ESE's works engine tuner

[Muhr]

Awesome i want that.

[Tim Ey]

Awesome i want that.
The specs sound good! What is the rough pricing?

I got a question concerning sparkplugs:

I wanted to draw a head for a 50cc engine but the 14mm Sparkplug is very design-restrictive. Has anyone ever tried a smaller thread diameter than 14mm?
With a smaller plug it would be possible to cool more area of the combustion chamber with water.

[Frits Overmars]

I wanted to draw a head for a 50cc engine but the 14mm Sparkplug is very design-restrictive. Has anyone ever tried a smaller thread diameter than 14mm?Emot uses 10 mm plugs on its 50 cc racing sets. KTM uses 10 mm on various MX-models. I intend to use 10 mm plugs wherever possible.
337007 337018

[wobbly]

Rob asked me about the nozzle in the stinger of the GP-NSR 110 that is in the sim.
Here is the assembly that I use, makes it real easy to change the insert.
In this case I have drawn the stinger as 25.4 ID - 1.6mm wall tube, with a 23mm ID insert , that is 20 long with a 45*chamfer on the exit.
This I have tested on the KZ2 engines and seems to work the best.
You could go to 1.2mm wall stinger tube and test that with a bigger OD insert.
This would have more effect on the return wave coming back from the muffler,and may make better power.
A couple of spring hooks and a header spring make the joint flexible and helps prevent weld cracking in this area.

[TZ350]

.
Great, thanks for that Wob.

[wobbly]

Looking at the spec of that Denso Iridium plug - it does not appear to have a resistor element.
This will most probably cause issues with noise when using a digital ECU like an Ignitech.
I have used spiral wound core plug leads with just a resistor cap, and no plug resistance , and this worked with no crashing of the ECU.

[jbiplane]

The specs sound good! What is the rough pricing?

The SmartEMS light in aluminum milled case start 205 usd
wire harness with all connectors 68 usd
5-axis milled throttle body starts 110 usd.
Remaining sensors possible get from us or from any local shop which sell automotive or ATV components.
We can prepare complete instalation kit by customer specs.

[TZ350]

.
I would love to see more photos of all the bits and pieces available posted here.

[jbiplane]

.
I would love to see more photos of all the bits and pieces available posted here.

Please have a look. At moment we have most of documentation in Russian, but going to translate on English, German and French soon.

http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=71655&d=1527425811
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=71656&d=1527425857
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=71657&d=1527425884
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=71658&d=1527425914

40cc model engine
http://www.reaa.ru/yabbfiles/Attachments/GF40.jpg

https://www.youtube.com/watch?time_continue=57&v=h3btzJ3bYLM
Some components looks rude, but they are more reliable than nice looking parts. We dont tested EFI at higher than 10000 rpm, but dont think it will a problem, espetialy using few nozzles.

Note: O2 sensor can be used in learning mode and disconnected afterwards. If correctly placed survive in 2-strokes for about 150 hours only.

Easiest way to get additional info is push me by e-mail

Valeriy Rutkovskiy
jbiplane@gmail.com

[TZ350]

Please have a look.
Easiest way to get additional info is push me by e-mail
Valeriy Rutkovskiy
jbiplane@gmail.com

Great looking gear, will be in touch, thanks.

[oldjohnno]

Here's a video I stumbled across recently. It's quite old but I think it's very very good, and seeing as our two strokes are almost entirely dependent on wave action to produce high outputs I thought some of you might enjoy it as well. Presented very clearly and I particularly liked his demo machines.

https://www.youtube.com/watch?v=DovunOxlY1k&feature=youtu.be

[guyhockley]

The (injected) Suter has arrived in the Isle of Man(n) for another crack at the TT.

[guyhockley]

If you try to get away without welding, then you seems lose a lot of weight gain.

JBB 250 V-twin con-rod.

[RomeuPT]

thank you wobbly for the information, I tested the new housing modena mkz it is more power on the whole curve I controlled the changes brought then more volume of low crankcase we arrive at 520cc atdc before 490cc inclination of the angle for the reed box 2 degrees down and another shape inside what do you think wobbly changes made? thank you333208333209333210333211333212

Hello.

I wonder if there are new insight's of the new reed setups used in the TM compared to Vforce's....

Any better news about the ryger?

Thanks

[wobbly]

After I tried really hard to get a VF to work better in a TM, I found no free lunch.
I was sure that a smaller bodied VF with a larger or the same tip curtain area would prove better.
The best I came up with was a VF4 from a Banshee - they gave me a whole bunch of things to try, and I glued together new fixing plates to suit the bolt pattern.
But the restraining issue at the end of the day was that you cant create compound petal systems in the VF due to the assembly clamping method.
The stock TM allows very soft/stiff petals,spacers, and backup strips of all shapes and thickness/stiffness to be combined.
On the flow bench i found that at certain air velocities a single petal will flutter uncontrollably, but that this is easily damped out using a backup that is spaced away from the
main reed.
This allows much softer main petals to be used that open quicker, and further - invariably making more power that is easy to tune to the intake and case Helmholtz action.
The backups can also be used to stiffen the main petals outer sides, controlling the flow that spills over sideways from the opening.
This forces a bending action laterally in the petal, and as a side effect it seems to reduce petal tip shattering, that usually occurs on the outer corners.

[breezy]

Here's a video I stumbled across recently. It's quite old but I think it's very very good, and seeing as our two strokes are almost entirely dependent on wave action to produce high outputs I thought some of you might enjoy it as well. Presented very clearly and I particularly liked his demo machines.

https://www.youtube.com/watch?v=DovunOxlY1k&feature=youtu.be

thanks i enjoyed that:2thumbsup

[husaberg]

If you try to get away without welding, then you seems lose a lot of weight gain.

JBB 250 V-twin con-rod.

Ariel Arrow had knife rods in the 50's
Herman Meiier introduced them on the racer and they were used on the production bikes as they were cheaper to make.
He got the idea for them from DKW on their racer 3 cylinder same as the lab seals with piston rings.
337039
Alpha cranks also had them. tuning for speed gives diagrams of converting std rods to that shape.
Although not hollow like the JBB ones
Falcon cranked make what they call knife rods to reduce windage
337035
http://www.faliconcranks.com/1pc.html
http://www.faliconcranks.com/2pc.html
pretty sure they don't do two stroke ones though.

The Knife® - the most streamlined shape connecting rod design in the industry is shaped like an airplane wing to resist twisting and reduce the turbulence in the crankcase for horsepower gains and efficient oil flow.We designed this new generation Knife connecting rod using Computer Modeling and Finite Element Analysis and tested them on the track. Stronger, lighter and more aerodynamic means more power with better reliability.These connecting rods are designed for press-together roller-bearing cranks.Unlike our competitor's rods, ours do not have a pressed-in bearing race that will move or crack under loadThe Knife® - the most streamlined shape connecting rod design in the industry is shaped like an airplane wing to resist twisting and reduce the turbulence in the crankcase for horsepower gains and efficient oil flow.We designed this new generation Knife connecting rod using Computer Modeling and Finite Element Analysis and tested them on the track. Stronger, lighter and more aerodynamic means more power with better reliability.These connecting rods are designed for press-together roller-bearing cranks.Unlike our competitor's rods, ours do not have a pressed-in bearing race that will move or crack under load.

here are some ariel twin rods for those not familiar with them.
337038337037337036337034
As the two stroke doesn't have the cyclic variation that a four stroke does I don't think rod strength is a pressing two stroke issue.

[chrisc]

Hey team. Posting here because I know a bunch of you have been curious on my 2t racing in the past. I've just put up a tonne of photos from my racing at Hockenheim 2 weeks ago in the Klassik Motorsport championship where I'm racing a Freetech 50 bike. Over the weekend we also raced at a little street circuit called Schleizer Dreieck in Schleiz, east Germany. It was an amazing circuit with a tonne of elevation change and some super tight racing. It has two super fast down hill sections making it faster than both Hockenheim and Assen for these little machines of ours. It's also very twisty and complex which suited my riding more since I'm not on a fast machine.

There's also loads and loads of cool classic 2 stroke racers here with everyone camping at the track over the weekend. Loads of drinking, partying and laughs after the racing. It's what I'd imagine the continental circus was like back in the day. I'm too young to have experienced it properly so this is a great second best.

Head over to my facebook page to check out my racing: https://www.facebook.com/grandprixmachine
or here for the photo album from Hockenheim: https://www.facebook.com/GrandPrixMachine/photos/?tab=album&album_id=1019552428196027

[TZ350]

Head over to my facebook page to check out my racing: https://www.facebook.com/grandprixmachine
or here for the photo album from Hockenheim: https://www.facebook.com/GrandPrixMachine/photos/?tab=album&album_id=1019552428196027

Great, thanks Chris.

[guyhockley]

As the two stroke doesn't have the cyclic variation that a four stroke does I don't think rod strength is a pressing two stroke issue.

I was a bit taken aback to find that CR500 rods are used by XS650 tuners, but they work OK, apparently.
The JBB rods were made (I think) by JPX in France who also (I think) had a lot to do with George Beale's Honda 6 replicas.

[RomeuPT]

After I tried really hard to get a VF to work better in a TM, I found no free lunch.
I was sure that a smaller bodied VF with a larger or the same tip curtain area would prove better.
The best I came up with was a VF4 from a Banshee - they gave me a whole bunch of things to try, and I glued together new fixing plates to suit the bolt pattern.
But the restraining issue at the end of the day was that you cant create compound petal systems in the VF due to the assembly clamping method.
The stock TM allows very soft/stiff petals,spacers, and backup strips of all shapes and thickness/stiffness to be combined.
On the flow bench i found that at certain air velocities a single petal will flutter uncontrollably, but that this is easily damped out using a backup that is spaced away from the
main reed.
This allows much softer main petals to be used that open quicker, and further - invariably making more power that is easy to tune to the intake and case Helmholtz action.
The backups can also be used to stiffen the main petals outer sides, controlling the flow that spills over sideways from the opening.
This forces a bending action laterally in the petal, and as a side effect it seems to reduce petal tip shattering, that usually occurs on the outer corners.

Alot of science in the petals only, I don't know if is really worth the time and effort just for some fun bikes.

Any dynos can be shown comparing a good reed setup and a vforce or something?

thanks

[F5 Dave]

Wow Chris, you'v stumbled into two stroke heaven from the looks.
everyone has spent the bucks on paintwork.

[Muhr]

JBB 250 V-twin con-rod.

Tried a hollow model but has not seen any benefits yet. Buckling does not seem to be a problem when weight loss is focused on the small end.



Ariel Arrow had knife rods in the 50's
Herman Meiier introduced them on the racer and they were used on the production bikes as they were cheaper to make.
He got the idea for them from DKW on their racer 3 cylinder same as the lab seals with piston rings.

Alpha cranks also had them. tuning for speed gives diagrams of converting std rods to that shape.
Although not hollow like the JBB ones
Falcon cranked make what they call knife rods to reduce windage

As the two stroke doesn't have the cyclic variation that a four stroke does I don't think rod strength is a pressing two stroke issue.

I'll see if I can try some CFD. Just it takes so much time to do

[wobbly]

The reed setup in a KZ engine is a bit of a special case in that the rpm power range is from 9800 to 14800.
With peak power at about 13500.
This makes getting the petal 1st order resonance very critical, too soft and you loose control and top end, too stiff and power drops everywhere.
The stuffer has just as much effect as the petals,and I have spent plenty on 3D printed inserts with splitters and wings of every conceivable shape to
try and get the impossible - better mid AND top end overev.

[TZ350]

.
Husa has found some interesting info on swing arm swaps, may be useful for that next Bucket build.



have a look at Mike Costins site
http://www.micoproducts.net/500cc%20page.htm

if you google R6 swingarm swap you will likely find the width within a few minutes
https://www.motorcykelgalleri.dk/fotoalbum/guider/24161-svingarm__bagsvinger_maal
do the same with the 3ma.
the straight swap is to use the TZR125 banana arm tzr125 4dl sp swing
http://pure2strokespirit.net/forums/index.php?PHPSESSID=04vmu76n6l6hpkpbgs07dmv654&topic=114.0
http://i1186.photobucket.com/albums/z376/tzr250-3ma/TZR250%20HYBRID/3maracerm.jpg
also adding the fzr wheel
http://pure2strokespirit.net/forums/index.php?topic=286.msg6469#msg6469
https://billeder.bazoom.dk/motorcykler/album/71/m/351166/svingarm--bagsvinger-maal.jpg
A:
Honda VTR SUPERHAWK (all years) - 165mm
Honda VFR 800 (1998-2001) - 165mm
Honda CBR 929 (2000-2001) - 180mm
Honda CBR 954RR (2002-2003) - 180mm
Honda RC51 SP2 (2002-?) - 180mm
1976 Suzuki GT500 - 185mm
Yamaha XS650 - 190mm
Honda VFR400 - 192mm
Honda MC18 NSR250 - 197mm
Yamaha FZR250 - 200mm
Honda XL600R - 200mm
Yamaha LC RD350 - 200mm
Honda RVF400 - 202mm
Honda NS400R - 205mm
Honda MC21 NSR250 - 205mm
Honda CB400F - 205mm
Suzuki RGV250 - 205mm
Yamaha RZ350 - 205mm
Yamaha YPVS RD350 - 205mm
1986 FZ600 - 215mm (without spacers/covers), - 220mm with spacers/covers
Suzuki Bandit GSF600 - 220mm
1992-1998 Yamaha Seca II - 220mm
1990-1996 Yamaha FZR600 - 220mm
2005 Suzuki GSXR 1000 - 225mm
1976-1982 Kawasaki KZ600 - 225mm
1994-1997 Honda VFR750 - 227mm
2001-2002 Suzuki GSXR1000 - 228mm
Kawasaki Z650/Z750 - 230mm (frame width at pivot)
2004-2005 Suzuki GSXR750 - 230mm (without washers on ends)
Suzuki TL1000S - 232mm
Honda Hawk GT650 - 235mm
Honda RC30 - 235mm
2008 Kawasaki Ninja ZX6R - 235mm
Kawasaki Z900/Z1000 - 235mm (frame width at pivot)
Honda RC30 - 235mm
1999-2002 Suzuki SV650 - 235mm
2006 Suzuki GSR500 - 238mm (w/o spacers)
2003-2009 Suzuki SV650 - 240mm
1998-2007 Yamaha YZF600R - 240mm
1990-1993 Honda VFR750 - 242mm
2005-2006 Kawasaki Ninja ZX6R (636) - 242mm
1987 Kawasaki Ninja ZX750R - 244mm
1987 Yamaha FZ750 - 245mm
2006-2011 Kawasaki Ninja 650R - 245mm
1998-2003 Suzuki Katana GSX600/750F - 245mm
2007 Yamaha YZF-R6 - 248mm
Honda RC45 - 250mm
Sucati SR4S - 255mm
2003 Kawasaki Z1000 - 255mm
MV Agusta F4 - 255mm
Kawasaki ZX10R (Gen 1-3) - 257mm
2002-2005 Yamaha FZ1 - 257mm (20mm pivot bolt)
2001 Yamaha YZF-R1 - 250mm
2003-2006 Yamaha YZF-R1 - 260mm (without caps) - 264mm (with caps)
Triumph 955i - 285mm
BMW K100 - 310mm

GT500 '76 185mm
SV650 K5 240mm
VFR400 192mm
RVR400 202mm
NS400R 205mm
XS650 190mm
FZR250 200mm
MC21 NSR250 205mm
GSF600 bandit 220mm
CB400F 205mm
MC18 NSR250 197mm
'86 FZ600 215mm (without spacers/covers)
RZ350 205mm
05 GSXR 1000 225mm
Z900/Z1000 235mm (frame width at pivot)
Z650/Z750 230mm (frame width at pivot)
LC RD350 200mm
YPVS RD350 205mm
Gen 1-3 ZX10R 257mm
XL600R 200mm
MV Agusta F4 255mm
VTR SUPERHAWK (all years) 165mm
CBR 954 RR (2002-2003) 180mm
CBR 929 (2000-2001) 180mm
VFR 800 (1998-2001) 165mm
RC51 SP2 (2002-?) 180mm
RC30 235mm
RC45 250mm

B:
Make Model Year Shock Length(mm) Shock Stroke
(mm)
Suzuki Bandit 600 2000-2004 319 55
Suzuki Bandit 650 2005 319.5 65.5
Suzuki Bandit 1200 1996-2000 306 64
Suzuki Bandit 1200 2001-2005 320 (+6/-0) 61
Suzuki GSXR 600 1992-1993 312 (+12/-0) 67
Suzuki GSXR 600 2001-2003 325.5 (+6/-0) 74
Suzuki GSXR 600 2004-2005 332.5 (+6/-0) 74
Suzuki GSXR 750 1985-1987 290.5 61
Suzuki GSXR 750 1988-1991 312 (+12/-0) 67
Suzuki GSXR 750 1992-1995 312 (+12/-0) 67
Suzuki GSXR 750 1996-1999 356 (+6/-6) 79
Suzuki GSXR 750 2000-2003 325 (+6/-0) 74
Suzuki GSXR 750 2004-2005 332.5 (+6/-0) 74
Suzuki GSXR 1000 2001-2002 329.5 (+5.5/-0.5) 74
Suzuki GSXR 1000 2003-2004 332.5 (+6/-0) 74
Suzuki GSXR 1000 2005 319 70
Suzuki GSXR 1100 1986-1988 315 69
Suzuki GSXR 1100 1989-1992 312 70
Suzuki GSXR 1100 1993-1998 312 70
Suzuki Hayabusa 1999-2006 330 72
Kawasaki ZX6R 2003-2004 340 (+12/-0) 72.5
Kawasaki ZX6RR 2003-2004 340 (+12/-0) 72.5
Kawasaki ZX6R 2005 335.5 (+12/-0) 64.5
Kawasaki ZX6RR 2005-2006 330 (+12/=0) 63.5
Kawasaki ZX7R 1996-2001 350 (+12/-0) 75
Kawasaki ZX9R 1994-1997 348 79
Kawasaki ZX9R 1998-1999 330 (+12/-0) 69
Kawasaki ZX9R 2000-2001 338 67
Kawasaki ZX9R 2002-2003 338.5 67.5
Kawasaki ZX10 1988-1989 314.5 67
Kawasaki ZX10R 2004-2005 338 (+7/-5) 69
Kawasaki ZX12R 2000-2005 338 (+7/-5) 67
H*nda CBR 600 F 1987-1990 292 50
H*nda CBR 600 RR 2003-2006 313 (+0/-6) 59.5
H*nda VFR 800 FI 1998-2001 325 58
H*nda VFR 800 FI 2002-2005 317.5 53.5
H*nda CBR 900 RR 1992-1995 319 (+12/-0) 54
H*nda CBR 900 RR 1996-1997 305 (+12/-0) 60
H*nda CBR 900 RR 1998-1999 303 (+12/-0) 57
H*nda CBR 900 RR 2000-2001 286 (+4/-2) 57
H*nda CBR 900 RR 2002-2003 288 (+2/-4) 57
H*nda CBR 929 2000-2001 286 (+4/-2) 57
H*nda CBR 954 2002-2003 288 (+2/-4) 57
H*nda RC51 2000-2005 326 (+10/-2) 63
H*nda CBR 1000 RR 2004-2006 314 (+6/-0) 58
H*nda VTR 1000 F 1997-2005 346 60
H*nda VTR 1000 SP1 2000-2001 326 (+10/-2) 63
H*nda VTR 1000 SP2 2002-2005 326 (+10/-2) 63
H*nda CBR 1100 XX 1997-2005 319 52
Yamaha YZF 600 1994-1999 360 (+12/-0) 70
Yamaha YZF R6 1999-2002 305 (+4/-2) 62
Yamaha YZF R6 2003-2004 295 (+5.5/-0.5) 62.5
Yamaha YZF R6 2005 300 (+0/-6) 62.5
Yamaha FZR 750 1987-1988 300.5 54
Yamaha FZR 750R 0W01 1989-1991 360 76
Yamaha FZR 1000 1987-1988 300.5 54
Yamaha FZR 1000 1989-1995 340 70
Yamaha YZF 1000 1996-2000 340 (+12/-0) 69
Yamaha YZF R1 1998-2001 300 (+11/-1) 65
Yamaha YZF R1 2002-2006 300 (+5.5/-0.5) 64.5

Make Model Year Shock Length(mm) Shock Stroke
(mm)
Suzuki Bandit 600 2000-2004 319 55
Suzuki Bandit 650 2005 319.5 65.5
Suzuki Bandit 1200 1996-2000 306 64
Suzuki Bandit 1200 2001-2005 320 (+6/-0) 61
Suzuki GSXR 600 1992-1993 312 (+12/-0) 67
Suzuki GSXR 600 2001-2003 325.5 (+6/-0) 74
Suzuki GSXR 600 2004-2005 332.5 (+6/-0) 74
Suzuki GSXR 750 1985-1987 290.5 61
Suzuki GSXR 750 1988-1991 312 (+12/-0) 67
Suzuki GSXR 750 1992-1995 312 (+12/-0) 67
Suzuki GSXR 750 1996-1999 356 (+6/-6) 79
Suzuki GSXR 750 2000-2003 325 (+6/-0) 74
Suzuki GSXR 750 2004-2005 332.5 (+6/-0) 74
Suzuki GSXR 1000 2001-2002 329.5 (+5.5/-0.5) 74
Suzuki GSXR 1000 2003-2004 332.5 (+6/-0) 74
Suzuki GSXR 1000 2005 319 70
Suzuki GSXR 1100 1986-1988 315 69
Suzuki GSXR 1100 1989-1992 312 70
Suzuki GSXR 1100 1993-1998 312 70
Suzuki Hayabusa 1999-2006 330 72
Kawasaki ZX6R 2003-2004 340 (+12/-0) 72.5
Kawasaki ZX6RR 2003-2004 340 (+12/-0) 72.5
Kawasaki ZX6R 2005 335.5 (+12/-0) 64.5
Kawasaki ZX6RR 2005-2006 330 (+12/=0) 63.5
Kawasaki ZX7R 1996-2001 350 (+12/-0) 75
Kawasaki ZX9R 1994-1997 348 79
Kawasaki ZX9R 1998-1999 330 (+12/-0) 69
Kawasaki ZX9R 2000-2001 338 67
Kawasaki ZX9R 2002-2003 338.5 67.5
Kawasaki ZX10 1988-1989 314.5 67
Kawasaki ZX10R 2004-2005 338 (+7/-5) 69
Kawasaki ZX12R 2000-2005 338 (+7/-5) 67
H*nda CBR 600 F 1987-1990 292 50
H*nda CBR 600 RR 2003-2006 313 (+0/-6) 59.5
H*nda VFR 800 FI 1998-2001 325 58
H*nda VFR 800 FI 2002-2005 317.5 53.5
H*nda CBR 900 RR 1992-1995 319 (+12/-0) 54
H*nda CBR 900 RR 1996-1997 305 (+12/-0) 60
H*nda CBR 900 RR 1998-1999 303 (+12/-0) 57
H*nda CBR 900 RR 2000-2001 286 (+4/-2) 57
H*nda CBR 900 RR 2002-2003 288 (+2/-4) 57
H*nda CBR 929 2000-2001 286 (+4/-2) 57
H*nda CBR 954 2002-2003 288 (+2/-4) 57
H*nda RC51 2000-2005 326 (+10/-2) 63
H*nda CBR 1000 RR 2004-2006 314 (+6/-0) 58
H*nda VTR 1000 F 1997-2005 346 60
H*nda VTR 1000 SP1 2000-2001 326 (+10/-2) 63
H*nda VTR 1000 SP2 2002-2005 326 (+10/-2) 63
H*nda CBR 1100 XX 1997-2005 319 52
Yamaha YZF 600 1994-1999 360 (+12/-0) 70
Yamaha YZF R6 1999-2002 305 (+4/-2) 62
Yamaha YZF R6 2003-2004 295 (+5.5/-0.5) 62.5
Yamaha YZF R6 2005 300 (+0/-6) 62.5
Yamaha FZR 750 1987-1988 300.5 54
Yamaha FZR 750R 0W01 1989-1991 360 76
Yamaha FZR 1000 1987-1988 300.5 54
Yamaha FZR 1000 1989-1995 340 70
Yamaha YZF 1000 1996-2000 340 (+12/-0) 69
Yamaha YZF R1 1998-2001 300 (+11/-1) 65
Yamaha YZF R1 2002-2006 300 (+5.5/-0.5) 64.5

[husaberg]

.
Husa has found some interesting info on swing arm swaps, may be useful for that next Bucket build.
husas still looking for a set of TZR2501KT forks or FZR1000 forks and a DT1 swingarm. anyone?:innocent:

[speedpro]

It just occurred to me that TZ350 is having problems with air flow off pipe and looking at ways of measuring it so he can determine the quantity of fuel to inject. Is it possible to use a Mass Airflow Sensor(MAS) such as has been used in various motor vehicle engine management systems. The MAS output could be utilized only at a certain combination of throttle and revs.

[husaberg]

It just occurred to me that TZ350 is having problems with air flow off pipe and looking at ways of measuring it so he can determine the quantity of fuel to inject. Is it possible to use a Mass Airflow Sensor(MAS) such as has been used in various motor vehicle engine management systems. The MAS output could be utilized only at a certain combination of throttle and revs.

There are plenty of diesel's that measure exhaust pressure and cars that seem do it for emission's stuff and some turbos use direct exhaust pressure measurement as well how do they translate the information?
that's a question as I have no idea.

I had a silly idea of just using the violtage signal to trigger a led array like a led tacho or voltage set then just using the appropriate trigger voltage where on over run or off the pipe where you want to switch off or down the fueling just to optically detect the appropriate level from the appropriate led . dirty yes
http://www.autospeed.com/cms/article.html?&title=Universal-Bargraph-Voltage-Display&A=110623
http://www.autospeed.com/cms/article.html?&title=DIY-Voltage-Monitor&A=1369



https://ieeexplore.ieee.org/document/7859475/
http://kth.diva-portal.org/smash/get/diva2:305816/FULLTEXT01
https://www.ms-motorservice.com/en/technipedia/post/electrical-motor-vehicle-signals/

[guyhockley]

Suter have posted a video on their facebook page of Ian Lougher coming back from practice. I'm a bit deaf and was listening on crappy earphones plugged into a crappy netbook but he seems to be describing fuelling problems...

[Greg85]

Hello.

I wonder if there are new insight's of the new reed setups used in the TM compared to Vforce's....

Any better news about the ryger?

Thanks

Hello Romeu then yes I have already tried the vf double strength but I have never had more power, stake and flow diverter that and very important as Wobbly said in the previous post it greatly influences the input flow as I can see by having purchased the modena with the VFlow a significant power loss compared to the original box... As for the ryger I have no information on this engine legend and I think nobody has news about it

[wobbly]

I have posted several comments on Suter pages, where all they show is full throttle dyno runs - deathly silence every time.
My spies at the TT, say the thing sounds horrible on part throttle, just like last year.
And Lougher was saying that when he backed off into a corner, it took several seconds to actually " slow down ".
Man, I hope these guys get on top of it,they have had 12 months to test it to death, but all we see is wank pointless full throttle videos.

[Flettner]

Why aren't Suter injecting at the transfer port?

[RomeuPT]

The reed setup in a KZ engine is a bit of a special case in that the rpm power range is from 9800 to 14800.
With peak power at about 13500.
This makes getting the petal 1st order resonance very critical, too soft and you loose control and top end, too stiff and power drops everywhere.
The stuffer has just as much effect as the petals,and I have spent plenty on 3D printed inserts with splitters and wings of every conceivable shape to
try and get the impossible - better mid AND top end overev.

Thanks Wobbly!

Should yet I give more crankcase sideways clearance for a VF2 reed cage, this relating to page 1844?

[Nath88]

Suter have posted a video on their facebook page of Ian Lougher coming back from practice. I'm a bit deaf and was listening on crappy earphones plugged into a crappy netbook but he seems to be describing fuelling problems...

If I were Suter, I'd have the main throttles electronically controlled, but always open to 10% (or the lowest the engine can sustain without misfire), then have individual butterflies on each cylinder that snap open as the throttle opens. Say at 2%, 4%, 6% and 8% throttle. Once all cylinders are lit the main throttles open. Easier than trying to control the engine near the misfire limit, have each cylinder either constantly firing or not.

The problem with airflow measurement is the delay. You need to wait for the engine to start pulling the air before you can measure it, then do the ECU calculation routine, then it takes 1ms to open or close the injector. By the time you can make a change to the fuel quantity delivered, the air has already entered the crankcase and the cylinder so you've missed the boat. TPI helps but ideally you want some airflow prediction, be it cylinder pressure, exhaust pulse pressure, pressure as transfer ports open (KTM uses this). Carbs work well because they work in real time, the only delay is the inertia of the fuel in the passages.

[TZ350]

I have posted several comments on Suter pages, where all they show is full throttle dyno runs - deathly silence every time.

It is real easy to get perfect full throttle performance with 2T EFI.

Drivability is the real issue. I dont know of anyone who has managed that on a small cylinder capacity high performance 2T road race engine.

I am working hard on it and hope to be the first.

[jbiplane]

The problem with airflow measurement is the delay. You need to wait for the engine to start pulling the air before you can measure it, then do the ECU calculation routine, then it takes 1ms to open or close the injector. By the time you can make a change to the fuel quantity delivered, the air has already entered the crankcase and the cylinder so you've missed the boat. TPI helps but ideally you want some airflow prediction, be it cylinder pressure, exhaust pulse pressure, pressure as transfer ports open (KTM uses this). Carbs work well because they work in real time, the only delay is the inertia of the fuel in the passages.

Hi Nath88
Most of ECU math work a bit different. It calculates how much fuel must be sprayed for given throtle position, acceleration of throttle opening angle (you can regulate vehicle acceleration). With geared dent wheel it analyze crankshaft accelerations during each turn and spray with corrections according numerous sensors (themperature, pressure, etc.) for the next crankrotation.
"Carburetors is a always a bit magic". Lets magic go to a hell.
Using practically any EFI you will at least 5% more power on a max rpm (we observe 9% with our low BMEP engines) and at least 25% fuel saving.

Finally I hate carbs, all this Mikuni, Keihin, Dellorto, Walbro ... Small carburetor cannot be as good as their big brothers using on cars.
Few days ago we installed engine with 32mm Mikuni on test dyno with hydro brake. Some setting were wrong and before we realyze the engine crankshaft was ruined. Woodroof destroyed and crank was bent. Can make and sent photos.
Afterwards we install EFI on the same engine, complete initial settings in few minutes and finally tune fuel maps in 30 minutes...

[jasonu]

Why aren't Suter injecting at the transfer port?

Apparently they don't want to be seen to be copying KTM.....

[TZ350]

..... pressure as transfer ports open (KTM uses this)

KTM measures what pressure, where?

[TZ350]

Why aren't Suter injecting at the transfer port?
Apparently they don't want to be seen to be copying KTM.....

They could try copying Flettner, after all he was doing "B" transfer port injection against the air stream before KTM. Flettner even clued KTM onto the concept but KTM turned him down saying they were going to do something more sophisticated, well that didn't go well and then they went with Flettners suggestion. LOL.

[peewee]

Ariel Arrow had knife rods in the 50's
Herman Meiier introduced them on the racer and they were used on the production bikes as they were cheaper to make.
He got the idea for them from DKW on their racer 3 cylinder same as the lab seals with piston rings.
337039
Alpha cranks also had them. tuning for speed gives diagrams of converting std rods to that shape.
Although not hollow like the JBB ones
Falcon cranked make what they call knife rods to reduce windage
337035
http://www.faliconcranks.com/1pc.html
http://www.faliconcranks.com/2pc.html
pretty sure they don't do two stroke ones though.


here are some ariel twin rods for those not familiar with them.
337038337037337036337034
As the two stroke doesn't have the cyclic variation that a four stroke does I don't think rod strength is a pressing two stroke issue.

ktm used knife conrods on alot of engines during 70s and 80s https://m.ebay.com/itm/1988-KTM-250-MXC-Vintage-block-crank-trany-clutch-clutch-cover/251942536811?epid=1624459328&hash=item3aa8f2066b:g:w9cAAOxy0bRS~-z5

[sispeed]

Ronax is doin very well with their EFI Stroker.
Saw them several times racing in classic events and compared to a Suter it is cheap. Ok, not really, but in comparison ;-)
http://www.ronax500.com/en/ronax_tech.php
https://www.youtube.com/watch?v=6qNcttBSw9Y

Regards Siggi

[karter444]

Hi Wobbly
can you tell me when detonation usually occurs in a kz engine . Three possible times could be.
1. pulling hard out of a corner at lower rpm ie 9800
2. when the engine pulls through peak HP ie about 13500
3, at peak engine rpm ie 14800.
it seems most people eliminate deto by lifting the needle so Im thinking it wont be option 3 , but this doesnt mean they are doing it the right way as I know most dont even change jets etc with changes in RAD
cheers Richard

[TZ350]

Ronax is doin very well with their EFI Stroker. Saw them several times racing in classic events and compared to a Suter it is cheap. Ok, not really, but in comparison ;-)

http://www.ronax500.com/en/ronax_tech.php

https://www.youtube.com/watch?v=6qNcttBSw9Y (https://www.youtube.com/watch?v=6qNcttBSw9Y)

Regards Siggi

That is great Suggi, thanks. The Ronax500 sounds great and sounds like it comes back on the pipe cleanly after shutting off for a corner. That coming back on the pipe is the hard part with 2T EFI and is where I am having my own problems.

Well it looks like I wont be the first to crack it so hopefully I will be able to post about how it's done so others can experiment with the technology too.

[TZ350]

337055 Ok Kiwibiker, upside down .... why???

It's real easy to get a EFI 2T to run very well on anything over 25% throttle because the airflow is consistently predictable. Predictable air flow makes it easy to get a EFI 2T to drag race out of the corner once its on the pipe.

But because air flow through a two stroke is very much influenced by resonance and the more highly tuned an engine the more the symbiotic resonance waves reinforce each other and the more easily they are disturbed which greatly changes the air flow pattern through the motor and it all becomes much less predictable at reduced throttle settings. This is particularly evident below 25% throttle on a tuned engine. I think there has to be some way to see these air flow changes as they happen and I am looking for it.

The Ronax500 looks like its got the low throttle changeable air flow prediction sorted and the Suter is still struggling with it.

[Pursang]

And Lougher was saying that when he backed off into a corner, it took several seconds to actually " slow down ".

With Braking 'detection' and an electronic throttle it should be possible to cut the fuel and brake with Full (not restricted) engine compression.

cheers, Daryl.

[wax]

Another Blow down question.
Ok we know if you have not enough blow down you ended up with reversing the flow in the transfers and your engine will not want to rev.
I have read where Frits or jan said the more blow down you can get the better. SOOO the big question, how much to to much?
My cylinder clocks up at 204/ 126 so by my calculations thats 39 degrees of blow down. To much ?? I dont know, what is the effect from having to much.

[TZ350]

And Lougher was saying that when he backed off into a corner, it took several seconds to actually " slow down ".

I can only guess but my guess is that they have fueled it for the lowest common denominator of air flow. Leaned it down so much at low throttle settings that its running HCCI on some of the engines combustion cycles as it runs into the corner. They would have leaned it off to try and stop it getting over rich on randomly collapsing air flow cycles.

I think the wave action collapses or picks up unpredictably on closed/low throttle trailing through a corner and the leaning down is to help the engine to clear and pick up again in the drive out from the corners apex. My guess based on my own experience.

One thing I am sure of though, is that you can't apply four stroke fuel injection thinking to highly tuned two strokes.

[Frits Overmars]

I have read where Frits or jan said the more blow down you can get the better. SOOO the big question, how much to to much?
My cylinder clocks up at 204/ 126 so by my calculations thats 39 degrees of blow down. To much ?? I dont know, what is the effect from having to much.Jan and I both said that, Wax. You can hardly have enough blowdown, but you can have too much exhaust timing, and that may be the case with your cylinder.
For efficient exhaust wave superpostion (read all about it on Kiwibiker somewhere) you'd want about 190° exhaust timing.
Yes, the Aprilias ran 202°, which was a compromise between insufficient blowdown time.area at over 23 m/s piston speed and imperfect optimum wave superposition.
Calculating the blowdown angle doesn't mean all that much; it's the time.area that counts.
The effect of too much exhaust timing can be threefold: loss of work stroke, an increased risk of transfer short-circuiting and the already mentioned imperfect wave superposition.

[husaberg]

I have posted several comments on Suter pages, where all they show is full throttle dyno runs - deathly silence every time.
My spies at the TT, say the thing sounds horrible on part throttle, just like last year.
And Lougher was saying that when he backed off into a corner, it took several seconds to actually " slow down ".
Man, I hope these guys get on top of it,they have had 12 months to test it to death, but all we see is wank pointless full throttle videos.



I can only guess but my guess is that they have fueled it for the lowest common denominator of air flow. Leaned it down so much at low throttle settings that its running HCCI on some of the engines combustion cycles as it runs into the corner. They would have leaned it off to try and stop it getting over rich on randomly collapsing air flow cycles.

I think the wave action collapses or picks up unpredictably on closed/low throttle trailing through a corner and the leaning down is to help the engine to clear and pick up again in the drive out from the corners apex. My guess based on my own experience.

One thing I am sure of though, is that you can't apply four stroke fuel injection thinking to highly tuned two strokes.

My thoughts as well, too lean on the pilot or idle screw can cause a hanging idle where the engine is slow to return to normal speeds in relation to throttle position
Frits mentioned Cagiva also had the overfueling problem on over run common on fuel injected bikes although for some reason they also suffered it even with carbs and they worked around the issue with spacers under the red petals so they never completely closed.

Several riders of the Cagiva 500-4 works racers experienced a painful demonstration of this stubbornness:
When closing the throttle for a corner (a 500-4 will need that from time to time) engine power dropped. But when they reopened at the corner exit.... nothing happened. The reeds had to be opened by the suction of the exhaust pipe, but when there is no combustion, there is no suction. So the riders opened up a little more. And a little more. And more.... And then, at some point, there was once more sufficient combustible mixture in the cylinder to be ignited. The pipe suction returned from its coffee break and the whole two-stroke resonance cycle was reinstated - with the four carbs wide open. That hurt....
The problem was solved by inserting thin strips under the reeds, so they never really closed completely. It messed up the carburation and cost over 10 HP, but it improved both the lap times and the mileage you could put on a rider.Later, because of those carburation problems, Cagiva was one of the first to switch from carbs to injection.
I have mentioned had the same issue occurs with diaphragm pumper carbs on a two stroke where it bogged before suddenly clearing and coming in with a bang.
The only race test of a Cagiva fuel injected bike mentioned the same thing as did Foggy when he tried it.
The KTM 250 GP bike had a fuel injector I believe that only worked on over run, I wonder how they triggered it and why it didn't cause them issues with over fuelling?



If I were Suter, I'd have the main throttles electronically controlled, but always open to 10% (or the lowest the engine can sustain without misfire), then have individual butterflies on each cylinder that snap open as the throttle opens. Say at 2%, 4%, 6% and 8% throttle. Once all cylinders are lit the main throttles open. Easier than trying to control the engine near the misfire limit, have each cylinder either constantly firing or not.

The problem with airflow measurement is the delay. You need to wait for the engine to start pulling the air before you can measure it, then do the ECU calculation routine, then it takes 1ms to open or close the injector. By the time you can make a change to the fuel quantity delivered, the air has already entered the crankcase and the cylinder so you've missed the boat. TPI helps but ideally you want some airflow prediction, be it cylinder pressure, exhaust pulse pressure, pressure as transfer ports open (KTM uses this). Carbs work well because they work in real time, the only delay is the inertia of the fuel in the passages.

Neat idea, The Motogp bikes use auto throttle blippers and they do the same with some throttle bodies not shutting completely.
At times on over run some like a single which I guess some effectively become one.
Its something that would be pretty easy with fly by wire throttles. (they do this to stop the bikes locking the rear wheel as a high tech sprag clutch)

Our new work utes have normal power and economy settings.
They feel hugely powerful in power mode, but very touchy on the throttle.
I suspect the power setting just opens the throttle wider for a given input of accelerator pedal.
much like a quick action twistgrip.

[wax]

Jan and I both said that, Wax. You can hardly have enough blowdown, but you can have too much exhaust timing, and that may be the case with your cylinder.
For efficient exhaust wave superpostion (read all about it on Kiwibiker somewhere) you'd want about 190° exhaust timing.
Yes, the Aprilias ran 202°, which was a compromise between insufficient blowdown time.area at over 23 m/s piston speed and imperfect optimum wave superposition.
Calculating the blowdown angle doesn't mean all that much; it's the time.area that counts.
The effect of too much exhaust timing can be threefold: loss of work stroke, an increased risk of transfer short-circuiting and the already mentioned imperfect wave superposition.
Thanks Frits. I understand that about the exhaust port timing. The issue with this cylinder is its a single exhaust port thats stuck between two studs and so they went high on the port timing to try and get them to run better. Its hard to make it lower so im using what i have. Thanks as always for your help

[guyhockley]

I can only guess but my guess is that they have fueled it for the lowest common denominator of air flow. Leaned it down so much at low throttle settings that its running HCCI on some of the engines combustion cycles as it runs into the corner. They would have leaned it off to try and stop it getting over rich on randomly collapsing air flow cycles.

I think the wave action collapses or picks up unpredictably on closed/low throttle trailing through a corner and the leaning down is to help the engine to clear and pick up again in the drive out from the corners apex. My guess based on my own experience.

One thing I am sure of though, is that you can't apply four stroke fuel injection thinking to highly tuned two strokes.

Carburettored 2 strokes were hard to jet on the island, too, because of the elevation and or weather changes.

[peewee]

Thanks Frits. I understand that about the exhaust port timing. The issue with this cylinder is its a single exhaust port thats stuck between two studs and so they went high on the port timing to try and get them to run better. Its hard to make it lower so im using what i have. Thanks as always for your help

frits is right. you can greatly reduce the working stroke when the exh roof is to high. my philoshepy is make the port as wide as reasonably possible and be sure the passage is of good design. a long time ago i think jan even said he improved blowdown by simply improving the passage. ive seen alot of people make a large window but their passage is crap.

[jonny quest]

https://www.racebikemart.com/adverts/aprilia_RSA_125_Cilindro__1459369440.php

Perfect for someone's Bucket. Cheap too!

Oring's for cylinders.... shaped ones like Aprilia has in the pics above link.

How would you go about making some?

[F5 Dave]

A snip at 3000 Euro:lol:

[Haufen]

https://www.racebikemart.com/adverts/aprilia_RSA_125_Cilindro__1459369440.php

Perfect for someone's Bucket. Cheap too!

That's about the level you'd pay at serviceaprilia, too, I think.



https://www.racebikemart.com/adverts/aprilia_RSA_125_Cilindro__1459369440.php
Oring's for cylinders.... shaped ones like Aprilia has in the pics above link.

How would you go about making some?

Ideally, you don't. You just fit a round o-ring with the right length into the curved o-ring groove.

But if you must, o-rings are cast parts, so for about 7 of these RSA cylinders you can officially have molds made at some of the rubber companies and from then on get your custom o-rings for around 20ct a piece or so.

[jonny quest]

I figured as much for casting. Seems like a expensive process. Didn't know if there was a trick to take a round one, put in mold and flash freeze or chemical to apply that would allow oring to hold memory of desired shape

[jonny quest]

TZ350, have you thought about timing the injectors to your disc valve below a certain RPM?

Have you confirmed it's just too rich at low rpm?

A reed valve is constantly being open and shut by demand. A disk valve is fixed timing.

Cool thought, strain gage on reed petals linked to ECM letting ECM know engines needs.

[wax]

frits is right. you can greatly reduce the working stroke when the exh roof is to high. my philoshepy is make the port as wide as reasonably possible and be sure the passage is of good design. a long time ago i think jan even said he improved blowdown by simply improving the passage. ive seen alot of people make a large window but their passage is crap.
Im not disagreeing with him. I just cant change it this year. Maybe next year i can get another cylinder but not right now

[Haufen]

I figured as much for casting. Seems like a expensive process. Didn't know if there was a trick to take a round one, put in mold and flash freeze or chemical to apply that would allow oring to hold memory of desired shape

I have managed for o-rings to change their shape, but only because they had been misused (heavily overpressed, overheated etc) :devil2::rolleyes: The cheapest way is to get o-ring wire and o-ring glue from a rubber shop and just glue the ends together after you've generated the desired shape. You can also use the glue to fixate the o-ring inside the groove in e.g. tight bends or so. If the groove is as it should be (height and width), no special shape should be necessary.

Do you have a special application in mind?

[jonny quest]

I was going to oring my RG500 cylinders. I knew I could just use a round one and use grease/glue to hold in place. Was just one of those what if there's a different way.... head gaskets are annoying.

[Pursang]

Here's some 2 stroke FI technology that manages idle/"off the pipe" to full RPM performance.

Vertigo, a Barcelona company, claims that the fuel-injected two-stroke motor in the Combat Camo Works — one of a three-bike professional Combat line (the other two are the Combat Ice Hell and titanium-festooned Combat RR) — puts out 31 horsepower at 9200 rpm. Both of those numbers are unheard of in the trials world.

Thanks to the use of fuel injection, the engine has a wide variety of tuning options. There are four power maps in the computer (a maximum of 24 can be loaded), and I used the softest setting. Sensors tell the ECU the gear position, crankshaft position, and other vitals, which allows the computer to do such novel things as regulate the electric water pump, along with essential adjustments that include different power delivery in different cogs in the six-speed gearbox.

Starting the Vertigo Combat Camo is unique. Unlike the Ossa and Montesa Honda fuel-injected trials bike that use the kickstarter motion to power the fuel pump for starting, Vertigo has a small lithium iron phosphate battery. Push a button and wait for the whir of the pump, then kick within 20 seconds. Unlike the Montesa Honda thumper, which is usually a one-kick affair, the Vertigo sometimes takes a few prods to get the high-compression two-stroke to fire up.

Once fired up, the 300cc motor has a nice sound, thanks to the EFI’s steady delivery of the air/gas/oil mixture. Throttle response is rapid, and with 31 horsepower on tap, it is essential that you ride the Vertigo Combat Camo with a sensitive right hand. I don’t know what 31 horses will do in a section and, unless it’s an insane sand hillclimb, I don’t want to find out!

The sensation of the Vertigo Combat Camo’s motor is unlike anything in trials. Power is extremely strong off-idle — if you stall this bike, you have made a serious error (starting it on the fly in a section will be tricky) — and the powerplant is more than willing to rev. Given that, for most riders — and I’m an Intermediate — you’re rarely going to do more than just crack the throttle.

A fascinating combination of gobs of torque, amazing traction-finding tractability, and a relatively light flywheel, means that you will have to recalibrate your brain from whatever bike you’re used to. Again, slightly opening the throttle will likely get you over any obstacle you will encounter. Revving the Vertigo Combat Camo is neither necessary nor desired.

Modern trials bikes are typically ridden in first gear in most sections. In the case of the Vertigo Combat Camo, second gear will find quite a bit of use. With a bit less mechanical advantage, it smooths out the Vertigo’s ample power and gives you a wide range of possible speeds in a section, without shifting. Plenty of torque is still there off idle, yet you can get good momentum going should you need it on a long uphill.


Gear selection is another useful "Input" for FI mapping and telling the engine how you want it to respond.

Cheers, Daryl.

[Nath88]

KTM measures what pressure, where?
They have a hose from the crankcase to a pressure sensor.
I could be wrong, but I assume they're looking for the presence of the exhaust suction.

I have a mate with a KTM TPI. Might see if I can get the injector output up on the scope and see what it does when it's misfiring.

Agree with your conclusion regarding the Suter, if you run it lean enough to keep it firing this is what you get. I know when my engine was lean enough, it would break into HCCI and start accelerating, it's very efficient.

[monkeyfumi]

Maybe that's because a 300cc 31 hp single trials engine never really gets "on the pipe".

Gas dynamics in a 125 road race (or 110 bucket) engine would be very different.

[Pursang]

TZ's concern is at 1/4 throttle and under the power band.

At that point the exhaust is just a header pipe attached to a box......just like a trials bike.

Vertigo seem to have developed FI and ignition mappings that work extremely well under those conditions.

And, if it can rev to 9200, it will have port timings that are a bit wilder than the usual trial bike.

Cheers, Daryl.

[Pursang]

They have a hose from the crankcase to a pressure sensor.
I could be wrong, but I assume they're looking for the presence of the exhaust suction.

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Vertigo+FI+wiring+.JPG

Item 17 is a combined pressure (vacuum?) & temperature intake sensor.
The exploded parts pics don't indicate where it is fitted.

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Vertigo+FI+a.JPG

Single point injection, after the throttle body and straight into the reeds.



Agree with your conclusion regarding the Suter, if you run it lean enough to keep it firing this is what you get. I know when my engine was lean enough, it would break into HCCI and start accelerating, it's very efficient.

Way back in the Olden Days, when we used to race with carburettors, we'd tune them to idle well, then lower the slides so they wouldn't/couldn't.

[peewee]

Im not disagreeing with him. I just cant change it this year. Maybe next year i can get another cylinder but not right now

if new barells are expensive you could always lower your existing roof by welding and add extra exh ports while your there. likely you would gain a heap of power and perfect gearbox spacing wouldnt be nearly as important

[TZ350]

They have a hose from the crankcase to a pressure sensor.
I could be wrong, but I assume they're looking for the presence of the exhaust suction.

Yes, very possible or the strength of the suction. You would think change in suction = change in air flow.


I have a mate with a KTM TPI. Might see if I can get the injector output up on the scope and see what it does when it's misfiring.

That would be very interesting.

[TZ350]

https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Vertigo+FI+wiring+.JPG

Item 17 is a combined pressure (vacuum?) & temperature intake sensor.
The exploded parts pics don't indicate where it is fitted.

Interesting that they are only using a MAP manifold absolute pressure sensor and a inlet air temperature sensor in the inlet. MAP and inlet air temperature, that is the same as my Ecotrons system so there is some hope.




https://s3.amazonaws.com/WEBPOSTS/KIWI+ESE/Vertigo+FI+a.JPG

Single point injection, after the throttle body and straight into the reeds.


This is where it gets interesting, 300cc cylinder with a single injector spraying into the reed block.

For myself I have several rules of thumb for 2T EFI. (a lot of this I have learnt from Flettner and Speedpro).

The longer the squirt duration the easier it is to get it right, so use the smallest injectors possible.
A long squirt mimics a carb.
A 360 deg squirt would be ideal especially if it coincides with the engines point of maximum charging efficiency.
Inlet injection maybe Ok for reed valve inlets but it is not so good for rotary valve engines. I have tried this.
There is a sweet spot for timing the finishing of the squirt. Usually somewhere around BDC to TPC.
Cylinders 250cc or greater are easier to get right.
MAP sensors have a settling time 2 - 6ms and they get confused if things get to busy.
Less than 9,000 rpm and you only need 1 injector. Because a small injector up to 9K rpm still has enough time to get the job done.
Above 9,000 rpm and your going to have to quickly start thinking about two stage injection using a small and big injector.
Injectors in the "B" ports are aimed downwards against the air flow.
Or better yet, if its physically possible, from the back aim the injectors horizontally across the bottom of the "B" and "A" ports.
For two stage injection, the single small injector is aimed under the piston for homogeneous mixing.
Alcohol based fuels are much more forgiving of changeable air flow, because they can be run real rich during moments of crappy air flow.
The more industrial the engine and/or application the easier it is to tune properly.
The more the engine depends on symbiotic reinforced wave action for making its power the harder it is to tune below 25% TP.

A EFI Honda RS125 engine would be a challenge to get throttling properly for negotiating corners.


Way back in the Olden Days, when we used to race with carburettors, we'd tune them to idle well, then lower the slides so they wouldn't/couldn't.

That is good info, tells me something about the minimum fuel required on closed throttle over run.

[F5 Dave]

Item 17 is a combined pressure (vacuum?) & temperature intake sensor.
The exploded parts pics don't indicate where it is fitted.



Single point injection, after the throttle body and straight into the reeds.



Way back in the Olden Days, when we used to race with carburettors, we'd tune them to idle well, then lower the slides so they wouldn't/couldn't.
In the not so olden days when we used to race with carburetors we'd tune them then wind up the idle to quite high to take the weight off the front and aid cleaner throttle opening.

Heck TZ just turn it up to 8000 and ride around any inconvenience that might cause.

[Muhr]

Tried a hollow model but has not seen any benefits yet. Buckling does not seem to be a problem when weight loss is focused on the small end.




I'll see if I can try some CFD. Just it takes so much time to do


Not so insanely interesting or unpredictable but maybe fun to see

[jonny quest]

TZ350, as an expirement I'd try disabling PV to full open. Then try a try it.

The NSR as well as later generation CR125 offer little to no blowdown when PV is closed.

This could play a huge part as to why it's so difficult to tune. I would definitely limit the PV travel.

[Muhr]

By the way had this in the computer regarding previous discussions about transfer radius.

[jasonu]

A snip at 3000 Euro:lol:

Some have spent more on their Buckets.

[F5 Dave]

Not many. Fraction of a percent.

[SwePatrick]

By the way had this in the computer regarding previous discussions about transfer radius.

What does the colours stand for?
Speed, density, pressure?

First thing that comes to mind is that the runners are having some problems at the beginning, and as i said before, one should be careful with to much tapering in a runner.
Secondary what comes to mind, is the simulation based on constant flow or a pressurized volume with a sudden release when piston is opening the port?

[pete376403]

I have managed for o-rings to change their shape, but only because they had been misused (heavily overpressed, overheated etc) :devil2::rolleyes: The cheapest way is to get o-ring wire and o-ring glue from a rubber shop and just glue the ends together after you've generated the desired shape. You can also use the glue to fixate the o-ring inside the groove in e.g. tight bends or so. If the groove is as it should be (height and width), no special shape should be necessary.

Do you have a special application in mind?

Loctite make (made) a kit for that. As assortment of cross sections and different materials, and adhesive to suit

[F5 Dave]

Many times. But its a skill not to create a hard spot, but also roll the ring on a bend to expose an open side.

[TZ350]

TZ350, as an expirement I'd try disabling PV to full open. Then try it.

PV fully open is not a bad idea, I saw a PV curve recently that had the PV fully open when the engine was idling. I am not sure if that is the norm or not. But I will re visit the PV, thanks for suggesting it.

My first 2T EFI attempts were with an air cooled Suzuki GP125 engine and they don't have power valves. Made 31 RWHP @ 12250 RPM but still had the throttling problem below 25%.

337065337063337064337062337066

The first air cooled cylinder had direct through the B port and under piston injection. The second air cooled cylinder had under piston injection and injection across the A and B port entrance at the crankcase. I liked that arrangement, it gave promising results.

Flettner has talked about something similar, two primary injectors firing against the air flow in the B ports and secondary's in the A ports but with them all firing when the trapping efficiency is peaking and the motor is making real power. This arrangement would keep fuel away from the exhaust port when the trapping efficiency was not that great and air was spilling out the exhaust.

The water cooled cylinder has B port injection but squirting against the air flow. All the cylinders have three physical injectors but only two logical injectors as the B port injectors are fired together. The fourth picture shows the underside with the piston at TDC.

I have tried a lot of different combinations, primary injector in the inlet, in the crankcase, in the B ports with the secondary in the alternative injection ports. And all sorts of other combinations like firing from one side of the crankcase across the top of the flywheels and directly into the incoming inlet air.

The least successful was direct inlet injection from the outside (the 5th picture), my favorite was under the piston and horizontal across the transfer ports but that is difficult to arrange with the water cooled cylinder. But under piston for the slow injector and injecting in the B ports against the air flow makes good power and looks to be more economic than a carburetor too. With EFI there is much less of a fuel puddle on the dyno deck beneath the inlet. With a carb there is a much bigger puddle.

Along the way I have learnt a lot and figured out most of the puzzle but I am just missing that last piece of the jigsaw, how to account for randomly changing air flow through the motor below 25% TP. It seems that the more highly strung the motor the more unstably changeable the air flow is below 25% throttle position.

Its like trying to sail an unstable "P" class learner yacht in gusty changeable wind conditions, its much easier when the wind is steady and consistently from one direction.

337067

I am hoping that a MAP sensor in the crankcase and an Arduino Nano interpreting what it sees might be able to make sense of the air flow below that troublesome 25% throttle position.

[Muhr]

What does the colours stand for?
Speed, density, pressure?

First thing that comes to mind is that the runners are having some problems at the beginning, and as i said before, one should be careful with to much tapering in a runner.
Secondary what comes to mind, is the simulation based on constant flow or a pressurized volume with a sudden release when piston is opening the port?


Yes, things happen different before and after this simulation.
What I tried with here was to study flow separation on the top of the inner radius. The color is velocity.
Based on what I've seen, Fritz is right that a larger constant radius is better for flow separation

[RomeuPT]

I suggest you look at the IAME piston,that has a 5* angled edge for around 7mm that then becomes a flat top.
This setup in a TM with a new insert ( with the plug alot closer to the piston and a very flat bathtub ) makes better power than the 4* TM setup ( same cc ).


Any reason this shape or a 4º degree taper might not work so good on a T port Honda cylinder?

[jbiplane]

I have tried a lot of different combinations, primary injector in the inlet, in the crankcase, in the B ports with the secondary in the alternative injection ports.

We made in 2015 injection in intake noise silencer for experimental 50cc 4-cylinder axial engine rotating 24000 rpm (12.5cc per cylinder). Intake silencer volume was about 1400cc and flow inside was practically luminaire.
The only one nozzle were firing inside silencer according air volume flow with few time less frequency than rpm. May be similar approach will work in other cases?

[jonny quest]

Fabricate a quick straight pipe 4 stroke style. That will tell you if it's the pipe causing havoc under 25%.

[F5 Dave]

TZ, that curve with PV open at idle may, if you look again, be so it is open for kickstarting then closes for idle which might be at say 1300rpm.

[TZ350]

TZ, that curve with PV open at idle may, if you look again, be so it is open for kickstarting then closes for idle which might be at say 1300rpm.

Good point, we are playing with Av's GP/NSR110 on the dyno now. Things aren't going well, suspect some other issue is clouding the results.

337069

[wobbly]

Romeu, the IAME piston I use in the TM engine,is in my opinion only, the best shape for a 2T piston.
It combines all the elements that have been used over the years with success, all for different reasons.
Yamaha have used a very narrow, angled edge that than becomes a flat top for many years in many designs.
The angled edge helps flow ( bulk, and cooling attachment ) at small port opening angles, and of course the flat top allows the use of a toroid to get the plug down very low
within the combustion space.
The IAME has an angled edge 7mm wide that matches a normal squish width in a 125 bore,but in the case of the KZ engines we cant go that wide.
But the next test,using a 1mm radius on the timing edge, combined with its 0.5mm higher deck height, makes what I consider a really good setup for the kart engine
where I cant use a toroid.
I have already proven the angle/flat top makes more power than the straight 4* conic that TM use,so if the radius added is better again, then that will be a real winner.
In a T port engine, the same logic would apply, but in your class of racing you can use the toroid as well - and get better power again than I can.

[TZ350]

Fabricate a quick straight pipe 4 stroke style. That will tell you if it's the pipe causing havoc under 25%.

Good idea, might try that if I cant make any progress with the Arduino amd MAP sensor idea.


We made in 2015 injection in intake noise silencer for experimental 50cc 4-cylinder axial engine rotating 24000 rpm (12.5cc per cylinder). Intake silencer volume was about 1400cc and flow inside was practically luminaire. The only one nozzle were firing inside silencer according air volume flow with few times less frequency than rpm. May be similar approach will work in other cases?

Very clever idea, injector firing half or quarter time into the air silencer volume, and using the silencer volume like a plenum full of the correct air/fuel mixture.

337072

I had tried the air/fuel mixture plenum idea when I was running a carburetor as a way to push past our racing class's 24mm carb restriction rule for 2T's > 104cc.

It ran Ok. https://youtu.be/YxiEo8cgopg .... https://youtu.be/p4ef-WUO1Qs

But gave it up when I realized there was a lot of fuel dropping out and pooling in the bottom of the plenum.

337071 337070

Ironically a plenum is what got me started on EFI as a way to avoid the fuel dropout and the ensuing poor air/fuel mixture control and doubtful engine lubrication.

Now 2T EFI has become an interest in itself.

[ken seeber]

Good & open fairly detailed coverage of the Suter @ Isle of Man...around 14 mins or so:

https://www.facebook.com/suter500/videos/1756407281112852/

[husaberg]

Good & open fairly detailed coverage of the Suter @ Isle of Man...around 14 mins or so:

https://www.facebook.com/suter500/videos/1756407281112852/

Nice find ken
Gee that airbox looks small esp compared to the NSR500.
twin
337090
various 4's
337091337092337093337094337095

[husaberg]

RGV
337096337097
YZR
337099337098yeah i know
Cagiva
337100337101i swear the air filter on the first Cagive injected pic is a ram flow like the webber on my 1600 MK1 esky had.

[RomeuPT]

Romeu, the IAME piston I use in the TM engine,is in my opinion only, the best shape for a 2T piston.
It combines all the elements that have been used over the years with success, all for different reasons.
Yamaha have used a very narrow, angled edge that than becomes a flat top for many years in many designs.
The angled edge helps flow ( bulk, and cooling attachment ) at small port opening angles, and of course the flat top allows the use of a toroid to get the plug down very low
within the combustion space.
The IAME has an angled edge 7mm wide that matches a normal squish width in a 125 bore,but in the case of the KZ engines we cant go that wide.
But the next test,using a 1mm radius on the timing edge, combined with its 0.5mm higher deck height, makes what I consider a really good setup for the kart engine
where I cant use a toroid.
I have already proven the angle/flat top makes more power than the straight 4* conic that TM use,so if the radius added is better again, then that will be a real winner.
In a T port engine, the same logic would apply, but in your class of racing you can use the toroid as well - and get better power again than I can.

Thanks. I was not sure so I rather asked first before going on and try.

you mean 1mm radius on the piston edge like it seems on this ktm piston? I would like to hear if possible of the test conclusion, this radius may help flow at transfer and exhaust closing angles!?

337102

[Frits Overmars]

All the best Jan!
337105

[SwePatrick]

Yes, things happen different before and after this simulation.
What I tried with here was to study flow separation on the top of the inner radius. The color is velocity.
Based on what I've seen, Fritz is right that a larger constant radius is better for flow separation

Yes constant radius is good as air takes it 'shape' and you don´t 'alter it'.
But what i find might cause a problem is that the runner is tapered to hard.

And to use in calculations, the highest crankpressure is just before you open the transfers.
Some sort of a small blowdown(blow in?) period so to speak.
Thereby you would have the highest airspeed some degrees before btdc.

[TZ350]

All the best Jan!
337105

Happy birthday Jan and many thanks for your contributions to this thread.

[TZ350]

337108

I am still very interested in the plenum idea because when I was experimenting with it on the dyno I saw a very very large low end boost in power. At about the same point that I would usually see a large dip from the pipe being in anti phase and working against the engine. You don't forget things like that.

I put the power boost down to the plenum/inlet system being in happy resonance with the engine.

What a power spread boost it would be if we could keep a variable volume plenum in happy resonance with the engine over a wide rev range.

337107 337106

Another useful thing was being able to divide the inlet tract in half. Variable inlet kinetic energy I guess. This had the benefit of cleaning up the carburation considerably.

In my wildest dreams I dream of using a variable volume plenum and a variable inlet controlled by something like an Arduino because I think they could show great improvements in two stroke performance and power spread. Imagine a high performance 2T with a 6-7K power spread instead of the usual 3-4.

337109

Include a variable pressure bleed in the exhaust and you could have true 2T magic.

I dream of combing all these concepts on one of the Team ESE engines along with the more conventional state of the art 2T tuning techniques.

[TZ350]

.
I have enjoyed a bit of success today.

Used EngMod2T to simulate a series of runs so I could look at the variations in crankcase pressure just to see if there is a consistent change that can be measured and reflect changes in air flow through the motor.

These are pressure ratios, absolute crankcase pressure divided by atmospheric pressure.

337117

This series of runs were taken at 8,000 rpm and is where the engine is really starting to get on the pipe.

Looking at the graphs. It is obvious that I only need to know when the end of each cycle is and that I wont need to know where in the cycle the high and low occurs only that it does and its amplitude.

The objective today was to see if the Arduino could read the MAP sensor and output a sensible result.

337116 337118

MAP sensor plugged into a spare injection port in the crankcase and the laptop and volt meter setup to monitor the Arduinos (true) analog voltage output.

The Arduino program looks for the highest and lowest pressure and the average for each cycle.

Then it outputs the sum of the average plus the difference.

337119 337120

Flashed the bike up and gave it a couple of blips. The analog voltages coming out of the Arduino look to be in the ball park and changed in a way that reflected real pressure changes (read, air flow) in the crankcase.

Its looking good for tomorrow. When I will connect the Arduino to the EFI CPU's MAP input.

With the new simulated MAP sensor input I expect the fueling to get messy but as long as I can use ECOCAL to data log some of the EFI CPU's output including the MAP trace I will be happy, ecstatic if it looks like it is the answer to seeing the un predictable air flow through the motor at less than 25% throttle position.

It is looking hopeful, Fingers crossed.

[husaberg]

Happy Birthday Jan
Thanks for sharing the information.
337126

[Juho_]

I am still very interested in the plenum idea because when I was experimenting with it on the dyno I saw a very very large low end boost in power. At about the same point that I would usually see a large dip from the pipe being in anti phase and working against the engine. You don't forget things like that
When your accelerating below pipe's "powerband" with full throttle and the engine reaches that large dip in the power curve; does the engine get past that dip if you use only half throttle ?

I had the same problem on my 55cc minarelli am6 with pwk carburetor.
Afr went very lean at that dip for some reason.

Then I replaced it with Mikuni TM28 and after some adjusting the engine worked a lot better, produced a bit more power and the dip got a lot smaller (didn't require half throttle to get past it).

Didn't really think a different carburetor could do any difference on that problem...but I was wrong.

[F5 Dave]

You should have tried a kiehin. They totally kick mikuni arse
Pwk 28 is ok for a fairly hot 50.

Yeah I know.

[Frits Overmars]

On the off chance that somebody here is interested in motorcycle racing:
live-stream of the Italian Grand Prix at Mugello
http://live.drakulawidget.com/streamvideo10/motogp-live-sreaming-4669250.html

EDIT: here's another link in case the first link stopped working, as it did on me:
http://www.fixalen.tv/20180601/vv-1982240-motorsports-5b10d4e6c29381.87771154.html

[Juho_]

You should have tried a kiehin. They totally kick mikuni arse
Pwk 28 is ok for a fairly hot 50.

Yeah I know.
I had tried 2 different keihin pwk (24 and 26mm) copy carburetors.
Oko and ysn branded.

Didn't find any keihin pwk 28mm (used) that had a price tag less than 80€.
Used pwk copy carbs can be easily found for 30-50€ and I paid for the mikuni tm28 40€.

Cheap carburetors.
For testing purposes I don't like to pay a lot for some part that I'm not 100% sure if it actually has benefits (= help to produce more power).

[Frits Overmars]

On the off chance that somebody here is interested in motorcycle racing:
live-stream of the Italian Grand Prix at Mugello
http://live.drakulawidget.com/streamvideo10/motogp-live-sreaming-4669250.html

EDIT: here's another link in case the first link stopped working, as it did on me:
http://www.fixalen.tv/20180601/vv-1982240-motorsports-5b10d4e6c29381.87771154.html

[Muhr]

Yes constant radius is good as air takes it 'shape' and you don´t 'alter it'.
But what i find might cause a problem is that the runner is tapered to hard.

And to use in calculations, the highest crankpressure is just before you open the transfers.
Some sort of a small blowdown(blow in?) period so to speak.
Thereby you would have the highest airspeed some degrees before btdc.

I have done many different simulations with many different speeds and designs, even blow back.
below might explain why this was done.

[teriks]

Happy birthday Jan and many thanks for your contributions to this thread.
Happy birthday, and.. what TZ said. Cant come up with anything better to say..

[katinas]

Happy Birthday Jan, best wishes and thanks.

https://www.youtube.com/watch?v=UQD3LJhwDt0

[Muhr]

I have not met or talked to you but I have spent many hours trying to understand and learn from the imprint you put in 2-stroke development. Thanks and happy birthday

[TZ350]

.
Ok, another little step along the way.

337143

Gave the Arduino concept a try out today.

The EFI CPU was still running on only the Alpha-N map so I expected it to run fairly badly (to rich) but only really wanted to see what the crankcase pressure readings looked like and whether it looked like it might be useful for seeing changes in air flow at low throttle settings.

Fired the Beast up and gave it a few blips.

337144

Map sensor = Green line, TPS = Blue and RPM = Brown.

The MAP sure looks responsive enough and the numbers make sense.

It looks like we can now see real time changes in air flow at throttle settings below 25%.

The next move is to re do the mapping to include a VE table (may take a week) and see what the drivability looks like.

I am starting to feel hopeful that we are on the right path now.

[peewee]

happy birthday jan. thanx for all the great work you did over the years. it has helped me a lot, as I was able to apply it to my own engines . thnx :first:

wob you might be interested to know the bored out 3.5 float valve is working great on a running engine. worked good on all bench tests but I wasn't sure if the engine vibration or head pressure from the tank could cause a unforseen problem but it did fine. spent atleast 5hrs today tuning and Its running real well, maybe the best its ever ran. lowering the com ratio from 16 to 12.5 seems to really help it rev more easy. im not sure how much the new exh spigot reducer is helping but I don't think its hurting. for the first time ever, i was able to use 20% volume nitro with no run away at close throttle :clap:, I think partly because the fuel mix was 26.5c. unfortunately the needle was richened far as it can go, so i have to make it richer somehow if i want to go above 20% or if the fuel density goes higher. i thought of grinding a small groove in the top portion of the needle to supply more fuel at close throttle but a guy told me i could get 400grit sand paper and sand the top portion. you ever tried the sand paper trick ? seems like it wouldn't be difficult to sand off .25mm at a time and try it. video camera died but i have still photo from my secret testing facility :lol:

[TZ350]

.
That sir is a real Beast, very impressed, good work ..... :niceone:

[wobbly]

You can easily tune a Methanol motor by " sanding " a needle in the correct position where you want to adjust the mixture.
We used to do this all the time with the needle in a battery drill and 300 wrapped around a 6mm axle key.
But just remember that Keihin who only change needle diameter, and Dellorto say that change the tube diameter ( needles as well ) only go in 0.01mm increments.
I know that for example changing from a 2.64 tube that runs perfectly, to a 2.66 tube makes a 125 a blubbering mess on petrol.
Same with a needle that runs perfectly at 2.5mm dia, then go to a 2.48mm parallel section and its rich as a dog fart.
Changing from a 3.15 tube that is a little rich on Methanol, to a 3.2 tube, makes that a blubbering mess.

[Martin1981]

Wobbly,

could you please tell me what limits the Banshee/RD350 engines Power and maximum rpm?

it has a 54mm stroke so one could think it should or could make peak power at 13000 and rev on to 14500 like your kz engines. but it doesn`t. even tuned engines with cpi cylinders seem not like to rev much more than 10000rpm.

i think one of the reasons are the oversquare layout and the narrow cylinders (piston center to center distance)


what was the most powerfull rd350 engine you ever built (350ccm) and what was it`s max rpm?

Thanks!

as usual i appreciate answers of other members (Frits for example) as well of course!


Jan, belated best Birthday wishes!

[shnaggs]

Sorry fellas, I had to scrap my PC and got a newer one, and I do not have any of the links saved. How are you guys doing advanced searches for this forum again??? I know its been posted multiple times, and of coarse I cant find it :crazy:


Also Frits, not long ago you were talking about piston pin location of the 2 stroke in relation to the foul stroke. I am trying to remember why it is that the piston pin is so low on the 2 stroke? Why can we not move it up closer to the rings, and reduce some of the piston rock?

[DoldGuy]

"" exhaust duct site:https://www.kiwibiker.co.nz/ (https://www.kiwibiker.co.nz/forums/showthread.php/) "".... :Punk: sure makes finding stuff on the ESE thread a breeze.


Works well for me....

[DoldGuy]

Leverage is not my main concern and neither is dwell time at TDC/BDC; the variation would be minuscule.
Reduction in con rod angle and a corresponding reduction in friction is one good reason. Crankcase volume is another one. But my main reason is piston mass.
The bulk of a piston's mass is concentrated between its crown and the gudgeon pin holes. Raise the pin and you'll lighten the piston, simple as that.
This does not even depend on con rod length. It's true that I prefer a long con rod, but I would prefer a high piston pin in combination with any rod length.
And don't worry about the piston tipping over. Just look below at the piston hight, or rather lack of it, that four-strokes get away with. And two-stroke piston skirts are invariably longer than their four-stroke counterparts because when in TDC, they must keep the exhaust port closed.
333883 333884 333885


And Frits reply to the Pin Height...

[peewee]

i once seen a diagram of heat distribution in a piston. seems most of the heat is at the crown and gets lower down the skirt. wouldnt this be a good reason to have the pin lower ? (less heat transfered to the small rod end and bearing). just thinking

[TZ350]

Sorry fellas. How are you guys doing advanced searches for this forum again??? I know its been posted multiple times, and of coarse I cant find it :crazy:




"" exhaust duct site:https://www.kiwibiker.co.nz/ (https://www.kiwibiker.co.nz/forums/showthread.php/) "".... :Punk: sure makes finding stuff on the ESE thread a breeze.Works well for me....

Another search method is to flick through the 12,000+ pictures on this thread.

337155

"Thread Tools" then "View Thread Images"


337156

Use the sort function to get 70 to a page.

337157

Click on the blue "N/A" to go to the associated post.

[wobbly]

The huge issue with any engine developed on the Yamaha RD case that started life as a 250, is its 102 bore centers.
This kills any thoughts of trying to make good power as the transfer ducts are squashed between the bores in the middle.
The stroke at 54 is easily capable of reving to 14,000 like a KZ, but as is the case with a 350 a bore of 64 makes for heavy pistons.

Thus in answer to your question, the best 350 I have simmed would be the LSR engine at 55Hp/cylinder at 11,000 with overev to easily 12,000.
This used a TZ250G - 3G3 cylinder and had reeds on the back.
That translates to around 100Hp at the rear wheel on a Dynojet.
It needed wasted studs and a bridged intake with a 3 port Exhaust and used a 58 stroke Banshee crank with 115 rods, and lighter 61.5mm H1 Kawasaki pistons.

CPI cylinders dont fit on the RD case due to the stud layout,but the RZ/Banshee has the same bore center width of 102mm.
The porting layout is 8 transfer ports with a bridged intake and 3 port exhaust, and they are easily capable of making the same or better power from a 350.
But you would have to get special castings done with the smaller bore, to get nearer to square, and the resulting much better STA numbers.
CPI will do this but want you to pay for 3 cylinders,to guarantee getting 1 good one - I did this with a 400 and got two usable castings at 66 bore.

[RomeuPT]

Parabéns Jan :)




Wob, I was searching but could not find, I remember that a lenght from reeds to carb mouth of 135 to 145mm was spoke about for a 125 with decent carb size making peak power at around 13k.

I am setting a pwk 38 for racing, and thinking if I should cut the mouth like it is presented in this pic so I can get that lenght closer or is there other reason for this to be like this?

Are the vents better be completly removed for a high end scenario?

337168

Thanks

[wobbly]

Getting the intake short enough is hard.
Using the very short straight rubber manifold from the very early NF4 RS125 ( NLA ) that was built on MX cases is worth 1-2 Hp over the later longer
version,but the later RS125 short carb with the electronic powerjet is the shortest and best flowing.
If you dont want the powerjet then a PWM is by far the better carb for power everywhere.
Any carb with the guide plates on the floor is useless, even with them removed, I could not equal a PWM.
Also a shortened PWK wont make the power of the PWM or the short late model race carb.
No free lunch - again , sorry.

For the last little bit of power, filling in the slot for the choke, and filling in the slot in the floor of the bellmouth for the idle and main
air corrector circuits is for sure worth it.
But you MUST use small alloy tube inside the epoxy to allow the added tubes to be entering air at plain atmospheric pressure , or you will never get the jetting to work.
Here is one I did for an old Mikuni 38mm round slide on a TZ350.
This added around 3Hp in the twin at peak and double that in the overev at 11500.

[Flettner]

this would be better, no jets, vents or produding things into the gas flow. Just smooth, clean, short inlet, straight in with not even a reed block cage in the way. Long live the rotary valve engine. Injection, the way of the future, past.
I know, same old, but next generation on the way.
https://youtu.be/v5jLX4KtpXs

[TZ350]

.
Yep, rotary valve, inlet as short as, and fuel injection..... its the way ...... :yes:

[wobbly]

It sure is the way TeeZee, but you and Suter and Cagiva seem to have had a little trouble along the way making the ECU do the right things at the right time
on a racebike.
MX has been done by Flet, and I did it with a Motec in a Champ Jetski , but a full noise racebike application has eluded everyone so far.
Really do hope you can find the key.

[husaberg]

It sure is the way TeeZee, but you and Suter and Cagiva seem to have had a little trouble along the way making the ECU do the right things at the right time
on a racebike.
MX has been done by Flet, and I did it with a Motec in a Champ Jetski , but a full noise racebike application has eluded everyone so far.
Really do hope you can find the key.
I think Honda won the all japan championship with a Fuel injected NSR250 in the early 90's a couple of years prior to Itoh being the first ever 500 GP bike to go over 200MPH.
Not sure where I found that morsel but think it was in Motocourse.
Edit
Oh well maybe not
okay they just raced it
337177

[RomeuPT]

Getting the intake short enough is hard.
Using the very short straight rubber manifold from the very early NF4 RS125 ( NLA ) that was built on MX cases is worth 1-2 Hp over the later longer
version,but the later RS125 short carb with the electronic powerjet is the shortest and best flowing.
If you dont want the powerjet then a PWM is by far the better carb for power everywhere.
Any carb with the guide plates on the floor is useless, even with them removed, I could not equal a PWM.
Also a shortened PWK wont make the power of the PWM or the short late model race carb.
No free lunch - again , sorry.

For the last little bit of power, filling in the slot for the choke, and filling in the slot in the floor of the bellmouth for the idle and main
air corrector circuits is for sure worth it.
But you MUST use small alloy tube inside the epoxy to allow the added tubes to be entering air at plain atmospheric pressure , or you will never get the jetting to work.
Here is one I did for an old Mikuni 38mm round slide on a TZ350.
This added around 3Hp in the twin at peak and double that in the overev at 11500.

Thanks

The issue...
337178

Yep, I wish I could use the PWM but there is no room, for the pwk to be closer has possible I already grinded a bit of the engine case support and the carb is angled enought too. Guess I can get with 135mm with worked pwk, maybe far from the best, but without cuting cases and major rumble is pretty much where I can get on my engine...

[_____]

Thanks

The issue...
337178
.

I'd cut the section where the bowl needs to be, fit helicoils in the airising outer two ears and screw it to the frame with two short screws.

[wobbly]

Will a carb bowl clear the rear mount if it is dead straight on the manifold - with the plus of making a couple of extra Hp for free.
Most carbs would be way too downdraft and would spew fuel out the pilot system under brakes.
But a Lectron can be run very steep with no issues at all.
What is that motor you are working on ?

[husaberg]

Will a carb bowl clear the rear mount if it is dead straight on the manifold - with the plus of making a couple of extra Hp for free.
Most carbs would be way too downdraft and would spew fuel out the pilot system under brakes.
But a Lectron can be run very steep with no issues at all.
What is that motor you are working on ?

Its a NSR125 or 150 Wob
https://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/GeoAAOSwo4pYSYnl/$_1.JPG?set_id=8800005007 (https://www.google.co.nz/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=&url=https%3A%2F%2Fwww.ebay.ie%2Fitm%2FHonda-NSR-125-H1-JC20-2J338-Engine-Crank-Case-Bottom-End-%2F232168341382&psig=AOvVaw3VqJysICXlQoyRjm2UHvC_&ust=1528325501897654)https://d2t1xqejof9utc.cloudfront.net/screenshots/pics/357bd6ce958f551d0429a027d715b00d/large.jpg (https://www.google.co.nz/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwionZnK073bAhWKv7wKHUiCDRsQjRx6BAgBEAU&url=https%3A%2F%2Fgrabcad.com%2Flibrary%2Fhonda-nsr-125-jc20-engine-top-end-1&psig=AOvVaw2fWILh38FOurKsMIyx-_wb&ust=1528326907988290)........
He might have to go Mikuni TDMR or a Keihin FCR or a Keihin of a NSR250 or RGV TMSS Mikuni
That rear upper mount is in the way.

[RomeuPT]

Will a carb bowl clear the rear mount if it is dead straight on the manifold - with the plus of making a couple of extra Hp for free.
Most carbs would be way too downdraft and would spew fuel out the pilot system under brakes.
But a Lectron can be run very steep with no issues at all.
What is that motor you are working on ?


I'd cut the section where the bowl needs to be, fit helicoils in the airising outer two ears and screw it to the frame with two short screws.

Its a NSR 125 engine.

yes it has a straight manifold and the front bolts of the carb bowl are already touching the mount.

The carb is not very angled down to be a problem, or at least that I have noticed.

I had a shortened tmx 38 already touching the mount, but the keihin works better at lower ranges, does not bog... I am trying to improve

Dont know what to do, maybe just grind the the mount some mm and work the pwk :tugger:

Inside the engine mount is where air circulates in/out the engine, I dont think removing it is a good idea :/

[TZ350]

.
The mount looks like it also serves as the breather tower for the gear box.

I wouldn't hesitate to cut a big scoop out of the middle of that mount to clear the carb.

If you break through just glue in some hard foam, 1mm alloy sheet or similar to stop the gear box oil splashing out.

Leave some of original mount on the outsides. You don't have to crush it up tight in the frame for it to still hold the engine up.

Any way do you even need all three engine mounting points, the lower front and rear may be enough.

[wobbly]

That intake rubber is huge - the old NX4 one is only around 25mm overall,so that pulls the whole carb and bowl way closer.
16210-NX4-000 - hard to find though.
A downdraft oval bore Keihin carb off a NS400 would be the go,its been done before.
As would a 36mm downdraft off an Aprilia RS250 road bike.
But the Lectron would work to.

[jonny quest]

https://www.bbc.com/sport/motorsport/44176061
Watch the NW200 highlights around 18 seconds, the green bike blows past the other bikes like they're standing still!

Did the RSA125 act like that? With around 5hp more than the competition, how did it not?

[Frits Overmars]

...the green bike blows past the other bikes like they're standing still! Did the RSA125 act like that?It would have, against a competition of reed-valve Hondas and KTMs. But except for the RSA's first outing, where it only displayed its full potential in a breathtaking final lap, there were always other RSAs around, and RSWs, that were not much slower.

[Muhr]

Maybe someone thinks it’s interesting

http://portal.research.lu.se/portal/files/4527297/625826.pdf

[RomeuPT]

That intake rubber is huge - the old NX4 one is only around 25mm overall,so that pulls the whole carb and bowl way closer.
16210-NX4-000 - hard to find though.
A downdraft oval bore Keihin carb off a NS400 would be the go,its been done before.
As would a 36mm downdraft off an Aprilia RS250 road bike.
But the Lectron would work to.

337182337183

Say I could grind 1cm and raise the flange lenght to fit a PWM, still good advantage over a worked pwk?

Guess I will buy the PWM and still test the worked PWK

[wobbly]

If you can find an NX4 manifold it would be as long as what you have shown, less the extra rubber and extra hoseclip on the carb.
I have seen several PJS carb for sale, that is the short race carb off the later Honda RS125.
It has TPS and the solenoid PJ - that makes the same power as a PWM, but depending on your end use, the PJ makes a huge difference to overev..

[RomeuPT]

If you can find an NX4 manifold it would be as long as what you have shown, less the extra rubber and extra hoseclip on the carb.
I have seen several PJS carb for sale, that is the short race carb off the later Honda RS125.
It has TPS and the solenoid PJ - that makes the same power as a PWM, but depending on your end use, the PJ makes a huge difference to overev..

I am pretty happy with the overrev I got already just with ignitech etc, dont need to blow parts even more.

Going to try both pwk and pwm

Hope to ear about any test of piston edge radius.

cheers

[wobbly]

Has someone got a pic of the Aprilia cylinder, looking directly at the Exhaust duct with a spigot fitted.
I want to see what the steps actually look like at the bolt on face.

[husaberg]

Has someone got a pic of the Aprilia cylinder, looking directly at the Exhaust duct with a spigot fitted.
I want to see what the steps actually look like at the bolt on face.

https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=335347&d=1518939634 (https://www.kiwibiker.co.nz/forums/album.php?albumid=4839&attachmentid=335346)

https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=303412&d=1413018844 (https://www.kiwibiker.co.nz/forums/album.php?albumid=4839&attachmentid=303410)https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=314144&d=1438074177 (https://www.kiwibiker.co.nz/forums/album.php?albumid=4839&attachmentid=314143)

[jamathi]

Has someone got a pic of the Aprilia cylinder, looking directly at the Exhaust duct with a spigot fitted.
I want to see what the steps actually look like at the bolt on face.

Is this what you want Wobbly?337215

[TZ350]

Maybe someone thinks it’s interesting

http://portal.research.lu.se/portal/files/4527297/625826.pdf

Yep, interesting. thanks.

[wobbly]

Thanks Husa and Jan.
I have a new cylinder to test from TM (designed with the side ears right thru the spigot ) and i want to run it with exactly the Aprilia style steps first
then several versions with top/bottom steps removed with added material in the spigot.

[jamathi]

337216
Thanks Husa and Jan.
I have a new cylinder to test from TM (designed with the side ears right thru the spigot ) and i want to run it with exactly the Aprilia style steps first
then several versions with top/bottom steps removed with added material in the spigot.

The flange was 40-41 conical. Length 40mm

[wobbly]

The best TM spigot at the moment matches the oval duct exit, then matches the round header entry.
But with the added area of the ears down the side,I have reduced the oval height - to keep the exit area the same as previously.
Thus of course being a 2T you cant assume anything about what will make the best power with such a big change , so i will test all the different configurations again.

[SwePatrick]

That discussion about methanol and corrosion.

This floatbowl is from my VM44 carb, it has been lying in my garage since september untouched unopened.
A couple of days ago i was curious if it was mayhem inside the bowl.

This is what i saw: (dark spots were there when i bought the carb)

337225

[SwePatrick]

News from Bidalot, a new hot 50cc cylinderkit

337226

They say it will be a 70cc model also in the future.

Originalpost on facebook:
https://www.facebook.com/bidalot.technologies/posts/1689852161083705

[RomeuPT]

337182337183

Say I could grind 1cm and raise the flange lenght to fit a PWM, still good advantage over a worked pwk?

Guess I will buy the PWM and still test the worked PWK

Worked the pwk, bellmouth shortned 11mm, front shortened 2.5mm, air vents grinded, choke holes filled. and gone for some straight's. no plug checks yet.

Mid to high range seems to had a little lost, overrev seems to be a litle improved.

[dtenney]

I have searched and have not been able to find pictures of pipes with a deto button(small deflector) welded into the header on the pipe. Does anyone know where to find these pics? They were pretty early in this thread.

Thanks,

DT

[DoldGuy]

That discussion about methanol and corrosion.

This floatbowl is from my VM44 carb, it has been lying in my garage since september untouched unopened.
A couple of days ago i was curious if it was mayhem inside the bowl.

This is what i saw: (dark spots were there when i bought the carb)

337225

That definitely looks like corrosion, could come from just sitting & collecting moisture, but that is what Methanol will do if you don't purge with gas & oil (I like Castor mixed a little heavy).

[katinas]

I have searched and have not been able to find pictures of pipes with a deto button(small deflector) welded into the header on the pipe. Does anyone know where to find these pics? They were pretty early in this thread.

Thanks,

DT

Yamaha Yzr 500

[TZ350]

I have searched and have not been able to find pictures of pipes with a deto button(small deflector) welded into the header on the pipe. Does anyone know where to find these pics? They were pretty early in this thread. Thanks, DT

The good old Google "SITE:" search turned up this:.....

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


... follow the posts for the RGV500 version and pictures

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258136&stc=1&thumb=1&d=1329761342http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258135&stc=1&thumb=1&d=1329761341http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258134&stc=1&thumb=1&d=1329761339

[tjbw]

I have searched and have not been able to find pictures of pipes with a deto button(small deflector) welded into the header on the pipe. Does anyone know where to find these pics? They were pretty early in this thread.

Thanks,

DT


https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page1041

[SwePatrick]

That definitely looks like corrosion, could come from just sitting & collecting moisture, but that is what Methanol will do if you don't purge with gas & oil (I like Castor mixed a little heavy).

Did you read what i wrote?
I wrote that the darkspots already were there when i bought the carb.
And before me it has never seen methanol.

And by that,, it hasn´t corroded any since i began using methanol.

[Nath88]

Update on my YZ, cylinder is now overbored from 250cc to 265cc, so I'm scaling then porting to suit, but also wanting to shift the powercurve up about 800rpm at peak, since I'm gearing limited already.

Stock cylinder transfers give STA of 0.000936 at 8500rpm. For the 265, I widened the ports so the % of bore width was the same as stock 250, then increased duration to the same STA as stock but at 9300rpm. Went from A: 116°, B: 116°, C: 121° stock, to a slightly staggered A: 122°, B: 121°, C: 119°. Relative power from 48hp to 55.6hp.

Stock exhaust gives STA of 0.000130 and 0.000168 with aux ports open. I widened the main exhaust to the full width of the PV blade, slightly reduced the radius on the upper corners, and increased duration from 185° to 190°. I'm reluctant to go much more duration as 190° is getting a bit much for 9300rpm. I left the aux ports at 185° to give them some stagger. I think this is about the limit of what I can do with the exhaust, but gives an STA of 0.000122 and 0.000157 with aux ports open. Power handling from 55.3hp to 58hp. So the transfers are still limiting.

Is this the right way to go about reaching my goal? Will having the exhaust smaller relative to the old arrangement make it more peaky? It's only 5 speed so I need to keep the power curve pretty wide...

337235

Just need to get this laser cut to a thin sheet and start cutting!

[TZ350]

.
More Dyno adventures .....

Had one of the very front running 4T's (Paul's EFI Yam 150) on the dyno today.

4T Blue Line 2T Red line.

337237

When you look at the low end torque of the 4T and extremely wide curve you can see why mere mortals on 2T's get well and truly trounced by the 4T's drive out of the corners.

337238

Had a chance to try the Arduino MAP simulator today.

RPM brown line, TPS blue and Arduino MAP simulation is the Yellow line.

337236

The Arduino uses a MAP sensor to measure crankcase pressure and looks for the maximum and minimum pressure and outputs the difference as a simulated MAP value to the EFI's CPU.

Bike sounded good and was even starting to show signs of improved drivability.

I was rely starting to enjoy myself laying consistent runs and making little improvements with ignition/fuel and PV adjustments.

Things were going real well, on the home run I thought, then I heard the dreaded dyno death rattle...... :(

Quick as a flash, in with the clutch and let the beast coast to a stop.

(&^%%$#$#^+_!!! could be the problem this time.

Turns out that it had drunk all its cooling water during 20-30 runs.:Oops: .... wasn't expecting that .... :facepalm:

Have not taken it apart yet but I suspect that small pressure drilling I put in a while back may be leaking or the head "O" ring. Not many other possibilities.

[DoldGuy]

Did you read what i wrote?
I wrote that the darkspots already were there when i bought the carb.
And before me it has never seen methanol.

And by that,, it hasn´t corroded any since i began using methanol.

Yes, I read what you wrote & replied regarding to its content ( or lack there of ) , did you read what I wrote?

[tdc211]

[QUOTE=TZ350;1131100765].
More Dyno adventures .....

Had one of the very front running 4T's (Paul's EFI Yam 150) on the dyno today.

4T Blue Line 2T Red line.

337237

When you look at the low end torque of the 4T and extremely wide curve you can see why mere mortals on 2T's get well and truly trounced be the 4T's drive .

That's why you gotta use everytjing you can to your advantage. 3 stage baffles. Low and wide tranfers. Staggerd tranfers.
Longest pipe you can get away with. And good inner/outer radius. Radius on the right in pic, is absoulty terrible thru the whole curve.

[SwePatrick]

Yes, I read what you wrote & replied regarding to its content ( or lack there of ) , did you read what I wrote?

You assumed things, and thereby you disqualifies yourself *lol*

[teriks]

That discussion about methanol and corrosion.

This floatbowl is from my VM44 carb, it has been lying in my garage since september untouched unopened.
A couple of days ago i was curious if it was mayhem inside the bowl.

This is what i saw: (dark spots were there when i bought the carb)

337225I don't suffer corrosion on my stuff when I neglect them for a while either.
We do live in a rather dry climate though, especially in the winter time, that for sure helps.
In my case the 20% castor helps a lot too, but gives other problems than corrosion if left for too long. ;)

[Carel H]

337236

The Arduino uses a MAP sensor to measure crankcase pressure and looks for the maximum and minimum pressure and outputs the difference as a simulated MAP value to the EFI's CPU.



Too many ups and downs in the graphic. There are RPM's that are up, and RPM's that are down, close to each other, looks like a bandwith measurement problem. Try to get a datasheet of the MAP sensor, look at the response time and find out if you can take like 8-10 samples per revolution. Choose the 8-bit resolution ADC conversion off the Arduino to speed the software part up. Get rid of noise: sample deeper.

If I look at it filtered, I see the data increasing with rpm ,without significant spike.

Bandwith is just like: I want to look into this at let's say 12000 rpm, thats 200/sec, so you sample sort of valid at 2000/sec.

[Grumph]

I don't suffer corrosion on my stuff when I neglect them for a while either.
We do live in a rather dry climate though, especially in the winter time, that for sure helps.
In my case the 20% castor helps a lot too, but gives other problems than corrosion if left for too long. ;)

The dry climate is probably the biggest factor in preventing corrosion.
The worst customer carbs I ever had were those used on the West Coast of the South Island of NZ - Husaberg's home territory.
They'd regularly come back to me white with corrosion inside and out.

The 18 metres of annual rainfall may have had something to do with that.....wait for husa's response, LOL.

[wobbly]

I have tested the Suzuki type deto cone, and the Yamaha type ( penny on a stick ) is better.
Piston and insert are ready to test the edge radius, will have some dyno results in a day or two.

[ken seeber]

TeeZee, I just think you need 3 more cylinders:

https://www.youtube.com/watch?v=ZO_31uvQe2w&app=desktop

https://www.youtube.com/watch?v=nL8Jq6MJJxs&app=desktop

[husaberg]

The dry climate is probably the biggest factor in preventing corrosion.
The worst customer carbs I ever had were those used on the West Coast of the South Island of NZ - Husaberg's home territory.
They'd regularly come back to me white with corrosion inside and out.

The 18 metres of annual rainfall may have had something to do with that.....wait for husa's response, LOL.

I agree with the corrosion, When i was working in CHCH i could always tell just by looking at a trade in if it was from the West Coast or Canterbury.
But over here its not really true thats its totally the rainfall though, I would suggest its the hot sub tropical climate, plus because the salt laden zone extends 10km inland.
You need to consider how little corrosion occurs in cold climates.
https://i.pinimg.com/originals/e9/5a/ed/e95aed3686de4ee21e7edb771fe1fbda.jpg

https://www.youtube.com/watch?v=CE9j-W_8USw

[TZ350]

TeeZee, I just think you need 3 more cylinders:

Me too .... :laugh:

337253

The Beast had run out of water but the cylinder had survived unscathed. Tough Basted.

337252

The head is dirty but basically unmarked.

337251337254

Turns out it had run a big end bearing. Now the question is, is there limited oiling from Port injection EFI or was it the water?

Not so expensive to repair, but much more work. Glad its only a single cylinder.

[ken seeber]

"Turns out it had run a big end bearing. Now the question is, is there limited oiling from Port injection EFI or was it the water?"


Are you using premix or using a separate pump feed?

[TZ350]

Are you using premix or using a separate pump feed?

Pre mix, 20:1

I will be seriously looking at a small 12V peristaltic pump for an additional oil feed to the inlet.

But because I have to disassemble the motor I could also look at an oil feed to the main brg and then directly to the big end like the Suzuki Posi Lube system. My Suzuki model, the GP did not have that but other models around the same time did.

Something to think about.

337255

[ken seeber]

TeeZee,

Thinking that if the fuel & oil are all going in via the transfer ducts, then there is less opportunity for any oil to get down to the big end. So a Posiforce style system would be a great help. Short of that, if you could arrange the oil discharge from your pump to align with the centre line of the crank, that’d be an improvement. Maybe thru a cantilevered tube (hypodermic size) to dump the droplet (which in reality wouldn’t be a droplet, but some vibration and airflow induced state) such that the big end would intercept it, might offer a greater improvement.

[guyhockley]

TeeZee, I just think you need 3 more cylinders:

https://www.youtube.com/watch?v=ZO_31uvQe2w&app=desktop

https://www.youtube.com/watch?v=nL8Jq6MJJxs&app=desktop
Couple of interesting points about the second video.
MCN's racer tests are usually done by Adam Child who is a useful racer - wonder if this bloke pulled rank to get the gig :msn-wink:
Despite all the talk about updated cycle parts, EFI (and bigger engine) I think Bruce Anstey is still fastest lap and race record holder for 2 strokes at the TT on a YZR500.
I think Ian Lougher was a bit off his game this year, though.
Picking up TZ's point about beating 4 strokes, I was a bit taken aback when Bruce said he thought it would be possible to approach Supersport times around the Isle of Man. Surely the YZR is more powerful and lighter than those and on a horsepower track, too.
Finally, I heard lots of people saying how much Bruce Anstey was missed at this year's TT and that he was ill, but I didn't realise how ill until someone posted a picture of him in a hospital bed with no hair (or beard!). If good wishes and prayers actually had any medical value, he should make a full recovery.

[wobbly]

Yea, I really hope Bruce Almighty pulls thru - a real personal hero.
There are YZR500s and there are YZR500s , but how many years of no development have gone by on those bikes.
Tires are WAY better now, and as Andy has said to me,the Britten would be way faster on these new designs of tire, but that it would take a huge
amount of effort to get an old GP bike to work with them.
Im still very disappointed that if the claims are true of 195Hp/135Kg are even close , the Suter should completely annihilate any Superbike - but not
if the injection still has the staggers like every other race effort has failed to fix.

[TZ350]

.
He has been such a big name at the TT, I am very sorry to hear Bruce Anstey is being faced with a health challenge, I hope he recovers well.


TeeZee, you could arrange the oil discharge from your pump to align with the centre line of the crank, that’d be an improvement. Maybe thru a cantilevered tube (hypodermic size) to dump the droplet such that the big end would intercept it, might offer a greater improvement.

Great idea Ken, I will look at that. I might be able to use a small peristaltic pump driven by the Ignitec's PWM power jet output to match the volume of oil delivery to the RPM.

[DoldGuy]

TZ,

The old Suzuki "Hop Up Kit" for the TS50 required the oil pump to remain & wired open at approximately 1/4 position. I think the reasoning is for the big end lubrication, as we never had a problem with the bottom end back then & that little motor turned a lot of RPM.

[Grumph]

TZ,

The old Suzuki "Hop Up Kit" for the TS50 required the oil pump to remain & wired open at approximately 1/4 position. I think the reasoning is for the big end lubrication, as we never had a problem with the bottom end back then & that little motor turned a lot of RPM.

Most of the Suzuki 50's had a pressed steel piece with a nose locating into the open end of the crankpin and a raised lip around the edge.
It spun with the crank and the oil delivery only had to be into the area inside the lip to get to the big end. Worked well and it was simple.
Wouldn't be hard to duplicate.

[husaberg]

Most of the Suzuki 50's had a pressed steel piece with a nose locating into the open end of the crankpin and a raised lip around the edge.
It spun with the crank and the oil delivery only had to be into the area inside the lip to get to the big end. Worked well and it was simple.
Wouldn't be hard to duplicate.
The TS/TF125 had them as well, its on the pic (TS90) TZ used a couple of posts above named as the guide plate.
Commonly called oil slingers.

[F5 Dave]

My T125 is a marvel of drilled pins, slingers and all sorts.

[Peter1962]

Pre mix, 20:1

I will be seriously looking at a small 12V peristaltic pump for an additional oil feed to the inlet.

But because I have to disassemble the motor I could also look at an oil feed to the main brg and then directly to the big end like the Suzuki Posi Lube system. My Suzuki model, the GP did not have that but other models around the same time did.

Something to think about.

337255

edit : this link gives some details on the different oil pumps that the japanese used on their two stroke auto lube engines. Mostly Mikuni material.
http://www.dansmc.com/2_stroke_oilpump.htm
TeeZee, here is a link to drawings of the different systems of yamaha, suzuki and kawasaki for "auto-lube" systems. Some were rather primitive, with oil only through the inlet port. Others like kawa had also an oil line to the main bearings. (I do not understand why ktm did not choose this solution for their new 250 and 300 TPI bike, they only feed oil through the injectors, nothing for the bearing)
http://www.dansmc.com/2_stroke_pump_views.htm

BRP use bearing oil feed on their E-Tec 600, and 800 engines since 2010 and built an even more efficiënt oil feed system tot their latest creation the E-tec 850cc.
Here a link tot a Ski Doo versus Polaris Cat ranting on who has the best oil feed system. http://www.dootalk.com/forums/topic/1283938-doo-vs-catpoo-crank-lubrication-methods/

[sidecar bob]

I found this beautiful & delicate machine in the Wigchers private collection in Schnoonoord NL today.
Im sure some contributors to this thread may recognise it.:niceone:
Some people may also recognise the gentleman standing behind it. Egbert Streuer, Dutch former multiple world sidecar champion.
Well done Mr Thiel, they are pure art.

[peewee]

Thanks Husa and Jan.
I have a new cylinder to test from TM (designed with the side ears right thru the spigot ) and i want to run it with exactly the Aprilia style steps first
then several versions with top/bottom steps removed with added material in the spigot.

dont say steps are no good now. i havent the patience or time to go back and change mine:eek:

[wobbly]

Honda started the step debate years ago with their tune up sheet that said " do not remove steps from cylinder , this looses 1.5 Hp ".
They were right of course, but the next " step " was to add material to the spigot, that then became a matching oval to round transition " nozzle ".

In varying forms this is what I have been using forever , but when you have huge ears added to a 3 port, that extend the side ducts right down thru the spigot
to the header start , then because 2Ts are contrary bastard things I am not going to assume that having a matching spigot with no steps at all will be the best.
TM kart engines have never had anything but a plain oval exit - and I have seen all manner of variations , with a step only at the bottom, only at the top , and both ( like the Aprilia ).

But the dyno says that for a plain oval - the matching transition works best, as long as the spigot floor is parallel to the cylinder floor.
So now I have a new TM cylinder with the ears , and the correct exit area as well , I will have to test the combinations all over again.
Bastard expensive, time consuming , and frustrating, but when you are trying to out power the best in the world you cant leave anything on the table - or you get beat.

[RomeuPT]

I suggest you look at the IAME piston,that has a 5* angled edge for around 7mm that then becomes a flat top.
This setup in a TM with a new insert ( with the plug alot closer to the piston and a very flat bathtub ) makes better power than the 4* TM setup ( same cc ).

I was drawing and thinking of the head design to use with the iame piston on my honda and read this and got a little confused.

The flat top radius Iame piston is meant to work on a toroid right? not bathtub shape chamber ?!
Since it will raise compression compared to a flat top and the same chamber, should I just take the some radius of the toroid to get more volume!?

thanks

[katinas]

Some interesting things in this sketch of Honda NSR 2001/RSW 250 2009 GP engines.
Staggered reed block and longer conrod ( about 110 mm) on latest RSW (Aoyama), no steps cylinder/spigot, reed block angle on NSR ......

[husaberg]

Some interesting things in this sketch of Honda NSR 2001/RSW 250 2009 GP engines.
Staggered reed block and longer conrod ( about 110 mm) on latest RSW (Aoyama), no steps cylinder/spigot, reed block angle on NSR ......

Nice pics
I am not sure that going twin crank was one of Hondas better decisions.
I would hazard a guess it had more to do with trying to shorten the wheelbase than peak HP.
the NSR250s never followed the clear development path of the 500 with the inlet staying behind the engine until very late in the design.
They also sacrificed performance and weight with the Pro arm just for style and selling road bikes.

[wobbly]

Romeu, the Iame isn't strictly a flat top, it has a 7mm wide 5* conical angle on the timing edge, then an almost flat top ( 1mm rise ).
Thus its a combination really of a dome and flat top.
I feel this is better than Yamaha had with a very small angled edge, then a flat.
Due to the flat top area of the piston the plug is already alot closer to the piston than would be the case with a dome.
So i have used a bathtub ( to get it even closer ) but yes if I was permitted to , i would drop the plug even more with a toroid.
In the KZ application I have already established that the bathtub is better than the normal hemi shape when using the stock TM 4* straight conical piston
but as the class rules mandate pouring 13cc down the plug hole , using a proper toroid isnt possible.

The Honda 250 had the matching oval to round transition spigot for many years before the 125 GP engine did , but to my knowledge they didnt discover the advantage of dropping the spigot centerline
to make the floor of the duct and the spigot co-linear.
I found that during the SKUSA CR125 spigot testing.

[Frits Overmars]

The Honda 250 had the matching oval to round transition spigot for many years before the 125 GP engine did , but to my knowledge they didnt discover the advantage of dropping the spigot centerline to make the floor of the duct and the spigot co-linear. I found that during the SKUSA CR125 spigot testing.Shouldn't that read raising the spigot centerline Wob?

[RomeuPT]

Romeu, the Iame isn't strictly a flat top, it has a 7mm wide 5* conical angle on the timing edge, then an almost flat top ( 1mm rise ).
Thus its a combination really of a dome and flat top.
I feel this is better than Yamaha had with a very small angled edge, then a flat.
Due to the flat top area of the piston the plug is already alot closer to the piston than would be the case with a dome.
So i have used a bathtub ( to get it even closer ) but yes if I was permitted to , i would drop the plug even more with a toroid.
In the KZ application I have already established that the bathtub is better than the normal hemi shape when using the stock TM 4* straight conical piston
but as the class rules mandate pouring 13cc down the plug hole , using a proper toroid isnt possible.

The Honda 250 had the matching oval to round transition spigot for many years before the 125 GP engine did , but to my knowledge they didnt discover the advantage of dropping the spigot centerline
to make the floor of the duct and the spigot co-linear.
I found that during the SKUSA CR125 spigot testing.

Thanks

Yes I know its a combo of the two types, I have got the Iame piston and now need to design a chamber to suite, I think I will modify a NX4 stock chamber I have to more cc..

The spignot exit will be offset then?

[guyhockley]

My T125 is a marvel of drilled pins, slingers and all sorts.
I'm away from my workshop at the moment, but I think Vic Willoughby said Helmut Fath used end fed cranks on Phil Read's TD2 for double the crank life.

[Tim Ey]

Some interesting things in this sketch of Honda NSR 2001/RSW 250 2009 GP engines.
Staggered reed block and longer conrod ( about 110 mm) on latest RSW (Aoyama), no steps cylinder/spigot, reed block angle on NSR ......

Oh My!
I totally love technical drawings of twostroke stuff!
Where did you get that from? Is there a chance that there might be more? :-)

Regards
Tim

[Flettner]

this EFI project has an old school autolube, feeding into the end of the crankshaft. Shaft is hollow, crank pin is drilled ( carbide drill) so oil can be delivered direct to the bigend.
Cable operation will be connected to the power valve spool, not throttle cable.

[wobbly]

Yes sorry Frits, with the spigot CL symmetric, the angle of the floor and roof of the oval to round transition are the same.
ie both steepish.
But if you lift the spigot CL upward, the floor angle straightens out - to where you can eventually make it co - linear with the duct exit.
In this case the roof angle from the top of the oval, out to the top of the round header entry, is VERY steep.
I am even starting to vaguely think this just might be like having a deto button in the header roof , the steep angle facing the pipe may shield the duct from infra red heat
or the floor shape promotes return flow up the ski jump - but retards it along the duct roof.
Who knows, not me - but as usual the dyno she dont lie.

[guyhockley]

this EFI project has an old school autolube, feeding into the end of the crankshaft. Shaft is hollow, crank pin is drilled ( carbide drill) so oil can be delivered direct to the bigend.
Cable operation will be connected to the power valve spool, not throttle cable.

This design was supposed to run carbon pistons "dry" and use no oil, hence the oil-seals on the crank pin. Designed, and supposed to have been built by a bloke some consider a genius and others regard as "a bullshitting fantasist with no business morals". Don't think it ever made metal.

[guyhockley]

Then there's old school...

[Frits Overmars]

I think Vic Willoughby said Helmut Fath used end fed cranks on Phil Read's TD2 for double the crank life.Fath did indeed, and it far more than doubled the crank life.

[TZ350]

.
All this information about crank/big end oiling is very Interesting .... Thanks.

[guyhockley]

Fath did indeed, and it far more than doubled the crank life.

Suzuki seems to have made the greatest efforts in lubrication, especially on the triples, but I was once approached by a bloke who said I was riding his old "works" bike (MZ250). Sadly, not racers, he had been a dispatch rider for a South Coast (UK) printers and claimed that his other work bike was a GT250 that did 100,000 miles on the original crank before being replaced.

[katinas]

Oh My!
I totally love technical drawings of twostroke stuff!
Where did you get that from? Is there a chance that there might be more? :-)

Regards
Tim
Picture from 2017 RACERS vol. 44 magazine, and I too still enjoy very much, when see such drawings.

For me, the last NSR 250 (98-01) was little bit mystical bike, maybe engine is some copy of Aprilia, but when I nearly touch Kato's bike at 2001 Brno GP on quiet Thursday evening, like it very very much. It was so nice to be around the best strokers, especially as the teams were not so secretive on Thursday evening. For me it was one of the most enjoyable evening

https://www.ebay.co.uk/itm/racers-vol-44-honda-nsr-rs-rw-250-japanese-text-photographic-magazine/113057447439?hash=item1a52bfbe0f:g:KyMAAOSwcmhZlIN d

Japanese still releasing special magazine for two strokers

https://www.amazon.co.jp/2%E3%82%B9%E3%83%88%E3%83%AD%E3%83%BC%E3%82%AF%E3% 83%9E%E3%82%AC%E3%82%B8%E3%83%B3-Vol-15-NEKO-MOOK/dp/4777021378

Honda NS 400 conversion to 500
https://page.auctions.yahoo.co.jp/jp/auction/s548150038?u=%3bdmrjapanfactory

[wobbly]

Cant believe it - I thought I was real clever using staggered length backup reed tensioners to equalize flow thru the reed ports - and there Honda were doing it years ago.

I found a Yamaha style deto button in a box of bits.
Head is 20x2mm , stalk is 10mm with M6 and a couple of slots for 8mm spanner.

[EssexNick]

I'm still at a loss as to just how a deto button works. It clearly goes, I just can't get my head round the concept.
On a different note, can anyone recommend a suitable sealant for use in a fiberglass petrol tank? I'm only planning to use unleaded.

[diesel62]

Hi could you please comment on this piston. I am not sure what is causing the wear above the ring. It is in a maxter kz2 engine. Has seen 15 litres of fuel. The last piston looked the same
I emailed Meteor (piston manufacturer) and got a reply back saying as the skirt was modified that is what the problem is.
The piston has not been modified although the photo is on a funny angle so it looks like the opposite skirt is short.
I have measured the piston against an earlier Vertex piston (measures the same) above and below the ring. Funny thing is that the Vertex piston does not show any wear above the ring.
Any help is appreciated. Cheers https://uploads.tapatalk-cdn.com/20180615/02a7751758e31a300a2ff697aed77533.jpg

Sent from my SM-P555 using Tapatalk

[wobbly]

The Meteor is obviously expanding more above the ring, and the land is dropping into the Ex port.
You can see the wear pattern that matches exactly the shape of the Ex port timing edge.
The problem may be a very common one in that the manufactures often will grind the Ex duct timing edge too far up, and thus there is very little chamfer left.
Normally this will quickly trap the ring, causing real damage.
This has happened to many so called " factory selected " cylinders , where they seem to be selected, then ground after plating - this should be the other way around.
You may be able to get a some more lead in chamfer with less sharp edge to kill the piston , using an impregnated cotton mop in a die grinder.

[diesel62]

Thank you. I will investigate further
The Meteor is obviously expanding more above the ring, and the land is dropping into the Ex port.
You can see the wear pattern that matches exactly the shape of the Ex port timing edge.
The problem may be a very common one in that the manufactures often will grind the Ex duct timing edge too far up, and thus there is very little chamfer left.
Normally this will quickly trap the ring, causing real damage.
This has happened to many so called " factory selected " cylinders , where they seem to be selected, then ground after plating - this should be the other way around.
You may be able to get a some more lead in chamfer with less sharp edge to kill the piston , using an impregnated cotton mop in a die grinder.

Sent from my SM-P555 using Tapatalk

[Mike Fisher]

Then there's old school...

Not a 2 stroke question but... That looks like a Hurst Airheart master cylinder in the inset photo. Did the Enfiled run a rear disc, or was it a rear hydraulic drum brake, in '65?

[wobbly]

Well here finally is the result of the change to the semi flat top IAME piston with a 1mm edge radius.
The piston is 0.5mm higher, so equivalent to dropping the cylinder 1/2 the radius.
I can see why the MX guys like this mod - added power all the way up the front side ( +1.3 max in this case ) but it drops off past 14,000.
This I believe is simply due to the cylinder being a little low, so I will next jack it up 0.2mm, and drop the insert the same amount down the bore.
But really what needs to happen next is to not move the cylinder, but go with a 1.5mm radius - then depending upon the result even bigger as Frits has alluded to.

[ken seeber]

Wob, good stuff.

Did the spigotted head profile match the radiussed piston edge profile right up to the side of the bore? She'd be sharp edged right at the end, possibly very vulnerable to handling damage and also deto issues.

Why did I say she ? Can't say he in these "enlightened" Ozzie days, so really I should have said it. :bs:

[wobbly]

Yes Ken, the spigot matched the piston shape,with a sharp edge at the bore.
I broke the corner with a tiny radius ( easy in CNC ) but once I have tried the other variations of a higher cylinder, and then a bigger radius , the real go is to have a small step at the bore top so the
spigot face is a small flat.
This will make it reliable against deto - but in my case not as vital , as all my fast engines now have no spigot at all.

You really cant say fuck all nowdays mate, but hey , good thing is they cant ban you twice.

[speedboy]

Well here finally is the result of the change to the semi flat top IAME piston with a 1mm edge radius.
The piston is 0.5mm higher, so equivalent to dropping the cylinder 1/2 the radius.
I can see why the MX guys like this mod - added power all the way up the front side ( +1.3 max in this case ) but it drops off past 14,000.
This I believe is simply due to the cylinder being a little low, so I will next jack it up 0.2mm, and drop the insert the same amount down the bore.
But really what needs to happen next is to not move the cylinder, but go with a 1.5mm radius - then depending upon the result even bigger as Frits has alluded to.

Interesting. How many measurements for the average curves?

[RomeuPT]

Well here finally is the result of the change to the semi flat top IAME piston with a 1mm edge radius.
The piston is 0.5mm higher, so equivalent to dropping the cylinder 1/2 the radius.
I can see why the MX guys like this mod - added power all the way up the front side ( +1.3 max in this case ) but it drops off past 14,000.
This I believe is simply due to the cylinder being a little low, so I will next jack it up 0.2mm, and drop the insert the same amount down the bore.
But really what needs to happen next is to not move the cylinder, but go with a 1.5mm radius - then depending upon the result even bigger as Frits has alluded to.

Great!

But changing from a 4º taper used in TM right?!

Thanks

[wobbly]

Each graphed run is 3 averaged.
And yes the change to the radiused semi flat IAME was from a 4*TM.

[Muhr]

The block begins to take shape!

[Muhr]

Well here finally is the result of the change to the semi flat top IAME piston with a 1mm edge radius.


Great stuff! how much duration did you run?

[wobbly]

The spec for a TM KZ10C selected factory cylinder is 27mm ATDC = 82.54* = 194.92* Duration.
That certainly doesn't mean they actually are.
But with the piston radius , there is some conjecture as to what the real timing is effectively.
It would appear that changing the cylinder height 1/2 the radius on the piston has the effect of great front side power at the expense of overev.
So now I need to experiment with a slightly higher adjustment, then try an increased radius as well.
Does anyone know what VHM did with their option piston and insert using a radius.
They reported a 1 Hp increase , but didnt seem to loose overev in the dyno sheet i have seen.

[TZ350]

The block begins to take shape!

Looking good. .... :2thumbsup

[peewee]

what could be the reason for not casting in a large bullnose at the transfer inner wall bore face ? https://m.facebook.com/pg/brcracingcanada/photos/?ref=page_internal&mt_nav=1

[marsheng]

I'm rebuilding a T250. I wanted to fill in a bit of the head to make a squish band. Welded a bit, but was full of pores. Dug out 2.5 mm of material to a clean base and tried again. Black soot and bubbles still kept coming up. Kept the heat on hoping that the air pockets would eventually float to the surface. It never happened. Just when I thought it was good the weld puddle rose and a new bubble popped out.

http://www.marshland.co.nz/ftp/T250/WeldPocket.JPG

I let it cool and to my surprise, most of the fins had newly formed bubbles on them. Looks like there is something that vaporizes at a lower temp than the alu melt and the creates the bubbles.

http://www.marshland.co.nz/ftp/T250/HeadFins.JPG

[peewee]

marsh im not sure if this is your first go at something thats been oil soaked for 20yrs but it can be a bit tricky. try adjusting the machine balance so theres a bit more cleaning action. also be sure you havent dipped the tungsten in the weld or it becomes contaminated and puts contamination back into the weld. also make sure you have proper shielding gas flow and no atmosphere wind is disturbing the shielding gas. these are some of the reasons you see the black shit. once you see black its best to stop and grind it out, determine whats causing it then proceed on. other wise youll likely have a million pinholes and garbage when you go to machine it

im not sure of the bubbles. maybe someone has coated the fins with spray paint ? watch out for toxic fumes as well. you never know what chemicals a old head may have soaked up over the years. only use acetone as a cleaner since some brakecleaners can produce phosgene during the weldig process

[ken seeber]

I'm rebuilding a T250. I wanted to fill in a bit of the head to make a squish band. Welded a bit, but was full of pores. Dug out 2.5 mm of material to a clean base and tried again. Black soot and bubbles still kept coming up. Kept the heat on hoping that the air pockets would eventually float to the surface. It never happened. Just when I thought it was good the weld puddle rose and a new bubble popped out.

Actually I reckon that the head is high pressure die cast, something that the Japs got into with heads, cheaper than sand casting. To assist production, they added zinc and other crap which makes it near impossible to weld. This is evident also in Yamaha KT100S kart engines, making the earlier sand cast heads desirable.
So, what some dudes over here do in these situations is to not try to weld, but to build up by brazing using oxy or even propane due to the much lower temps of the brazing rod. Even though the melt temps are lower, the stuff stays on during running.

Here's just one of many:

https://www.aluminumrepair.com/aluminum-brazing/

I'm sure that there will be something similar of the shelf in Kiwiland.

[Grumph]

Ken's right as usual.
What I would also suggest is to go see a powdercoater and get anything you want to weld soaked in a Trichlorethylene bath.

[Haufen]

Well here finally is the result of the change to the semi flat top IAME piston with a 1mm edge radius.
The piston is 0.5mm higher, so equivalent to dropping the cylinder 1/2 the radius.
I can see why the MX guys like this mod - added power all the way up the front side ( +1.3 max in this case ) but it drops off past 14,000.
This I believe is simply due to the cylinder being a little low, so I will next jack it up 0.2mm, and drop the insert the same amount down the bore.
But really what needs to happen next is to not move the cylinder, but go with a 1.5mm radius - then depending upon the result even bigger as Frits has alluded to.

Thanks, looking good. What would be the normal curve that can be expected from a standard setup which is dropped .5mm? I assume that this mod will always be at least a little bit more likely to lack overrev or for the curve to fall on it's face as it works in the other direction, too, thus supports burnt gases to enter the transfers.

[F5 Dave]

Ken's right as usual.
What I would also suggest is to go see a powdercoater and get anything you want to weld soaked in a Trichlorethylene bath.
Yeah but hurry. You'll need to get there before the turn of last century.

[guyhockley]

Not a 2 stroke question but... That looks like a Hurst Airheart master cylinder in the inset photo. Did the Enfiled run a rear disc, or was it a rear hydraulic drum brake, in '65?

I cropped the Enfield bits from an article about TT technical trends or some such, think the disc brake was on a sidecar outfit. Not at home for a few days, I'll have a look when I get back.

[JanBros]

I'm rebuilding a T250. I wanted to fill in a bit of the head to make a squish band. Welded a bit, but was full of pores. Dug out 2.5 mm of material to a clean base and tried again. Black soot and bubbles still kept coming up. Kept the heat on hoping that the air pockets would eventually float to the surface. It never happened. Just when I thought it was good the weld puddle rose and a new bubble popped out.

http://www.marshland.co.nz/ftp/T250/WeldPocket.JPG

I let it cool and to my surprise, most of the fins had newly formed bubbles on them. Looks like there is something that vaporizes at a lower temp than the alu melt and the creates the bubbles.

http://www.marshland.co.nz/ftp/T250/HeadFins.JPG

Had the same problem trying to weld a Honda Sky head. nothing you can do about it. After trying lot's of stuff, you think you've got it, but then when you machine the head it still looks like Swiss cheese inside.
I ended up turning an insert and pressed it in the head, and welded the circumferrence for better heat-disipation.

[marsheng]

Ken's right as usual.
What I would also suggest is to go see a powdercoater and get anything you want to weld soaked in a Trichlorethylene bath.

I milled out 2.5 mm before welding and I cut it dry.

Done enough welding on castings to know this is not normal. The bubbles in the fins are evidence of that. These is something they put into the cast to make it nice and clean on the outside but crap on the inside. That is probably why of the 6 or so heads I have here, 3 are cracked right through the castings.

The brazing looks like an emergency repair method and I'll get some rods. Could be very useful. For long term, either find out how to weld these or cast new ones. I need a long term solution.

These them ?

https://www.aliexpress.com/item/4pcs-Low-Temperature-Welding-Rod-Aluminum-Tig-Soldering-Brazing-Rods-4mmx230mm-with-Corrosion-Resistance/32813597481.html

Bit cheaper than the local agents !!!

Not sure if I saw it on this forum or not, but a courier said he had 100K on a T250 before a crank rebuild.. So excellent motors.

[TZ350]

Not sure if I saw it on this forum or not, but a courier said he had 100K on a T250 before a crank rebuild.. So excellent motors.

Yes, post 29942, just a page back.

[oxracer]

Ken's right as usual.
What I would also suggest is to go see a powdercoater and get anything you want to weld soaked in a Trichlorethylene bath.Hello, may I drop into this conversation? I'm a long time reader of this thread but never posted before! I feel the need to say that even if you could get your parts cleaned with Trichloroethylene that it would be a really bad idea as this is the chemical that turns to phosgene gas when arc welding!! A guy at my work nearly killed himself doing just that.

https://link.springer.com/article/10.1007/BF00539023

Sorry to make my first contribution such a negative one, I'll try to bring some positive vibes to the party next time I promise!:rolleyes:
Mark
Ps: This is a great thread by the way! Thanks to all the contributers and thanks to TZ for starting it.

[190mech]

It would be nice to have unfinished precast aircooled heads of various sizes available so the older iron could be kept running with a better designed combustion chamber...

[guyhockley]

Nothing new under the sun department:
This is from a description of the Scott 6 cylinder car engine and touches on a couple of recent topics.

"Crankcase compression for each chamber was maintained by the oil film in the mains roller races, which were of a special close-tolerance type, each with a positive oil-reed from one of two metering pumps situated fore and aft of a chain-driven auxiliary shaft. There were actually four oilpumps working in the same system: the main primary pump drew lubricant from the sump and fed it under pressure to the intakesof the two metering pumps. A pressure relief valve discharged oil to the auxiliary shaft bearings and chains, and a scavenge pump withdrew surplus oil from each erankchamber and returned it to the sump. The " metering pumps " were operated by swashplates coupled to the throttle linkage: as the opening increased, so did the stroke of the six plungers in each pump body. (One to each main bearing, and one to each cylinder bore.)

Cylinder construction was novel and provisionally patented : the lower section of each bore was formed by a sleeve in which ports were accurately machined, and which was pressed into position up a -counter-bore in the cylinder proper—a chromidium iron casting with normal exhaust and transfer ports. The protruding port-sleeves spigoted into the crankcase, while the upper junction of each liner and cylinder was adapted as an oil-groove communicating with a surrounding gallery fed from one of the swashplate pump plungers. Evenly spaced notches admitted the oil to conventional Scott heat-treated Y-alloy deflector pistons, and small cuts aroundthe skirts distributed it evenly around the bore."

[Grumph]

Yeah but hurry. You'll need to get there before the turn of last century.

Are you saying they're now OSH banned Dave ? Last time I was in to my favoured coaters in ChCh, the bath was still there and appeared to be in use.

The powdercoaters appear to get around the gas problem by doing the preheat in a vented oven.
It's still the best way of getting a contaminated casting clean IMO.

[JanBros]

Here is the first test-file of my Porting Excel : http://users.telenet.be/jannemie/JanBros%20Porting%20Test.xlsm

http://users.telenet.be/jannemie/Porting%20test%20Exh.png

http://users.telenet.be/jannemie/Porting%20test%20TR.png

I've already tested it a lot, but might be better if other people test it to . any comment is welcome. Especialy if someone with Engmod would like to compare the results :not:

It is based arround the Bimotion-Idea (only the idea, it's all mine ;) ) because it gives total freedom in port-design. Ports are not limited to any geometrical shapes at all. I know it is not the "handiest" way to design ports quickly, but that does not outweigh the advantage of free design in my opinion. Especialy if someone with Engmod would like to compare the results :not:

It shows actual portmap, portlay-out from top, calculates : A.A, T.A, width between all bridges, exhaust port width % of bore, the direction of the scavenging column, the ideal safe-exhaust-port-roof-depending on the width of the port, and lot's more basic stuff.

still need to make a "how to use it" file, but most is obvious and there are lot's of remarks on it with explanation.
feel free to do anything you want with it, as long as you leave me as the creator and Frits for his help (not personaly, but through the forum) mentionned somewhere, even if it is only small, stashed away in a corner out of sight.

[F5 Dave]

Are you saying they're now OSH banned Dave ? Last time I was in to my favoured coaters in ChCh, the bath was still there and appeared to be in use.

The powdercoaters appear to get around the gas problem by doing the preheat in a vented oven.
It's still the best way of getting a contaminated casting clean IMO.
None of the ones I know have one, well at least they admit to. Got told they got rid of them ages ago. But hey maybe some retain them.

[guyhockley]

None of the ones I know have one, well at least they admit to. Got told they got rid of them ages ago. But hey maybe some retain them.
Factories where I worked in the seventies usually had a bucket of "trike" so you could wash your hands before eating your sarnies!

[Peter1962]

.
All this information about crank/big end oiling is very Interesting .... Thanks.

Imagine a modern 250 or 300 enduro engine, the ktm TPI which has Fletner type injection, oil injection but sadly enough limited to the throttle body, and a balance shaft. If this engine could be equiped with a BRP E-TEC 850 oil pump, and a crankshaft with rollers like in this engine we would then have a MX engine with four stroke reliability for the crankshaft.
Wobbly told us that a ktm 250 can be tuned to 65+ HP but when revved to 11.000 rpm the engine needs frequent maintenance. I wonder if an E-Tec type of crankshaft + forced oiling system could overcome that handicap and make the engine more reliable.

The electronic oil pump is not cheap, 370 dollar, but the specific crankshaft of the E-Tec is expensive to the extreme. 2900 dollar
Not sure if this is because it is made of unobtanium or some form of extra terrestrial metalurgy or just greed from BRP...

https://www.ronniesmailorder.com/oemparts/a/ski/59f0d9fd87a8661168f97ecb/oil-system-engine-850-e-tec

http://www.dootalk.com/forums/uploads/monthly_03_2016/post-105883-0-03359500-1459089445.jpg

https://www.snowest.com/Images/Articles/4029/Crankshaft%20Oil_850%20E-TEC.jpg_600.jpg

[jonny quest]

TZ350, you might find this useful.

https://youtu.be/8YgCcV16MnU

[TZ350]

.
OxyRacer, JonnyQuest, Peter1962, GuyHockly and JanBros.

Thanks, great ideas I will have a good look at them.

[F5 Dave]

I'm pretty sure I don' want a 65hp dirtbike:doctor:

[DoldGuy]

I'm pretty sure I don' want a 65hp dirtbike:doctor:

I'm pretty sure I DO want a 65hp dirtbike (75hp would be even better) :niceone:

[Peter1962]

I'm pretty sure I don' want a 65hp dirtbike:doctor:

I surely would one, if equiped with a Power CDI ignition to make the horsepower usable.

The 450 foulstrokes make 52 to 54 hp from factory. The best tuned engines (like Chad Reed his bike) make 64 hp on the dyno. Not with standard ignition system of course.

[wobbly]

Yes it is very possible to get 65 RWHp from a 250 MX engine, but even with an Ignitech driving the PV and ignition functions
it has NO throttle response below around 7500 and is specifically designed to rev past 11,000 so that when hitting 5th gear ( no 6 speeds any more )
it doesnt drop into a torque hole and simply will not accelerate ( due to aero ).
The pipe is so fat it would be all but impossible to fit and when the power valve opens the hit is so hard it would instantly break traction every gearchange.
In short, not MX suitable even remotely.

[TZ350]

TZ350, you might find this useful.

https://youtu.be/8YgCcV16MnU

I very much like this....

[TZ350]

.
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

Choose a likely looking option and check it out and you will probably find a quality post like the one below.


... follow the posts for the RGV500 version and pictures

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258136&stc=1&thumb=1&d=1329761342http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258135&stc=1&thumb=1&d=1329761341http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=258134&stc=1&thumb=1&d=1329761339
.........
.
There are over 12,000 images attached to this thread and there is a lot of gold to be found there too.

337312

To look through them use the "Thread Tools" option at the top of the page and then the "View Images" option.

Then they can be sorted by:-

"Posted Within" ........... I use from the "Beginning".
"Images Per Page" ....... and I prefer 70 images per page.
"Order Results" ............ and they can be in Descending or Ascending date order.

When you see a picture that interests, you can click on it to view it or click on the "N/A" symbol below it to go through to the original Post.

.............
.

Page 1000 ... https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page1000?p=1130773139#post1130773139

Page 1000 has a lot of directory information pointing to the good stuff. Click on the Blue chevron in link above to go there.


Page 1500 .... https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page1500?p=1130957586#post1130957586

Page 1500 has a lot of new directory information on it.

I have been trying to find the posts that talk about pipes and collate and edit them. There is heaps of it, mostly from Wobbly and pages 620 630 640 650 660 670 680 690 700 710 720 730 740 750 760 770 780 1040 and 1050 have un edited collections of raw material.

Also page 500 about mid way down BucketRacer has a links list on:-
How to build a 1978 30hp aircooled Suzuki GP125 https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page500

[TZ350]

.
Blowdown STA (Specific Time Area) is everything and determines the RPM ceiling and power output of your motor.

Optimum Exhaust Port Duration for maximum symbiotic resonance is 190 deg but blowdown STA requirements may force you to use a longer exhaust duration.

Wob often refers to the vital pipe dimensions and Frits posted a diagram of them. Stick to these %%% to get good results.

337379

Frits suggested design criteria for a good pipe.

337378

And Transfer Ports. Low and Wide is the go….



Here are the RSA values.
A-ports timing 130°, roof angle 25°
B-ports timing 132°, roof angle 10°
C-port timing 132°, roof angle 50°


337380
Transfer Port Theory

Click on Husabergs link to read everything you might want to know about Frits's theory on transfer ports.


Turbulence is caused by the breakdown of the main flow. Because of the viscosity (in effect the internal friction of the fluid) the main flow progressively break down into ever smaller eddies and if left long enough all the main flow and all the eddies will stop.

The main flow is from the transfer port loop and a stronger better directed flow with more kinetic energy can generate a lot of turbulence before it stops. If you have weak flow by the time combustion happens you need the extra flow from the squish to generate extra turbulence to get good combustion.

On the other side if you have strong flow and thus good turbulence the extra turbulence can speed up the combustion too much and you loose power but mostly overrev. This explains why engines do not always behave the same to squish changes. Good engines use squish to minimize end gas to stop detonation while poor engines use squish to add turbulence.

Turbulence cannot reverse, it is a one way street after creation. The bulk flow with the squish opening will loop slower and slower, both because of the increase in volume and because it keeps generating turbulence until it completely stops.


337385
As an empirical rule Wobbly's 75% of the total exhaust port area works very well. But I prefer to base the port exit area calculation on the blowdown area, not on the total port area. The drawings shown below you will find the Aprilia's blowdown area (and the angle.areas for blowdown and scavenging).

337381

I think the duct should just be able to handle the flow during the blowdown phase; any more cross section area in the duct only increases its volume which should be avoided.

Wobbly hits on an important point: the higher the exhaust timing, the smaller the header diameter should be for a given rpm range. It would take me too far to explain the fundamentals here, but you can find the relationship in my 'simple exhaust concept' below.

337378

Stinger nozzel
337387




As always I have to agree with Frits analysis - tying the duct geometry to the blowdown is way more accurate - as this number is crucial to achieving the power an engine will make in reality.

[TZ350]

Expanding on Wobs very practical idea of setting the duct nozzle area at the header at 75% of the "effective" exhaust port area for multi port and 90% for a single exhaust port and the distance to the nozzle from the exhaust window is 1.5 times the bore diameter.

Effective port area is not blow down area but the total combined area of all the exhaust ports, main plus auxiliary's combined times the cosign of the ducts down angle, so just a little smaller than the total visible area of the exhaust port. The 75% for a multi port has been extensively tested but the 90% for a single port is not as well proven but still makes a good rule of thumb.

And if you had good simulation software like EngMod2T then the target Mach number in the header nozzle and exhaust stinger nozzle is 0.8. More or less than 0.8 looses power and 0.8 is easy with a multi port but not easy to achieve with a single exhaust port.


It seems that in many engines going to around 0.8Mach at the exit seems to work best. As I have stated a hundred times that 75% of the effective port area at the oval duct face will get you close every time, as will the 90% area for a single port.


Any well developed race engine is ultimately Blowdown restricted, and you will always see the Tr Port pressure ratio rise when they open. That effect is what makes port stagger work.

The first port to open, initially has backflow, it must, as there is more pressure above than below. Then the rest of the ports open and eventually begin to flow into the cylinder due to the depression created by the pipe diffuser.

Thus the port that opens first, flows last. Counter intuitive, but reality, proven on motored, instrumented engines in the lab and reported in a raft of SAE papers - and now shown in the sim. Getting a balance between the blowdown needed to achieve the power you want, and the transfer area available is the tuning trick most valuable.

Superposition at ExPort opening is loosely referred to as pipe/port resonance, and is best achieved over the widest range with low Ex duration's down at 192*. Unfortunately this is countered by needing a lot more blowdown than these numbers allow, and around 198 is needed to achieve the best bmep numbers. In this scenario we try to achieve resonance at peak and beyond, to give plenty of overev power.

Next issue that is my favorite hobby horse for today is Ex duct exit area. You will find a heap of free power, when using a T port or a Tripple port configuration, by limiting the duct exit area to around 75% of the Total Ex Port Effective area. 90% for a single exhaust port.

337386 Wobbly

Then make the header start at the area = to the Total Effective. Join these with an oval to round adapter in the spigot or flange, where the width = the header dia all the way thru, to enhance the flow from the blowdown area,and the height at the flange face forms an oval to give the correct 75% area.

The Temp Av in the pipe should be around 500 as in any fast engine you would measure around 600 in the header.
The TuMax should be around 1000, any more and you get deto, a lot less and it means the temp/pressure rise in the chamber isn't high enough, and you are restricting the "push" on the piston. But can also mean that you are using retarded timing to get heat into the pipe, not create pressure on the piston.


I have been studying the work of the exhaust nozzle for a long time, so I'm very glad that Wobbly wrote about it in details.

Wobbly!

Is it possible that the cause of the '75% rule' is that after the opening of the exhaust port the positive pressure in the exhaust port/duct lasts until 55-60 degrees, and then the diffusor starts to work, so the suction will be determinative? This area of the exhaust port at 55-60 degrees is the same as the exhaust duct's area should be (cc 75%).

If the presumption is right the exhaust port's lower edge doesn't have to be at ATDC 180 degrees, it would be enough at 135-145 degrees. In this case the proportion of the effective exhaust port area and the exhaust duct area would be 1:1. Of course the shape of the port is not the same and there is some important factors as well, but in general the abovementioned are right, aren't they?

By the way what is your opinion, where the exhaust nozzle has to be, how far from the exhaust port?


The idea of reducing the duct volume was pushed along by Jan at Aprilia where they CNC cut the shape.

337389 Frits

He lifted the floor, but more importantly the bottom corner radius was increased, this also reduced the volume, and helped reduce short circuiting from the A port.

337388 Frits

With the cosine of the 25* down angle taken into consideration, I would guess the area at the port exit was quite small in the cylinder.

I have found that the 75% rule works OK in a triple exhaust port cylinder, as does making the duct exit area the same as the main port area only ( often works out to be the same value ) but that the exit area must include the 1/2 moon cutouts, or be very oval shaped, depending upon 3 port or T port. Changing the volume affects the HelmHoltz frequency, as does changing the length.

As it stands, the nozzle being part of the flange is all we can do with an existing cylinder. Welding up the last part of the duct works OK, but I always try and get as far up into the duct as I can to reduce the vertical height gradually, and widen it to get the Aux ducts to flow better.

Page 1710 is worth a visit..... https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page1710


The 75% number came about from doing alot of testing on flanges and duct shape for a customer building aftermarket RS125 cylinders. The best beta cylinder ended up with an oval at 41 by 32mm.

It was about this time I started doing alot of sims using Neels code, and it struck me that so many engines went the best - on the screen and on the dyno with that 75% idea.

Then I later confirmed that an oval to round transition within the spigot worked the best. I have not had a chance to try Jans idea of continuing the 1/2 moon cutouts down into the header, making that somewhat oval as well.

All I do know is that dozens of customers and hundreds of others have used the 75% rule of thumb and it works every time - way better than the over 100% seen so often.. Some engines like more - some less. 75% seems to work every time ( TZ350 ) but some like even less if the port is VERY high, like big drag race Kawasaki triples etc.


Wobbly, How close do you run your EGT probe to the port? I noticed on both the new KTM 125/250 MX bikes that I could not see EGT's over 1000*F. leaning it out didn't change much on the temp, but once I heard popping on over-rev, I then came back the other way. I did run the probe about 3" from the face of the pipe, so maybe I was too far away from the port face, making the readings a bit low?


There are a couple of things in play that affect the egt reading of a perfectly well running engine. If you look at the velocity and temp profiles as we have seen in CFD analysis of the Exhaust port/header you see that the temp varies dramatically with not only position along the duct, but also across its profile.

I know that the very short probes as sold by some manufacturers for kart/bike use only intrude some 10 to 15mm into the header,and these read much lower than if the tip is on the center line.

So I try to standardize on 3X bore down the header and in the middle,using exposed tip probes from EGT industries - the only type that have a guarantee, 2 years for the Stinger type.

The exposed tip is way faster reacting and as long as the data sample rate is high enough ( above 10Hz ) you get to see what is actually happening in real time. Some gauges only update the screen readout every couple of seconds - useless.


If you can only get to 500* then there is a serious problem.

It can only be a few issues that will cause this, way too much compression or timing for the fuel, or severe short circuiting.

I had the short circuiting problem on a 250 MX engine that had the Aux ground around to bore center.It ran just fine but when the piston was changed from a Wossner to a Prox it ran like shit and would not respond to leaner jetting changes at all.

Finally in desperation I pulled it down ,to discover that the Wossner had a machined hole in the skirt above the small end that did not go around past the centerline. The Prox had a huge cast in cutout,that was well past centerline and this was seriously joining the Aux and A transfer together as the piston passed over them.

Changing the piston fixed the jetting issue immediately,where previously it would run rich ( 500* ) no matter what jet was in it.
Any engine on petrol should be able to run past 600* in the header without any problems at all, no matter what the cc,rpm or bmep.


Hi Wobbly, when you say short circuiting do you mean exhaust gas entering the transfers or transfer outflow entering the exhaust duct .

With regard to the piston cutout it seems most pistons have some form of cutout that will link the Aport to the aux exhausts , why is this cutout there and why do some pistons have such different size cutouts . as you mentioned a cr 250 wossner has a relatively small cutout while a kx 250 pro x has a large cutout , both would join the A port and aux ex to some extent ,so I imagine some joining of these ports is acceptable
cheers Richard


If the Aux port is in front of the pin hole then no linking occurs,same with the skirt holes or pockets for weight reduction.
When linking does occur there must be transfer mixture entering the Ex as the egt drops,and going leaner does not fix this.


I also cool the back of the spigot, with slots thru the casting into the water.
The pic is an old version done by hand as a test - also shows the smaller exit now being used in red line.
The extended Aux ducts have a huge effect on the Blowdown Cd, Jan said he saw this extra flow pattern right up the diffuser on an Aprilia pipe when it was cut open.

[TZ350]

I discovered that making the underside of the transfer ports even with the piston in BDC
was very important: considerably more power, less detonation and far better piston cooling.
We started to have the exhaust ducts CNC machined in 1999 I think.
But first we had to overcome the new fuel regulations in 1998
102 octane had to be used instead of 130 octane.
We expected BIG problems.....
But within a couple of month's we had more power than before!
The compression ratio was lowered from 19,5:1 to 16:1
And the tailpipe restrictor was made 0,25mm bigger.

337390

Then a very serious combustion chamber development was started.
The result was that parallel squish was the best, with a squish height of 0,75mm
Less squish height would give more torque but less revs.
At 0,45 the piston touched the head....
Then a head insert with a much wider squish band (50% of cylinder surface) was tried.
And that proved to be the final touch.
We now had more power than with the 130 octane fuels, and less problems.
The sharp edge between combustion chamber and squish band proved to be very important.
Even a small radius would give 0,5HP less..


Transfer ducts. Many transfer ducts with small differences were tried.

We found more power by enlarging the A-port in the direction of the exhaust.
Only the lower half, but it was important to give the A-duct an inclination away from the exhaust!

The ducts were very conical, the smallest point being the port.
In and outside walls of the ducts had a constant radius from top to bottom.
The flow remained attached to the inside radius and so cooled the piston and eliminated detonation.

Flow bench testing and the Jante type testing proved useless for power improvement.

337395 "A" is better than "B"

Giving the rear side of the "yellow" B-duct an inclination versus the middle of the cylinder gave a big improvement


Pistons: We had cast and forged pistons.
Cast pistons gave slightly more HP, but sometimes cracked.
0,8mm piston rings gave more HP than 1mm rings.

As the auxiliaries and transfers overlapped each other a certain power loss was caused by this.
So closing the pin hole in the piston was tried.
There were many solutions that were tested, but they all caused some trouble.

337396

In the end the best, and most reliable, solution was welding then closed.
This was very well done by PANKL in Austria, and never caused any trouble!



Do you mind me asking why do you think cast pistons made more hp than forged?
Because forged pistons had a tendency to 'bend' their dome inwards.


When modifying a cylinder measuring duct sizes is not easy, especially in the curves!
You can see our solution to this problem on the photo....
Round 'sensors' fitted to a piece of welding rod!
We had them from 7-7,25- 7,5 and so on until 28mm.

337397

Behind the cylinder, in the wooden block.


Detonation. This started te be a problem when 50cc engines started giving more than 17HP, around 1975.
At the time I thought this was a limit on engine power.
Nikasil plated cylinders were very prone to detonation.
Because of the rounded off edge at the top.
At Minarelli/Garelli I solved this problem by sticking the cylinder head insert 3mm into the cylinder.
A good solution, used for many years.
But at Aprilia we found an even better solution: plate the first 5 mm around the bore at
the top of the cylinder.
Later this was machined to a very sharp corner, and this eliminated completely the unnecessary
'dead room' at the top of the cylinder, it also gave 0,3HP more.....
A little bit of still remaining detonation was eliminated by modifying the inner wall of the
transfer ducts, cooling the piston.
But part-throttle detonation remained a problem.....
Which we never had on the dyno!
On the photo you see a piston after a 54HP run...
As long as you keep the throttle wide open a 2 stroke doesn't brake down!


The lower the water temperature was the more power there was!
40° was the lowest we tried, each 5° more giving a power loss of about 0,4-0,5HP.
On the dyno we normally used 50°
The exhaust duct had to be cooled really well, especially the bridges in it.
In the beginning we had some trouble with holed pistons, caused by auto-ignition.
But bringing the water closer to the spark plug cured this completely!
We also found out that the quicker the water circulated the better.
An electric water pump was insufficient!!


At Aprilia we never had any high tech equipment, just an EGT sensor.
Nothing else was needed for finding more power!

And a very good Dyno to measure the results.


We tried various flat, and radius-ed pistons, but the original ROTAX dome always gave the best results.
With flat pistons the flow detaches which gives less piston cooling.



Did you try the hybrid Yamaha style? Flat top with chamfered edge?
Yes, of course....not better!


Mainly working on the crankcase.
Improved water cooling passages, which were far too small
And I really came to hate reed valves!!!!
Being used to rotary valves that never gave any trouble......


We never had any trouble with the rotary valve!
With the reed valve we had trouble every day....


Of course the reed valve is a big obstruction for inlet flow.....
While a rotary valve is not!
And when dyno testing the reeds keep breaking, costs you half of your time.....
The rubber detaches itself from the reed case after some time.
I really HATED it!!!!



Jan, how were you able to know when the flow was attaching or not to the transfer walls?By looking at the piston.

337398




Hi jan i was wondering if you saw any increase in revs when the rsa125 compression ratio dropped from 19.5 to 16:1 ? i have 19.5 also and worry it might hurt my revs
Yes, we got 500 rpm more!


Sometimes riders complained about not being able to change gear.
With their 'spark interruption' system.
So I had a button fitted to my desk so that I could interrupt the ignition.
At certain revs the engine kept running without a spark!!!
The power did not change, and there was no detonation......


Yes, I think it was HCCI
Auto-ignition by a too hot spark plug had quite a different effect!
That always ended with a seized engine....
HCCI caused no damage at all, the engine ran very well.
It happened with max. power carburation, and around and above max power.
I did very few experiments with it, which now I regret!
The test without spark was only done to find out where the gear change problem came from....

There was also part-throttle auto ignition which caused a lot of damage to piston and head!
Incredibly strong detonation!


Kel sent me this ......

jan thiel on part throttle deto

"I am 100% convinced our engine could have run for 6 hours at max power without seizing.
The problems arise when you close the throttle, or run part throttle!
The piston is mainly cooled by the transfer flow.
And at part throttle there is less transfer flow, causing detonation (auto ignition)
The entering fresh charge is ignited by the remaining, hot, burned gases!
You can see very severe damage to the piston after maybe 10 seconds at 20% throttle.
This still is an unresolved problem! I was thinking about a way to reduce engine power without closing the throttle. But how can you do this? I did not find a solution before I retired.
And nobody else was really interested.
At 100% throttle the engine was undestructible!
By making the transfer ports as wide as possible we had very good piston cooling."

No answer here but at least we are not alone with engines that fail on part throttle

I scraped the full coversation below from here:- http://www.pit-lane.biz/t3173p60-gp1...vermars-part-2

Brian Callahan
Jan or others, how did you control the tuned pipe wall temperature (or EGT directly?) when testing on dyno? This seemed the most difficult thing to mimic when testing either the GP engines at QUB or my R/C boat engines, in the lab. The inertial dyno or computer controlled brake seem to work best because we can match the test engine's acceleration with reality. On steady-state testing, EGT would simply climb 500, 600, 700, 750 °C until way past reality and the piston would seize.

Frits Overmars
This has always been one of Jan's greatest handicaps. He has asked for an inertial test bench over and over, but Aprilias race director Witteveen, or The Great Leader as we call him, never deemed it necessary....

Jan Thiel
When EGT goes up and up there should be some serious problem with the engine.
We never had pistons seize during our steady state tests.
Working on the dyno continuously 5 days a week!
I am 100% convinced our engine could have run for 6 hours at max power without seizing.
The problems arise when you close the throttle, or run part throttle!
The piston is mainly cooled by the transfer flow.
And at part throttle there is less transfer flow, causing detonation (auto ignition)
The entering fresh charge is ignited by the remaining, hot, burned gases!
You can see very severe damage to the piston after maybe 10 seconds at 20% throttle.
This still is an unresolved problem! I was thinking about a way to reduce engine power without closing the throttle. But how can you do this? I did not find a solution before I retired.
And nobody else was really interested.
At 100% throttle the engine was undestructible!
By making the transfer ports as wide as possible we had very good piston cooling.

As Frits has written, I would have liked to have also a dynamic testing possibility, with a flywheel.
In my opinion you should simulate a straight, starting at around 10.000 rpm, and shift through the gears
until you reach top speed. And with the airbox as used on the bike, with a ventilator that simulates the raising
air speed as it would be on track! Maybe it is interesting to know that without a ventilator the engine gave
less power with the airbox fitted.

I was told that such a testing system was too expensive.
And unnecessary as we won anyway!

I can also see a disadvantage of 'dynamic' testing.
Because the duration of the test is so short you can get away with very extreme (too extreme?) settings,
without damage.

GrahamB
Remember that retarding the ignition is used at high rpm to increase exhaust temps and effectively shorten the pipe. So it's likely to increase the heating of the front edge of the piston...

Haufen
Yes I know, but part load egt is usually lower than full load egt. And I think most of us would prefer higher part load egt over part load detonation. Of course, how far one could go and how far one would need to go would have to be tested, and how much would be needed would depend on the engine.

Mic
How about much larger travel on the exhaust power valve.
With a shorter exhaust port duration power is lower. And this is already controlled with the stepmotor over the ECU.

Jan Thiel
This causes detonation (auto ignition)
The problem is that the burned gases do not exit the cilinder!
Retarding ignition also does not make sense.
As you have an AUTO-inition problem!
So the engine does not 'listen' to its ECU anymore!
What you would need is the same fresh gas flow, but with less HP!
Not easy to achieve!
A variable tailpipe might help.

Jan Thiel
Haufen, We also had such a test bench at Aprlia.
The prototype of this test bench was developed by Apicom in collaboration wit Aprilia.
So we had it first, and now anyone can buy it.
It was helpful but not what I wanted.
A so-called step test.
And without the airbox!

Frits Overmars
Like Jan wrote, a shorter exhaust duration will worsen the detonation. What happens is this:
During normal operation, the blowdown time.area of the exhaust ports is sufficient to drop the cylinder pressure below the crankcase pressure before the transfer ports open, even at high rpm.
At part-throttle that cylinder pressure will drop to the same level, but now the crankcase pressure is much lower and exhaust gases will enter the transfer ducts, contaminating and heating the fresh mixture even before it enters the cylinder.
A theoretical solution would be a power valve that enlarges the normal exhaust timing instead of lowering it. But that is impractical as it would ruin the shape of the exhaust duct and it would cause cooling problems in the cylinder's exhaust area.
A variable tailpipe area, like Jan says, can be a more practical approach. I designed a simple solution, shown in the drawing below, but then two-stroke development at Aprilia was terminated because of Dorna's ban on two-strokes

Howard Gifford
Another way to lower HP without sacrificing piston cooling would be to richen the mixture when you want to lower the power. With a signal to a fuel enrichening solenoid you could achieve a power range. It would then be instantaneous and programmable. Not enviornmentally friendly but would work for racing. The mixture ratio difference from high power to low power would need to be just rich enough before a misfire and just lean enough for sustained high power.

The variable tailpipe idea will work but I suspect the pipe temperature would drop off and it would take several seconds to regain full power. But then again rich mixture may have the same problem.
Two strokes are like redheads. Hard to figure out and very temperamental. But when they are happy they are a lot of fun!
HG

Jan Thiel a écrit:
The entering fresh charge is ignited by the remaining, hot, burned gases!
You can see very severe damage to the piston after maybe 10 seconds at 20% throttle.
This still is an unresolved problem! I was thinking about a way to reduce engine power without closing the throttle. But how can you do this? I did not find a solution before I retired.
And nobody else was really interested.

Institute of TwoStrokes
On aftermarket ignitions I use there is a mode I can switch on where a number of indivdual sparks are cut, depending on throttle position. It is now only configured for cutting 1 in every 3 sparks on over run(tps <10% with high rpm). Would that sort of system solve the part throttle detonation? If the number of sparks cut could be varied along with TPS for this to begin and end? If it would be helpful I'm certain the manufacturer would only need a software change to do this.

Jan Thiel
I certainly thought about cutting sparks.
But remember: the problem was AUTO-ignition!

GrahamB a écrit:
Remember that retarding the ignition is used at high rpm to increase exhaust temps and effectively shorten the pipe. So it's likely to increase the heating of the front edge of the piston...

Jan Thiel
Indeed, retarding too much caused detonation!

Institute of TwoStrokes a écrit:
Jan Thiel a écrit: The entering fresh charge is ignited by the remaining, hot, burned gases! You can see very severe damage to the piston after maybe 10 seconds at 20% throttle.
This still is an unresolved problem! I was thinking about a way to reduce engine power without closing the throttle. But how can you do this? On aftermarket ignitions I use there is a mode I can switch on where a number of individual sparks are cut, depending on throttle position. Would that sort of system solve the part throttle detonation?

Frits Overmars
As Jan pointed out, once you have auto-ignition, the engine does not listen to its ECU any more. So you would have to start skipping sparks well before the onset of detonation.
In a foul-stroke your proposed system does work, but a two-stroke would react far from linear. For example, if you skip 1 in 4 sparks, you will loose much more than 25% of engine power because that one missing spark will cause the gasdynamics processes to collapse. The main problem would be to realise a smooth transition from intermittent to full ignition.


Jan Thiel a écrit:
Retarding ignition also does not make sense.
As you have an AUTO-inition problem!
So the engine does not 'listen' to its ECU anymore!
What you would need is the same fresh gas flow, but with less HP!
Not easy to achieve!
A variable tailpipe might help.

Haufen
I think I expressed myself unclearly. What I meant was the following:
Imagine your engine with the throttle opened just above the auto-ignition range. Then you have sufficient transfer flow, but too much power. To lower the power, now retard the ignition. Then you still have sufficient transfer flow, but with less power.

I think Honda used auto-ignition to their advantage on two-strokes. As far as I remember they did it with a (very) variable exhaust power valve.

Frits Overmars a écrit:

Mic a écrit:
How about much larger travel on the exhaust power valve. With a shorter exhaust port duration power is lower. And this is already controlled with the stepmotor over the ECU.

Frits Overmars a écrit:
Like Jan wrote, a shorter exhaust duration will worsen the detonation. What happens is this:
During normal operation, the blowdown time.area of the exhaust ports is sufficient to drop the cylinder pressure below the crankcase pressure before the transfer ports open, even at high rpm.
At part-throttle that cylinder pressure will drop to the same level, but now the crankcase pressure is much lower and exhaust gases will enter the transfer ducts, contaminating and heating the fresh mixture even before it enters the cylinder.
A theoretical solution would be a power valve that enlarges the normal exhaust timing instead of lowering it. But that is impractical as it would ruin the shape of the exhaust duct and it would cause cooling problems in the cylinder's exhaust area.
A variable tailpipe area, like Jan says, can be a more practical approach. I designed a simple solution, shown in the drawing below.

337391

Haufen
I think I have not gotten behind the variable tailpipe idea, yet. What would you like to vary with it and to achieve which effects? At little throttle openings the pressure inside the exhaust pipe is already very close to atmospheric pressure (if not even) on most engines. And if you had say 100mbar inside the pipe at the critical throttle opening, then the engine might have had more power with a bigger tailpipe.

Frits Overmars
'Opening' the end of the reflector will cause a substantial weakening of the reflected pulse and thus less charging of the cylinder. Izze simple, no?

Haufen a écrit:
Variable transfer timing would be nice also, if feasible.

Frits Overmars
That would be my ideal. Lowering all the transfer roofs would shorten the transfer timing and lengthen the blowdown timing, so the cylinder pressure would drop further before the transfers would open. It would cure the hig revs/low power-detonation and it would improve the power band because a too early-returning exhaust pulse would have less opportunity to push the fresh cylinder contents back into the crankcase.
A controllable transfer height would even make a throttle valve unnecessary.
There's only the little problem of how to build it...

Jan Thiel
Haufen, Auto-ignition usually occurs between 10 to 40% throttle at high revs.
In fast, non full throttle corners.

Retarding the ignition was tried to diminish power.
This makes the exhaust very hot.
Then, when you need full power, it is not there because the exhaust temperatures are wrong.
This takes a little time, when the engine is back to full power you are already at the end of the straight!
The same goes for water injection in the exhaust.
It was tried by Rotax about 25 years ago.
There was a LOT more power at low revs, so the rider had to take it easy when opening the throttle.
But the engine revved a little bit less, because the exhaust temperature did not recover at high revs.
And lap times became actually slower.
After a day of testing the system was switched off.
Lap times immediately improved!

A very important thing when accelerating is the power you have after changing gear.
Spark interruption may be not so good for this!
As I did not have the dyno I wanted this gearchange effect could not be tried on the dyno, very regrettably!
Retarding the ignition and weakening the mixture by powerjet can also have a negative effect on this.
The exhaust temperature should be 'Right' for the No. of revs after you change gear.
If the temperature is too high there will be less power!

So it is REALLY complicated!

Part throttle deto.

[TZ350]

.

Follow the link to read the whole story about Team ESE's GP/NSR110cc engine build. You will have to follow the links to see the whole post, pictures and related links.

Page 1680 ......:Police: https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page1680

This is Team ESE's formula for a reliable 110cc water cooled Bucket racing Engine.

It's very simple, NSR cylinder, de stroke crank, long rod, to give enough room for a thick spacer plate to marry the NSR cylinder to the GP100 crankcase, can't get any easier than that.


333324

Building another Suzuki GP100 NSR 110 hybrid using a re plated but standard NSR250 cylinder.

Stroke 48mm Bore 54mm for 110cc ... (an NSR is 54 x 54).
Inlet opens 140 BTDC closes 80 ATDC
Exhaust opens 80 ATDC
Transfers open 114 ATDC

The shorter stroke gives me a very useful increase in blow down time area without having to do any porting at all.


329021.... https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page1681

How to make a decent light weight racing 12 Volt generator stator for the Suzuki GP/TF/TS RG50 from a Lifan after market magneto kit. We have spun these to 14,000 rpm plus on the dyno and they have proved reliable on the track.

The Lifan back plate and modified flywheel fits perfectly into the Suzuki GP/TF/TS and RG50 cases.

329025

Basically the conversion involves transferring the center from a Suzuki flywheel to the Lifan.

329023 ... 329024

Chambers starts by spinning the heads of the rivets off of the Suzuki flywheel. He then punches out the rivets of the Suzuki fly wheel to free the Suzuki's center boss.

He then bores the Lifan boss out to suit the Suzuki boss, a close fit is required here, basically size for size, with minimal clearance. And then he spins the heads of the rivets off the Lifan flywheel.

The next move is to orientate the Suzuki boss and Lifan flywheel so that there is an appropriate gap between the heal of the trigger tooth and trigger coil at TDC, usually 20 deg.

329026 ... 329022

The last move is to secure the Suzuki boss to the remains of the original Lifan boss left inside the Lifan flywheel. Chambers drills and taps through the Lifan flywheel and the remains of the original Lifan hub and rivet's. If a rivet turns, he gives it a little touch with the TIG, just a small tack weld is all that is needed to hold a loose rivet while it is drilled and tapped.

We cut the two Lifan high Voltage winding's off and re wind the three empty stater polls for extra 12 Volt current capacity. Although you can get away with using just the three original 12 Volt coils for powering an Ignitec but if you want a water pump too then you need to rewind the empty three polls.

Use a Lifan voltage rectifier/regulator and a 36V 2200uF capacitor for powering an Ignitec CDI ignition. If you do try winding on extra coils remember they are wound in alternating directions, ie; the first clockwise the second anti clockwise, the clockwise again and so on around the stater.

We use the Lifan stater assembly to power our Ignitec ignitions. We have not tried it but you may get away with using the complete Lifan racing ignition package and CDI. The Lifan CDI is probably better for engines that don't rev much past 10k or so.



328247

The Bad news .... a broken tooth which showed the classic signs of a fatigue crack ending in a fracture.

The Good news is that there is plenty of oil getting to the gears. No sign of damage that could be attributed to a lack of lubrication.


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Case spacer and extra wide spacing between crank halves for a bit of extra crankcase volume.

328244

Gearbox oiler tube and KE175 rotary valve cover.

328248

NSR cylinder showing one of the fuel injector ports and rotary valve inner. Not much room left between the RV and gearbox input shaft.

The good thing about having to pull the motor down is that I am now very comfortable with gearbox oil feed of about 1L min from those small pumps is well and truly sufficient.


Dr Evil does it, a F4 class legal water cooled 110cc engine.

337400...... 337399

Finally, after several weeks of detailed finishing work Mr Bigglesworth's Frankenstein engine is ready.

Possibly the worlds first ever 1979 learner/commuter Suzuki GP100 engine fitted with EFI, digital ignition, a dry sump six speed gear box conversion, an oversize KE 175 rotary valve, a servo power valve and water cooling.

324039

All that remains is to fit it into the frame. Being 12mm wider than the original five speed air cooled unit and needing a radiator, pump and associated plumbing, it is not a straight swap but hopefully I will get it all done this week.


323698

Making progress with the six speed Suzuki GP110cc engine. Spent my evenings after work for the last couple of weeks test assembling everything to make sure that they fit and the clearances are correct. Lots and lots of detail work has been required to get things right.

323702

Micro polished gear-set courtesy of Morgan Engineering.

323700323701

Lots of port area. Exhaust opens 80 atdc transfers open 114-116-117 atdc and inlet opens 145 btdc and closes 80 atdc. No porting work has been done on the cylinder at all. The port timing has been obtained by adjusting the cylinder up and down with a spacer plate and shims until I got the timing that EngMod suggests as being optimal.

Between the variable timing of the exhaust port power valve and a pressure reducing valve in the expansion chamber I hope to get a wide spread of useful power.

The inlet tract is a nominal 30mm with a short 24mm venture restriction at the engine end of the carb to satisfy class regulations. From previous experience, I am not expecting the venture restriction to have much real effect on power output.

323699

Major crankcase volume, it will be interesting to see how that goes. Slow speed injector port on the right hand side. The injector port is angled so the injection stream fires directly into the face of the incoming inlet air stream. The timing of the injection squirt can be adjusted in the EFI software for best effect.

323703

The top of the cylinder was skimmed 2mm and the head insert also protrudes into the cylinder 2mm. The insert itself is a blank that can be machined to what ever combustion chamber you like.

The beauty of reducing the stroke on a 2T motor is that even without any porting on the cylinder, the exhaust blowdown time area is automatically increased.

I was unsure about the legality of using a VHM head but no where on the paperwork does VHM call it a racing part. It is clearly labeled as being for a NSR250 which is a class legal non competition engine.


It is a over size rule so the motor would have to start out as a 100cc or 150cc ?, just building a 110cc or a 158cc is against the rules is it not? I have wondered about the fxrs as many seem to build them out to the oversize limit straight off the bat , not as a need to do so after a blow up which I would consider to be outside the rules . After talking to a couple of people at the track yesterday ,they had similar feelings any thoughts on this.


I agree building an engine to max oversize straight off is a grey area that probably needs addressing along with other issues like, what size is a 24mm carb and how much of an engine can be homemade before it is no longer based on a non competition engine. We have had a pretty common sense approach to this until now and I understand some of the AMCC Bucket committee members are looking at how a re write of the rules could address some of these grey areas.

Just for the record, when this extra oversize rule was mooted for the convenience of a limited few MB100 pilots I made a submission to MNZ opposing it. Now that it is here and available to all, I am going to enjoy it.

319215 Suzuki GP100 bottom end with rebored (replated) NSR cylinder.

I expected a bit of opposition. So I was careful to start with a 100cc engine. A air cooled Suzuki GP100 that I had previously raced and after adding an old water cooled NSR cylinder and porting it, the cylinder was rebored (replated in this case) because it needed it.

Old dud cylinders are cheap to buy. So it is a totally legal within the rules and the spirit and the intent of Bucketracing endeavor. Which started of as a 100 and finished up as a re bored 110, my arse is totaly coverd rule wise.

The only difference between what others have done and what I am doing is approach, different approach same result, a water cooled F4 2T100


317507

Old air cooled Suzuki GP100 soon to be a 30+hp water cooled 110cc six speed Suzuki GP-NSR Frankenstein engine.

Another step forward, the cylinder to crankcase adapter/spacer plate.

317506

I picked up all the finished machining for the crankcases yesterday. There is still a lot of hand work too be done on things like cutting in the transfer ports and inlet tract but now I have everything to start finishing it off and putting it together.

317508

The engine is going to run a dry sump for the primary gears and clutch. The wet clutch plates are going to be lubricated by pumping oil up the center of the gearbox input shaft to the inside of the clutch hub. Where it will get centrifuged out through holes in the inner hub to lubricate the clutch plates. After that it will drain back into the sump leaving the clutch assembly free to rotate in air instead of churning around in a bath of power robbing oil.

For a pump I am going to use a diaphragm fuel pump. I had thought of running the gear cluster dry sump as well but just did not have the courage to rely on getting the oil spray right for lubricating the gears, maybe next time.

At the GP, someone in the know told me there are those planning to get the 110 rule thing that was 105, now 110 changed back to 107. That will work for the shorter stroke MB100 boys who got the rule changed in the first place so they could run the cheap over sized KT100 pistons but it would disadvantage all the other 100cc makes like Kawasaki and Suzuki who then couldn't. To be fair, a rule change to make the KT100 piston available without de stroking the crankshaft needs to make the advantage available to everybody in that class. And that means 110cc max oversize for F4 100cc 2T's if you wan't to share the love around with the cheaper over sized pistons.

In the end it does not really matter to me what cc rule change advantage they try to give themselves. If it disadvantages my current build, I will just make another crankshaft with a stroke to suit. :laugh:

Currently I have been working with old cylinders that need re plating to meet the re bored part of the rule. On any cylinder shortening the stroke increases the blow down STA without any porting required. So if I have to shorten the stroke anymore to stay within any new tricky dicky rule change I will be able to enjoy the advantage of the correct amount of blow down and not having to port and re plate the cylinder. Basically I will be getting the same power/rpm for the effort of a crank build, as much power as before for less effort, a win win in my book. I just wish I had figured that before I started the 110cc version.

317511

Oooo look another crankshaft could this be a 106cc version, I have been thinking ahead and now have 115cc 110cc and 106cc crankshafts for the GP/NSR hybrid and could easily build a 100cc version if I had too. A 125cc version would be difficult because of limited space in the crankcase.

The only rule change that would really effect Team ESE would be banning the spirit of Bucket racing and limiting cleverness. There is the Hyosung standard production cup, class, or whatever it is, for those who want to take the easy path and not have to make any real effort to develop a reliable front running engine. That sort of racing is as interesting as Bat shit in my opinion.

The history of Racing is littered with good ideas that have effectively been banned because others have been to lazy or technically challenged to keep up. In Buckets, part of winning is building something special, and in this class I think attempts to limit that are wrong.


The Dry Sump and Gear Oiler, not to sure how well this idea will work so I am going to try it on the old air cooled engine first.

317734 317736

The oil spray bar. The oil level in the crankcase will be minimal and well below the gears and clutch hub. The bulk of the oil will be held in a sump tank.

The oiler drops oil onto the gear pairs, I sure hope the oil mist generated will find its way to the gear bearing surfaces and the ball races.

317738 317737

The oiler lubricates the clutch hub gear through a small hole near the end of the spray bar and the end of the tube sprays oil onto the outside of the clutch hub itself, some of it will hopefully dribble down to the output shafts plain bush bearing. There is a new hole in the input shaft to lubricate the clutch hub bearing. The input shaft hole was a challenge as the shaft is as hard as the hobs of hell. Thankfully Chambers found a way of doing it with Dremel and diamond bit.

317735

Oil is feed to the spray bar and up the inside of the gear box input shaft to lubricate the clutch hub and release bearing.

317733

As well as the dry sump and gear oiler I am trying a longer rod for more crankcase volume.

The motor was going together really well until I fitted the cylinder. Then I found the fatter rod was jamming around TDC. Now the cases need relieving, bugger, I have to take them apart again.



Another step on the way to building the Suzuki GP/NSR110 super Frankenstein engine, the crankshaft.

316848t

The GP/NSR110 crank parts.

316844

Old balance holes plugged with alloy and a Mallory slug opposite the big end. 22mm diameter 60mm long big end pin from a diesel, 115mm RD400 rod, RGV250 big end bearing and small hardened thrust washers. I made the bigger thrust washers out of material that is tough as shark shit.

316849316847

0.8mm side clearance. The flywheels are champhered to allow the wind to flow over the inner edges so the air mass can resonate into and out of the center section with less disruption, (hopefully).

316845316846

50% balance factor. The balancing was achieved by skimming the inside faces of the crank, removed 2mm each side. Plenty of crankcase volume with this baby.

Back in the 80's a friend once fitted an RD350 crank into a set of RD400 cases, lots of extra case volume with the smaller 350 flywheels. I predicted it wouldn't work, not enough crank case compression, not the done thing etc. etc.... but it worked like a charm.


Many thanks to Kickaha for the GN clutch.

316505

Honda copy Monkey Bike primary gears are straight cuts which have the same C/C distance as the GP.

GN Clutch on the left and GP one on the right. Previously I had managed to squeeze an extra plate into the GP one. The original GP 6 plate clutch would slip under power, modifying it for 7 plates cured the slip.

316506

The big gear is smaller than the original GN125 and GP125 helical gears.

316507

Once the straight cut gear is fitted to the GN clutch it will spin faster, transmits the same power but the plates are subjected to less torque and the need for cramming in an extra plate to stop clutch slip.

The new GP/NSR110 is going to have straight cut primary gears and conventional clutch springs.


Spent a happy afternoon checking out the balance of the new 48mm stroke NSR GP110 crank and the NSR cylinder port STA's with the 48mm crank.

316341316345

The crank overall is 12mm wider than a standard GP crank. After setting the crank up and working out the balance weights required for a BF of 50%. I found the Mallory slugs that were fitted to be to heavy but this is good news because I can now keep skimming the inside faces of the crank halves until it comes right. In the end there will be plenty of volume between the crank webs.

316344 316343

Checking out the timing, things worked out much better than I could have hoped for.

With a 15mm spacer the Exhaust is opening at 80 deg ATDC and Transfers at 118 ATDC and the piston just clearing the port floor at BDC.

316346

The deck height is -5.7mm for 0.8mm squish. This all matches the optimum STA's worked out with EngMod2T for this project.

316342

A 15mm cylinder spacer/adapter plate brings the port timing into perfect alignment. (with 115mm RD400 rod, 2010 RM125 piston, 48mm stroke).

Not bad, a 54mm stroke cylinder fitted to a 48mm stroke motor and the timing works out perfectly.

Great, up until now it was all on faith and a belief that I could overcome any problems with the idea, but now I know it really is going to work.


The Suzuki V100 2T Scooter cranks have a 48mm stroke and NSR 250 MC21 cylinders are a 54mm bore, 48 x 54 = 109.9cc. The crank is getting a 22mm bigend pin for a 115mm RD400 long rod.

316268 316269

Here is the rest of the story:-

Original 100cc Suzuki GP motor being fitted with a re-plated (re-bored) NSR MC21 cylinder.

God Bless those that had the rules changed to 110cc max over bore allowance so they could use cheap over-sized KT100 pistons without going to the trouble required of de stroking to stay within the old 105cc rule ...... :D


Thanks to some very expert engineering help the six speed spacer plate has been made and fits perfectly.

315900

With the spacer plate fitted the new gearbox has the right sort of end float and spins over very nicely.
Next move is the long rod crankshaft.


Here is a "thing" we machined up today, facilitate a six speed gearbox I believe ;)

[JanBros]

found an error because of "re-organising" tables, same link with new file : http://users.telenet.be/jannemie/JanBros%20Porting%20Test.xlsm

[Muhr]

The spec for a TM KZ10C selected factory cylinder is 27mm ATDC = 82.54* = 194.92* Duration.
That certainly doesn't mean they actually are.
But with the piston radius , there is some conjecture as to what the real timing is effectively.
It would appear that changing the cylinder height 1/2 the radius on the piston has the effect of great front side power at the expense of overev.
So now I need to experiment with a slightly higher adjustment, then try an increased radius as well.
Does anyone know what VHM did with their option piston and insert using a radius.
They reported a 1 Hp increase , but didnt seem to loose overev in the dyno sheet i have seen.

Do not know what or if VHM did something with a cylinder head
https://www.youtube.com/watch?v=4KRwOObWCtA

[wobbly]

I have searched all over the net, and have seen that video from VHM. You can see the piston edge radius but they dont seem to have revealed the insert anywhere I can find.
And I dont intend on spending the silly money they want for pistons or heads - far rather learn how its done myself , alot more interesting as well.

[schutten]

The inlet channel of the vforce is not symetric,is this through the carb offset angle?
The engine has plenty of midrange,but losing on top.
The engine has a Keihin pwk 38 airstriker, and thinking of replacing pwk for pwm and add a scalvini exhaust.

Are there more people with experiences with the 2014 TM MX125 engine?

[dutchpower]

Closer at home

[schutten]

I have searched all over the net, and have seen that video from VHM. You can see the piston edge radius but they dont seem to have revealed the insert anywhere I can find.
And I dont intend on spending the silly money they want for pistons or heads - far rather learn how its done myself , alot more interesting as well.


For the 85cc mx engines, they look like this.

[Muhr]

The block begins to take shape!

And this is what will look like dressed up.

[JanBros]

TZ, came across this : https://ac.els-cdn.com/S1876610217337578/1-s2.0-S1876610217337578-main.pdf?_tid=d7044e50-a744-4c97-9eae-ba15a67c2d0f&acdnat=1529420973_646f4304e72860c6c042e75e70332750

didn't reed it, but might be useful for you ?

[wobbly]

VeeForce make the carb stuffer to match the stock rubber manifold that has had the ears cut off.
You can buy the stuffers and cut them in 1/2 to make even a perfectly round entry,this is worth about 1.5 Hp in a TM MX engine.
Dump the angled manifold, for a straight version, and dump the Airstriker carb ( if you dont need throttle response at 4000 rpm ).
The straight manifold ( short as possible ) with a PWM gives a huge boost in power everywhere, but especially top end overev.

The 85cc piston does not appear to have an edge radius at all - only a small angle like Yamaha use ?????

[F5 Dave]

And this is what will look like dressed up.

So. . When you are producing the gearbox version in significant numbers as a road- legal bike at a consumer product price. . . Make sure you export a bunch over here won't you? :first: