/175cc?

jbiplane

4th December 2018, 02:40

Airsal has a massive range of cylinders for all sorts of mopeds, scooters, bikes and so on...

Thanks, looking their site. We have Athena representative in country, but dont sell less than 3000 Euro per order.

1. I can buy from Taiwan: PIAGGIO A/C Bige Bore:¢50x39.2(77cc)
https://www.cens.com/cens/supplier/3271/product/98615/BIG.jpg
With delivery each set will cost 91 USD
Any idea what power possible get?

2. Can get in China 47.6MM oversize Jog
https://sc01.alicdn.com/kf/HTB1SEHYmWSWBuNjSsrbq6y0mVXaI/Replacement-Motorcycle-Cylinder-Head-Kit-Cylinder-Head.jpg

Is any of this variants good? What real power possible get?

piaggio hexagon/NRG 125/175cc?
Seems it can be only liquid cooled?

TerraRoot

4th December 2018, 04:15

there are aircooled versions, https://www.pmtuning.co.uk/malossi-aluminium-mhr-172cc-cylinder-kit-piaggio-125cc-150cc-air-cooled

not certain of the models, maybe a skipper 125/150 is another

jbiplane

4th December 2018, 12:35

there are aircooled versions, https://www.pmtuning.co.uk/malossi-aluminium-mhr-172cc-cylinder-kit-piaggio-125cc-150cc-air-cooled not certain of the models, maybe a skipper 125/150 is another

Nice link. They provide estimated hp data https://www.pmtuning.co.uk/polini-evolution-ii-70cc-cylinder-kit-piaggio-50cc-air-cooled

flyonly

5th December 2018, 22:35

That then is the problem with the AM6.
If you have holes in the skirt above the small end that connect the Aux and the A transfer,then it will run rich,and will not respond at all
to jet changes.
The seemingly rich mixture in the Exhaust is caused by the short circuiting, not by rich jetting, so you go leaner and nothing happens.

A file I have of a fully tuned TZR50 that puts out 18Hp Crank at 13,000 with triple Exhaust ports and this has a spigot exit area equivalent to 22mm.
This is 78% of the Exhaust effective area, and gives a Mach of 0.8 , absolutely fine.
Going slightly bigger in displacement or making more power than this would put the exit velocity close to sonic, so yes this may well be an issue as well.

The case com ratio is a very important element, guessing or not measuring it correctly isnt an option.
PS - you have a worn out piston available, drill a hole in it.

What did you use the TZR50 engine for?

Sent from my iPhone using Tapatalk

flyonly

5th December 2018, 23:20

The 50cc pipe shown is an early version ( based on Aprilia style cones ) done for a customer that wanted peak power at only 13,000,and that translates to a tuned length
in the 760 ballpark.
Later more powerful versions of that pipe were even fatter,and had a single rear cone , but the length remained similar to suit the powerband requested.

Hi Wobbly. What was the pipe designed for Road racing? MX?...

Sent from my iPhone using Tapatalk

wobbly

6th December 2018, 14:46

flyonly

6th December 2018, 22:15

No idea what the customer wanted to do with the engine.
I was told where to put the peak power , and of course argued till I was blue in the face that 13,000 was plain idiocy , in that it was capable of
making way more power - over a wider bandwidth if it went to 18,000.
But in the end I did the port and pipe sim as requested, took the money and shut the fuck up.
Not something that came naturally I must say.

I know it's a big topic.

Could you please explain the benefits of moving the power up the rev range? What sort of things do you need to take into account? I am sure you have to get everything working well together. The right clearances, correct squish, right size and port angles, right size carb, good crank balance ?

Sent from my iPhone using Tapatalk

wobbly

7th December 2018, 07:31

Very basically Power =Torque X RPM.
If you increase the rpm by 30% and hold up the torque , you get 30% more power.
Added to this the intake and Ex tuning action can be alot stronger at the higher rpm level, but of course you must create a synergy between the port STA numbers
and the tuned lengths of each system .
For me the biggest area that can be addressed is because the pipe must by definition be alot shorter , the angles will naturally be steeper for the same belly diameter.
There is a finite amount of energy in the Ex wave front travelling down the pipe elements and this is affected by the belly dia /pipe vol.
To get the same reflection amplitude from a fat pipe needs steeper ( shorter ) rear cones , and there is a quickly reducing return on efficiency if the volume becomes too big as
would be the case if you kept increasing diameter to obtain steeper diffuser angles.
I had a little chuckle to myself one day on another forum when someone asked Jan " why not just make the Aprilia pipe fatter to make more power ".
He simply said " bigger is not necessarily better , be it ports or pipes".

wobbly

8th December 2018, 07:43

lodgernz

8th December 2018, 09:08

It has been done properly by these guys.
50cc 24.5Hp 18000.

https://www.facebook.com/sprintperformancedutch/videos/767717930050083/?t=0

Notice that it takes full throttle and pulls hard at 10,000 and then spins past 18,000

Impressive!
Wobbly, I was expecting to see fuel spraying out of the powerjet but didn't see that. Why would they have had it closed for the whole pull?

husaberg

8th December 2018, 21:05

looks like ktm invented TPI a few years after Fletner
2015 acccording to this blub intersting read with protypes pictures including an orbital collaboration

Yet somehow not too long ago, less than two years we are told, there was the switch to the fuel injection model. It was using a lot of standard type parts like the injectors and sensors from the four-stroke bikes, as well as the in-tank fuel pump and filters. An oil injection system, necessity for clean emissions was already in use so that would be even easier. For sure the software would need to be all-new but KTM had a great location of the injectors in the rear transfer ports which would be very key going forward. Shooting fuel in here is about as close to the combustion chamber as possible but also as far away from the exhaust port as possible. This allows the fuel now mixing with the oil/air mixture to get into the combustion chamber, stay there and fill up–then also get bounced back by the return wave inside the exhaust while the exhaust port is still open. KTM showed journalists some of the engine modeling and how this whole two-stroke thing works,
Read more at https://dirtbiketest.com/fresh-dirt/two-stroke-fuel-injection-ktms-path-to-tpi/#vEo5PidhLc79kme1.99
339810339811339812339813339814

https://dirtbiketest.com/fresh-dirt/two-stroke-fuel-injection-ktms-path-to-tpi/#fySEUwSGM5SqJfjA.97

Tim Knopper

8th December 2018, 23:42

It has been done properly by these guys.
50cc 24.5Hp 18000.

https://www.facebook.com/sprintperformancedutch/videos/767717930050083/?t=0

Notice that it takes full throttle and pulls hard at 10,000 and then spins past 18,000

Built by two brothers Alexander and Rob v. Rossum (RVRT ) and 23 pk is the limiet reed engine as wel rotary
They say making new cilinder but till this moment COMPLETE SILENCE

And Wobbly they have nothing with simulation software (playstation game)

jbiplane

9th December 2018, 01:09

Hi folks. Looking for drawings of exhaust ball connectors. At moment did by myself, but may be exist some standards or best pracrics?

Frits Overmars

9th December 2018, 01:37

Hi folks. Looking for drawings of exhaust ball connectors. At moment did by myself, but may be exist some standards or best pracrics?https://www.google.nl/search?newwindow=1&hl=nl&biw=1280&bih=644&tbm=isch&sa=1&ei=AMgLXMLxNp2Bi-gPi_mysAc&q=Rotax+ball+flange+exhaust+connector&oq=Rotax+ball+flange+exhaust+connector&gs_l=img.3...154839.156150..157060...0.0..0.73.392 .6......1....1..gws-wiz-img.wx9Fjq8fbVM

https://www.google.nl/search?newwindow=1&hl=nl&tbm=isch&source=hp&biw=1280&bih=644&ei=9scLXOWuGdDlkgWz67yIAQ&q=ball+flange+exhaust+connector&oq=exhaust+ball+connector&gs_l=img.1.0.0i8i30.1052.7009..9014...0.0..1.142.1 552.20j2......1....1..gws-wiz-img.....0..0j0i30j0i19j0i8i30i19.LgqqqJiycEk

These websites show mostly foul-stroke connectors. But I seem to remember that a number of kart engines also had a ball exhaust coupling, Rotax for example.

136kg136ps

9th December 2018, 05:39

Looks like a good way to try different venturi inserts.

Juho_

9th December 2018, 19:36

Impressive!
Wobbly, I was expecting to see fuel spraying out of the powerjet but didn't see that. Why would they have had it closed for the whole pull?
Power jet can be used at higher rpm's or @ wot below pipe.

My 55cc engine seems to want richer mixture around 8-9krpm.
When adjusted for best peak hp/torque and overrev, it will bog at 8-9krpm when trying to start pull with full throttle.
If the main jet is too big (power loss, and lack of overrev); it does pull without trouble even from 5,000rpm and only slight power loss at 8,000-9,000rpm (just before, when pipe starts working).

Retarding or advancing ignition timing at 8,000-9,000rpm area has not done any good.
Solenoid controlled power jet could be the solution.

I have Mikuni TM28 carb on it. No dyno runs on 'real dyno' to see what kind of power figures I could actually be able to get this time... expecting around 17-18hp@14,5krpm with maximum of 16,000rpm.
GSF Dyno has shown more than 20% gain at peak hp and same torque output versus the pull compared to 'real dyno' (Fuchs: 15,1hp@11,228rpm and 9,8nm@10,770rpm.. max rpm 13,800rpm).
But it must be kept on mind, "street dynoing" can never be truely compared to dyno.

24,5hp from 50cc engine is very, very impressive. It must have taken a quite long development to achieve that kind of numbers.
For me it has taken over 2 years to achieve good driveability and power, but also enough overrev. Small karting tracks on mind.

peewee

10th December 2018, 06:34

guys I was able to start some welding. it took a while to figure out how to bring the aux ears into the main passage and transition the whole mess into a round spigot at the end, so that held me up for a bit. but I think I got it right or mostly right I hope :laugh:. my plan for next two weeks is grind the floors and weld on the passage and do the buildup for the aux passage then weld on the outer water shell

peewee

10th December 2018, 08:12

does anyone know if theres a place making wristpin plugs or is that something you have to make yourself ?

wobbly

10th December 2018, 08:34

F5 Dave

10th December 2018, 21:02

So ignitech P2 vs PV RZ servo. Set up so power disconnected. Up 2120mV. Down 1240mv. There's room above the PV at top, just I'm not driving it that far.

Set up servo screen with these figures and servo power plug back in.
Turn ignition on and cycles. So far so good.

But using test button it goes up and then back down. Doesn't stay up. Down button just groans a second as already down.

Under test buttons says 500ms. Altering this doesn't seem to do anything.

Can't see how to alter hysteresis either.

wobbly

11th December 2018, 08:20

Hysteresis is on the servo map page.
The 500 on the test page is the test speed ( time to go up ).
I will be setting up a P4 very soon on Charlets RZ400 so will see what that does , but seems normal to me that if you press down, and its already down
on a hard limit then it will only try to go to the programmed value plus the hysteresis.

TZ350

11th December 2018, 12:04

F5 Dave

11th December 2018, 12:12

339837

This is the PV curve from the Black Beast.

You can probably get away with just three points. I suspect the more points there are on the graph the slower the response.

The + - thing on the test page moves the PV then returns it back to its original place.

Its does? Wicked. Would have been more useful to leave it open so you can check it I would have thought. But I guess that is one reason Wobblys instructions I saved were to disconnect the power and move manually.

Thanks guys.

S'funny. Yours is the P2 Race. Mine has Servo enable box in the top left corner and I don't think anything in that row shown where yours is. I'll recheck and I have an older P2 as well to compare.

marsheng

11th December 2018, 12:44

Juho, the symptom you describe can be due to two main variables.
Ist is the main air corrector is wrong , this is something that TZ350 has described at length in his project on here.
A bigger main with a bigger air corrector , in general ,will be richer at lower rpm then lean out both sides of peak Hp.
2nd , the fuel ratio in the situation of WOT at low rpm is set specifically by the needle end diameter sitting in the emulsion tubes bore area.
This annulus area , when correct ,sets the A/F ratio so efficiently you can remove the main jet and it will run fine well up the rpm range before going rich.

This may be my problem well. I used the 3 days at the Southern Classic to 'play' with my bike. On the rebuild, I reduce the compression from 11.8 : 1 to 10:1 and the bike became much more ride able. I could tootle around at low rpm quite well and then open it up to get going. Very nice.

I found 2 problems, one as you describe above and it happened going from 5K to 5.5k. The motor just fluffed around but still pulled till 5.5k, then it reved well through to 8.5k.

The other I have never had before. The motor fluffed a bit for around 1.5 to 2 laps over the bottom rev range and wasn't quite crisp at high. Felt like too rich. Once I had a a few good burns down the straight, the motor then woke up and ran very nicely. I was wondering if the exhaust enclosed in the fairing made the difference. In the past, I seemed to loose a bit of power after a few laps. Once the motor was 'warm' this time it pulled well lap after lap. .

wobbly

11th December 2018, 14:40

TZ350

11th December 2018, 15:13

Its does? Wicked. Would have been more useful to leave it open so you can check it I would have thought.

What I do for checking PV position is to move a couple of the servo map points on the left in the engine stopped rpm range to some new place, then Program. Then power the bike down then up again. On power up the Ignitec moves the PV servo to this new dummy position on the map. I use this method to find the upper and lower PV position or start and finish mV range for my map. Actually it has been a while, but come to think of it. Just hitting "Program" may be enough to get the servo to move to the new test position.

The last big hurdle was setting up the power valve servo control in the Ignitec software. I have never had a power valve before and had no idea how it is supposed to be done but this is how I went about it.

Found an old post.....

F5 Dave

11th December 2018, 20:04

Ahh. Primo. I set servo for full open at idle and that's where it goes. Down button now cycles down and then back to open. Put back to as was.

Hmm. Tiny box just under 1st entry. Maybe that's hysteresis. Set to 100 now.

As can see closed off to hide hole before 7. Dyno tomorrow to play.

Due to lose access to it after like a couple of decades and before when Chris Sayle owned it.

Matt@TYGA

11th December 2018, 22:24

https://www.google.nl/search?newwindow=1&hl=nl&biw=1280&bih=644&tbm=isch&sa=1&ei=AMgLXMLxNp2Bi-gPi_mysAc&q=Rotax+ball+flange+exhaust+connector&oq=Rotax+ball+flange+exhaust+connector&gs_l=img.3...154839.156150..157060...0.0..0.73.392 .6......1....1..gws-wiz-img.wx9Fjq8fbVM

https://www.google.nl/search?newwindow=1&hl=nl&tbm=isch&source=hp&biw=1280&bih=644&ei=9scLXOWuGdDlkgWz67yIAQ&q=ball+flange+exhaust+connector&oq=exhaust+ball+connector&gs_l=img.1.0.0i8i30.1052.7009..9014...0.0..1.142.1 552.20j2......1....1..gws-wiz-img.....0..0j0i30j0i19j0i8i30i19.LgqqqJiycEk

These websites show mostly foul-stroke connectors. But I seem to remember that a number of kart engines also had a ball exhaust coupling, Rotax for example.

The Aprilia RS125 street bike has a ball type exhaust connector.

Matt@TYGA

11th December 2018, 22:45

Yes you are correct TeeZee. With a bunch of points on the curve the response time is alot slower.
Enough that you can see it cant keep up , on the dyno when accelerating real quick in the lower gears.
Personally I dont like the Race servo operation, as the thing supplies power to the servo motor if its even 1mV off the programmed value.
In a P2 as soon as the position is within the set value , including the hysteresis , the power is off completely.

Interesting that you should say this Wobbly.
I tried the Ignitech Race unit on my RS250NX5 and got shite results due to the exhaust valve doing all sorts of weird stuff. I only did half a run and aborted as the servo movement was obviously way off the mark. I'd fiddled a bit with the ignition map, but I'd left the valve map as they'd delivered it, just to see what their settings were like, but it was just so wrong that I thought that something was smoked! The actual power at peak. and after peak was slightly more than the HRC unit, but it lost all mid range as the valve seemed to have no idea what it was supposed to be doing!

FYI between the first and last (start/end) points, there's 9 points in between, which seems very excessive!

Thankfully I just finished my NX5 bench test unit so am now able to map the stock CDI ignition timing and valve timing to see where it's at, and I can then play a bit more seriously with the Ignitech.

Matt.

wobbly

12th December 2018, 07:50

TZ350

13th December 2018, 20:08

339880

This is pretty much how all the team bikes looked when we started out building Buckets. Made some progress since then.

Had the Black EFI Beast on the dyno tonight. Pipe kicks in at 8,000 rpm and the engine hits the rev limiter at 13,500 rpm.

Suzuki GP100 engine with a RD400 connecting rod and massive crankcase volume.

13,500 rpm is getting a bit frightening.

Fueling is no where right yet, too rich up top. So the big question is, can it take a few more revs.

Frits Overmars

13th December 2018, 20:41

Had the Black EFI Beast on the dyno tonight. Pipe kicks in at 8,000 rpm and the engine hits the rev limiter at 13,500 rpm. For a Suzuki GP100 engine with a RD400 connecting rod, massive crankcase volume. 13,500 rpm is getting a bit frightening. Fueling is no where right yet, too rich up top. So the big question is, can it take a few more revs.With a pressure-fed big end: easily.

andreas

13th December 2018, 23:39

With a pressure-fed big end: easily.

This was not a repy to a post, but a question in general. When a pressure wave encounter a baffle, does it reflect (and spread) progressively in a linear fashion or does it or is the 'bounce' effect somehow accumulated by other means? So if yes a linear reflection and a multi-staged baffle could be used to dress the power delivery, the positive wave will want to go back to a sawtooth shape-how great is this tendency?

andreas

14th December 2018, 15:20

I think the SoS in air is around 331m/s, and at 480* it's around 550m/s.
That's the figure I usually use, but maybe Frits is already factoring that into his formula, and expects us to use the SoS in air.
Can't eat choc fish. Hurts my knackered old teeth.

Not answering the 88 constant, but speed of one positive pulse is higher than speed of sound, as is a negative slower, there is also different gas properties than air.

Matt@TYGA

14th December 2018, 20:03

I fail to see how any "map " as delivered in any CDI can be used without first entering the full up, and full down mV values
with the servo driving the valve via correctly adjusted cables.
Even tiny cable adjustment will change the values.
As I have said before , the simple way to do the up/down check is to disconnect a power wire to the servo, and manually drive the servo wheel to the limits
and note the values off the on line screen.
I know for sure that in the RS125 be in NF4 or NXA the Ignitech cdi will not drive the Honda coils as the resistance and or inductance of the primary is wrong.
Use Suzuki or Aprilia coils ( less than 0.2 ohm ) and it works fine - or you can use a P2 and parallel the outputs with the stock coil.
I use a P4 in twins and do the same thing with Aprilia coils as well - mega spark power.

Wobbly,

I will proceed with more caution when I do the next test.
Just threw my meter on an RS250 NX5 coil. 0.8 ohm. Also tested an NSR250 coil while I was in the shed; 0.5 ohm. I have some RGV stuff kicking around at home somewhere, so it would be an interesting test to try to different coils side by side.

I see Ignitech have a low resistance (0.2 ohm), low inductance (0.08mH) coil (gnition coil IC-CDI-Fi). Have you tried this? And if so, how does it compare with the RGV coils?

I don't have a P4 in stock. Just a handful of P2's. Maybe I should be looking at throwing a P4 on the bike, with the coils you recommend, and enjoying "mega spark power" ;)

So quick question. Why do HRC use such a huge beefy coil? I guess that it's just the way things worked with Shindengen CDIs back in the day.

Cheers,

Matt.

TZ350

14th December 2018, 21:28

339882

I found that on its own the direct big end oiler delivered to much oil. So I connected it to one of the Ignitecs power jet controllers and now I can program when it runs. The oiler only runs now at WOT and high load, high RPM..... Job done.

339489 339490 Made a direct big end oiling pump for the Beast from a micro peristaltic pump and mini VSD drive.

339318 ... direct B/E oiling modification.

339239 back together again after replacing the rod kit and using a special crank pin Flettner made for me that has direct posi lube oiling to the big end.

F5 Dave

15th December 2018, 07:48

A bit frustrated and running out of dyno time. Might sneak one more in before it goes.

But I'm losing power trace as power approaches 100hp on my RZ350/496. I'd thought it was clutch slip and modified the clutch for an extra plate alongside the stiffer springs. And it still did it. Tying it down harder stopped the issue last year.

This week I'd found the drum on the old dynojet was oily so have cleaned that off and I need to tie it down pretty tight.

I suspect I'm getting tyre slip as the trace just stops still on the way up, say 500rpm from peak at circa 97hp. Viewing in mph instead of revs doesn't help.

Might try lower tyres pressure. Centre of drum might get a can of brake clean. It isn't as knurled in centre any more. But maybe it is still the clutch.

Hmm:scratch:

wobbly

15th December 2018, 08:18

Matt , the Ignitech coils seem to work the same as the RGV / RS250 coils.
Its a matter of matching the output circuit of the DCDC converter to the reactive impedance of the coil.
Ignitech have chosen one pairing , Honda another.

TeeZee , HRC on the RS250 road bikes also put full pump flow into the crank when on the overun ie high rpm - no throttle.
Same as KTM did with an injector on the GP engines - and for the same reason.

TZ350

15th December 2018, 11:19

Centre of drum might get a can of brake clean. It isn't as knurled in centre any more.

We sometimes have the same problem. Same sort of wear on the drum too. Cleaning the Drum and Tyre, especially the Tyre with lots of brake clean and wiping with a rag generally sorts it.

TZ350

15th December 2018, 11:22

TeeZee , HRC on the RS250 road bikes also put full pump flow into the crank when on the overun ie high rpm - no throttle. Same as KTM did with an injector on the GP engines - and for the same reason.

Thanks for the heads up. I can program that into the Ignitec.

F5 Dave

15th December 2018, 11:24

We sometimes have the same problem. Same sort of wear on the drum too. Cleaning the Drum and Tyre, especially the Tyre with lots of brake clean and wiping with a rag generally sorts it.

Roger. Will get on it. Tyre is hardly worn but pretty old, to my shame.

Matt@TYGA

15th December 2018, 15:19

andreas

16th December 2018, 02:41

Page 500 .....

No need to have a peaky engine. Here are Two Very useful Tools. EngMod2T a 2-Stroke simulation package and a handy (and cheep) Porting Calculator from:- http://www.porting-programs.com/ which is based on Blairs work.

263589Rich's 4-Stroke

There are over 3,500 images on this thread. To find the interesting ones use Thread Tools near the top of this page and View Images, then sort them from the Beginning and 70 to a page. Click on the Image to view it and the little N/A sign to go to the Post about it.

On each decade page, 490, 480, 470, 460 etc there is a collection of links or a collection of the more interesting technical posts from the last ten pages.

A bit of an index .....

Page 490 The Trombone, Ex port resonance and Transfer port stagger.
Page 480 A vid of the Trombone, transfer timing and hot gases entering the transfers because of insufficient blow-down for the rpm.
Page 470 Blow-down STA ... Specific Time Area.
Page 460 No list but the page talks about Boost Bottles.
Page 450 Links to the basic info for building a 30+ hp Bucket.
Page 440 No list, page talks about power and air correction jets.
Page 430 Carb inlet lengths and crankcase volumes.
Page 420 Transfer ports and the importance of the up swept angles, the Leaning Tower of Pisa principle explained.
Page 410 Rolling road dynos, main and power jet ratio.
Page 400 Links to the basic info for building a 30hp Suzuki GP125 Bucket engine.
Page 390 Links to Frits collection of Aprilia stuff.
Page 380 Transfer duct shape and STA's.
Page 370 No list but the page talks about Jan Thiel and racing 50's.
Page 360 Frits chamber calculations formula.
Page 350 PJ switching, Wob and crank shaft balance.
Page 340 Muriatic Acid, main brg float, Husburgs con rod dimensions.
Page 330 No list, page talks about expansion chambers, race gas.
Page 320 High temp silicon, Yama Bond, crankcase sealing, air solenoids Vid clips of Mamola.
Page 310 Copper for cooling, sprockets for cooling, steering head brgs.
Page 300 How to determine STA numbers.
Page 290 B/E dimensions, delivery ratio, Honda Ex Step, stinger nozzel
Page 280 Aprilia RSA port layout explained, pumper carb, links to gluing up the GP cases.
Page 270 Link list on how to make a decent high 20's hp Suzuki GP125 Bucket engine.
Page 260 Over rev cough and what it means, Mallory metal for crank balancing.
Page 250 27hp from a 1978 Suzuki GP125
Page 240 Aprilia RSA cylinder stuff.
Page 230 Porting Calculator and a lot of other useful tech links.
Page 220 RG50 part numbers, 2-stroke carb atomisers explained
Page 210 Page is mostly about the results from the TRRS
Page 200 Simple 18 hp Suzuki GP Bucket engine using a RG250 pipe.

Etc ...
Very helpful quick guide, there is some 2000 pages here, interesting indeed, but i'm looking for exhaust pipe discussion, the more physical the better. Do you have any suggestion? Thanks.

Frits Overmars

16th December 2018, 03:29

... i'm looking for exhaust pipe discussion, the more physical the better. Do you have any suggestion? Thanks.If you don't find it here, you might try http://www.pit-lane.biz/t117p246-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-1-locked
If nothing else, it will get you through the Christmas period, Andreas.

andreas

16th December 2018, 04:56

If you don't find it here, you might try http://www.pit-lane.biz/t117p246-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-1-locked
If nothing else, it will get you through the Christmas period, Andreas.

Haha that will be my reading of choise.

TZ350

16th December 2018, 05:57

Very helpful quick guide, there is some 2000 pages here, interesting indeed, but i'm looking for exhaust pipe discussion, the more physical the better. Do you have any suggestion? Thanks.

To find what you want, try the Google "site:" search option.

.
There is a lot of gold to be found in this thread.

To search for it use the good old Google "SITE:" search option which turned up this on Det Buttons: ......

det button site:https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner (https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?)

337313

Also take a look at pages 1,500 and 2,000.

TZ350

16th December 2018, 06:12

https://www.goodfood.com.au/good-living/entertaining/dinner-party-ideas-what-do-chefs-cook-when-they-have-friends-over-for-dinner-20170220-gugulj

... i'm looking for exhaust pipe discussion, the more physical the better.

339887

This thread is like a good show and tell dinner party where people put something on the table to share, ideas, talk, and laughter with friends.

Enjoying whats on the table is good and sharing makes it better.

Andreas please tell us something about your project.

F5 Dave

18th December 2018, 06:08

Just for update, cleaned dyno roller and tyres. No slip on the way up. 2nd issue is I was watching the bike tachometer rather than the dyno one as I usually do. Not sure why, maybe just got scared as it was whipping up go 11,000. Actually that was a real 10,000 so a few more revs and my peak was recovered and drops. Don't want to go crazy over revving a big engine. (7mm stroked RZ350 with 72mm CPI barrels).

Happy enough tickle under 100hp at 9800 with the air box back on. Fine for a road bike in a diminutive 250 chassis.

TZ350

18th December 2018, 06:52

.
100 rwhp street legal RZ250 look alike sleeper, very impressive....... :niceone:

F5 Dave

18th December 2018, 11:57

Well looks more like an RGV250. . .

TZ350

18th December 2018, 12:32

Well looks more like an RGV250. . .

100 hp RGV250 is very impressive, I am both impressed and jealous as..... any pictures?

F5 Dave

18th December 2018, 20:04

As it turns out. . .

https://www.kiwibiker.co.nz/forums/showthread.php/51274-F5’s-first-ever-brand-new-bike!

See what I mean about the old tyres:confused:

But there's been, reasons. Time to get it going again for summer.

Frits Overmars

19th December 2018, 01:53

Some Christmas reading:
http://translate.google.com/translate?hl=fr&sl=ja&tl=en&u=http%3A%2F%2Fwww2s.biglobe.ne.jp%2F~casa%2Fg-story-top.htm

I borrowed the link from my other favorite forum: http://www.pit-lane.biz/t1694p196-oldies-influence-de-son-pass-sur-les-travaux-de-kaaden
This may not be the right thread for it,
but
A: it's my favorite Kiwibiker thread
B: I didn't know where else to put it
C: chapter 38 may interest TZ350

TZ350

19th December 2018, 07:35

As it turns out. . .

https://www.kiwibiker.co.nz/forums/showthread.php/51274-F5’s-first-ever-brand-new-bike!

That is a great read, love the story behind the bike, thanks...:niceone:

Some Christmas reading:

http://translate.google.com/translate?hl=fr&sl=ja&tl=en&u=http%3A%2F%2Fwww2s.biglobe.ne.jp%2F~casa%2Fg-story-top.htm

I borrowed the link from my other favorite forum: http://www.pit-lane.biz/t1694p196-oldies-influence-de-son-pass-sur-les-travaux-de-kaaden

chapter 38 may interest TZ350

I am looking forward to getting into the Xmas reading, thanks.

TZ350

22nd December 2018, 07:24

339939 this is where the story got to with the Ecotrons 2S EFI system on my F4 Suzuki/NSR 110cc Bucket.

People have asked what am I doing with my new EFI system and why is it taking a bit of time? Should be easy to swap over, Right!, because EFI is EFI.

And I find it easiest to explain that I had written an EFI story using a foreign language (Ecotrons). Which as it turns out, does not work that well for high performance 2S's. So to change the ending of the story I need to use a different language, like the open source (Speeduino).

But to change the ending I first have to re write the original story in the new Speeduino language so that it reads the same as it did with the old Ecotrons one. When I have done that, then I should be able to change the ending to a more interesting one. Learning and getting proficient with any new languages takes time.

Frits Overmars

22nd December 2018, 23:57

People have asked what am I doing with my new EFI system and why is it taking a bit of time? ....And I find it easiest to explain that I had written an EFI story using a foreign language (Ecotrons). Which as it turns out, does not work that well for high performance 2S's. So to change the ending of the story I need to use a different language...
Learning and getting proficient with any new languages takes time.Boy, can I confirm! I spend most of my time between people whose language was conceived by seasoned sadists. I'm not doing too bad with German, but not a day goes by that I don't think how wonderful English is by comparison. You guys don't know how lucky you are.
Back on topic: you describe perfectly what it takes to switch from one programming language to an other. Initially the switch won't even improve the quality of the program; that can only come after utilizing the plus-points of the new language.

TZ350

23rd December 2018, 13:31

339945339946339947

Last year a friend of Team ESE had been trying his hand at land speed record breaking in Aus. For this year over the Xmas break we are helping Jim out with a bit of dyno time and hopefully Jim and his daughter Kath will get in some more good runs at lake Gardner. I am not entirely sure of the rules for his class but they look like they may be very similar to our Bucket rules and he is using an ex David Diprose bike.

This is Jim's wright-up from last year.

Hi All
Thought I'd pop you a note on the trip to the DLRA Speedweek at Lake Gardner, SA.

I was going to go with a mate from Scott Machinery who is a bit of a petrolhead and also knows how to speak Australian, however he got quite unwell and couldn't come. So daughter No2 -Katherine said "I'll come Daddio". So that was that!
Sent bikes to Adelaide in Box/Trailer I made.
Met up with Don Short-an expat Kiwi and we jointly rented a camper through Shareacamper and also split accommodation and travel costs.
Traveled up to Augusta and stayed overnight.Katherine had expressed an interest in riding the 50 in one of the two classes it was entered in so as she had NEVER ridden a bike before it occurred to me she may benefit from a wee riding lesson before we got to the salt. So we stopped at a little outback town called Kimba, unloaded the 50 and within about half an hour she was cruising through the gears and settling into it amazingly well. Got to the lake later that day and checked out the salt.
Tech inspection next morning and both bikes went through with nil issues.
Did my rookie run and the 50 started missing -pulled carb apart and cleaned out-fixed.
Kath did her rookie run after lunch and recorded 68mph. Crikey!! This turned out to be the best we could get from the 50-wasn't entirely surprised as it was built as a 1 hr endurance bike and my best at home was 72 mph on Hakarimata Rd (in front of our house)
I did my run on the 50 with fairings on and then turned my attention to the 100. First run was 71mph with a slipping clutch. Pulled the engine out 3 times and substituted front and back plates, added spacers etc etc and by the last run had raised the speed to 86.915 mph at 11500 revs-still with a clutch slip problem. Bike was accelerating strongly up to 11500 revs but was slipping freely after that but engine will pull strongly through to14500.
Ran out of time on the last day to have one more run by which time I had locked up the clutch. Four records set but we did not achieve our target speeds which was the primary goal of course
Target speeds were-80mph+ for the 50 and 100mph+ for the 100.
So -unfinished business of course.
Plan going forward-Improves to the 50:
Upcarb from 18 to 26mm with external mixture adjustment.
Better Ignition
Better Chamber
EGT, O2 and ambient airtemp sensors,
all linked into a CPU that has WiFi to my phone and makes tuning quite friendly.-(theoretically anyway)

Keep Katherine on it as number 1 rider!!
She told me the other day she had to throttle off a bit on her rookie run because of the cross wind!

100
Better clutch plates and stronger springs.

Had a wonderful/busy time-met a raft of interesting neat people who treated us almost like family.
And the Lake: A stark,serene and somewhat surreal geological wonder that I can't really do justice to with adjectives alone. The sunsets are really something else!!
Kath is going to do a write up of her own of the little trip complete with pics etc of course.

Jim & Katherine Goulter

wolfie

23rd December 2018, 15:15

Hi ive been a lurker here for a while, picking up some hints on 2 stroke performance as I race at Lake Gairdner as well. RGV250 with a best speed of 140 mph.

Here is a link to the 2019 rule book that is free to download from the DLRA site. https://www.dlra.org.au/rulebook.htm

Looks like they are running in and got some great speeds.

50-MPS-CG
50-M-CG
100-APS-CG
100-M-CG

Ill keep an eye out for Jim & Kath next year. Always good to get some more smoke on the lake.

Dave

speedpro

23rd December 2018, 16:20

100 Better clutch plates and stronger springs.

Not required.

With a bit of machining an extra pair of plates can be fitted and with the standard springs the clutch is good for about 25hp. Feel at the lever is identical to a standard clutch. The addition of small spacers on the springs will see it good for about 30hp @ 14,000, not sure what torque which is the critical bit. The fibre plates are all the same in that vintage of Honda.

husaberg

23rd December 2018, 17:39

Not required.

With a bit of machining an extra pair of plates can be fitted and with the standard springs the clutch is good for about 25hp. Feel at the lever is identical to a standard clutch. The addition of small spacers on the springs will see it good for about 30hp @ 14,000, not sure what torque which is the critical bit. The fibre plates are all the same in that vintage of Honda.

Gen CR80 from about 87 are meant to be better material though, Kevlar i think rather than pulp
you can also adapt the XR200 style realese bearing and alloy spring retainer with a larger push rod
The XR200/185/125s hub can be added its deeper buts an additional few plates but it requires the center pressed out some machining and the cover spaced out and other mods that i have likely forgotten about.
As a side note if the rules allowed i would use a late CR80/85 hub and primary as they have far narrower gears and a lighter hub
i havent tried the spline on ther crank yet but the ratio and the hub is the same

oldjohnno

23rd December 2018, 22:58

For applications like LSR - where instant response isn't important - additional flywheel mass helps the clutch (and the whole transmission for that matter) to survive. The extra rotating mass lops the top off the torque spikes produce by a single cylinder engine. Does wonders for traction too with things like trials bikes.

Frits Overmars

23rd December 2018, 23:21

100: Better clutch plates and stronger springs.

Not required.
With a bit of machining an extra pair of plates can be fitted and with the standard springs the clutch is good for about 25hp.... The addition of small spacers on the springs will see it good for about 30hpMaybe not good enough; once that 100 starts producing decent power, it ought to exceed 30 hp. And maybe not required either.
There is a new transmission oil, developed for wet-clutch racing engines, that exceeded all expectations (3 German roadracing championship titles in 2018).
I doubt whether you'll already find it in NZ or OZ, but you can get it from Langtuning who helped develop it:
https://langtuning.de/Shop2/ADDINOL-RC-80W-Racing-Getriebeoel ; kontakt@langtuning.de
or from Emot: http://www.emot.nl ; stehouwer@emot.nl .
339951

Frits Overmars

23rd December 2018, 23:27

All the best to all of you, folks!
339952

yatasaki

24th December 2018, 01:08

Hi to all
Decided to surprise myself for Christmas by registering to this too-far-away forum as I have some serious questions.
My name is Frano, mechanical engineer, two stroke moped and classic/old timer racer, doing more than great so far as rider and builder. Coming from one of Croatian islands. Presently building two engines for 4 hours moped endurance race.

Frits Overmars

24th December 2018, 07:38

Dobrodošli Frano. Any chance of pictures?

TZ350

24th December 2018, 07:49

Dobrodošli Frano. Any chance of pictures?

I would love to see some pictures too. But there maybe a minimum number of posts required before attaching pictures is automatically allowed???

yatasaki

24th December 2018, 08:27

Obviously
...
https://i.postimg.cc/G8W9twSy/IMG-20171217-WA0003.jpg (https://postimg.cc/G8W9twSy)

yatasaki

24th December 2018, 08:28

katinas

24th December 2018, 08:57

Latest tests with KTM SX 125 engine was much harder than on SX 50/65/85. It was very difficult to rise power and at the same time not lost the mid range.

With rounded piston, engine respond not as good as on the smaller engines, maybe because this time we cant try bigger stinger and SX 125 piston is flat top, but difficult to say.

Interesting, this time with rounded piston ( just 0,5 mm , with 1mm no gains, maybe HGS pipe stinger is too small), engine works better with raised ( + 1mm), not lowered, cylinder. And only raised piston side cuts itself gave some power (add photo).

Photo with heads- upper cracked VHM at 2 clock, two others what we made for tests.

Power valve opens around 7000 rpm.,
Blue - what we gave from owner.
Red - where we ended ( no more time to test, owner want to take it back, but still not tested on the track because of snow.)

Good Christmas time to all and many thanks for this Thread.

husaberg

24th December 2018, 11:27

Celebrating your coming-out, Husa? Coz those don't look like season's wishes to me :whistle:
By the way: all the best to all of you, folks!
339952
Personally i am more a lesbian woman trapped in a mans body.
Merry Xmas

https://www.youtube.com/watch?v=RBOqfLVCDv8
https://www.youtube.com/watch?v=lGeJ__WsB3E

Some on Bike 500 footage

https://youtu.be/1R63ctXJfDE?t=445

peewee

24th December 2018, 15:35

not a lot of updates to report but im still chipping away at it every chance I can. exh passages are welded on and now its just a bunch of grinding away the existing outer shell and extend the aux ears to the end of passage. maybe the exh spigot would of been fine with three bolts attaching it to the cyl but I decided to use four

lohring

25th December 2018, 03:31

It worked...
So which pictures? Thematic or beauties (natural) from my island?
https://i.postimg.cc/YGRmGdZ3/IMG-20180528-163934.jpg (https://postimg.cc/YGRmGdZ3)
Let's stick to two stroke
Above is 2016 and 2017 winning moped cup cylinder, my first question is about the ports added between main exhaust and A ports ( forget about exh boost ports, they were added later on and added short circuiting) I used to call them golmans, like to prevent or slow down a bit mixture from rest of the transfer ports from going to exhaust. Timing of these subA ports was half of the A ports which are 126° angled 10°, B 130 ° angled 70° and C 132° angled 70°upward. So B and C are heading torwards cylinder head...exhaust 168°.
Any similar idea or comment?

RC car engines have used transfer ports somewhat like that. They use Yam 12 (very poor) transfer passage shapes, though. We were able to improve the power of a 35 cc race engine with the pictured liner modification. The stock liner is on the left. The best power modification is the second liner from the left. All these designs try to block the flow out of the exhaust. I think the RC car liner designs may also be for marketing more than serious performance improvement. They come out with different porting every few years.

Lohring Miller

339960 339961

teriks

25th December 2018, 06:57

Frits Overmars

25th December 2018, 08:36

Above is 2016 and 2017 winning moped cup cylinder, my first question is about the ports added between main exhaust and A ports ( forget about exh boost ports, they were added later on and added short circuiting) I used to call them golmans, like to prevent or slow down a bit mixture from rest of the transfer ports from going to exhaust. Timing of these subA ports was half of the A ports which are 126° angled 10°, B 130 ° angled 70° and C 132° angled 70°upward. So B and C are heading torwards cylinder head...exhaust 168°.What kind of transmission are you using Frano? Gearbox, CVT, centrifugal clutch?

peewee

25th December 2018, 08:49

Thats one hell of an effort, hope it pays off!

thank you sir. without any cutting or welding I believe these cylinders do a bit over 100hp on methanol, that's what ive heard any way. but I think I can do better than that. if nothing else, atleast Ill gain more welding and fabrication experience for later down the road on other projects :laugh:. theres a few more things I wanted to do , like raise the exh floor since its so low but that would add a fair bit more time so I decided against it. transfers have very little up angle going into the cyl so ill likely put epoxy in there. ill keep updating as I go, will have five more days off work next week and should be able to make quit a bit more progress

jbiplane

25th December 2018, 20:05

Test of digital ignition (part of our SmartEMS) at 17750 rpm.

https://www.youtube.com/watch?v=ABDLwn7m4dw

yatasaki

25th December 2018, 20:51

Frits, this one was ordinary gearbox, clutch ratio 4.07 ,1st ratio 3.8 ,2nd 2.28, 3rd 1.59,4th 1.24, 5th 1.07
So porting and everything else is done starting from gearbox ratios which cannot be changed ( rulebook you know hehe)
https://i.postimg.cc/9DWWm2hH/IMG-20181225-092257.jpg (https://postimg.cc/9DWWm2hH)
This one is from two stage centrifugal clutch, but with reed valve same arrangement ( later converted to piston induction for much better performance, can you imagine that!?...rulebooks again)

Lhoring, I can see that transfers open at the same time? Wouldn't be better to flow them much last to let A,B and C's do the scavenging?
Greetings to all!

Frits Overmars

25th December 2018, 22:23

... the ports added between main exhaust and A ports... I used to call them golmans... Timing of these subA ports was half of the A ports...Frano, calling your golmans 'subA ports' may cause some confusion. The convention is that the transfer ports closest to the main exhaust port are called the A-ports. Any additional sets of ports are then called B-ports, C-ports, and so on. So in your case the 'golmans' are the A-ports.
339962

yatasaki

26th December 2018, 01:09

Right,.. called them subA cause closest to exhaust and aiming upward like C ...but for further confusion A is closest to exhaust.

TZ350

26th December 2018, 07:37

Test of digital ignition (part of our SmartEMS) at 17750 rpm.

https://www.youtube.com/watch?v=ABDLwn7m4dw

3.04ms/0.9dutycycle=3.38ms
1000/3.38ms=295.86Hz
295.86*60=17,751 RPM

Tuning Studio gauges all add up for 17,750 RPM, very impressive.

Demonstrating the spark by cutting paper, :laugh: I love your work.

peewee

26th December 2018, 11:11

thank you sir. without any cutting or welding I believe these cylinders do a bit over 100hp on methanol, that's what ive heard any way. but I think I can do better than that. if nothing else, atleast Ill gain more welding and fabrication experience for later down the road on other projects :laugh:. theres a few more things I wanted to do , like raise the exh floor since its so low but that would add a fair bit more time so I decided against it. transfers have very little up angle going into the cyl so ill likely put epoxy in there. ill keep updating as I go, will have five more days off work next week and should be able to make quit a bit more progress

Thats one hell of an effort, hope it pays off!

some time ago I found this photo but im following the same design they have done with the exh duct. im doubling its length (original was only 1x bore diam). also extending ears to the spigot . effective area at bore face will reduce to 75% at spigot exit. and the whole thing will be cooled from water. with other engines the exh is far to short because the chassis cant allow anything longer but now I have no chassis compromise and its free to do as I wish

lodgernz

26th December 2018, 13:00

Frits: You've posted a new version of your Transfer Axial Angle formulae on another forum.
While the A transfer angle stays the same, the B port angle is different and the Boost Port angle is markedly different.
Can I just ask you to confirm that this is not an error, before I go ahead and cut to the new formulae?

wobbly

26th December 2018, 15:59

Anyone got a GT750 cylinder and head I could look at.
I have a possible job to model a billet head with inserts as no one it seems has done this before.
And as with the RD/TZ the water route needs changing.
Please PM if you can help.

Frits Overmars

26th December 2018, 23:15

some time ago I found this photo but im following the same design they have done with the exh duct. im doubling its length (original was only 1x bore diam). also extending ears to the spigot.Here are a couple more pictures to go with yours. They're Aprilia RSA, but you would know that, wouldn't you Peewee?

katinas

27th December 2018, 01:23

Some results from testing with direct intake from carb to transfers windows ( via crankcase )on Honda NS cylinder.
It is just feelings from riding on the road ( no dyno ). Intake duration 210 degrees.

Starting is much easier than with std. and feels like engine work much cleaner at lower revs without flooding, even cold. There is no typical 1-2 gear flooding smoke at the start of riding, its more like with four stroke.

Max power with Std feels little higher at 11000 rpm and then drops, but in the power band with direct intake, power feels more linear from 11000 to 13000 rpm , again more like on 4t and about 750 revs more than std.

Engine reaction to higher intake duration ( 245 degrees ) very interesting. Feels like lost power everywhere and at 12000 rpm engine stopped and then again revs up ( add drawing)

Frits Overmars

27th December 2018, 01:30

peewee

27th December 2018, 03:34

Here are a couple more pictures to go with yours. They're Aprilia RSA, but you would know that, wouldn't you Peewee?

yes. i cant think of any better engine to copy :third:

lodgernz

27th December 2018, 07:43

You are right, it was a mix-up of old and new versions. Thanks for pointing it out. Here is the correct version.

Cool, thanks Frits. Had me worried there for a minute...

Haufen

27th December 2018, 08:13

You are right, it was a mix-up of old and new versions. Thanks for pointing it out. Here is the correct version.
339970

thanks. What led to these changes?

yatasaki

27th December 2018, 08:16

For aux exhaust ports being few degrees lower from main benefits power curve, but what if we have to use much lower angles, say 160-175°, is it better to open all ports at the same time to have all possible blowdown or few degrees after would benefit power, same as for larger openings?
https://i.postimg.cc/N93Yjp2M/IMG-20181201-WA0003.jpg (https://postimg.cc/N93Yjp2M)
This is exhaust ports arrangement for my endurance moped, aux are four degrees late, floor is 4 mm above transfers bottomline, as cylinder casting was like that.
Because dyno is impossible to reach around here I'm using straight road ,marked with two points, gps, mychron with plug temp and always same chain ratio. So small changes leading to bigger result is almost impossible to notice.
Hope not interrupting some serious talk here cause You guys are more R&D department...me.. trying to build competitive bike from semi-product but not giving up

TZ350

27th December 2018, 11:22

Because dyno is impossible to reach around here I'm using straight road ,marked with two points, gps, mychron with plug temp and always same chain ratio. So small changes leading to bigger result is almost impossible to notice. Hope not interrupting some serious talk here cause You guys are more R&D department...me.. trying to build competitive bike from semi-product but not giving up

I am impressed by your work, and the way you are trying to solve the problems of developing your bike, you fit right in here...... :yes:

Frits Overmars

28th December 2018, 00:49

Some results from testing with direct intake from carb to transfers windows ( via crankcase )on Honda NS cylinder.No problems with big end lubrication Katinas?

For aux exhaust ports being few degrees lower from main benefits power curve, but what if we have to use much lower angles, say 160-175°, is it better to open all ports at the same time to have all possible blowdown or few degrees after would benefit power, same as for larger openings?I would think that all exhaust ports should have a minimum of 190° timing. So if your main exhaust port has 190° timing, the auxiliary ports should also have those 190°.

This is exhaust ports arrangement for my endurance moped, aux are four degrees late, floor is 4 mm above transfers bottomline, as cylinder casting was like that.4 mm has no meaning to me without knowing at least your engine's stroke.

Hope not interrupting some serious talk here cause You guys are more R&D department...me.. trying to build competitive bike from semi-product but not giving upI completely agree with TZ350. You fit right in.
I just wasted a couple of hours trying to keep up with all the rubbish that is written in a Facebook group called "2 Stroke research & development".
After that, it's a delight turning to Kiwibiker and meeting with some sense.
I wonder: would Einstein have had some Facebook-experience?
339990

yatasaki

28th December 2018, 04:43

Feeling already warmer, thanks TZ and Frits..
Regarding exh duration...our mopeds (for serial class)are restricted to 16.5ish mm carb diameter, (widened dellorto SHA, Bing ) alltogether intake length 65-70 mm, mopeds are mostly 60 +/-2 cc, stroke 43. Anyone appears with duration more than 175° will use his clutch untill burn and will finish last. (Maybe gear ratios posted on previous page would explain situation further for rev drop) For open class you are allowed any diameter and any type of carb so exh duration are 180-194° BUT expenses between these two classes are at least trippled...
When asked "what are yours timings" nobody used to believe me.

husaberg

28th December 2018, 07:14

thank you sir. without any cutting or welding I believe these cylinders do a bit over 100hp on methanol, that's what ive heard any way. but I think I can do better than that. if nothing else, atleast Ill gain more welding and fabrication experience for later down the road on other projects :laugh:. theres a few more things I wanted to do , like raise the exh floor since its so low but that would add a fair bit more time so I decided against it. transfers have very little up angle going into the cyl so ill likely put epoxy in there. ill keep updating as I go, will have five more days off work next week and should be able to make quit a bit more progress

I was meant to post this ages ago i think i described the construction only at the time.
Notice the oval to round transition
This is one piece but would be pretty easy to fabricate out of a thick wall pipe and flange. Pipe turned down on outside afterwards.
339993339994339992339997
4 spring holes
3 turtle doves
two locating dowels
and two o-rings for belts and braces safety.

andreas

28th December 2018, 07:28

To find what you want, try the Google "site:" search option.

Also take a look at pages 1,500 and 2,000.

Thank you TZ. Was too busy reading on pit- lane and that dreaded fb site haha, will be searching for that gold now.

andreas

28th December 2018, 07:47

https://www.goodfood.com.au/good-living/entertaining/dinner-party-ideas-what-do-chefs-cook-when-they-have-friends-over-for-dinner-20170220-gugulj

339887

This thread is like a good show and tell dinner party where people put something on the table to share, ideas, talk, and laughter with friends.

Enjoying whats on the table is good and sharing makes it better.

Andreas please tell us something about your project.

I very much agree. Say I'm backyard tuner, its a rd 125 converted to 175, 130/ 198 three port, yz 125 reeds, vm 38. I'm trying to get a good 'grip' on the pipe functions, this one I have is kind of based on Blair, This far I get good tourqe but it's reluctant to rev. Happy holidays.https://scontent.fbma3-1.fna.fbcdn.net/v/t1.0-9/48891129_2863980633615914_3452578446654308352_n.jp g?_nc_cat=103&_nc_ht=scontent.fbma3-1.fna&oh=58ecb377caeb90179ec53575d0fb9f34&oe=5C92B29Bhttps://scontent.fbma3-1.fna.fbcdn.net/v/t1.0-9/48377938_2863981226949188_6553266370161672192_n.jp g?_nc_cat=110&_nc_ht=scontent.fbma3-1.fna&oh=e29839dae7ff89709c9747870f915e6d&oe=5C905BBF Pipe litterary welded on the parking lot.

wobbly

28th December 2018, 08:01

You are right again Frits, I have given up even going onto " 2 stroke R&D " site - as I told them im not interested in a dick measuring discussion
that seems to be the general tone of those self made men praising their makers.

OopsClunkThud

28th December 2018, 09:00

Question about transfer port profiles.

Having gathered that a constant radius and a tapering port area are desirable I've been working with two offset circles to define a shape that meets this. So far I've been sizing the rest of it to give the desired entrance to exit area ratio. But depending on the length of the port this can result in a wide range in the taper.

So, is there an ideal taper that should drive the design? Or is the area ratio more important? Or is it a balance where both are important? Or does the smaller radius needs more taper to keep the flow attached?

To illustrate the point I've drawn two "ports" with the same area ratio but vastly different taper.
339998

F5 Dave

28th December 2018, 09:24

I very much agree. Say I'm backyard tuner, its a rd 125 converted to 175, 130/ 198 three port, yz 125 reeds, vm 38. I'm trying to get a good 'grip' on the pipe functions, this one I have is kind of based on Blair, This far I get good tourqe but it's reluctant to rev. Happy holidays.https://scontent.fbma3-1.fna.fbcdn.net/v/t1.0-9/48891129_2863980633615914_3452578446654308352_n.jp g?_nc_cat=103&_nc_ht=scontent.fbma3-1.fna&oh=58ecb377caeb90179ec53575d0fb9f34&oe=5C92B29B Pipe litterary welded on the parking lot.
Seems like a chunk of money but an ignitech can remove large swathes of ignition restrictions in a single move. Not sure local setup but there's a German shop bikeside that sell on ebay, I bought several CR250 ones when Wob couldn't get any at the time. They are all the same (DCCDI)P2 in that kit, but do check they are.
Hmm, looks like single but should be fine anyway

https://www.ebay.com/itm/IGNITECH-programmierbare-Zundung-Aprilia-RS125-2008-DC-CDI-P-Ignition-NEW/223034972044?hash=item33edeb978c:g:4JcAAOSwbdpWWzV 4

That header pipe looks a billion miles long.

andreas

28th December 2018, 10:53

Seems like a chunk of money but an ignitech can remove large swathes of ignition restrictions in a single move. Not sure local setup but there's a German shop bikeside that sell on ebay, I bought several CR250 ones when Wob couldn't get any at the time. They are all the same (DCCDI)P2 in that kit, but do check they are.
Hmm, looks like single but should be fine anyway

https://www.ebay.com/itm/IGNITECH-programmierbare-Zundung-Aprilia-RS125-2008-DC-CDI-P-Ignition-NEW/223034972044?hash=item33edeb978c:g:4JcAAOSwbdpWWzV 4

That header pipe looks a billion miles long.

Thanks Dave, I do consider a modern ignition, gonna look in the link. And yes it's rather long, it was intended for recreational use primarily and is shorter now.

teriks

28th December 2018, 11:24

I just wasted a couple of hours trying to keep up with all the rubbish that is written in a Facebook group called "2 Stroke research & development".
After that, it's a delight turning to Kiwibiker and meeting with some sense.
I Wonder: would Einstein have had some Facebook-experience?
339990
I think I know which thread inspired that quote, amazing...

lodgernz

28th December 2018, 13:01

Thanks Dave, I do consider a modern ignition, gonna look in the link.

This is not cheap, but should be a big improvement.
https://www.hpi.be/item.php?item=210K176

Tim Knopper

28th December 2018, 21:02

I just wasted a couple of hours trying to keep up with all the rubbish that is written in a Facebook group called "2 Stroke research & development".
[/QUOTE]

Very strange reaction of Master Jan on Wobbly

jamathi

28th December 2018, 21:44

I just wasted a couple of hours trying to keep up with all the rubbish that is written in a Facebook group called "2 Stroke research & development".

Very strange reaction of Master Jan on Wobbly[/QUOTE

There is no reaction of mine on Wobbly at all!
All the contrary, I respect and admire him....
And I think he is the best 2-stroke tuner in the world at the moment!!!

dutchpower

28th December 2018, 22:19

Tim

Jan has a special way of humour if you understands his humour you know beter :rolleyes:

jamathi

28th December 2018, 23:11

Tim

Jan has a special way of humour if you understands his humour you know beter :rolleyes:

I REALLY mean what I say!!!

andreas

29th December 2018, 02:40

This is not cheap, but should be a big improvement.
https://www.hpi.be/item.php?item=210K176

Perhaps. The ignitech seems like a good option though.

andreas

29th December 2018, 03:17

peewee

29th December 2018, 06:10

I was meant to post this ages ago i think i described the construction only at the time.
Notice the oval to round transition
This is one piece but would be pretty easy to fabricate out of a thick wall pipe and flange. Pipe turned down on outside afterwards.
339993339994339992339997
4 spring holes
3 turtle doves
two locating dowels
and two o-rings for belts and braces safety.

yes i plan to make the spigot like you describe. it will be fully round where at exit. four hold down springs, two at top and two at bottom. it will bolt on the cylinder with only sealer and no gasket as this method has worked good for me before. not sure yet if ill use steel or aluminum

katinas

29th December 2018, 06:49

[QUOTE=Frits Overmars;1131119962]No problems with big end lubrication Katinas?

[ATTACH=CONFIG]339990

Before first road tests I worry about this, but looks like reality is opposite. Every time when I take off cylinder, crank was much more oiled than usual with std. Maybe isolated crankcase space, when piston is at BDC, holds oil around crank ( with autolube, directly to crankcase would be really good). All summer tests was without any big end troubles.

From gas dynamic side with this configuration, I cant really understand whats going on in transfers ports and crankcase space, just try to imagine.

Tried every possible combination of holes in the piston (add pic piston with 210 and 245 duration), but power always was worse. So I try to eliminate all holes with block plates, screwed to the piston inside with bolts. I am lucky that one of the bolts broke just, when most tests was done with this piston.

Frits Overmars

29th December 2018, 10:12

Having gathered that a constant radius and a tapering port area are desirable I've been working with two offset circles to define a shape that meets this. So far I've been sizing the rest of it to give the desired entrance to exit area ratio. But depending on the length of the port this can result in a wide range in the taper.
So, is there an ideal taper that should drive the design? Or is the area ratio more important? Or is it a balance where both are important? Or does the smaller radius needs more taper to keep the flow attached?
To illustrate the point I've drawn two "ports" with the same area ratio but vastly different taper.
339998In addition to your drawing there is another factor to be considered: the axial exit angle. Together with the requirement of the largest possible inner radius that will fit between crankcase and transfer window, your choices are already fairly restricted. The geometry of the RSA A-duct, below, may illustrate what I mean.
If you google Helmholtz, you will find an explanation involving a volume and a cilindrical duct. A conical duct like a transfer duct makes things a bit more complicated.
Port length + taper comes down to the same thing as port length + area ratio. They offer me the opportunity to create a conical duct with the Helmholtz property that will work at a desired frequency in combination with a given crankcase volume and port timing.
340016

husaberg

29th December 2018, 10:34

yes i plan to make the spigot like you describe. it will be fully round where at exit. four hold down springs, two at top and two at bottom. it will bolt on the cylinder with only sealer and no gasket as this method has worked good for me before. not sure yet if ill use steel or aluminum

The two orings are for the pipe sealing rather than Cylinder to spigot (lower 50mm in pic)
340018
the locating dowels were a nice touch as well, bottom of pic about the size of needle rollers)

340020

These pics of a Riley Will Spigot better illustrate the cutouts that merge the Aux ex ports.
340025

The turtledoves are optional
I have a suspicion there is a ceramic coating on thre inner walls of the spigot of the DEA one
There is a pic in the Frits files of a Gen Aprilia one on a Cylinder (Flet has my dea one ATM)
Here is what i believe was the progression of the design from Rotax RSV to RSA
340024
The bottom ones are BRC Riley Will but i think they follow the late Aprilia pattern
Interestingly the multiple overlapping spigot is how i did mine back in the day only i just used different pipe and only one lathe cut and the flanges were cut with handtools
Maybe Frits or Jan can correct any of the progression i got wrong

peewee

29th December 2018, 18:42

frits to have any chance of sucess, the facebook group has to be private. other wise every idiot on the planet is making comments of bullshit :facepalm:

Frits Overmars

30th December 2018, 01:16

frits to have any chance of sucess, the facebook group has to be private. other wise every idiot on the planet is making comments of bullshit :facepalm:As far as I'm concerned, Facebook simply is not the right medium for any in-depth exchange of ideas. Forums are far more suitable for that kind of thing.
Kiwibiker is not a private medium either, but at least here we can have quoting, a timeline that does not get cluttered up three times a day, and some social control.

OopsClunkThud

30th December 2018, 06:55

In addition to your drawing there is another factor to be considered: the axial exit angle. Together with the requirement of the largest possible inner radius that will fit between crankcase and transfer window, your choices are already fairly restricted. The geometry of the RSA A-duct, below, may illustrate what I mean.
If you google Helmholtz, you will find an explanation involving a volume and a cilindrical duct. A conical duct like a transfer duct makes things a bit more complicated.
Port length + taper comes down to the same thing as port length + area ratio. They offer me the opportunity to create a conical duct with the Helmholtz property that will work at a desired frequency in combination with a given crankcase volume and port timing.
340016

Thanks!

As a followup, how important is the smoothness of the rate of change in the duct cross section? seems like that would be important, but how to control for that condition is not obvious. If it is important, and we are constrained to the inner radius being constant, then an equiangular spiral could be used for the outer surface. In this example the outer surface has a constant 8° angle to the inner radius.

Is it worth the trouble?
340062

Frits Overmars

30th December 2018, 07:28

As a followup, how important is the smoothness of the rate of change in the duct cross section? seems like that would be important, but how to control for that condition is not obvious. If it is important, and we are constrained to the inner radius being constant, then an equiangular spiral could be used for the outer surface. In this example the outer surface has a constant 8° angle to the inner radius. Is it worth the trouble?Smoothness is important. Any irregularity can be seen as a very small, abrupt radius, causing turbulence and loss of pressure.
We are not constrained to the inner radius being constant, but in order to avoid flow detachment, the inner radius should increase as the flow velocity increases along the duct. Or to phrase it another way: the inner radius should increase as the duct's cross flow section decreases.
Decades ago I came to the conclusion that the optimal duct shape could be described with two e-curves. Some decades later I came to the conclusion that it wasn't worth the trouble :D.

andreas

30th December 2018, 08:03

andreas

30th December 2018, 08:51

So the KTM has an ignition curve with only one thing remotely "right ".
About 15* at peak power.
Throw in a bunch of advance below 11,000 and juggle that with the PV full open point and suddenly mid range power will appear from nowhere.
Then correct the idiotic Aux port stagger issue and a huge mid increase is available.
This may need the main lifting a little as part of the " fix "to increase the peak and overev capability , but for sure the torque hole will be gone.

Wobbly, what is your rule of thumb for delaying aux-exhust ports?

katinas

30th December 2018, 08:59

Looks like Honda tested everything that they wanted. Surprises again - 375cc 3 cylinder engine in 1994, before decide to work with 500 V2 configuration (100 hp at 8000 rpm. and 100 kg. !!!)

WilDun

30th December 2018, 09:20

As far as I'm concerned, Facebook simply is not the right medium for any in-depth exchange of ideas. Forums are far more suitable for that kind of thing.
Kiwibiker is not a private medium either, but at least here we can have quoting, a timeline that does not get cluttered up three times a day, and some social control.

I don't often post here as I'm not involved with practical "fine tuning"- wish I could be involved!....... I do look in now and again and
Possibly the only problem (if it is a problem), with this forum is that what you see in the posts doesn't always give the full picture.
I feel that there is some discussion going on in the private messaging, leaving big gaps in the conversation and making it hard to follow - we have all done that of course!

Hope this hasn't gone 'off topic' too much! :rolleyes:

Happy New Year.

yatasaki

30th December 2018, 09:46

A bit of Helmholtz...but sticking a bit to the 1st law of thermodynamics , not frequency.
Exhaust flange on air-cooled cast iron cylinder. To improve cooling I've made a cut to prevent heat going from duct/flange to cooling fins i.e. to cylinder. Pipe in the duct was step further, decreasing volume/diameter to calculated one but also adding Air barrier between hot gas and header. Is it the right thing to do? I was debated so much around here but no Dyno to witness. All I know bike was on pipe a bit later.
https://i.postimg.cc/MnHNtyDb/IMG-20181229-205302.jpg (https://postimg.cc/MnHNtyDb)

andreas

30th December 2018, 09:55

wobbly

30th December 2018, 10:03

The only practical advice re Ex stagger is to look at working examples , and the application.
A TM kart engine ( 54 square ) has a smidge over 1mm , but this is tempered by the fact that they dont use pin plugs and thus cant
grind the Aux around to bore center , nor pocket radius the outer edge to promote flow.
If you lift these to be the same timing you loose 3 Hp at 11,000 ( 10% ) but gain 6Hp at 14500.
This makes the driver moan real loudly about no off corner power - even though lap times are identical.
The RSA ( again 54 square ) had close to 2mm stagger , but those Aux went around to bore center.
That engine had a PV blade as well , so the lower wider Aux combined with the PV must have given the best overall result - on the dyno and on track.
That leads to the obvious question about pin plugs in the TM = + 1.5 Hp at 11,000 not much more anywhere else.
But widen and pocket the Aux and the pin plugs loose nothing against stock at 11,000 , but add the 6Hp back up at 14500.
Now that is a fast engine , even more so when the gearing is shortened to give better off corner drive and just slightly better terminal speed using the big overev.

yatasaki

30th December 2018, 10:25

andreas

30th December 2018, 10:26

Thank you Wobbly

andreas

30th December 2018, 10:30

No, it's not Yamaha, but it is tomos 15SL
Closest to fs1 is jawa90 around here
https://i.postimg.cc/Y42J4qwh/IMG-20181229-232013.jpg (https://postimg.cc/Y42J4qwh)
https://i.postimg.cc/dLmH8P6d/IMG-20181229-230933.jpg (https://postimg.cc/dLmH8P6d)

Yes I realized no fs1 too late. You have a bridge welded in the exhaust port? I can't see really in the pic but preferably the insert should meet with the duct in a smooth fashion.

OopsClunkThud

30th December 2018, 10:35

Smoothness is important. Any irregularity can be seen as a very small, abrupt radius, causing turbulence and loss of pressure.
We are not constrained to the inner radius being constant, but in order to avoid flow detachment, the inner radius should increase as the flow velocity increases along the duct. Or to phrase it another way: the inner radius should increase as the duct's cross flow section decreases.
Decades ago I came to the conclusion that the optimal duct shape could be described with two e-curves. Some decades later I came to the conclusion that it wasn't worth the trouble :D.

Ah! Now that can be done in a reasonable workflow by keeping the outer radius constant and using an equiangular spiral for the inner surface. In this position the curve is increasing radius. The parameters for the spiral can be solved for from the entry and exit positions and then intermediate points calculated to generate the spline.

With a bit of work this could be fully parametric to adjust to the exit angle and other dimensions, I think.

340064

yatasaki

30th December 2018, 11:20

Yes I realized no fs1 too late. You have a bridge welded in the exhaust port? I can't see really in the pic but preferably the insert should meet with the duct in a smooth fashion.
Made this cause friend of mine made almost 80% wide exhaust.
The bridge is a peace of cast iron cooling fin, from used cylinder, grinded to have about 5° between lower and upper surface(self locking), exhaust duct machined to match same cone slots up and down the duct, then put the fin into the duct (slots) to enter a cylinder a bit, hammer a bit just to stay in place (which it will cause of self locking angle) then spot weld upper and lower end closest to flange with Ni or bronze electrodes.
Later on cylinder has to be machined to oversize. Bridge was hand grinded in for 0.2 mm.
Tested during 12 trainings and races with approx 24 rhs on it without any issues

andreas

30th December 2018, 11:33

Made this cause friend of mine made almost 80% wide exhaust.
The bridge is a peace of cast iron cooling fin, from used cylinder, grinded to have about 5° between lower and upper surface(self locking), exhaust duct machined to match same cone slots up and down the duct, then put the fin into the duct (slots) to enter a cylinder a bit, hammer a bit just to stay in place (which it will cause of self locking angle) then spot weld upper and lower end closest to flange with Ni or bronze electrodes.
Later on cylinder has to be machined to oversize. Bridge was hand grinded in for 0.2 mm.
Tested during 12 trainings and races with approx 24 rhs on it without any issues

Ok, then I understand perfectly.

Frits Overmars

30th December 2018, 17:26

Frits, what sort of physics education/knowledge do you have? Do you follow quant-mechanics for instance?I'm 70 years old now, so my physics education started about the same time that fire was invented. That came in quite handy if thermodynamics is what you need.
Knowledge? That's simple: it's never enough. No matter what you study, if you're serious about your work, you'll always end up at the boundaries of your knowledge.
Quantum mechanics: I barely follow it; I still hope that one of these days someone will come up with a more elegant approach.

Exhaust flange on air-cooled cast iron cylinder. To improve cooling I've made a cut to prevent heat going from duct/flange to cooling fins i.e. to cylinder. Pipe in the duct was step further, decreasing volume/diameter to calculated one but also adding Air barrier between hot gas and header. Is it the right thing to do? I was debated so much around here but no Dyno to witness. All I know bike was on pipe a bit later.Improving cooling by preventing heat going from duct/flange to the cooling fins?? Yeah, if your goal is to keep the cooling fins cool. But you don't want cool cooling fins, you want all the walls that come into contact with fresh mixture to be cool.
Inserting a pipe in the duct will decrease duct volume and diameter, which is usually a good thing. And the air barrier between the pipe and the original duct will keep the original duct cooler, but it will keep the inserted part of the pipe hotter, which is a very bad thing.
The fact that with this solution the bike comes on the pipe a bit later is an indication that the exhaust gas stays hotter. In itself that is not a bad thing. But the hot inserted part of the pipe will also heat up the washed-through fresh mixture which is bad for power and provokes detonation.

yatasaki

30th December 2018, 19:15

Frits, why would then mostly air cooled kart cylinders, like these two, have flanges as closest possible to the cylinder without any fin attached to the flange? Looks to me that they are trying to cool cylinder as much as possible I.e. on a radial positioned fins like here, heat from flange would go directly to transfer ducts if fins attached to. On that cast iron cylinder of mine fins are axial positioned and no fins from flange are connected to the transfers. Looks like two situations and finally getting some answers!
https://i.postimg.cc/BXhMrrFN/IMG-20181230-074853.jpg (https://postimg.cc/BXhMrrFN)

F5 Dave

30th December 2018, 20:30

I'm 70 years old now, so my physics education started about the same time that fire was invented. That came in quite handy if thermodynamics is what you need.
Knowledge? That's simple: it's never enough. No matter what you study, if you're serious about your work, you'll always end up at the boundaries of your knowledge.
Quantum mechanics: I barely follow it; I still hope that one of these days someone will come up with a more elegant approach.

Improving cooling by preventing heat going from duct/flange to the cooling fins?? Yeah, if your goal is to keep the cooling fins cool. But you don't want cool cooling fins, you want all the walls that come into contact with fresh mixture to be cool.
Inserting a pipe in the duct will decrease duct volume and diameter, which is usually a good thing. And the air barrier between the pipe and the original duct will keep the original duct cooler, but it will keep the inserted part of the pipe hotter, which is a very bad thing.
The fact that with this solution the bike comes on the pipe a bit later is an indication that the exhaust gas stays hotter. In itself that is not a bad thing. But the hot inserted part of the pipe will also heat up the washed-through fresh mixture which is bad for power and provokes detonation.

Have to say. I love your turn of phrase.

Frits Overmars

31st December 2018, 00:39

Have to say. I love your turn of phrase.My pleasure Dave. And that's not just a figure of speech; I really like to weave some entertainment into my writing. It came in handy when I made a living as a technical editor and I still enjoy doing it.

Frits, why would then mostly air cooled kart cylinders, like these two, have flanges as closest possible to the cylinder without any fin attached to the flange? Looks to me that they are trying to cool cylinder as much as possible I.e. on a radial positioned fins like here, heat from flange would go directly to transfer ducts if fins attached to. On that cast iron cylinder of mine fins are axial positioned and no fins from flange are connected to the transfers. Looks like two situations and finally getting some answers!
That is right Frano. In those aircooled kart cylinders the exhaust duct was kept as short as possible, so it would pick up as little exhaust gas heat as possible.
There were no fins attached to the flange, simply because there was no place for them. But fins conducting heat from the exhaust duct to the transfer ducts need not be a problem because you can simply make interrupted fins like in my 1955 DKW.
340068

Those kart engines had issues that were completely different from the engines that I've been working with in the past decades. Cooling was a major weakness of course, with their shrunk-in cast-iron sleeves and aircooling. Because of their mediocre cylinder filling, detonation was less of a problem despite their high compression ratio.

Maximum power was not nearly as important as a huge overrev ability. The graph below shows the powercurve of a 100cc world champion with direct drive:
no clutch, no gearbox, just a chain from crankshaft to rear axle. Acceleration out of slow corners was paramount, so because of this direct drive those engines needed a very short gearing. And to avoid being overtaken further up on the straightaway they also needed this huge overrev capacity.
340069
This brings back memories. The first time I got in contact with these direct-drive engines, I immediately saw big opportunities: better port timings, better scavenging angles, better angle.areas, a better pipe, and so on.
It worked: lap after lap my driver managed to overtake two or three competitors on the straightaway. There was just one little problem: he was left standing after every slow and medium-speed corner. And in those days the tracks had more corners than straights. I believe they still do :p.

The only modification that survived this learning curve, was the brake light switch on the brake pedal, borrowed from a moped. There was no brake light, but the switch cut out the ignition, so the driver could brake and at the same time keep his right foot down: more mixture through the engine, better internal cooling and lubrication, and eliminating the dangerous practice of putting your right hand over the side-mounted rotary carb inlet, also with the intention of providing cooling and lubrication,
and with the risk of getting a finger caught in the chain. I've seen drivers taking off their right glove with a finger tip still inside it.

Matt@TYGA

31st December 2018, 04:24

Please excuse my incompetence, but trying to find a post from Jan where he mentioned rod length ratios and what have you. I'm obviously crap at searching this forum as I can find just about everything except what I actually want!! Any help appreciated

Cheers, Matt.

breezy

31st December 2018, 07:34

I first tried it on a 50 cc in 1074: more power.
Going from 80 to 85
Then at Aprilia in 1996: more power.
Without varying the crankcase volume.
We went from 112 to 113 and 115, later 118 was tried, still better.
For the RSA we had to lengthen the connecting rod from 115 to 120 to improve inlet flow: more power.
It is mainly due to piston friction I think.
NSU already found this in 1953, piston friction was the main source of friction in their 250 4-stroke engine.
It may be different for a reed valve engine, I have not much experience with these.
But the piston friction loss will, of course, be the same in a reed valve engine.

Of course at BDC there is no difference as you have to adjust the cylinder height!
Maybe it is interesting that with a longer connecting rod I could use higher transfer ports on my 50.
Getting still more power!

The crankcase volume also changes, of course, unless you change the position of the piston pin in the piston, as we did at Aprilia
This can be better or worse....
You can change your crankcase volume in many ways.
But always keep in mind that flow is more important than volume.....
On rotary valve engines I found the bigger the better, within reason of course....
The Aprilia engines had very narrow crank wheels, (16mm) so a very big crankcase volume. About 660cc in TDC
A big crankcase volume makes very long inlet timings necessary.
And big carburetors.

This is probably the reason why reed-valve engines need a smaller crankcase volume.
The reeds 'decide' for themselves when to open...
They need some depression.
And because maximum inlet flow is probably determined by the reed block, big carburetors won't work on a reed-valve engine.
They just slow down the flow in the carburetor, making for a difficult carburetor adjustment.

So I think that a rotary valve engine will always give about 3-4 HP more (125cc) than a reed valve engine.
Because of its unrestricted inlet flow and less pumping losses.

hello, was it this...conrod lengths?

wobbly

31st December 2018, 07:38

Matt , the Aprilia ended up with a 120 rod om 54.4 stroke.
Honda had a short 105 for ever , but finally saw some light in the last Aoyama RS250 that had 109.
In karting its still a matter of conjecture , but the shortest is 105 , the longest 115.
TM have 109.8 due to a CNC error 20 years ago.
Depends upon the intake system somewhat in that any RV loves a big case , so long rods make this easy to achieve.
Reeds seem to have a bottom limit of diminishing returns at about 1.3 ratio - any bigger case and you have to use excessively thin petals to get the case Helmholtz
and the reed first mode frequency correct.
Then the reeds start going spastic and you loose any extra power gained from the bigger case reservoir volume.

Muhr

31st December 2018, 08:09

The 3D map allows you to take timing out when pulling low/med rpm with little throttle opening.
This is where the engine will deto if running up around 28* in a single curve map.
But 28* is what you want when at low/mid rpm under the pipe , when at full or near full throttle.
This gives way better throttle response.

Thought that I would come back to a side project that we fiddle with to a friend who spends the weekends with Kart-cross. I wondered about experience of ignition systems and you answered unequivocally that Ignitech was the way to go. unfortunately they seem to be very busy, so I chose to go for zeeltronic PDCI-15V with programmable spark power. Hopefully we will not be too disappointed! Otherwise it starts to approach Dyno time !! Will return with results.
If someone has tampered with spark power, I would like to receive some experience.

peewee

31st December 2018, 08:13

on Friday I got started welding the ears then the worst possible thing happened. the torch head died and spit water out. probly be seven to ten days before I can have another torch to my house but this time I buyed two heads as a spare so this shit can never happen again. im alittle angry because I could have finished the welding already today :mad:

SwePatrick

31st December 2018, 08:44

Thought that I would come back to a side project that we fiddle with to a friend who spends the weekends with Kart-cross. I wondered about experience of ignition systems and you answered unequivocally that Ignitech was the way to go. unfortunately they seem to be very busy, so I chose to go for zeeltronic PDCI-15V with programmable spark power. Hopefully we will not be too disappointed! Otherwise it starts to approach Dyno time !! Will return with results.
If someone has tampered with spark power, I would like to receive some experience.

I had an older ignitech system on my machine a while ago, and it was baaad,,, well the coil was or the time loading the coil.
I had a batterycharger running at the same time as my dynopulls, and still it just soaked ampere when i was hitting the throttle, i tried different plugs, no success.
It just wasn´t to be done in my methanol engine, the voltage drop was HUGE during maxtorque and upwards, it was down to 9v.
And it had problems producing power ofcourse, when starting to get some power, it just began to misfire.
My old pvl '458' performed much better.

But i gave ignitech a chance again, i bought a new system from Emot.nl and he has combined the ignitech with a pvl coil.
Now i have no issues what so ever.

Rgds.

yatasaki

31st December 2018, 09:10

Frits, while still warm about aircooling, a few right or wrong statements:
Air-cooled cylinder to fit with metal gasket or without gasket,as needed ,under cylinder to improve cooling.
Crankcase to isolate by layer of something to keep mixture as cool as possible.Heat from cylinder then goes to gearcase and oil over the crankcase ( crankshaft will pick some over bearings)
Gearcase to roughen from inner and outer walls: Inner to keep oil longer on the walls, outer to increase cooling area.
Ignition and gearbox covers made from aluminium to mount without or with metal gasket to improve cooling. Oil would do heat transfer to cover when fit with paper gasket but why not both.

wobbly

31st December 2018, 09:53

Something TZ350 did that I thought was damn clever - he made a head gasket from copper sheet.
But the sheet extended out way past the head and cylinder fins.
Must have improved air cooling capability dramatically.

yatasaki

31st December 2018, 10:22

Copper gasket would be great...if fins are radial (and if not clogging fin-air passage) but in my case are axial

TZ350

31st December 2018, 12:20

Air-cooled cylinder to fit with metal gasket or without gasket,as needed ,under cylinder to improve cooling.Crankcase to isolate by layer of something to keep mixture as cool as possible.Heat from cylinder then goes to gearcase and oil over the crankcase ( crankshaft will pick some over bearings).

My experience with isolating the cylinder from the crankcase was that the crankcase/gearbox and oil by them self run very hot. Maybe as much as 80-90 or even 100 deg C in a long race when the water cooled cylinder was only ever at 40-45 deg C.

Next time you run your bike, afterwards feel the flywheel, it will be quite hot. That heat is mostly transmitted out to the flywheel and comes from the crankcase. I think that anything to cool the crankcase would be worth the effort.

340085340086340087

Speedpro took the copper head fin idea a step further and made a clutch cover copper gasket/fin that picked up heat from the hot gearbox oil and transmitted it to a large cooling fin on the outside.

husaberg

31st December 2018, 12:54

My experience with isolating the cylinder from the crankcase was that the crankcase/gearbox and oil by them self run very hot. Maybe as much as 80-90 or even 100 deg C in a long race when the water cooled cylinder was only ever at 40-45 deg C.

Next time you run your bike, afterwards feel the flywheel, it will be quite hot. That heat is mostly transmitted out to the flywheel and comes from the crankcase. I think that anything to cool the crankcase would be worth the effort.

Speedpro took the copper head fin idea and made a clutch cover copper gasket/fin that picked up heat from the hot oil and transmitted it to a large cooling fin on the outside.

The Kawasaki tandems that ran at Daytona one year had the oil levels lowered to prevent the oil splashing against the inner crankcase. with this mod they held their power longer.
i wonder if a plate kind of like a windage tray that stops the hot oil hitting the inner crank side would help. On bike where you cant water cool the cases.
Along with that Russian ceramic paint emot has on both inner surfaces.
340083
Another GP trick is to run separate oil for the clutch and gearbox just block up the holes between both that is where most of the heat actually comes from or better still make a dry clutch. this way you can run different levels
You have already stopped the friction from running the gears through a trough of oil with your gearbox oil pump set up so only need the oil to touch the bottom of the primary gears
the Kawa tandems They also ran 7 speed gearboxs at Daytona as the rules never said you couldn't that way if the wind changed on the bowl they would still be gear correct.

ps Remember how finned the air cooled Suzuki twins and triples crankcases were. bloody heavy and hard to cast but they did it. i dont think it was just fashion
<img src="http://3.bp.blogspot.com/-g9QMA-XeXkc/TxISNejELSI/AAAAAAAAAZ4/j_W_11Kxvio/s1600/100_4816.JPG" width="540px"/>
Greeves t i think used to run a ducted cavity between the bolt up gearbox
Frits posted a pic with the big Germans 50 with the massive weld on fins on the crankcase for some simpson? air cooled class
340080340081340082

a lot of Little tings add up.

yatasaki

31st December 2018, 19:41

My clutch is ON the crankshaft
Rulebook doesn't allow to weld anything
So engine itself has to look as from factory from outside.
Ok..maybe a bit oversize copper gaskets wouldn't be a problem

Muhr

31st December 2018, 20:50

ps Remember how finned the air cooled Suzuki twins and triples crankcases were. bloody heavy and hard to cast but they did it. i dont think it was just fashion

a lot of Little tings add up.

You also have a vortex solution on air-cooled crankcase

https://www.tkart.it/en/magazine/under-review/vortex-kz-2016-revolution/

F5 Dave

31st December 2018, 20:57

Just swapped my older zeelltronic for an Ignitech on my RZ/CPI 496. Man what a difference. Mainly for servo operation but ease of use immensely.

flyonly

31st December 2018, 20:58

The Kawasaki tandems that ran at Daytona one year had the oil levels lowered to prevent the oil splashing against the inner crankcase. with this mod they held their power longer.
i wonder if a plate kind of like a windage tray that stops the hot oil hitting the inner crank side would help. On bike where you cant water cool the cases.
Along with that Russian ceramic paint emot has on both inner surfaces.
340083
Another GP trick is to run separate oil for the clutch and gearbox just block up the holes between both that is where most of the heat actually comes from or better still make a dry clutch. this way you can run different levels
You have already stopped the friction from running the gears through a trough of oil with your gearbox oil pump set up so only need the oil to touch the bottom of the primary gears
the Kawa tandems They also ran 7 speed gearboxs at Daytona as the rules never said you couldn't that way if the wind changed on the bowl they would still be gear correct.

ps Remember how finned the air cooled Suzuki twins and triples crankcases were. bloody heavy and hard to cast but they did it. i dont think it was just fashion
<img src="http://3.bp.blogspot.com/-g9QMA-XeXkc/TxISNejELSI/AAAAAAAAAZ4/j_W_11Kxvio/s1600/100_4816.JPG" width="540px"/>
Greeves t i think used to run a ducted cavity between the bolt up gearbox
Frits posted a pic with the big Germans 50 with the massive weld on fins on the crankcase for some simpson? air cooled class
340080340081340082

a lot of Little tings add up.

You have sparked my interest about a dry clutch. How possible is it to convert a normal clutch to dry if there is not a bolt on kit. I assume you need different clutch plates and they won’t last as long (but that’s ok). What else do you need to think about?

Sent from my iPhone using Tapatalk

husaberg

31st December 2018, 21:12

You have sparked my interest about a dry clutch. How possible is it to convert a normal clutch to dry if there is not a bolt on kit. I assume you need different clutch plates and they won’t last as long (but that’s ok). What else do you need to think about?

Sent from my iPhone using Tapatalk

Generally you need a longer mainshaft for room to make and fit seal behind the clutch to seal off the primary gears it also needs a two piece clutch hub.
TZ detailed how to do the longer mainshaft about 3 months ago.
You will need to make a cover to accommodate the seal and depending on if the clutch is pull or pusgh the actuating mechanism the release bearing needs to be sealed as well
<img src="https://i.ebayimg.com/images/g/7P8AAOSwdsFUOzi6/s-l1600.jpg" width="440px"/><img src="https://forums.kartpulse.com/uploads/default/original/1X/e914ffb85f1e187b296362d5d91d2853c218f74b.jpg" width="440px"/>
So unless you already have a already fully developed race bike not worth the expense or effort, its the icing on the cake racer than the basic recipe boiled potatoes
Old pommy shit boxs are easy its harder to keep the oil in than out they slso have a Chain primary that you convert to belt drive.
pulp based plates seem to be fine wet or dry. Cork burns Aermacchi used to use bronze. late GP bikes Carbon fibre
They just need airflow to cool them and they make a hell of a racket when the clutch is engaged

TZ350

31st December 2018, 23:12

340089340090340091

Air cooled DKW engine with an isolating air gap around the crankcase.

husaberg

31st December 2018, 23:19

Greeves not as cool as the Deek though
<img src="https://www.picclickimg.com/d/l400/pict/191861882572_/1969-1970-Greeves-Griffon-250-56B-Enduro.jpg" width="440px"/><img src="https://i.ebayimg.com/images/g/AwwAAOSw~1FUYjOX/s-l1600.jpg" width="440px"/><img src="https://i.ebayimg.com/images/g/H2AAAOSwrx5UYjO7/s-l1600.jpg" width="440px"/><img src="http://www.greevesguru.com/images_final/motor.jpg" width="335px"/>

katinas

31st December 2018, 23:37

Peter1962

1st January 2019, 01:10

340089340090340091

Air cooled DKW engine with an isolating air gap around the crankcase.

Verry smart design ! The DKW engineers who designed this were way ahead on the competion of that period in time. Just like the MZ engineers.

yatasaki

1st January 2019, 01:31

You also have a vortex solution on air-cooled crankcase

https://www.tkart.it/en/magazine/under-review/vortex-kz-2016-revolution/
I did drill that double wall empty space

paul gane

1st January 2019, 03:13

F5 Dave

1st January 2019, 06:13

Dave, maybe you have some pistons photo from this nice project.

They are just typical Wiseco made for this kit.

husaberg

1st January 2019, 07:24

Happy New Year to all:2thumbsup

RE, crankcase volume, has anyone here ever measured the crankcase volume and crankcase compression ratio on 1980's TZ250G and a TZ350G.
They share the same cases and crank, just a different top end. The crankcase compression ratio can't be right for both. Has anyone used RD400
cases to improve the volume of a TZ350G. I have 400 cases here just waiting for TZ parts to go in.

Frits mentioned it was a common mod for more power

With the bigger case volume, your porting layout and the really fat pipes on the LSR bike, it should fly, Wob!

Boundary drag between crank wheels and cases rises steeply when you go under 1 mm clearance, Husa. But that's not the case here; the crankwheel diameter of the RD400 may be quite a lot bigger, but when you put a TZ350 crank in the RD400-cases, everything is fine.

Welding a bridge in the G's inlet port will certainly improve piston life, but it will also cause extra turbulence, reducing the effective flow area. The con rod is directly behind that bridge alright, but the inlet flow has already expanded by the time it encounters the rod, so the rod is less of an obstacle.

We wanted to avoid welding and the according cylinder distortion, and we wanted to make our own pipes, which became a lot simpler with the reversed cylinder block.
We had to make an airbox for the carbs sitting directly behind the front wheel, but that was no extra work because even if we hadn't reversed the cylinder we would have made an airbox in order to keep the engine from inhaling hot air from the radiator.
And we didn't care about the bike looking original because it wasn't a classic back then. It should win races, never mind the looks. And the best combination proved to be a reversed G cylinder block with 38 mm carbs on RD400 crankcases with their extra case volume. That bike really flew.

Pretty Sure one if not two of The Wobbly TZ400 engines use them as well.

wobbly

1st January 2019, 10:16

The Frepin TZ400 that Charlett has the Post Classic lap record at Hampton is a 350G cylinder sitting on a 400 case with a stroked stock size crank.
This pulls the com down to close to 1.3 - ideal.
Frits has done the 400 case conversion on a 350 piston port as well , he will have some insights im sure.

peewee

1st January 2019, 12:17

can probly fit the 118 ktm rod with spacer plate which brings case ratio down a bit also

ken seeber

1st January 2019, 14:14

I just wasted a couple of hours trying to keep up with all the rubbish that is written in a Facebook group called "2 Stroke research & development".
After that, it's a delight turning to Kiwibiker and meeting with some sense.
]

Sort of agree Frits, but beyond the dribble, there are some good postings by the serious tinkerers. But, yep, KB is outstanding.

jamathi

1st January 2019, 14:43

peewee

1st January 2019, 16:07

Sort of agree Frits, but beyond the dribble, there are some good postings by the serious tinkerers. But, yep, KB is outstanding.

rarely do i ever go on fb but i had to get a peek of the 2t development group frits was refering to. sure enough, alot of rubbish and nonsense from quit a few people that clearly have almost no 2t knowledge. yes there was some skilled members but it was painful to weed out all the bullshit and find the good info. i couldnt agree more with frits, fb is definatly not the type of place for sharing ideas, for the reasons he mentioned

jamathi

1st January 2019, 16:14

rarely do i ever go on fb but i had to get a peek of the 2t development group frits was refering to. sure enough, alot of rubbish and nonsense from quit a few people that clearly have almost no 2t knowledge. yes there was some skilled members but it was painful to weed out all the bullshit and find the good info. i couldnt agree more with frits, fb is definatly not the type of place for sharing ideas, for the reasons he mentioned

Yes indeed, a very bad group...

peewee

1st January 2019, 17:16

Yes indeed, a very bad group...

one guy said theres better flow over a flat top piston. if this were true, wouldnt cars still have flat roofs as well :laugh:

wobbly

1st January 2019, 18:48

Thank you Jan for your kind words on here.
Getting to work for TM would not have happened without your support.
Have a very good year my friend.

Vannik

1st January 2019, 19:38

Getting to work for TM would not have happened without your support.

Buongiorno Wobbly, come stai? :laugh:

And the best for the new year to all.

jamathi

1st January 2019, 21:52

Thank you Jan for your kind words on here.
Getting to work for TM would not have happened without your support.
Have a very good year my friend.

I simply KNEW you would succeed at TM Wobbly!!
I would have betted on it....

Greg85

1st January 2019, 22:02

Hello twostrokers happy new year 2019 to all members of the kiwibikers group and thanks to the two stroke pros for sharing their immense knowledge

Frits Overmars

2nd January 2019, 06:33

Remember how finned the air cooled Suzuki twins and triples crankcases were. bloody heavy and hard to cast but they did it. i dont think it was just fashion.Finning the crankcases may be a great idea, but maybe not in combination with those exhaust headers running right in front of it... Here is another example that makes you think how it could have been done better.
340125

wobbly

2nd January 2019, 07:46

Do you mean my pipes could have been done better Frits - sorry I will try harder in the New Year.

Frits Overmars

2nd January 2019, 08:07

Do you mean my pipes could have been done better Frits - sorry I will try harder in the New Year.Yeah, it's about time you'd start producing something useful - like better pipes for TM kart engines :D.
Seriously though, a heat shield between those beautiful wobblypipes and those crankcase pre-heating cooling fins wouldn't be a bad thing.

WilDun

2nd January 2019, 08:52

Finning the crankcases may be a great idea, but maybe not in combination with those exhaust headers running right in front of it... Here is another example that makes you think how it could have been done better.
340125

I really did have an unconditional love for the Ariel! - nice frame and forks, good handler - despite its crappy 'old school' gearbox with its sintered iron bearing, chain primary drive, crowded roller big end bearings, bronze small ends, shrouded cast iron cylinders with tiny transfers, crappy brakes and 16" wheels (more sensible 18" on this case of course). ........ its still beautiful and unique, and the 'wobblypipes' make it even more beautiful - but yes I do agree that crankcase really was designed to attract cold air !

Happy new year!

yatasaki

2nd January 2019, 09:56

Happy New year to all!

So fins connecting exhaust and transfer ducts is no good. To 'disconnect' these two we have to cut fins on two pieces. Which duct is getting bigger part of the fin?
If we talk water-cooled engines Wobbly found redirecting flow on transfers first as a gain, and overcooling of exh. duct/spigot as a loss ..as I remember.
Could it be answered without Dyno?
I would go for transfers 70/30% of the divided fin area.

Grumph

2nd January 2019, 10:17

Yeah, it's about time you'd start producing something useful - like better pipes for TM kart engines :D.
Seriously though, a heat shield between those beautiful wobblypipes and those crankcase pre-heating cooling fins wouldn't be a bad thing.

Bear in mind Frits, that the Brits didn't anticipate global warming - or probably export sales to a warmer climate either....
Or anyone getting more than about 19hp out of one....

Have a good year everyone.

husaberg

2nd January 2019, 11:02

Finning the crankcases may be a great idea, but maybe not in combination with those exhaust headers running right in front of it... Here is another example that makes you think how it could have been done better.
340125

I think all things considering as especially as the old 4t Boys network at Ariel were not that happy about the 2t. Val Page did alright with that engine.
He did borrow a bit from the German Adler but so did everyone else.
He did at least have the foresight to mount the clutch on the gearbox which took another 10 years before Yamaha figured that one out with their version of the German Adler.
340126

2005bully

2nd January 2019, 14:40

I have not posted for quit some time. But viewing this forum is part of my daily routine. For all those on this forum that have openly shared their thoughts with the rest of us..... May the new year bring you happiness and prosperity. Thank-You Kermit Buller

jamathi

2nd January 2019, 15:35

Yeah, it's about time you'd start producing something useful - like better pipes for TM kart engines :D.
Seriously though, a heat shield between those beautiful wobblypipes and those crankcase pre-heating cooling fins wouldn't be a bad thing.

I tried this on the Minarelli, in 1981, it worked: 300 rpm more on the Mugello straight....
But it was a lot of trouble fitting it.
Later we achieved the same result by wrapping the pipes with asbestos tape..

wobbly

2nd January 2019, 16:05

In my defense , that engine ran on Methanol , so crankcase cooling wasnt a limiting issue at all.

Matt@TYGA

2nd January 2019, 20:42

Thanks for the info on the rod lengths guys.

I'm hoping for more time this year to do some engine projects instead of just staring at my computer screen 24/7.......

I'm wanting to pull my Honda NSR150SP apart for a bit of a make over, using several of the ideas from this most informative site.

Wobbly, I read before that you'd used 3D printed reed stuffers. How about a 3D printed reed valve? I understand sealing and integrity would be an issue in the long term, but it might be enough to last a dyno run or three. my cheapo 3D printed does PLA and ABS without issue, and PETG at a stretch. Worth a shot maybe? I think with the incoming mixture helping with cooling that it won't just end up in a nasty blob in the bottom of the case, and should it fail catastrophically then hopefully no engine damage will occur. I'm just thinking about Wobbly's work with thick and thin reed petals to direct flow. Maybe worth a shot at actually having an angled valve to direct flow instead of relying on the petals.

Got the extendo, water cooled exhaust port stub to try also. Looking forward to seeing what that does. Only got the 3D printed version at the mo which was just to test fit. Will knock something up in aluminium for a dyno test. Been using the oval to round transition since 1994 for my NSR250s, so I know that works.

NSR150SP rod length is 110mm. Perhaps this length would have been a better choice for the 250, based on other info here ;-)

Anyway, here's hoping that I can get these other projects done and dusted so that I can have some fun!

husaberg

2nd January 2019, 21:03

thanks for the info on the rod lengths guys.

I'm hoping for more time this year to do some engine projects instead of just staring at my computer screen 24/7.......

I'm wanting to pull my honda nsr150sp apart for a bit of a make over, using several of the ideas from this most informative site.

Wobbly, i read before that you'd used 3d printed reed stuffers. How about a 3d printed reed valve? I understand sealing and integrity would be an issue in the long term, but it might be enough to last a dyno run or three. My cheapo 3d printed does pla and abs without issue, and petg at a stretch. Worth a shot maybe? I think with the incoming mixture helping with cooling that it won't just end up in a nasty blob in the bottom of the case, and should it fail catastrophically then hopefully no engine damage will occur. I'm just thinking about wobbly's work with thick and thin reed petals to direct flow. Maybe worth a shot at actually having an angled valve to direct flow instead of relying on the petals.

Got the extendo, water cooled exhaust port stub to try also. Looking forward to seeing what that does. Only got the 3d printed version at the mo which was just to test fit. Will knock something up in aluminium for a dyno test. Been using the oval to round transition since 1994 for my nsr250s, so i know that works.

Nsr150sp rod length is 110mm. Perhaps this length would have been a better choice for the 250, based on other info here ;-)

anyway, here's hoping that i can get these other projects done and dusted so that i can have some fun!

vf3 cr125......
Not as much fun but well tested.
Out of interst what are the differences with the SP to the Std.
Shame those Those NSR 125 and 150 need such long inlets to clear that rear top engine mount.

Matt@TYGA

2nd January 2019, 22:48

vf3 cr125......
Not as much fun but well tested.
Out of interst what are the differences with the SP to the Std.
Shame those Those NSR 125 and 150 need such long inlets to clear that rear top engine mount.

Hi Husa,

Yes, well tested indeed, but we do because we can. And I could whittle a reed valve from granite with a tooth pick for less than VF charge :laugh:

I haven't had anything much to do with the std NSR150, but I do know that the cylinder is totally different. Still a bridged exhaust port, but tiny in comparison to the SP. no data on the timings as all I did was look at one in the Honda shop. The head is also different and I think that the piston is different too.

The old model NSR150R was a single port with a single flap exhaust valve. We cut auxiliary ports when I raced one back in 1995. Also welded up the valve and trimmed it to a nice snug fit. What was noted then has been well documented here in that the wider one went with the auxiliaries, the more power it made. Right up until we broke into the water jacket. the way to go would have been to cut in from the outside, weld up and fit a patch, but we weren't allowed to alter the outside look of the cylinder. Crying shame.

We ended up at about 40hp at the rear wheel, on avgas. Honda gave us the bike at 21hp.......

The piston and crank had to be stock. As did the reed valve, but you were allowed to modify the reed valve. Had a PJ34mm carb.

I didn't really fit that well on it and much preferred the 250.

Yes on the intake. Fitting an MC21 carb boosts things at the top end, but need to make a spacer block to get clearance, which is a pain.

Matt.

ken seeber

2nd January 2019, 23:11

While we're on about crankcase cooling, I reckon that the Vortex KZee thru flow ventilation system is pretty good. One might even say cool. Certainly couldn't do any harm.

340147

TrackTen

3rd January 2019, 01:25

Frits Overmars

3rd January 2019, 03:33

While we're on about crankcase cooling, I reckon that the Vortex KZee thru flow ventilation system is pretty good. One might even say cool. Certainly couldn't do any harm.Never say never, Ken. Having air flowing between crankcase and gearbox is a good thing for sure. But then this air exits right under the exhaust header. Not under the first part of the duct, that should be cooled, but under the remainder of the header, where gas energy should not be used for global warming, but for efficient wave action. A heat shield wrapped around the header would be the obvious solution in my opinion, but I could not discover any trace of it on the Vortex documentation.

yatasaki

4th January 2019, 10:46

As air cooling question is more or less elaborated, next question about added transfer ports. On the drawing is common moped/old timer arrangement. Easiest is to drill/grind finger B ports. But, because of intake port there is very little or no space for adding finger-C port ,then additional "bypass" C ports are fed from B ports.
So cross section of B duct untill starting of "bypass" should be equal B+C ports after junction to spread the flow more or less equally.
Is it better to have only B ports with uninterrupted flow or to use as much area as possible with C port?

The other issue is that all added B and C ports are aiming upward cyl head which is good for overrew as I could see on my test track and mychron. Lowering upward angle of B ports to 10°( which is sometimes achievable:sweatdrop)like on "modern" cylinders added some power but lost a bit of overrew.
Any comments?

pete376403

4th January 2019, 13:01

Never say never, Ken. Having air flowing between crankcase and gearbox is a good thing for sure. But then this air exits right under the exhaust header. Not under the first part of the duct, that should be cooled, but under the remainder of the header, where gas energy should not be used for global warming, but for efficient wave action. A heat shield wrapped around the header would be the obvious solution in my opinion, but I could not discover any trace of it on the Vortex documentation.

Isnt this the best argument for reversed cylinders, with the heat up and out the back where is doesn't mess with the rest of the engine, and intakes on the cold side?

andreas

4th January 2019, 13:17

TZ350

4th January 2019, 13:26

340171 340172

That is very interesting , is the base gasket made of 3 parts / sheets ? No problem with leaking ?

The question is, do you want to shield the cylinder from the heat generated in the crankcase or isolate the cylinder heat and keep it away from the crankcase. Which side needs the extra cooling the most?

340170

No problems with sealing when you use copper head gasket sealing paint/glue.

340168

Copper under the exhaust tract to improve cooling in that area.

340169

Crankcase air cooling, you can go as crazy as you like.........

husaberg

4th January 2019, 13:35

Isnt this the best argument for reversed cylinders, with the heat up and out the back where is doesn't mess with the rest of the engine, and intakes on the cold side?

Engine further forward better handling
Straighter pipe

husaberg

4th January 2019, 13:37

340171 340172

The question is, do you want to shield the cylinder from the heat generated in the crankcase or isolate the cylinder heat and keep it away from the crankcase. Which side needs the extra cooling the most?

340170

No problems with sealing when you use copper head gasket sealing paint/glue.

340168

Copper under the exhaust tract to improve cooling in that area.

340169

Crankcase air cooling, you can go as crazy as you like.........

Maybe check the rules rob does it say liquid cooled or water cooled.
if it says Water oil is on the table
nope has to be air cooled
https://www.mnz.co.nz/docs/default-source/manual-of-motorcycle-sport/appendix-a---championship-classes-(road).pdf

TZ350

4th January 2019, 14:21

Maybe check the rules rob does it say liquid cooled or water cooled. if it says Water oil is on the table, nope has to be air cooled
https://www.mnz.co.nz/docs/default-source/manual-of-motorcycle-sport/appendix-a---championship-classes-(road).pdf

:laugh: ......... whats the answer if the aim is to air cool the base of the cylinder and the transfers and any extra air cooling of the crankcase and its oil is just collateral damage.

husaberg

4th January 2019, 14:35

:laugh: ......... whats the answer if the aim is to air cool the base of the cylinder and the transfers and any extra air cooling of the crankcase and its oil is just collateral damage.

https://media1.tenor.com/images/e6bec27c8458c7b428d08043976e5d84/tenor.gif
Pack it with paraffin
https://ntrs.nasa.gov/search.jsp?R=20150003481
http://www.andores.com/sale-9516724-paraffin-wax-pcm-phase-change-material-pcm-in-energy-storage-system.html
http://www.autospeed.com/cms/article.html?&title=The-Fusion-Intercooler&A=110772

Specifically, its typical characteristics are:

Melting point: 52 degrees C
Specific heat: 3.27 kJ per kg per degree C
Specific heat of fusion: 210 kJ/kg
So to increase the temp of 1kg of the wax from 47 to 52 degrees takes 16.35kJ, but to push it past 52 degrees takes nearly 13 times as much energy. (Or, to risk causing confusion, you could dissipate in it a power of 14kW for 15 seconds to melt 1kg.)

Paraffin wax is non-toxic, doesn't explode (although it will catch fire if you expose it to a naked flame) and is easily handled. Special waxes designed specifically for this change-of-state heat storage purpose are also available with melting points in 10-degree C increments from 50 degrees to 100 degrees C, however their availability is obviously less than simple candle wax.

TZ350

4th January 2019, 14:56

340174

That was part of my air cooled RGV project. I abandoned it when I was handed the gift of 110cc max oversize for H2O 2T's....... :wings:

husaberg

4th January 2019, 14:59

340174

That was part of my air cooled RGV project. I abandoned it when I was handed the gift of 110cc max oversize for H2O 2T's....... :wings:

Sometimes clever people make their own luck.
That said cooling that gear box oil would be pretty easy and cheap old trans cooler or oil cooler off XR400 are neat or even pitbike.
340175340176
https://newmanz.co.nz/shop/index.php?main_page=product_info&cPath=4_60&products_id=177&zenid=9517h0j7ph2r2l567mce443pq5
some of the car ones are WC now

https://www.aliexpress.com/item/Transmission-Oil-Cooler-for-2012-2017-Toyota-Camry-2-5L-2ARFE-ASV50-33493-33030/32826806175.html
340177340178
Hondas too.
https://www.aliexpress.com/item/Heat-Exchanger-Aluminum-Oil-Cooler-for-HONDA-CIVIC-1-8-16V-OE-124100-7821/32815895771.html?spm=2114.10010108.1000014.2.5ee41 5cdH2r1Q6&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.13338.112237.000000000000000&scm_id=1007.13338.112237.000000000000000&scm-url=1007.13338.112237.000000000000000&pvid=4cdbc398-3202-45bd-9c5d-636aa08949b6
this one appears to go straight to the trans look at the other pics open at back?
looking at theses you could run dual water circuits easy colder water for cases and cylinder ex port hotter for head.

TZ350

4th January 2019, 18:27

pete376403

4th January 2019, 18:31

.
The oil coolers are very interesting. As I am running a dry sump I have a gear box oil pump so it should be pretty easy to add an oil cooler. A water one would be great as the radiator runs about 40 deg C.

Some Mazdas (no idea sorry) had a little radiator to cool the power steering fluid. I've read of one being used in a water cooled CPU computer rig

koenich

4th January 2019, 18:42

Some Mazdas (no idea sorry) had a little radiator to cool the power steering fluid. I've read of one being used in a water cooled CPU computer rig
nearly all cars with an automatic double clutch transmission have a gearbox oil cooler. the issue I see is once the oil temps drops the viscosity will increase and therefore the losses, so you might ne to readjust for the cooler temperatures.

yatasaki

4th January 2019, 19:36

If your drawing is somewhat to scale. I would have a piston-window fed single c port.
It's schematic. In reality, with single dykes ring piston there is 2mm space between top of the inlet and ring.

husaberg

4th January 2019, 20:21

Some Mazdas (no idea sorry) had a little radiator to cool the power steering fluid. I've read of one being used in a water cooled CPU computer rig

Mazda 6
https://i.ebayimg.com/images/g/kfIAAOSwJd1b6znw/s-l500.jpghttps://i.ebayimg.com/images/g/D8gAAOSwAuJb6znw/s-l500.jpghttps://pmt5.com/img/spares/resized/11BY1-spares-11BY1-10230-7d6fbdb346.jpg

or these
340191

pete376403

4th January 2019, 20:40

nearly all cars with an automatic double clutch transmission have a gearbox oil cooler. the issue I see is once the oil temps drops the viscosity will increase and therefore the losses, so you might ne to readjust for the cooler temperatures.

Yes,but this as a small rad, maybe 100 x 100mm, small enough to mount on a bike without over cooling

Vannik

4th January 2019, 21:10

.
The oil coolers are very interesting. As I am running a dry sump I have a gear box oil pump so it should be pretty easy to add an oil cooler. A water one would be great as the radiator runs about 40 deg C.

If I remember correctly, Martin Wimmer on his TZ250N, back in '85 ran a transmission oilcooler in an effort to cool the crankcases. I think it was done by Helmut Fath.

Muhr

4th January 2019, 21:23

https://www.thinkauto.com/acatalog/On_line_shop_C43_Engine___transmission_cooler_18.h tml

husaberg

4th January 2019, 21:26

if i remember correctly, martin wimmer on his tz250n, back in '85 ran a transmission oilcooler in an effort to cool the crankcases. I think it was done by helmut fath.

fairing nose?
340192

Although this is 83
340193

if they kept using it..........

andreas

5th January 2019, 04:12

It's schematic. In reality, with single dykes ring piston there is 2mm space between top of the inlet and ring.

Yes, that wont work.

andreas

5th January 2019, 04:18

https://media1.tenor.com/images/e6bec27c8458c7b428d08043976e5d84/tenor.gif
Pack it with paraffin
https://ntrs.nasa.gov/search.jsp?R=20150003481
http://www.andores.com/sale-9516724-paraffin-wax-pcm-phase-change-material-pcm-in-energy-storage-system.html
http://www.autospeed.com/cms/article.html?&title=The-Fusion-Intercooler&A=110772

TZ could you reverse the cylinder?

Norman

5th January 2019, 05:17

How hot can the transmission oil typically be in a two stroke high performance engine?

TZ350

5th January 2019, 07:29

TZ could you reverse the cylinder?

Yes, very easily.

340198

But unfortunately the fat part of the pipe would be in the most restricted part of the bike.

340197

Katie's air cooled GP125 gives an idea of how crowded the Honda RS125 NF4 frame is.

340204

Tim's NSR-GP110. The mono shock and "A" frame swing arm are the biggest obstructions to reversing the cylinder.

TZ350

5th January 2019, 07:35

Mazda 6
https://i.ebayimg.com/images/g/kfIAAOSwJd1b6znw/s-l500.jpg

That Mazda oil cooler looks the go. I will have a look at Pick a Part for one.

How hot can the transmission oil typically be in a two stroke high performance engine?

It looked like 90 - 100 deg C on my bike. It would be much better to be 30-40 and used for cooling the crankcase and inlet tract of my RV.

TZ350

5th January 2019, 08:03

340200

Monocycle. not only is Sandra backing the bike into the corner like a flat tracker, the front wheel is off the deck.

https://www.motorradonline.de/leute/portraet-motorradrennfahrerin-sandra-stammova.615252.html

340202340203340201

andreas

5th January 2019, 08:17

Yes, very easily.

340198

But unfortunately the fat part of the pipe would be in the most restricted part of the bike.

340197

Katies air cooled GP125 gives an idea of how crowded the frame is.

250 kart? cylinder on the gp 125? in nsr 50? frame. Either way I like it.

husaberg

5th January 2019, 08:50

250 kart? cylinder on the gp 125? in nsr 50? frame. Either way I like it.

Honda RS125 NF4 frame

TZ350

5th January 2019, 09:24

340205

250 kart? cylinder on the gp 125? in nsr 50? frame. Either way I like it.

Honda NSR250, cylinder on a Suzuki GP100 engine, RS125 NF4 rolling chassis.

The plate down the center of the cases is so a six speed gearbox can be fitted to replace the old five speed unit. It has a Kawasaki KE175 rotary valve cover and runs a Yamaha RD400 con rod assembly and Suzuki RGV250 big end brg, it currently tops out at 13,500 rpm.

The whole story can be found here:-

Follow the links to read the whole story about Team ESE's GP/NSR110cc engine build.

There are several of these engines.

One is fuel injected. The fuel injection system is still under development:- https://www.kiwibiker.co.nz/forums/showthread.php/185773-Speeduino-2T-EFI-Project

andreas

5th January 2019, 10:07

340205

Honda NSR250, cylinder on a Suzuki GP100 engine, RS125 NF4 rolling chassis.

The plate down the center of the cases is so a six speed gearbox can be fitted to replace the old five speed unit. It has a Kawasaki KE175 rotary valve cover and runs a Yamaha RD400 con rod assembly and Suzuki RGV250 big end brg, it currently tops out at 13,500 rpm.

The whole story can be found here:-

There are several of these engines.

One is fuel injected. The fuel injection system is still under development:- https://www.kiwibiker.co.nz/forums/showthread.php/185773-Speeduino-2T-EFI-Project
There are several of these engines. Ok, I'm currently reading the story about Thomas, thought it was an alter ego at first, great reading

jamathi

5th January 2019, 14:18

How hot can the transmission oil typically be in a two stroke high performance engine?

About 100°C or more

TZ350

5th January 2019, 16:45

katinas

7th January 2019, 06:50

.

Two Stroke GP Restorations, worth having a look at. As well as pictures of their restorations there is a few clips of the "real" sound.

https://www.facebook.com/600952010035619/posts/1472219032908908/?comment_id=1472575532873258

.

Thanks, nice eye-catching picture.

MCN about RGV 500 1998, for photo collection.

http://www.mcnews.com.au/1998-suzuki-rgv500-grand-prix-500-aoki/

yatasaki

7th January 2019, 07:06

Anyone, variable crankcase volume. Piece of garden hose and different lengths (volumes)

wax

8th January 2019, 00:20

Im going to ask a question and I want a general answer
What does a pipe with a bid mid section have or not have in relation to a pipe with a mid section. Ie spread of power

Frits Overmars

8th January 2019, 00:43

Anyone, variable crankcase volume. Piece of garden hose and different lengths (volumes)Ideally the crankcase volume is one big volume without any nooks & crannies.
Your setup could act as a pneumatic damper, unless you use a short length of big diameter hose.

Im going to ask a question and I want a general answer
What does a pipe with a bid mid section have or not have in relation to a pipe with a mid section. Ie spread of powerI want a McLaren 720S. And a camper. What is a bid mid section?

yatasaki

8th January 2019, 01:10

[QUOTE=Frits Overmars;1131121299]Ideally the crankcase volume is one big volume without any nooks & crannies.
Your setup could act as a pneumatic damper, unless you use a short length of big diameter hose.

Probably this position neither, too close to the petals would disrupt flow sideways at some rews.
Longer hose-decrease in idle revs is what I notice.
Bigger diameter hose and direct to crankcase connection would be indeed right approach.

Muhr

8th January 2019, 02:42

I want a McLaren 720S.

I want a Speedtail:confused:

Frits Overmars

8th January 2019, 05:11

I want a Speedtail:confused:Ugliest car they ever made. And you don't even get four hubcaps for yer money.
340255

yatasaki

8th January 2019, 05:53

:cool:Similar design
...only two stroke in it
More appropriate for this thread

husaberg

8th January 2019, 07:28

Ideally the crankcase volume is one big volume without any nooks & crannies.
Your setup could act as a pneumatic damper, unless you use a short length of big diameter hose.

I want a McLaren 720S. And a camper. What is a bid mid section?

At the time the "......." engine came out the panel had discussions about what turned out to be an oil separator with connections to the crankcase some thought it might be a variable volume device with a bladder inside or diaphragm to vary the volume of the crankcase.
http://cms.knaf.nl/images/2016/KNAF_Fast_News/Editie_februari/knaf.jpg

Muhr

8th January 2019, 08:23

Ugliest car they ever made. And you don't even get four hubcaps for yer money

You are so hard.
sometimes beauty comes from within! It is possible to take a nap in the back seat, and store a Trangia kitchen in the glove compartment. And why not use the hub caps as plates. see best of both worlds:weird:

andreas

8th January 2019, 09:28

Im going to ask a question and I want a general answer
What does a pipe with a bid mid section have or not have in relation to a pipe with a mid section. Ie spread of power

The general answer is it converts more of the wave energy into a negative wave.

Norman

8th January 2019, 10:25

About 100°C or more

Thanks for the info Jan. And with the hot exhausts coming down the transfers at highest rpm and/or low throttle also heating up the internals of the crankcase I see the advantage of having high flow low temp liquid cooling of it..

husaberg

8th January 2019, 11:37

Thanks for the info Jan. And with the hot exhausts coming down the transfers at highest rpm and/or low throttle also heating up the internals of the crankcase I see the advantage of having high flow low temp liquid cooling of it..

The crankcase being bolted to a cylinder and head burning petrol at 1000's of degrees the friction of a piston and sealing ring and the act of compressing the air fuel mixture also account for most of the heat along with the gears meshing and clutch might account for a fair bit of that heat. as is just spinning shafts and bearings at high rpm's.
Just touching the outer gearbox cover of a hard running gearbox is pretty much an eye opener and hand burner.
Unfortunately due to the rules and design limitations on TZ's bucket ,water cooled crankcases although the obvious best solution isnt a really an option

peewee

8th January 2019, 15:06

At the time the "......." engine came out the panel had discussions about what turned out to be an oil separator with connections to the crankcase some thought it might be a variable volume device with a bladder inside or diaphragm to vary the volume of the crankcase.
http://cms.knaf.nl/images/2016/KNAF_Fast_News/Editie_februari/knaf.jpg

remember when photos of that engine were first seen and everyone was frantic to figure out how it worked and what secrets the large cyl spacer was hiding and what purpose was the glass jar and how could it possibly rev to 30k :laugh::laugh:. those are days ill never forget

jamathi

8th January 2019, 22:49

remember when photos of that engine were first seen and everyone was frantic to figure out how it worked and what secrets the large cyl spacer was hiding and what purpose was the glass jar and how could it possibly rev to 30k :laugh::laugh:. those are days ill never forget

It was all nonsense of course...
Not even 1 was sold

F5 Dave

9th January 2019, 06:52

So who's money was getting pissed away?

Peter1962

9th January 2019, 08:50

It was all nonsense of course...
Not even 1 was sold

This is the most recent status on their patent demand. https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2018024319&tab=PCTBIBLIO&maxRec=1000

No economic activity that I could find...
Mister Gerrits Gerrit Hendrik and the mysterious german Aumiller Danny Walter are good in hiding in the dark...

In 2016 he created a company called "Rygerbaas BV" that was cancelled in november 2018 https://drimble.nl/bedrijf/almelo/33575320/rygerbaas-bv.html

The original company "Ryger-Engine" that was created in 2013 seems to still exist https://drimble.nl/bedrijf/almelo/27531341/ryger-engine.html

husaberg

9th January 2019, 10:15

This is the most recent status on their patent demand. https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2018024319&tab=PCTBIBLIO&maxRec=1000

No economic activity that I could find...
Mister Gerrits Gerrit Hendrik and the mysterious german Aumiller Danny Walter are good in hiding in the dark...

In 2016 he created a company called "Rygerbaas BV" that was cancelled in november 2018 https://drimble.nl/bedrijf/almelo/33575320/rygerbaas-bv.html

The original company "Ryger-Engine" that was created in 2013 seems to still exist https://drimble.nl/bedrijf/almelo/27531341/ryger-engine.html
Gerit posted on a thread for a while
Aumiller drobve the kat in this video
https://www.youtube.com/watch?v=RJbxxdzhESA
But here he is
https://www.linkedin.com/in/danny-aumiller-383558134
He it seems is a engineer andd specialises in sealing etc

wobbly

9th January 2019, 11:11

Shame we had to ban one " engineer " from this site , who was till the end still reciting the company line " its almost ready ".
And the other " engineer " fixes compressors - about all is good for and manages to drive one faster than some 4T hire karts.
The whole thing was completely mismanaged from start to end and was doomed to fail , as everyone seemed to be either full of shit or highly narcissistic
or both - and I say that fully recognizing I am one.
Where the hell are all the engines that were built for the CIK homologation process , as no way would they have been signed off without them.

Grumph

9th January 2019, 11:36

Where the hell are all the engines that were built for the CIK homologation process , as no way would they have been signed off without them.

I'd pick locked in a container somewhere. If they'd been scrapped, someone would have latched onto one. Scrap yard guys are notorious for picking up anything they can make a buck from.

F5 Dave

9th January 2019, 11:40

Somebody/s lost some serious coin out of this. Glad I got a personal assurance when I ordered the V4 version or I'd be worried. It'll be ready soon, but it is taking a while. :confused:

TZ350

9th January 2019, 12:30

Where the hell are all the engines that were built for the CIK homologation process.

I had the impression that the cylinders and bottom ends were traditional 2T items and could be re built as ordinary engines. And it was basically the add on Ryger spacer plate and piston assembly that made them different and it could easily be discarded.

jamathi

9th January 2019, 14:57

Somebody/s lost some serious coin out of this. Glad I got a personal assurance when I ordered the V4 version or I'd be worried. It'll be ready soon, but it is taking a while. :confused:

You'd better start to worry...…
Somebody lost serious money, 1 million$ they say.
All 50 engines needed for the homologation are still there
Big silence now!!!

ken seeber

9th January 2019, 19:13

One thing that the Ryger did do was to get people thinking outside the square for a bit, possibly leading to some quantum leap in performance as the Ryger was purported to do. Alas, neither came thru.

The other thing that gave us the shits was the way one of our key 2 stroke posters here on ESE (and elsewhere) was badly compromised by the first stage of the Ryger story

jamathi

9th January 2019, 21:37

I had the impression that the cylinders and bottom ends were traditional 2T items and could be re built as ordinary engines. And it was basically the add on Ryger spacer plate and piston assembly that made them different and it could easily be discarded.

They can NOT be re build as an ordinary engine.
So they are only good for the scrap heap....
As nobody wants an unreliable 35HP kart engine.....

guyhockley

10th January 2019, 01:03

The crankcase being bolted to a cylinder and head burning petrol at 1000's of degrees the friction of a piston and sealing ring and the act of compressing the air fuel mixture also account for most of the heat along with the gears meshing and clutch might account for a fair bit of that heat. as is just spinning shafts and bearings at high rpm's.
Just touching the outer gearbox cover of a hard running gearbox is pretty much an eye opener and hand burner.
Unfortunately due to the rules and design limitations on TZ's bucket ,water cooled crankcases although the obvious best solution isnt a really an option

There was a bloke racing a Bantam at a Belgian meeting a few years back who had a small oil cooler/rad mounted to one side of the frame downtube even though the bike was plainly air-cooled.
Turned out he had an electric pump circulating water through copper pipe in the primary chaincase to "give the clutch a chance of coping with the awesome power"