ESE's works engine tuner

[jonny quest]

Yes Wobbly. .. except when WFO.

My thoughts are to get more heat into pipe faster at the lower revs thus widening powerband. The TPS settings are for different throttle openings... not for wicking it WFO at the lower revs waiting for motor to catch up to your wrist.

[wobbly]

But best throttle response is had with tons of advance at low rpm/WOT.
If you retard at low rpm/WOT the pipe may get hotter, but it will be very slow responding - due to the low cylinder filling and thus low dynamic com.
You have to use so much advance down low it will instantly deto if you run it at part throttle down there.
That is where the TPS is good in that you can pull out timing when at part throttle/low rpm,then add a heap when slamming it open to make it drive hard.

[FastFred]

You have to use so much advance down low it will instantly deto if you run it at part throttle down there.

This is the lesson Team ESE learned with their 30hp cylinder. The problem was not the cylinder or that it was making 30+hp but that they had optimized the programmable ignition timing on a dyno using WOT runs.

On the track the bike ran beautifully being hammered in practice but the piston failed in the slow warm up laps before gridding up for race one.

Happened at Taupo and then completely destroyed the piston/cylinder at Kaitoki, when they learned what the problem was they got a TPS and setup a 3D map in the Ignitec.

Been no problems since, they just need to make another big hp cylinder, can't buy em, have to make them.

[2T Institute]

Yes Wobbly. .. except when WFO.

My thoughts are to get more heat into pipe faster at the lower revs thus widening powerband. The TPS settings are for different throttle openings... not for wicking it WFO at the lower revs waiting for motor to catch up to your wrist.

Try pulsed power jets or a air solenoid.

[koba]

But best throttle response is had with tons of advance at low rpm/WOT.
If you retard at low rpm/WOT the pipe may get hotter, but it will be very slow responding - due to the low cylinder filling and thus low dynamic com.
You have to use so much advance down low it will instantly deto if you run it at part throttle down there.
That is where the TPS is good in that you can pull out timing when at part throttle/low rpm,then add a heap when slamming it open to make it drive hard.

This should have already absorbed in to my brain but it hasn't enough, must be stupidity.
I've had a few issues in the past with an ignition that had a lot of low end advance and part-throttle piston death.
Anyway, thanks, you just saved me a holey piston.

[wobbly]

I have a pending job to do a YZ85 ( 110 ) setup for flat track racing in USA - can anyone here lend me a pipe for a day so I can measure the bend centreline
to produce a new pipe.
Thanks in advance
wob

[TZ350]

For those not familiar with B track here is a video


http://youtu.be/5CUU_HBYRNw

BOB is coming up ... Battle of the Buckets its a pilgrimage, a must do, and then the next weekend is Greymouth for anyone who wants to ride at all the great racing venues.

[chuckit]

Has anyone tried using a different means of determining engine load? With a four stroke you'd be able to use a MAP sensor. Is that feasable on the 2T engines? The carbs used on these bikes rarely lend themselves to actuating a TPS.


This is the lesson Team ESE learned with their 30hp cylinder. The problem was not the cylinder or that it was making 30+hp but that they had optimized the programmable ignition timing on a dyno using WOT runs.

On the track the bike ran beautifully being hammered in practice but the piston failed in the slow warm up laps before gridding up for race one.

Happened at Taupo and then completely destroyed the piston/cylinder at Kaitoki, when they learned what the problem was they got a TPS and setup a 3D map in the Ignitec.

Been no problems since, they just need to make another big hp cylinder, can't buy em, have to make them.

[Drew]

Has anyone tried using a different means of determining engine load? With a four stroke you'd be able to use a MAP sensor. Is that feasable on the 2T engines? The carbs used on these bikes rarely lend themselves to actuating a TPS.A cable splitter and a remote TPS is hardly rocket science to install though.

[wobbly]

The RGV and Aprilias have a simple splitter box with TPS, easy to use with 1 in and 3 out for two carbs and oil pump.

[Yow Ling]

Has anyone tried using a different means of determining engine load? With a four stroke you'd be able to use a MAP sensor. Is that feasable on the 2T engines? The carbs used on these bikes rarely lend themselves to actuating a TPS.

EGT would be an indicator, mass airflow would probably be fairly accurate indicator, accelerometer, torque sensor, but I would have thought TPS would be the worst as it only shows TP not load

[chuckit]

I may have to try it one of these days. It'd be a neat and tidy solution if it works.

[richban]

Here you go Rob. An update on the NSR300. At the end of the lap the other 300 comes into view.

Disclaimer. The EGT is reading wrong. Its earthing out on the mount and reading hi. And the rev counter not working so just don't look at that.

<iframe width="560" height="315" src="//www.youtube.com/embed/2LjlfAecw8s?list=UUzagK2vhzjvKtWJ9cYZRuDA" frameborder="0" allowfullscreen></iframe>

[wobbly]

What rpm are you gearchanging the 300 at Rich ?

[richban]

What rpm are you gearchanging the 300 at Rich ?

Hard to know till I get the rev counter working again but should be around 11700. Peak is 11800.

[jasonu]

Here you go Rob. An update on the NSR300. At the end of the lap the other 300 comes into view.

Disclaimer. The EGT is reading wrong. Its earthing out on the mount and reading hi. And the rev counter not working so just don't look at that.

<iframe width="560" height="315" src="//www.youtube.com/embed/2LjlfAecw8s?list=UUzagK2vhzjvKtWJ9cYZRuDA" frameborder="0" allowfullscreen></iframe>

The box sounds really wide ratio on the up shifts.

[richban]

The box sounds really wide ratio on the up shifts.

Yeah its the normal street one. I like it. Just needs a taller 1st. Other bike has close F3 box.

[Bert]

Here you go Rob. An update on the NSR300. At the end of the lap the other 300 comes into view.

Disclaimer. The EGT is reading wrong. Its earthing out on the mount and reading hi. And the rev counter not working so just don't look at that.


Great work guys.
There was a lot of talk around the paddock about these Speedjunkie/fortyfive racing NSR300s.
You guys should be proud of the time and effort you have put into them. Clearly the best presented bikes on track and boy do they go....:niceone:

Do you have the full video of the last "carb class" race? Missed it dealing with the juniors...

[richban]

Do you have the full video of the last "carb class" race? Missed it dealing with the juniors...

Sorry mate. I wish I did have that on camera. I didn't film any racing that day. Won't make that mistake again. Team NSR300 going full bucket racer mental at each other from the first corner.

And thanks Team GPR for the 6 more hp on friday night:msn-wink:

[Bert]

Sorry mate. I wish I did have that on camera. I didn't film any racing that day. Won't make that mistake again. Team NSR300 going full bucket racer mental at each other from the first corner.

And thanks Team GPR for the 6 more hp on friday night:msn-wink:

Bum. If the last Superlite race was anything to go by, it must have been a corker...

And cheers for the plug. The GPR boys have enjoyed helping out. Getting a real understanding of these igntech. Now it's time to sort out the powerjeting and TPS based maps.

[F5 Dave]

Sounding nice Rich, and looking like its haulin.

[lodgernz]

I'd be interested to hear opinions good or bad on any of the racing plug electrode configurations (hopefully) attached.
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=300074&d=1408483304&thumb=1&stc=1

[Flettner]

I use the flat type, third one back on my Kawasaki, on ethanol fuel and heavy oil mix. Never fouled it yet. Ignitec fires it through both channels at once.

[Grumph]

I use the flat type, third one back on my Kawasaki, on ethanol fuel and heavy oil mix. Never fouled it yet. Ignitec fires it through both channels at once.

You need serious spark voltage for the surface gap plugs. Obviously you do have...I'm impressed.

As an aside you can get preignition - or autoignition - with surface gap plugs. They're plated on the large ring electrode, i've had the plating flake giving sharp, hot edges...Just machine a tad off.

[wobbly]

The middle one is the type developed by NGK for Honda RS125/250.
Been there done the dyno work - those special tip type plugs make more power - end of story.
They were originally a short body type, and cost a fortune, including the special short cap as well.
The R7376 has a normal body with that electrode configuration, Platinum fine wire earth, and Iridium fine wire centre.
Kicks arse with the Denso equivalent and the B10EGV type simply isnt in the same league.

[lodgernz]

The middle one is the type developed by NGK for Honda RS125/250.
Been there done the dyno work - those special tip type plugs make more power - end of story.
They were originally a short body type, and cost a fortune, including the special short cap as well.
The R7376 has a normal body with that electrode configuration, Platinum fine wire earth, and Iridium fine wire centre.
Kicks arse with the Denso equivalent and the B10EGV type simply isnt in the same league.

R7376 still costs a fortune Wobbly, more than $100 each. Thanks for the post anyway. Good info always appreciated.
Can I ask if you have any opinion on the cheaper Iridium NGKs, such as the CR9EHIX-9?

[chrisc]

http://www.accelerationkarting.com/ngkr7376-10racingsparkplug.aspx

Sets of 4 and 6

http://www.nengun.com/ngk/racing-spark-plugs-r7376-r7434-8

http://www.ebay.com/itm/NGK-R7376-RACING-COMPETITION-SPARK-PLUGS-HEAT-R7376-7-R7376-8-R7376-9-R7376-10-/320938019501

[wobbly]

I have got R7376 several times for around 35USD, about 1/3 of the cost of the shorty Honda style.
And I would never use an Iridium plug again in a real race engine.
They seemed like a great alternative till we lost several engines in a row, including dropping an earth electrode on
the last corner of the last lap - to take a 125 kart title 3 in a row.
The Iridium centre ceramic will crack and fall off the instant you see even the smallest amount of deto, and the reason the R 7376 style plugs are expensive is that the rare
earth ground strap is laser welded to the body - I have never seen or heard of one failing, and the ceramic can crack occasionally, but again I have never seen one drop out.
Its one of those things, just accept that you pay for what you get, and buy the best when it really matters.

[lodgernz]

Thanks for your help guys. Learning (slowly)...

[senso]

Good night everybody, I have finally the opportunity to use EngMod 2t, and I would like to know if someone as models of common reedvalve cages and common carburetors?
If not, when I measure what I have accurate tools to measure them I will do that and share the files for what I have access:
oko 24, oko 30, dell orto VHSB 34 and some other 32mm and maybe mikuni TM28.

In a side note, what kind of apparatus is the best thing to measure the transfers roof and floor angle?

Best regards, and hope I'm not nagging you guys and girls.

[F5 Dave]

Actually its lunch time here.


Mmm Lunch. Right I'm off to feed.

[jasonu]

Actually its lunch time here.


Mmm Lunch. Right I'm off to feed.

Fat git...

[F5 Dave]

There was salad involved.

. . . and fudge

How's that last 10yrs of American food been treating you?:msn-wink:

[jasonu]

There was salad involved.

. . . and fudge

How's that last 10yrs of American food been treating you?:msn-wink:

Actually mate not too bad. I left NZ in 1999 weighing 81kg and I currently weigh 72kg.
It is not the food, more the portion sizes. Plus the Yanks are on 4th generation fast food eaters.

[peewee]

Good night everybody, I have finally the opportunity to use EngMod 2t, and I would like to know if someone as models of common reedvalve cages and common carburetors?
If not, when I measure what I have accurate tools to measure them I will do that and share the files for what I have access:
oko 24, oko 30, dell orto VHSB 34 and some other 32mm and maybe mikuni TM28.

In a side note, what kind of apparatus is the best thing to measure the transfers roof and floor angle?

Best regards, and hope I'm not nagging you guys and girls.


im not sure how everyone else did it but i did it this way. just with a paper clip to find the roof and floor angle then used a protractor tool to measure the paper clip. i may have a reed cage loaded into engmod from a old dirtbike but im not sure what good it would do you

http://i1081.photobucket.com/albums/j357/doddledo/IMG_20131212_210642_zps43194598.jpg

http://i1081.photobucket.com/albums/j357/doddledo/IMG_20131212_211056_zps513ec45a.jpg


on your other angles i just used cardboard the size of the bore and used some wire inside the ports to mark the angles like so. be sure to have a line drawn through the center so you can measure all the angles based off that

http://i1081.photobucket.com/albums/j357/doddledo/IMG_20140706_151906_zpscef4fccf.jpg

[speedpro]

Which raises a point I've been pondering. Your paperclip in the port is measuring the angle perpendicular to the cylinder wall at the port. However most ports don't enter the cylinder perpendicular but at some other angle as per your other photo of the cardboard disc in the cylinder. What angle is EngMod telling you to use? I think it will be the vertical angle in the direction of the port flow which isn't often perpendicular to the cylinder wall.

[wobbly]

The radial angles are not actually needed to input the chordal port widths into EngMod ( perpendicular to the direction of the port flow ) but
the axial angle is used to correct the flow area by the cosine of the upward tilt.
There is a worksheet in the code that uses all the angle info to generate the correct widths, but it can just as easily be directly inputed from measurement.

[peewee]

Which raises a point I've been pondering. Your paperclip in the port is measuring the angle perpendicular to the cylinder wall at the port. However most ports don't enter the cylinder perpendicular but at some other angle as per your other photo of the cardboard disc in the cylinder. What angle is EngMod telling you to use? I think it will be the vertical angle in the direction of the port flow which isn't often perpendicular to the cylinder wall.

the paper clip will tell you the horizontal angle, from 90* of the cylinder wall, even though i used the cylinder wall. you can see in the pic its says 7*, that particular paper clip happens to be from a different cylinder i have laying around the garage. the cylinder in the top pic has horizontal angles more around 20* if i recall.

the main transfer page of engmod only asks for horizontal angles, maybe this is all it needs for its calculations, i dont know. theres a seperate page where you can input the vertical angles, i put those in also.

[lodgernz]

If anyone has the time to comment, I'd appreciate any opinions on the transfer port angles shown in the attached images.
I'm sure they need modification, but I'm not sure what is required to improve the scavenging.
300252300253

[wobbly]

Easy - double the A and B port axial angles.
Move the B port front edge as far forward as you can to make a narrow bridge - and grind it perpendicular to the front/rear axis.
Move the B port rear wall around as far as you can ( limited by the ring pins generally ) and get a hook in there pointing 1/2 way to bore centre.

[lodgernz]

Easy - double the A and B port axial angles.
Move the B port front edge as far forward as you can to make a narrow bridge - and grind it perpendicular to the front/rear axis.
Move the B port rear wall around as far as you can ( limited by the ring pins generally ) and get a hook in there pointing 1/2 way to bore centre.

Wow! Thanks Wobbly.
So you think the A port directions are OK? I thought they were supposed to converge somewhere, but not as far back as these would, if they actually did. If you know what I mean.
I don't want to raise the ports since the A duration is already 132*, so I'm going to have to widen them anyway.
Thanks again for the guidance on doing that.

The piston dome height is 2mm, so the edge angle is about 11*. Should either transfer try and match that angle upwards?

[wobbly]

The A port radials as they are, are good for mid power - but having the A port up at 132 is super high so epoxy filling the roof to get mid 20* axial on them
may let you drop down some timing as well.
Having the A port higher with the rest staggered down is good for a non powervalve engine - as is the steep backward A port radial - sacrificing peak for band width.
But with a T port as drawn you would need to be up close to 200* with over 90% width to justify that big number on an A transfer.
Getting the A port axial up at 25* puts that flow column up over the B ports, that if aimed directly at each other collide, slow down and attach to the boosts flow up the rear wall.
This all fits in with Frits leaning tower principal of a correctly directed efficient loop scavenging column.
As usual the ports need to be analysed properly to get them synergistically STA matched to the end use.

[peewee]

Wow! Thanks Wobbly.
So you think the A port directions are OK? I thought they were supposed to converge somewhere, but not as far back as these would, if they actually did. If you know what I mean.
I don't want to raise the ports since the A duration is already 132*, so I'm going to have to widen them anyway.
Thanks again for the guidance on doing that.

The piston dome height is 2mm, so the edge angle is about 11*. Should either transfer try and match that angle upwards?

if you look at the cardboard disk on the previous page, it sounds real similar to what wobbly is describing, unless im misunderstanding him. it might give you a general idea what to do. anyways ive learned a couple things the hard way. if you bring the B ports farther around back, be sure to pay attention to the ring pin locations like wobbly said. you can grind the port very close to the ring end but atleast let the ring end have alittle wall surface to ride on. ive let the ring end ride on alittle over 1mm of wall surface and never had a problem but it might not be a bad idea to use alittle more than 1mm though. better safe than sorry i guess but its your call

also if you bring the B port around back a significant amount, be sure the duct can be made of appropriate size also. seems like frits once said the rsa B window area was slightly larger than the duct opening but im not sure if its a good idea to have the window extremely larger than the duct opening. perhaps the shape up through the duct may be a factor in the size relationship between the window and duct entrance but i dont know

[peewee]

this might help you also. what i did is marked my ring pin locations with red marker. then use blue to mark where i wanted to grind the window. theres not much room between the ring end and window but it worked fine and i never had a problem with it

http://i1081.photobucket.com/albums/j357/doddledo/IMG_20140601_165450_zpsfcd8f86b.jpg

[Frits Overmars]

If anyone has the time to comment, I'd appreciate any opinions on the transfer port angles shown in the attached images.
300252300253Here are some suggestions: 300279


Getting the A port axial up at 25* puts that flow column up over the B ports, that if aimed directly at each other collide, slow down and attach to the boosts flow up the rear wall.This all fits in with Frits leaning tower principal of a correctly directed efficient loop scavenging column.You'll find it here: http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130452977#post1130452977

[lodgernz]

Here are some suggestions: 300279

You'll find it here: http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130452977#post1130452977

Thank you Frits. I'm ashamed to say that I'm familiar with both of those posts, and I've pored over them for hours, but I'm still struggling to fully understand the details. I'll try again (blush)

Thanks also Wobbly and Peewee for your good advice.

[lodgernz]

Frits, I also have a question for you.
Attached is an image of another of your wonderful posts from the pit-lane.biz GP125 thread.
In this post you give working target values for the blowdown and transfer STAs of the RS125A, but you don't offer a value for the exhaust.
I infer that the STA for the exhaust itself is less important than that for the blowdown.
Is this correct?

300281

[senso]

If the crm80 is 75cc honda engine that I know, be very carefull with the exhaust port, the casting is thin, with some radiusing only in the liner you can probably get to 190º(around 22 mm), then the exhaust duct will be narrower and if you try your luck you will rupture it, measure everything first.

And thanks for showing those measures, might come in andy when I get to re-assemble my ns-1 might as well re visit the cylinder, but I'm also striked how far back the A/primary transfers shoot.

About the ducts, the nsr/crm 75 engines have plenty of room in both the crankcase and in the cylinder to carve so nice big ducts.

[Frits Overmars]

Frits, I also have a question for you. Attached is an image of another of your wonderful posts from the pit-lane.biz GP125 thread. In this post you give working target values for the blowdown and transfer STAs of the RS125A, but you don't offer a value for the exhaust. I infer that the STA for the exhaust itself is less important than that for the blowdown. Is this correct?
300281Yep (that should have been my answer, but the forum software insists that I use at least ten characters. So here you are).

[wobbly]

Here is a typical STA analysis that in practice made exactly the power predicted - less around 12% losses as shown by RWHp on a DynoJet with
a heap of added load to simulate aero.
The blowdown and transfers are a match ( this engine has 8 transfers so doesnt need extra STA ) but the Ex STA is well low - makes no odds at all to the power made.
In fact as the duct is a stock TZ350 size its reduced area and volume would be helping the overall power ability.

[lodgernz]

If the crm80 is 75cc honda engine that I know, be very carefull with the exhaust port, the casting is thin, with some radiusing only in the liner you can probably get to 190º(around 22 mm), then the exhaust duct will be narrower and if you try your luck you will rupture it, measure everything first.
And thanks for showing those measures, might come in andy when I get to re-assemble my ns-1 might as well re visit the cylinder, but I'm also striked how far back the A/primary transfers shoot.
About the ducts, the nsr/crm 75 engines have plenty of room in both the crankcase and in the cylinder to carve so nice big ducts.


Thanks for that warning Senso. The CRM80 is the same cylinder as the NSR75/80.
If your NS-1 is a 50, those transfer angles of the 80 won't be correct as the cylinders are quite different. If you have a Euro NS-1 75 then they will be the same.

[lodgernz]

Yep (that should have been my answer, but the forum software insists that I use at least ten characters. So here you are).

Heh heh... Thanks Frits, good answer.


Here is a typical STA analysis that in practice made exactly the power predicted - less around 12% losses as shown by RWHp on a DynoJet with
a heap of added load to simulate aero.
The blowdown and transfers are a match ( this engine has 8 transfers so doesnt need extra STA ) but the Ex STA is well low - makes no odds at all to the power made.
In fact as the duct is a stock TZ350 size its reduced area and volume would be helping the overall power ability.

Thanks Wobbly, fascinating stuff. Can I take it from your comment that the engine made the power indicated for the transfers and blowdown, despite the exhaust indicating a lower possible HP?

[senso]

lodgernz its an euro ns-1(or as known in Spain NSR 75R).
The 50cc cylinder unfortunatelly has a simple oval exhaust port, but suffers from the same problem the outside of the exhaust duct sits at 21mm from the top of the cylinder, with some radius(maybe around 2mm curve radius) I was able to squeeze 21mm from top of cylinder to the start of the radiused exhaust port, but it them goes to a safer 19.5mm to keep some wall in the duct, I love my honda engines, currently I have two crm 50, and my ns-1, and I have four more crm and nsr engines for parts.

Funny thing regarding my tuned crm 50, it is just a turned head to bump the compression ratio to 12:1 with a 0.9 squish gap and around 50% squish band, I had a cr80 reed cage with brand new boyesen dual stage reeds that was going to the ns-1 but I tried it first in the crm, and low and behold after 6 months of use the reeds no longer close, and as expected, the top reed was covered in black carbon due to the lack of blowdown, has the engine will happily rev up to 14k rpm(short transmission ratio to ride in the woods around the house), the piston is covered in a uniform layer of carbon as well.

Is this normal to happen to reed cages that run without the metal stoppers?
The reeds that are worse are the bottom ones, it makes sense in my head, they are the ones that see first the intake pulse and there is also a huge port going straight down into the crankcase.
300300300299

Wobbly, there is one thing that confuses me a lot about the STA values for the reed-cages in engMod.
It reports in your example the Reed Block Ports has having an area of 1160.66 and then it says that the Reed Petal Opening has an area of 2950.
Is the first value the area of only the reed block ports and then it accounts for the angle of the reed cage and how much the reeds limit that area?

[wobbly]

The Ex port being smaller than the "old " required STA numbers in fact contributes to making even better power, as the duct velocity is higher at small port openings.
My experience has found as well that in a single Ex engine having the duct exit @ 90% of the effective port area makes the best power.

Re the reed STAs in EngMod - its the reed block ports that matter the most.
If the actual port effective area is too small, that becomes the choke point for power.
The reed numbers are the curtain exit area, these only become an issue if the stops are preventing enough lift and the reed curtain area is smaller than the port effective area.
So as long as the ports are big enough and the reed area is equal or greater, then the reed will work fine if the STAs match what you require.
Reeds do self compensate somewhat in that a small reed will simply be forced to stay open longer by the flow into the engine - so in many cases very little power is lost.
In fact they can and do work better than a reed that is oversize for the required application.

[F5 Dave]

In My triple ex port MB100 I am finally recreating (version one was about 1992) I have made the aux ports an ok sort of size but the cross sectional area of the tunnels are the compromise due to 'through barrel' studs (although I have a plan to avoid that, but it a bit too much hassle). So I've ovalised the tunnels to compensate but I'm wondering if just the reservoir of reasonably large aux ports will still benefit the initial blow down or will the tunnel be the ultimate restriction as I've read before in Tom Turners notes.

[TZ350]

300307300306

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

Near the bottom of the supercharging of small engines is a section on supercharging 2T' s ... two strokes.

[TZ350]

300308300309

I was wondering how to mount the sprocket carrier onto these 3.5x17 front wheels that I am using for rears. Chambers suggested this neat idea of M8 cap screws in the old disk mounting holes for driving dogs and just slipping the carrier over them. The carrier will have its own support bearing and trapped in place by the axel spacers.

[Grumph]

I was wondering how to mount the sprocket carrier onto these 3.5x17 front wheels. Chambers suggested this neat idea of M8 cap screws in the old disk mounting holes for driving dogs and just slipping the carrier over them. The carrier will have its own support bearing and trapped in place by the axel spacers.

Make the holes in the carrier bigger - and do some rubber or urethane bushes to suit - and you've got a cush drive....

[Ocean1]

I was wondering how to mount the sprocket carrier onto these 3.5x17 front wheels. Chambers suggested this neat idea of M8 cap screws in the old disk mounting holes for driving dogs and just slipping the carrier over them. The carrier will have its own support bearing and trapped in place by the axel spacers.

Urethane bushes on the cap screw heads?

Might want to make them a bid deeper in that case, or they might try to climb out...

[Grumph]

Urethane bushes on the cap screw heads?

Might want to make them a bid deeper in that case, or they might try to climb out...

Could always use shoulder bolts - and cut the heads off once they're loctited in...

RS125 drive dogs aren't much more than 10mm socket head size.

[TZ350]

Good suggestions, thanks.

300310

Using a Pit Bike front disk on the other side for a rear break.

[TZ350]

300313

Been having untold trouble with Av's F4 bike drinking its gear box oil.

300314300315

So after a few failed attempts at fixing it Chambers got serious and filled the gearbox with kero and leak tested it.

300316

Av going around the outside at Mt Wellington.

And Av peddling her 600 in Italy.

[Sketchy_Racer]

300308300309

I was wondering how to mount the sprocket carrier onto these 3.5x17 front wheels that I am using for rears. Chambers suggested this neat idea of M8 cap screws in the old disk mounting holes for driving dogs and just slipping the carrier over them. The carrier will have its own support bearing and trapped in place by the axel spacers.

Just for what its worth. I've run my cbr front wheel as a rear for years. I haven't bothered with a cush drive i don't think buckets really need them. I've just got a small aluminum adapter bolted onto where the disc was. Too easy.

[chrisc]

Been having untold trouble with Av's bike drinking its gear box oil.

300314300315

So Chambers got serious and filled the gearbox with kero and leak tested it.

That looks promising

[chrisc]

Just for what its worth. I've run my cbr front wheel as a rear for years. I haven't bothered with a cush drive i don't think buckets really need them. I've just got a small aluminum adapter bolted onto where the disc was. Too easy.

Sketchy, what are you running the CBR wheel on?

[Ocean1]

Could always use shoulder bolts - and cut the heads off once they're loctited in...

RS125 drive dogs aren't much more than 10mm socket head size.

Rough cunt.

Just make some washers 3-4mm thick and the same dia as the bolt heads.

Put carrier on the bench, put some masking tape around the bolt heads, pour potable urethane into the holes in the carrier and sit the hub in position. A timing mark across the carrier/hub would help keep the bolt heads central in the holes. Viola!

Actually, before the urethane sets take it apart and start again.

Make those washers a tad smaller than the bolt heads. Reassemble. Tape inside the carrier holes. Pour more urethane and refit the hub. This way the bushes are stuck to the hub. Not sure why but its better that way in my head...

[wobbly]

What you need to remember is a proven fact at the end of the day is that an Aprilia B port total effective area is greater than the duct
smallest CSA that is feeding it.
What is important is the radial and axial geometry of that port entering the cylinder, and the effect this flow regime has on the scavenging efficiency.
Jan the maestro himself wondered on a forum somewhere ,about something I realised ages ago,the volume that is held sitting in the transfer ducts is that - that ends up in the cylinder.
The case simply refills that volume - there is no " flow " as such from the case into the cylinder even when the pipes big diffuser negative pressure ratio, is creating the max bulk flow around BDC.

[F5 Dave]

That was kinda my thinking in reverse about the aux exhaust ports but they are under considerable more pressure and less volume.

[Sketchy_Racer]

Sketchy, what are you running the CBR wheel on?

It was on my mb100 which is now the super charger bucket. Suzuki rgv250 vj21

[senso]

About the wheels, I have mounted Derbi GPR 50 rims in my brothers Gas Gas EC 125, the screws only undid themselves once, now, they are glued in place and its rock solid.

[peewee]

What you need to remember is a proven fact at the end of the day is that an Aprilia B port total effective area is greater than the duct
smallest CSA that is feeding it.
What is important is the radial and axial geometry of that port entering the cylinder, and the effect this flow regime has on the scavenging efficiency.
Jan the maestro himself wondered on a forum somewhere ,about something I realised ages ago,the volume that is held sitting in the transfer ducts is that - that ends up in the cylinder.
The case simply refills that volume - there is no " flow " as such from the case into the cylinder even when the pipes big diffuser negative pressure ratio, is creating the max bulk flow around BDC.

this reminds me. hey frits was the duct volume ever measured on the rsa ? not just the tunells of the cylinder but all the way to the top of the crankshaft wheels paralell with the cylinder wall, which would be considered the full duct i believe ?

[Frits Overmars]

was the duct volume ever measured on the rsa ? not just the tunells of the cylinder but all the way to the top of the crankshaft wheels paralell with the cylinder wall, which would be considered the full duct i believe ?Not to my knowledge. Measuring the part above the cylinder base would be simple but as you say that is only half the story. Measuring the part below the base gasket would be much more complicated (and messy). But measuring isn't even necessary; if you have the drawings, the 3D drawing program can give you all the values you wish to know.
I was mainly interested in the total crankcase volume, including the transfer ducts and the inside of the piston (675 cc at TDC for the RSA); find my 'Helmholtz-Blues' and you'll see why.

[Frits Overmars]

What you need to remember is a proven fact at the end of the day is that an Aprilia B port total effective area is greater than the duct smallest CSA that is feeding it.CSA?? Enlighten me Wob; I do not have that much Kiwi.
Anyway, I can guess that you mean the duct entrance at the cylinder base and yes, it is a bit smaller than the duct exit. But the entrance is open all the time and the exit isn't.
Jan the maestro himself wondered on a forum somewhere ,about something I realised ages ago,the volume that is held sitting in the transfer ducts is that - that ends up in the cylinder. The case simply refills that volume - there is no " flow " as such from the case into the cylinder even when the pipes big diffuser negative pressure ratio, is creating the max bulk flow around BDC.This is going to be semantics: of course there is flow from the case into the cylinder, but not in one go. A particle, registered at the crankcase entrance, will show up in the cylinder after four to five crankshaft revolutions, as Wobbly implied.
How do you find out? Label that particle with radioactivity.
On second thought: don't try this at home.

[husaberg]

CSA?? Enlighten me Wob; I do not have that much Kiwi.
Anyway, I can guess that you mean the duct entrance at the cylinder base and yes, it is a bit smaller than the duct exit. But the entrance is open all the time and the exit isn't.This is going to be semantics: of course there is flow from the case into the cylinder, but not in one go. A particle, registered at the crankcase entrance, will show up in the cylinder after four to five crankshaft revolutions, as Wobbly implied.
How do you find out? Label that particle with radioactivity.
On second thought: don't try this at home.

Buggar I have a readily available source of high quality Yellow Cake.

[wobbly]

CSA is a term used in 4T port nomenclature to describe the smallest Cross Sectional Area, usually the venturi under the seat.
But in the Aprilia the CSA at the gasket line is well bigger than the actual CSA down further into the duct, that - is smaller than the chordal flow
area of the port.
Yes, the port is always gradually opening, gradually closing, or blocked, never really thought about that in relation to the duct feeding it.
But I have recognised in the past that really well designed cylinders ( like Calvins Cheetah for the RZ/Banshee ) seem to perform much better than
you would expect from the severely crap duct geometry ( small and very little inner wall ) due to the narrow bore centres.
They have a ton of port area, but the duct volume is very small, simply as there is no room and I believe the the small duct entry/exit ratio plays a large part in
allowing the system to work so well.
Same design route taken by Team Roberts in the Rainey era,they dynoed the factory cylinders to death ( and had a Czech CNC flow visualiser ) and the ducts on those
500s had a huge amount of epoxy added.
Their technology showed up later on the 250s that finally gave Yamaha a title with Jaques on board - that TZ was seriously fast at the time.

[peewee]

Not to my knowledge. Measuring the part above the cylinder base would be simple but as you say that is only half the story. Measuring the part below the base gasket would be much more complicated (and messy). But measuring isn't even necessary; if you have the drawings, the 3D drawing program can give you all the values you wish to know.
I was mainly interested in the total crankcase volume, including the transfer ducts and the inside of the piston (675 cc at TDC for the RSA); find my 'Helmholtz-Blues' and you'll see why.

i had to find out what the transfer volume was so i poured in oil, beyond just the cylinder ducts, mainly so i could get a approximation of the full duct volume down to the crankcase area. im not sure of the full crankcase volume however. anyways i got 150cc of oil in the 2 side transfers, x2 would be 300cc for all 4 side transfers. i didnt factor in the C port , but it doesnt even seem like a real duct on this engine. anyways the engine is 89x79 500cc with 144mm rod. i figured it would hold more volume in the transfers but i guess thats why its only a measly .13hp per cc :2thumbsup


http://i1081.photobucket.com/albums/j357/doddledo/IMG_20140827_184424_zpsd9765e6a.jpg

[peewee]

But I have recognised in the past that really well designed cylinders ( like Calvins Cheetah for the RZ/Banshee ) seem to perform much better than
you would expect from the severely crap duct geometry ( small and very little inner wall ) due to the narrow bore centres.
They have a ton of port area, but the duct volume is very small, simply as there is no room and I believe the the small duct entry/exit ratio plays a large part in
allowing the system to work so well.
.

i think calvin did a good job considering what he had to work with (crowded inline twin). his cylinders seem to run well even with the shit transfer duct geometry like you mentioned. still they dont hold a candle to the rsa in terms of hp per cc though. seems like frits mentioned one time that the 6 smaller side transfer port design really helps when you have crap duct geometry, other wise the cheetah may not run as well had it used 4 side transfers

[F5 Dave]

Well 72 odd mm compared to 54 it's a different kettle of fish.

[peewee]

yes indeed a different kettle but theres a smaller cub cylinder at 64x54 and those arent near the rsa level either. dont get me wrong i think calvin did a fine job considering what he was up against. ill probly buy some of his smaller cylinders, simply because ive had singles all my life and want to tinker with something different :headbang:

[F5 Dave]

I've got a 496 but life has got in the way of riding it much.

[136kg136ps]

Wob,as Calvin's cylinders were mentioned.What cylinders and configuration would be the maximum displacement you would use on a track bike?Given a competent chassis and a class to race it in and my local track being Daytona.

Thanks as always to TeeZee for the thread and to you and Frits et al for making it a class on winning twostrokes.

[peewee]

I've got a 496 but life has got in the way of riding it much.

theres alot of various combinations of cylinders. what is the bore and stroke on the 496 ? i wanted to give the 68x68 cub a go but i dont think that 68mm stroke crankshaft will fit in stock banshee cases. from what i hear, 64mm stroke is about the largest you can use in banshee cases and even then requires quit a bit of trenching and such to make it work. the billet cases for longer strokes above 64 are very expensive and out of my price range. i may have to settle on a 68x64 which should be possible on stock cases from what i hear. unfortunatly i dont think calvin made a 64mm cylinder intended for a 64mm stroke, which seems strange as that seems like it would be a good combo.

[husaberg]

Anyone know of a crankshaft from a 2 stroke twin 54-60mm stroke that has wide bore centres?
more like this.
300376
There must be something in the Snowmobile world.
IS anyone able to chip in with some bore centres say for RD series RZ, RG, NSR etc

[136kg136ps]

RZ350 YPVS Banshee 102mm

[husaberg]

RZ350 YPVS Banshee 102mm

Looking back it seems the RD series is 102mm also. Just the stud positions in the case are outside allowing for more space

[wobbly]

The 102mm bore centres on the RD/LC/TZ/RZ cases is a huge impediment to making any serious power - no matter what cylinder you use.
The biggest crank that will go into those engines without trenching an already weak case is 58mm.
But its not that hard to cut up a couple of case sets and widen the bore centres, as was done years ago by Yamaha Europe with the 3 cylinder 350
that simply had another piece of case welded onto one end.
Then the crank is easy to widen in the centre for a big twin with a push fit male/female spacer.
Having gone to all that trouble then its simply a matter of what cylinder to fit.
Calvins Sphynx has the ability to take a powervalve, so depending upon the end use that may be a very good idea.
But of course with wider bores - anything would fit.
The other factor to remember is that big engines need big pipes, and from experience with the 486 Cheetah, that 58/72mm combo is getting into the realm of diminishing
returns due to engine size being offset by having simply no room to fit the needed fat pipes to make more power.
The 486 Cheetah made 102 Hp on petrol and peaked at just over 10,000, the 400 Cheetah made 96 at 11,000 and still had 90 at 12,000, with slightly fatter pipes allowed
due to the shorter length.
Its all a matter of trying to keep a balance - the short stroke allows bigger revs, the bigger pistons are heavyer, so limit the revs.
The high rpms need shorter pipes so they can be fatter, but rule one for making the best power with any engine layout is to try and get as close to square bore/stroke ratio
as you can to keep the available angle area from the cylinder optimised.
If in doubt bore it out - is a very American approach to making power with cubes, but in a 2T it quickly starts to loose effectiveness due to angle area limiting and piston weight.
A certain wanker I was involved with was obsessed with the idea that simply using the hard parts from a Yamaha Ski 1200 tripple would be "easy and cheap" to make the ultimate
road rocket.
Sadly with an upper rpm limit of just over 8,000 rpm getting 3 pipes all of 1200mm long to fit on a bike justly demonstrated the insanity of the idea and the originator.
Same with another short sighted idiot that spent months designing a 1200 twin in EngMod - only to be shown that those pipes would need another couple of wheels on a trailer behind
the bike to support them.

[husaberg]

Its all a matter of trying to keep a balance - the short stroke allows bigger revs, the bigger pistons are heavyer, so limit the revs.
The high rpms need shorter pipes so they can be fatter, but rule one for making the best power with any engine layout is to try and get as close to square bore/stroke ratio
as you can to keep the available angle area from the cylinder optimised.
If in doubt bore it out - is a very American approach to making power with cubes, but in a 2T it quickly starts to loose effectiveness due to angle area limiting and piston weight.
A certain wanker I was involved with was obsessed with the idea that simply using the hard parts from a Yamaha Ski 1200 tripple would be "easy and cheap" to make the ultimate
road rocket.
Sadly with an upper rpm limit of just over 8,000 rpm getting 3 pipes all of 1200mm long to fit on a bike justly demonstrated the insanity of the idea and the originator.
Same with another short sighted idiot that spent months designing a 1200 twin in EngMod - only to be shown that those pipes would need another couple of wheels on a trailer behind
the bike to support them.

Don't worry, not interested in Big cylinders just wide centred crankshafts
I am looking for an off the shelf solution though, but only for crank.
More keen on the idea to make cc's with multiple cylinders.
300382

[peewee]

these guys make most of the billet crankshafts for the banshee which i assume is the same thing as what your looking for. most of the smaller stroke stuff i think is just the standard 102mm spread but since they create everything in house ill bet they would make any thing you requested http://crankworks.com/index.php/atv/atv-products/atv-cranks

you say you dont need cases but if you do, these guys make them. the wider spread centers are usually for the longer strokes but again, im sure they would make anything you requested as it should be rather simple for them http://www.mattoonmachine.com/Billet_Cases.html

[TZ350]

Page 990....



Wobbly!

We have talked over how important the blowdown and it's size are, but what about the blowdown's intensity? If the aux exhaust ports are opening later as the main exhaust port, the peak of the pression is smaller, meanwhile the blowdown lasts longer. Of course the STA is always the same. Here is an example 'One Half'

In case of almost every race cylinder the aux exhaust ports are opening later, and this can be observed in systems with or whitout a power valve. In case of a T port the top edge radius is not 0, but pretty much bigger.

Is it important? Why don't we open the ports the widest possible? That way the ports could be positioned lower what would be optimal.


There are two factors in play with the tripple port setup.
You have drawn them correctly with 68% main port width, as this allows greater blowdown area to be gained via the aux ports.
Out at 72% that has proven to be approx the reliable max width, you loose some blowdown, and gain total area. ( not relevant at all ).
The problem is that even at 68% you cannot run a flat port roof with 8mm corner radi, as the ring life will be zero.


Secondly is that it has been proven in many dyno sessions that having all 3 ports open together looses power.
I can only explain this as a function of the fact that the effective duct length from the outer corners of the Aux is alot longer than that from the main port
mid point to the header.
Thus you get a smearing of the initial wave amplitude ( wider but lower intensity ) as it exits the cylinder into the duct during blowdown.
This reduces the effectiveness of the expansion phase, creating less depression around BDC, and less plugging efficiency as the piston closes the port.


It would appear that having a 68% main port opening first gives a good, high amplitude wave action in the pipe, then the Aux STA gets the blowdown pressure dropped as much as is possible prior to the Trans opening.


A few pages back was a drawing I did years ago of a T port with the outer edges higher than the mid point, thinking that this would ameliorate the duct length issue, but later
testing proved it didnt work well at all.
So by inferrence even lifting the Aux higher than the main wont fix this issue either in a 3 port.


On another subject, if you'll bear with me, has anyone experience of porting a Nicasil cylinder?
I need to know what tools to avoid, any important techniques, etc.
The narrow little oval exhaust needs upping to get blowdown.
There is material fatness above the port but not to the sides, so no possibility of auxiliary ex ports or even T shape.


the cylinders i ported the nikisil was removed before hand and replated afterwards. but you shouldnt have much trouble with the right bits. i think diamond impregnated ones should work although i havent actually tried them yet. maybe theres something even better ?

if you have a welder perhaps you can cut a chunk out of the side of the barell and weld the outer side portion of the exh in the water jacket area then weld the cylinder chunk back in. this should allow aux ports to be used. it has been done on other cylinders, maybe it can work for you


You can lift the Ex port on a Nicasil cylinder using a diamond impregnated burr to cut thru the plating and then use RexCut cotton impregnated
rotary "mops " to put a smooth chamfer and radius back on the bore.
But the issue is that the ring , no matter what the port width is, will always bulge out into the port, and the top corner radius is what smoothly pushes it
back into the groove.
The cylinder will last a while like that, but It doesn't take long for the ring to wear thru to alloy around the port top edge, as there is no Nicasil going around the corner
into the duct to support the ring.
Best long term fix is to have the chrome removed, cut the port and re Nicasil it.
But for dyno testing the porting result, doing it the easy way is fine.


A 182MC is the only thing for small bores .


Running the pins each side of the Ex is completely unnecessary and dumb.
Having a ring pinned over the boost means that as the ring bulges out into the Ex port and is symmetrically eased back in by the top radi
then both ends of the ring approach the pin at the same time.
Any time a pin is offset, one end of the ring hits first, causing asymmetric ring movement in the groove, along with the possibility of bashing the pin out sideways.


im not sure how everyone else did it but i did it this way. just with a paper clip to find the roof and floor angle then used a protractor tool to measure the paper clip. i may have a reed cage loaded into engmod from a old dirtbike but im not sure what good it would do you

http://i1081.photobucket.com/albums/j357/doddledo/IMG_20131212_210642_zps43194598.jpg

http://i1081.photobucket.com/albums/j357/doddledo/IMG_20131212_211056_zps513ec45a.jpg


on your other angles i just used cardboard the size of the bore and used some wire inside the ports to mark the angles like so. be sure to have a line drawn through the center so you can measure all the angles based off that

http://i1081.photobucket.com/albums/j357/doddledo/IMG_20140706_151906_zpscef4fccf.jpg


The radial angles are not actually needed to input the chordal port widths into EngMod ( perpendicular to the direction of the port flow ) but
the axial angle is used to correct the flow area by the cosine of the upward tilt.
There is a worksheet in the code that uses all the angle info to generate the correct widths, but it can just as easily be directly inputed from measurement.


to measure the roof you wont ever need to bend the clip to a full 90* because every transfer port roof ive even seen had atleast some upward angle. just bend the clip on the table corner then put it in the port and see how well it fits. bend it alittle more or use a new clip and bend alittle less, until it fits well then measure the angle. only takes a few minutes

for the floors just bend the clip to the full 90* on the table corner (or as close to 90* as you can), then set it on the table top and bend alittle more past 90*. its rather easy

perhaps theres a better simpler way to measure the port angles but the paper clip was always simple and easy for me

you may have good luck with wire or even solder.


When I do not have my own equipment at hand I use solder. Works fine.


It's not crossing the line at all but at the moment it's asking for the impossible because I haven't got them with me and I have no pictures or drawings, apart from my bent feeler gauge with which I measure port heights.
I use a 1 mm gauge, bent at 45°, that I pinch between the piston edge and the port edge in such a way that the bent end is vertical (parallel to the cylinder bore).

300662

Then I measure from cylinder top deck to piston edge and subtract 1,41 mm from the measured value. It works for every port as long as its axial angle is not steeper than 45°, even when both the piston edge and the port edge are chamfered or radiused.


There's more to this than meets the eye. The piston is playing a double role: it pressurizes the cylinder and at the same time depressurizes the crankcase.

But even if the piston didn't move at all, there will be flow reversal if the transfers do not close at the right moment. It's a Helmholtz thing: gas flows from one vessel to another, the pressure difference will change sign, and the flow will slow down and reverse.

This is even more striking in the inlet system. The inlet port pops open, the inlet flow will fill the crankcase and at low revs it may reverse direction while the piston is still moving upward!



All 2Ts have some flow reversal when the transfers open, as the residual blowdown pressure is greater than the pressure in the case.

Bulk flow doesnt occur till closer to BDC if the pipe is correctly designed, and the diffuser depression holds the Ex port below atmospheric long enough to promote a differential across the open transfers.

I discovered the flow reversal, and the idea that the port to open first/flows last when I first Beta tested the Dynamation 2T code done by Kurt Leaverton of HotRods fame.

You can see the pressure rise in the transfers, when they crack open, in the running screen of EngMod - see the sample screendump where the green transfer line jumps up at EPO.



Perfectly correct, Jan Thiels setup in the Aprilia engines does exactly that - open the B first.

The B is wider than the A as well, and the lower A port helps to reduce the direct short circuiting upwards into the Aux Ex ports. This layout maximises the available transfer port STA and is great for peak power at high rpm levels.

The usual reverse stagger as seen in Honda T port engines, with the A port the highest, works better in the 3 port layout when you are looking for wider power bandwidth.
Best example would be the KZ2 kart engines, as with no power valve, and the need to be able to pull hard from around 9000 to 14000 + this layout gives better bottom end and overev power, at the expense of outright peak.

I have dyno tested high B port KZ2 engines, and been just over 50 Hp at the sprocket, but no matter what I tried with pipe length and ignition advance I could never generate
enough power down at 9000.

So although the cylinder was very fast in outright terminal speed, it lost too much off every slower corner, fine as a qualifying engine but no good diving under someone entering
a corner - as it simply would not pull out hard enough when on the "wrong " line.

[Drew]

The 102mm bore centres on the RD/LC/TZ/RZ cases is a huge impediment to making any serious power - no matter what cylinder you use.
The biggest crank that will go into those engines without trenching an already weak case is 58mm.
But its not that hard to cut up a couple of case sets and widen the bore centres, as was done years ago by Yamaha Europe with the 3 cylinder 350
that simply had another piece of case welded onto one end.
Then the crank is easy to widen in the centre for a big twin with a push fit male/female spacer.
Having gone to all that trouble then its simply a matter of what cylinder to fit.
Calvins Sphynx has the ability to take a powervalve, so depending upon the end use that may be a very good idea.
But of course with wider bores - anything would fit.
The other factor to remember is that big engines need big pipes, and from experience with the 486 Cheetah, that 58/72mm combo is getting into the realm of diminishing
returns due to engine size being offset by having simply no room to fit the needed fat pipes to make more power.
The 486 Cheetah made 102 Hp on petrol and peaked at just over 10,000, the 400 Cheetah made 96 at 11,000 and still had 90 at 12,000, with slightly fatter pipes allowed
due to the shorter length.
Its all a matter of trying to keep a balance - the short stroke allows bigger revs, the bigger pistons are heavyer, so limit the revs.
The high rpms need shorter pipes so they can be fatter, but rule one for making the best power with any engine layout is to try and get as close to square bore/stroke ratio
as you can to keep the available angle area from the cylinder optimised.
If in doubt bore it out - is a very American approach to making power with cubes, but in a 2T it quickly starts to loose effectiveness due to angle area limiting and piston weight.
A certain wanker I was involved with was obsessed with the idea that simply using the hard parts from a Yamaha Ski 1200 tripple would be "easy and cheap" to make the ultimate
road rocket.
Sadly with an upper rpm limit of just over 8,000 rpm getting 3 pipes all of 1200mm long to fit on a bike justly demonstrated the insanity of the idea and the originator.
Same with another short sighted idiot that spent months designing a 1200 twin in EngMod - only to be shown that those pipes would need another couple of wheels on a trailer behind
the bike to support them.

If someone goes to all that trouble, the room for pipes is easy to overcome by making one slug reverse port, no?

[F5 Dave]

theres alot of various combinations of cylinders. what is the bore and stroke on the 496 ? i wanted to give the 68x68 cub a go but i dont think that 68mm stroke crankshaft will fit in stock banshee cases. from what i hear, 64mm stroke is about the largest you can use in banshee cases and even then requires quit a bit of trenching and such to make it work. the billet cases for longer strokes above 64 are very expensive and out of my price range. i may have to settle on a 68x64 which should be possible on stock cases from what i hear. unfortunatly i dont think calvin made a 64mm cylinder intended for a 64mm stroke, which seems strange as that seems like it would be a good combo.
The 496 is 61x72. Typical cranks are 54 std. +4 / +7 /+ 10 /+ 14. But you get the 4 in std cases, the 7 & 10 with trenching which isn't that hard really and bore the cases to take the bigger sleeves. I got the local re conditioner to do it they set up those sort of jobs all day. Anything bigger is a liability and billet cases.

For or sure they are a serious compromise but a twin knocking on 100hp with better midrange and less weight than a tuned 4cylinder sounds attractive. And easy for a garage dweller to bolt together. Now I don't have the time or money to rego and ride two road bikes.

i wasted too much time on a porous barrel that wouldn't tune with water injection to some level.

[wobbly]

You try to get a 1200mm long pipe and THEN a muffler to fit onto the Exhaust port face and NOT stick out past the rear wheel.
I did this on a NS400 tripple and even with it tuned to 11000 and a length of 880, it barely fitted even with a big S bend under the seat.
The 500VDue had to use a U bend and face the muffler forward again - sorry I dont do ugly as shit.

[lodgernz]

On another subject, if you'll bear with me, has anyone experience of porting a Nicasil cylinder?
I need to know what tools to avoid, any important techniques, etc.
The narrow little oval exhaust needs upping to get blowdown.
There is material fatness above the port but not to the sides, so no possibility of auxiliary ex ports or even T shape.

[peewee]

the cylinders i ported the nikisil was removed before hand and replated afterwards. but you shouldnt have much trouble with the right bits. i think diamond impregnated ones should work although i havent actually tried them yet. maybe theres something even better ?

if you have a welder perhaps you can cut a chunk out of the side of the barell and weld the outer side portion of the exh in the water jacket area then weld the cylinder chunk back in. this should allow aux ports to be used. it has been done on other cylinders, maybe it can work for you

[F5 Dave]

On a 50 there is so little room it's hard to see how you would complete the weld. Microbots. That's what we need.

[peewee]

what 90* grinder is you guys using on them smaller cylinders ? ive got just the standard size like the ccspecialty 1MC. mostly i work on larger bore stuff above 80mm and it does ok but for smaller bores i think it would be much bulkier than i would like

[wobbly]

You can lift the Ex port on a Nicasil cylinder using a diamond impregnated burr to cut thru the plating and then use RexCut cotton impregnated
rotary "mops " to put a smooth chamfer and radius back on the bore.
But the issue is that the ring , no matter what the port width is, will always bulge out into the port, and the top corner radius is what smoothly pushes it
back into the groove.
The cylinder will last a while like that, but It doesn't take long for the ring to wear thru to alloy around the port top edge, as there is no Nicasil going around the corner
into the duct to support the ring.
Best long term fix is to have the chrome removed, cut the port and re Nicasil it.
But for dyno testing the porting result, doing it the easy way is fine.

[wobbly]

A 182MC is the only thing for small bores .

[Sketchy_Racer]

Hi guys,

sorry if this has already been covered, but I was wondering about ring pin positions.

I've done a bit of work for a mate who is working on his benelli and having a little issue with the pin positions on his pistons. They run in the middle of the transfer port and I'm worried about ring snag. Apparently in the stock motors the ring pin is on either side of the ex port but I have never seen that done before and was curious what the reasons behind that are?

Cheers,

-Sketchy

[kel]

Hi guys,

sorry if this has already been covered, but I was wondering about ring pin positions.

I've done a bit of work for a mate who is working on his benelli and having a little issue with the pin positions on his pistons. They run in the middle of the transfer port and I'm worried about ring snag. Apparently in the stock motors the ring pin is on either side of the ex port but I have never seen that done before and was curious what the reasons behind that are?

Cheers,

-Sketchy

If we are talking C port then absolutely fine, has been done on many motors including my own. The angle of the C port at 55 odd degrees eases the ring back in without any snag issue. One thing I would suggest is the bottom of the C port is lower than the ring position at BDC.
Reason is to maximise transfer port area. Or do you mean why do they run either side of the exhaust? I have no idea why you would do that.

[wobbly]

Running the pins each side of the Ex is completely unnecessary and dumb.
Having a ring pinned over the boost means that as the ring bulges out into the Ex port and is symmetrically eased back in by the top radi
then both ends of the ring approach the pin at the same time.
Any time a pin is offset, one end of the ring hits first, causing asymmetric ring movement in the groove, along with the possibility of bashing the pin out sideways.

[TZ350]

300430

Just got myself a Honda Lead 125cc 2T Scooter.

Possibly the beginnings of a CVT race bike.

300431300429

Engine and running gear shoe horned into a RG50 frame for a 17" front with small scooter wheel/slick on the back for a race Penny Farthing .... :scratch:... well maybe, maybe not.

300434

Racing Penny Farthings.


300433

Artists impression of what a Team ESE racing penny farthing might look like.

Any other Honda Lead - Aero - NH125 engine and/or drive train parts would be welcome ... PM me and we can do a deal $$$.

[Drew]

Run the rear wheel mount as a primary drive. Then you get less unsprung weight, a decent size rear wheel, and the weight as far forward as you want it. Plus you can change the gearing for maximum torque depending on what rider (how fat they are) is peddling it.

[F5 Dave]

An ironic name the Honda Lead. Unlike an Alanis Morrissett song (of which was a list of un-ironic things Moronically).

Mate used the water pump belt driven on a GP100 back in the early 80s.

[Bert]

Some found will looking for other Random shit on the web.
1960's Bridgestone racer conversions.

Fixed.. Thanks Chris

https://www.dropbox.com/s/oy6ljzvzecsg0es/BSTuning6%20pdf.pdf

[chrisc]

Some found will looking for other Random shit on the web.
1960's Bridgestone racer conversions.

https://dl.dropboxusercontent.com/content_link/qyUzVopKTZYbzcwfBpq2417kAcc9U8O3sMKecppNe3lzXJ3cDf SNZQhJLQjXX9qx?dl=1

Your link is dead mate, real dead

[Leed]

An ironic name the Honda Lead.

correct pronounciation Honda (/lɛd/)

http://www.sciencepicturecompany.com/_img/preview/Lead-Chemical-Element_spc-id-5105.jpg

NOT

https://c1.staticflickr.com/9/8112/8599487482_a3502c8231_z.jpg

makes more sense?

[F5 Dave]

What the? where did you come from? 39 posts, 2009 join date. How long have you been waiting for this set-up?

[wobbly]

But if you are Stralian then no matter how its spelt it will be Leed - cobba.
Of course when we say it they will hear Lud - which is probably right if its short for Luddite.

[husaberg]

Allegedly

HRC Honda RS125 NX4 2002 Model Cylinder Porting RS 125 98+ 99 00 01 02 03 04 05

12100-NX4-810
300508300509300510300511300512300513

[husaberg]

Allegedly

HRC Honda RS125 NX4 2002 Model Cylinder Porting RS 125 98+ 99 00 01 02 03 04 05

12100-NX4-810
Continued
300514300515
http://www.ebay.co.uk/itm/HRC-Honda-RS125-NX4-2002-Model-Cylinder-Porting-RS-125-98-99-00-01-02-03-04-05-/121337803133

[husaberg]

Allegedly 4JT-11311-30

TZ125 00-05
Not so sure myself unless it is a kit one I thought they ditched the PV?
But still looks very Honda LOL
300516300517300518300519300520300521

[husaberg]

Allegedly 4JT-11311-30

TZ125 00-05
Continued....
Not so sure myself unless it is a kit one I thought they ditched the PV?
But still looks very Honda LOL
300522300523300524

[husaberg]

Alledegly
Yamaha TZ125 4JT6 1998+ Model Cylinder Porting
300526300527300528300529300530300531

[husaberg]

Alledegly
Yamaha TZ125 4JT6 1998+ Model Cylinder Porting continued
300532300533
http://www.ebay.co.uk/itm/Yamaha-TZ125-4JT6-1998-Model-Cylinder-Porting-TZ-125-98-99-00-01-02-03-04-05-/121337807652

[husaberg]

Some very neat pics of the 87 Honda NSR500..........
Not sure what year they went to the carbs in front configuration but I guess it was around then.
300534300535300536300537300538300539

[husaberg]

Some more
300540300541300542300543
Last one looks later but still very Hondalicious
300544

[F5 Dave]

Those barrels look damaged. I wouldn't buy those Husi. I don't think they are supposed to come apart like that.

[husaberg]

Those barrels look damaged. I wouldn't buy those Husi. I don't think they are supposed to come apart like that.

Fair enough

Here is a Yamaha to keep you quiet then.
300546

plus this kitset version is on Trademe at the moment
http://www.trademe.co.nz/motors/motorbikes/motorbikes/classic-vintage/auction-774174269.htm

[Frits Overmars]

Allegedly 4JT-11311-30 TZ125 00-05 Not so sure myself unless it is a kit one I thought they ditched the PV?
But still looks very Honda 300516300517300518300519300520300521Maybe because it once was a Honda NSR500 cylinder :whistle:

[peewee]

http://i1081.photobucket.com/albums/j357/doddledo/Honda_NSR500_engine_front_Honda_Collection_Hall_zp s20c42d4f.jpg

[husaberg]

Maybe because it once was a Honda NSR500 cylinder :whistle:

Yes hense the lol looks like a Honda, still not 100% sure it is NSR500 though, in the advert it did say NSR500 (but gave a TZ125 part number) i had never seen a Bartol cylinder but i suspect you and Wobbly have, and wondered if it was one of those?, I understand they were copied directly off a Honda.
300559300560

[wobbly]

After years of humiliation by Honda power - Yamaha finally caved in and went long stroke and even used a T port for a while, but corporate pride was
involved I suspect and they never used the HRC dropping gate power valve to my knowledge.
A single blade in the centre and then finally their own bees knees and went back to the rotating spool, so a Yamaha with a dropping gate - dont think even Harold would
have got away with that.
I have exactly the same HRC cylinder cut up like that in a box here you can have for nothing.

[F5 Dave]

Fair enough

Here is a Yamaha to keep you quiet then.
300546

plus this kitset version is on Trademe at the moment
http://www.trademe.co.nz/motors/motorbikes/motorbikes/classic-vintage/auction-774174269.htm


Hmm, wonder if you could fit a pair of CPI barrels on that? You know sacrilege & money no object kind of stuff

[richban]

So the bike has done plenty of hours now in various states of tune. After looking at the numbers again comp is sitting at 15.9:1.


Its time to update the cylinder head shape to the steeper bath tub profile. I can't see any sign of det anywhere. There is a ring in the squish band but that looks like its touching on some of the carbon build up on the piston. If anyone can see any major problems in the pics sing out.

Cheers Rich



300567300568

[lodgernz]

VHM head Rich?

[husaberg]

After years of humiliation by Honda power - Yamaha finally caved in and went long stroke and even used a T port for a while, but corporate pride was
involved I suspect and they never used the HRC dropping gate power valve to my knowledge.
A single blade in the centre and then finally their own bees knees and went back to the rotating spool, so a Yamaha with a dropping gate - dont think even Harold would
have got away with that.
I have exactly the same HRC cylinder cut up like that in a box here you can have for nothing.

Yes Please..........
So do the numbers match the casting numbers in the pics?

[richban]

VHM head Rich?

VHM head with Custom insert. Care of Glen at Custom Components.

[Leed]

im not sure how everyone else did it but i did it this way. just with a paper clip to find the roof and floor angle then used a protractor tool to measure the paper clip. i may have a reed cage loaded into engmod from a old dirtbike but im not sure what good it would do you

http://i1081.photobucket.com/albums/j357/doddledo/IMG_20131212_210642_zps43194598.jpg


Ive just measured a 90° angle on my desk with a paperclip
there is no way to get 90° because of spring back
do you have a source of specially annealed clips?
but your methology must be bend it to the angle you think it is and see if it fits the fit nicely?
- I like the idea but will use softer galvanised garden wire

[peewee]

to measure the roof you wont ever need to bend the clip to a full 90* because every transfer port roof ive even seen had atleast some upward angle. just bend the clip on the table corner then put it in the port and see how well it fits. bend it alittle more or use a new clip and bend alittle less, until it fits well then measure the angle. only takes a few minutes

for the floors just bend the clip to the full 90* on the table corner (or as close to 90* as you can), then set it on the table top and bend alittle more past 90*. its rather easy

perhaps theres a better simpler way to measure the port angles but the paper clip was always simple and easy for me

you may have good luck with wire or even solder.

[Bert]

So the bike has done plenty of hours now in various states of tune. After looking at the numbers again comp is sitting at 15.9:1.


Its time to update the cylinder head shape to the steeper bath tub profile. I can't see any sign of det anywhere. There is a ring in the squish band but that looks like its touching on some of the carbon build up on the piston. If anyone can see any major problems in the pics sing out.

Cheers Rich



300567300568

Really interesting stuff Rich. Looking forward to others feedback on this.

What's the other cylinder look like??

[Frits Overmars]

...perhaps theres a better simpler way to measure the port angles but the paper clip was always simple and easy for me. you may have good luck with wire or even solder.When I do not have my own equipment at hand I use solder. Works fine.

[fatbastd]

Gate type power-valve on a Yamaha

I may have the wrong type of power-valve in mind, though I did see (about 5 years ago) an ex-works 500 Yamaha (across the frame 4, from about 1978 or 1979) in the UK with what I'd call a gate type valve - it wasn't a spool. Everyone at foist thought it was a TZ500 engine, though it was a0 too old (TZ500G came out in 1980) and had different cylinder stud spacing (I had several 500's to compare in the same shed). The engine came out of a hill-climb car...and had obviously fallen off the back of a Yamaha truck..

Barely relevant to the discussion, I know..

[senso]

When I do not have my own equipment at hand I use solder. Works fine.

If it isn't asking too much or crossing the line, could you show what kind of tools do you use to measure the ports angles?
Best regards.

[Drew]

If it isn't asking too much or crossing the line, could you show what kind of tools do you use to measure the ports angles?
Best regards.

Just make a beval, bevle, bevil. Nope, none of those spellings look right.

[merv]

Try bevel Drew.

[Frits Overmars]

If it isn't asking too much or crossing the line, could you show what kind of tools do you use to measure the ports angles?It's not crossing the line at all but at the moment it's asking for the impossible because I haven't got them with me and I have no pictures or drawings, apart from my bent feeler gauge with which I measure port heights.
I use a 1 mm gauge, bent at 45°, that I pinch between the piston edge and the port edge in such a way that the bent end is vertical (parallel to the cylinder bore). Then I measure from cylinder top deck to piston edge and subtract 1,41 mm from the measured value. It works for every port as long as its axial angle is not steeper than 45°, even when both the piston edge and the port edge are chamfered or radiused.

[lodgernz]

the cylinders i ported the nikisil was removed before hand and replated afterwards. but you shouldnt have much trouble with the right bits. i think diamond impregnated ones should work although i havent actually tried them yet. maybe theres something even better ?

if you have a welder perhaps you can cut a chunk out of the side of the barell and weld the outer side portion of the exh in the water jacket area then weld the cylinder chunk back in. this should allow aux ports to be used. it has been done on other cylinders, maybe it can work for you


You can lift the Ex port on a Nicasil cylinder using a diamond impregnated burr to cut thru the plating and then use RexCut cotton impregnated
rotary "mops " to put a smooth chamfer and radius back on the bore.
But the issue is that the ring , no matter what the port width is, will always bulge out into the port, and the top corner radius is what smoothly pushes it
back into the groove.
The cylinder will last a while like that, but It doesn't take long for the ring to wear thru to alloy around the port top edge, as there is no Nicasil going around the corner
into the duct to support the ring.
Best long term fix is to have the chrome removed, cut the port and re Nicasil it.
But for dyno testing the porting result, doing it the easy way is fine.


Thanks Peewee and Wobbly, good advice.

[Muciek]

Few pages ago I have asked about adding aux transfer ports in cylinder liner. I have made them and there was nice gain since without them motorbike was making 0-100km/h in 11,8s and now it's around 10,3s. Mid range and top end is better and engine can easier get out of that torque dip just before powerband. Piston looks like this (picture at bottom of the post). Is it good or something is wrong? Could someone tell me what this "batman" (I really don't have better word for this :laugh:) at middle of piston crown means? I run 50% SAR , 0,8mm squish and 32msv (RZ 350 piston) it's a play bike (off road and stuff, not RR). There are traces on squish band because main bearings failed and piston started hitting the head at 9000 rpm....

[TZ350]

Rode in F5 last Sunday at Mt Wellington, and did a good job of keeping the rider coming second to last honest.... :p

Great weather, great day and great racing.

The F5 (50cc) class lap record was broken again and the winning and second place times would have put those riders at 4th & 5th place in race 1 of F4 A grade and 6th & 7th in race 2.

To my surprise and delight, some anonymous person had pre paid my entry for me which is very nice. Thanks ... but because I don't know who they are I now have to be nice to everyone, just in case ..... :D.

Kel clocks a sub 30, F4 race one finishing order was 2T 2T 2T 4T and race two 2T 2T 4T 2T with 1st and 2nd running sub 30's and 3rd and 4th place recording laps either side of 30.


300705

The results of the 3rd round of the 14/15 season of AMCC bucket racing from yesterday are attached, for publication.
Tim will be updating the website & Mylaps.
There is a debate going over the sidecar points from the previous round which may result in a change. If so I will send an update.
F5 again delivered the closest racing & another new lap record.
Regards, David Diprose

Tim Frasers MyLaps results:- http://www.mylaps.com/en/events?sport=Bike&country=NZ
300702300701300700300704300706

[TZ350]

300715

Got my new RGV250 air cooled copper head back from being machined by Auto Flight today, looks good.

The copper was glued to the alloy block with the same high temp/thermal epoxy I used in the exhaust dam experiment.

The copper forms the squish area and is expected to draw the heat away from that part of the combustion chamber.

The combustion chamber was machined in true Wobbly Toroidal style with a sharp (no radius) transition from the squish band, it has also been machined so it takes a 3/4" reach plug.

At first glance the chamber looked to deep but a quick check with 10cc of kero soon left me re assured all was in order.

[wobbly]

So now you have stolen my head design where is the Blue Stilton.

[TZ350]

So now you have stolen my head design where is the Blue Stilton.

300719

It was yummy .. :D .. will share next time ... promise.

Hope this air cooled RGV thing works, seriously trying for 30hp at 10k rpm..... :yes:

[chrisc]

Hope this air cooled RGV thing works, seriously trying for 30hp at 10k rpm.

:rofl::rofl::Pokey:

[mr bucketracer]

300719

It was yummy .. :D .. will share next time ... promise.

Hope this air cooled RGV thing works, seriously trying for 30hp at 10k rp:gob::gob:m..... :yes:

free blowys:gob:

[TZ350]

free blowys:gob:

Yes it is a generous offer and I intend living a long time, but seriously I am very grateful to Wob for his help and tuning advice.

Hopefully we can get a bit of reliable hp and a decent power spread from the air cooled RGV project.

<iframe width="420" height="315" src="//www.youtube.com/embed/6Poynnb1LNY" frameborder="0" allowfullscreen=""></iframe>

RGV250 dyno run, 60+ rwhp, I am looking to do better than 30 hp with the single cylinder air cooled Suzuki GP/RGV125 half Beast.

300720300721300722

[wobbly]

Doing 30 RWHP means a crank power of around 35.
Do that at 12500 rpm and we are looking at 10 bar bmep - easy enough, even if not everything is done right.
At 10500 and that is 12 bar bmep, being aircooled and on a 24mm carb a 125 I believe would have to be so specifically designed and perfectly executed for that rpm
it would be completely useless everywhere else - Im still sleeping safe in the knowledge there wont be any need for random knob gobbling on my part.

[TZ350]

Doing 30 RWHP means a crank power of around 35. Do that at 12500 rpm and we are looking at 10 bar bmep - easy enough, even if not everything is done right.

This is realistically where I expect to get to with some reliability and a decent spread of power.

[wobbly]

Thank Christ for that, I can help no end with that endeavour as long as it doesnt involve shit I expect ( sorry - I would like ) my wife to be adept at - sucking the chrome off a tow ball.

[husaberg]

Thank Christ for that, I can help no end with that endeavour as long as it doesnt involve shit I expect ( sorry - I would like ) my wife to be adept at - sucking the chrome off a tow ball.

Those ones come with strings attached:msn-wink:

[bucketracer]

.... and on a 24mm carb ....

TeeZee probably hasn't forgotten about his plenum idea for dealing with the handicap of having to use a 24mm carb.

[TZ350]

Yep, have not forgotten. With a carb, fuel dropped out inside the plenum, fuel injection into the transfer ports was my attempt to fix the puddling in the plenum issue, if I can get the fuel injection sorted we will re visit the plenum idea.

[lodgernz]

In my quest for ultimate power, I have collected quite a few pistons from various 2T engines, and have carefully measured them all.
Most have an offset gudgeon pin, and mostly it is offset about 2% of bore toward the inlet side, but I have two pistons with offset of more than 4% toward the exhaust.
I've measured these two a dozen times to confirm this.
If I use one of these, is it going to cause me grief? Actually they always cause grief, but will these be worse?

[wobbly]

Not enough effect on power to make bugger all difference, it will just rattle more or less when cold.

[lodgernz]

Not enough effect on power to make bugger all difference, it will just rattle more or less when cold.

Thanks Wobbly, that's reassuring.
I thought the offset was always toward the inlet side. What do you think would be the reasoning behind offsetting the other way?

[F5 Dave]

Not enough effect on power to make bugger all difference, it will just rattle more or less when cold.Like its owner :laugh:

[husaberg]

Thanks Wobbly, that's reassuring.
I thought the offset was always toward the inlet side. What do you think would be the reasoning behind offsetting the other way?

Depends on the direction of rotation if it has a jackshaft in its origonal home ie arround 82 tz's the engines ran backwards
The effects of pin offset can be modeled in sims TZ did one a while back just to see the effect of a desaxel design.

[SwePatrick]

Wobbly, A question.
Can one ask you to make a calculation for a pipe(Friend will build pipe himself)?
Ofcourse nothings for free, i understand that.
If yes, can i pm you?

Best regards
Patrick
Sweden.

[lodgernz]

Like its owner :laugh:

That's cruel Dave, I roll rather than rattle. Then I pick up the bike and carry on

[lodgernz]

Depends on the direction of rotation if it has a jackshaft in its origonal home ie arround 82 tz's the engines ran backwards
The effects of pin offset can be modeled in sims TZ did one a while back just to see the effect of a desaxel design.

Thanks Husaberg, but the piston that is offset toward the exhaust is from a bike that rotates the usual way, i.e clockwise if looking from the right, with exhaust at the front.
Seems like the consensus is that it would rattle a bit but not cause any damage.

[fatbastd]

TZ's ran backwards way before 82..think BIG TZ's. Running the piston with the offset the wrong way won't make a blind bit of difference, in practical terms..BTDT.

[TZ350]

Most have an offset gudgeon pin, and mostly it is offset about 2% of bore toward the inlet side, but I have two pistons with offset of more than 4% toward the exhaust. If I use one of these, is it going to cause me grief? Actually they always cause grief, but will these be worse?

Piston pin offset theory and Engine noise reduction.

Below is a Thesis on the phenomenon of Piston Slap.

300829

http://dspace.mit.edu/bitstream/handle/1721.1/12156/30012843.pdf

[richban]

Just for you Mr Wobbly.

After you bagged my first attempt head, it has been eating me up inside ever since I installed it :sweatdrop ( not really ).

Here is the second attempt. 16:1 48% squish band .77 squish. Plug tip 5.8mm from piston top.

It will be interesting to see what happens on the dyno. The other heads seamed to be working very well. No sign of det.

[husaberg]

TZ's ran backwards way before 82..think BIG TZ's. Running the piston with the offset the wrong way won't make a blind bit of difference, in practical terms..BTDT.

This is true.
300832

[Bert]

Just for you Mr Wobbly.

After you bagged my first attempt head, it has been eating me up inside ever since I installed it :sweatdrop ( not really ).

Here is the second attempt. 16:1 48% squish band .77 squish. Plug tip 5.8mm from piston top.

It will be interesting to see what happens on the dyno. The other heads seamed to be working very well. No sign of det.

:niceone:
They have come up well, looking forward to running those up next week.
Now have your plugs arrived so we can do TPS maps???

[senso]

I was also intrigued about the desaxe layout, to apply in a 54mm x 44mm engine configuration, thinking that having the piston in the PMS after the crank as passed the 90º mark would improve the torque delivery, but to even see a difference with eng-mod I need to go crazy and put 5mm off-set in the piston.
Is it a bug, or is the "advantages" of the off-set pin something so reduced/limited?

[husaberg]

I was also intrigued about the desaxe layout, to apply in a 54mm x 44mm engine configuration, thinking that having the piston in the PMS after the crank as passed the 90º mark would improve the torque delivery, but to even see a difference with eng-mod I need to go crazy and put 5mm off-set in the piston.
Is it a bug, or is the "advantages" of the off-set pin something so reduced/limited?

Frits covered it further back........ Yamaha achieve it via offsetting the crankshaft and cylinder on quite a few modern bikes. ie YZF450
The port timing can be made asymmetric on a two stroke.
I think TZ ran the sim up to 12mm?

[senso]

Up to 4mm would be easy to do, just mill the crankcase off-set and add some guide pins, more than that would need welding, but given the over-squareness of 54x44mm its a strange layout to work with, the exhaust pipes need much different sizes when compared to a more conventional square or almost square engine, the combustion chamber is also stranger and more difficult to react to some changes talked here.

[senso]

And then there is the strange W shapped exhaust port, here with already a couple hours of work into it to gain the much needed blow-down to get this cylinder to really shine.
300837

[Drew]

And then there is the strange W shapped exhaust port, here with already a couple hours of work into it to gain the much needed blow-down to get this cylinder to really shine.
300837

There to hold the ring in its gove perhaps?

[senso]

Yes, without the "teeth" the exhaust port even with original specs/size would be over the safe 75% width, but they steal a lot of usable area.

[lodgernz]

And then there is the strange W shapped exhaust port, here with already a couple hours of work into it to gain the much needed blow-down to get this cylinder to really shine.
300837

Senso, is that a Gilardoni cylinder?

[senso]

Yes, gillardoni italkit for yamaha dt 80 lc, used a lot in the dt 50 lc in Portugal, with strokes from 40mm to 48mm, there is a dozen brands and home shops doing cranks for them.

[wobbly]

So tell me whats the advantage of having 3 overheating ' teeth ' hanging down ( up ) in the Ex port over a simple 68% main port and huge Aux
to generate the needed blowdown STA.
Unless you were intent on buggering the ports Cd numbers as well as heating up the returning plugging pulse - I really dont see it.

[wobbly]

Hey Rich that head looks alot like Mr Thiels for his Aprilia, hope it works as well.
Personally I would have done a toroid, but you have the plug plent close enough to the combustion burn space
so probably no free lunch to be had.

[wobbly]

Im happy to do a pipe for anyone, yes as you say nothing worth having is free, so I would want to model everything in EngMod
and that needs alot of input time.
PM me and lets get it on.

[TZ350]

I would love to see some posts of the pipe development process as it unfolds.

[richban]

Hey Rich that head looks alot like Mr Thiels for his Aprilia, hope it works as well.
.

Ah yes well, I found this picture on the interweb and thought well that looks pretty maybe I should give it a bash. Yep it's a copy it really matched up well to what i wanted. Will let you know if it makes more power or runs cooler hotter.

[chrisc]

I would love to see some posts of the pipe development process as it unfolds.

You and many of us too! I visit the ESE thread more than facebook/gmail/instagram (which is saying a lot for a 24 year old in NZ), so super appreciate anything more I can learn here.

Really keen to see your results with that head Rich

[Frits Overmars]

300846
Wouldn't it be better to put the cooling fins on the outside of the cylinder, instead of in the exhaust duct? Just a thought...

[TZ350]

PatAT Asymmetric Timing in Two-Strokes


300849

http://www.homebuiltairplanes.com/forums/2-stroke-aircaft-engines/18923-patat-asymmetric-timing-two-strokes.html

Asymmetric transfer timing, I have no idea if it works but its an interesting idea ....

[richban]

Really keen to see your results with that head Rich

Me 2. Hey if you are coming to manfield on the weekend come down Friday for the test day and bring your 125. Race it on Saturday. It would be a good track to get a feel for the bike. Lots of straight bits to relax on. There will be plenty of people keen to help you set it up me included.

[wobbly]

OK so if you guys want to learn,I am happy to detail the pipe design process for a specific end use, as long as the customer is fine with what he is paying for
being given away on a public forum.

[RomeuPT]

300846
Wouldn't it be better to put the cooling fins on the outside of the cylinder, instead of in the exhaust duct? Just a thought...

it's suprisingly the most tuned/used cylinder in Portugal. Made by Italkit for maybe more then two decades, still sells very wheel here, so much that other brands copied the most of it and offer a similar kit for a little less money.

The sucess of the kit it's not that it's amazingly good in performance but it's that cost's about 200€ with cylinder, piston and gasket's. And is actually reliable in most cases.

Some other's tried fairly good to input better cylinder kit's for the Yamaha DT/TZR in the nacional market, but at twice the price did not helped to sell.

[TZ350]

OK so if you guys want to learn

I am keen.

[RomeuPT]

Im happy to do a pipe for anyone, yes as you say nothing worth having is free, so I would want to model everything in EngMod
and that needs alot of input time.
PM me and lets get it on.

I did until now, two pipes for scooters, but I am not sure what exacly fit's to this engines.

My guess is, scooters are better for acelaration, so I did the diffusor start a litlee later and ending later too to improve power before peak hp.
Also they don't have gears and they can keep the engine in the rpm of most power in a race condition so probably narrow pipes work better.
I had also opted to do the biggest angle of the difusor around bdc.

Would this be wrong?

[wobbly]

We are probably loosing something here in translation - what do you mean by narrow pipes.
And also what do you mean by having the steepest diffuser around BDC,the point of maximum bulk flow should be around BDC for sure -
but in reality as the pipe length is fixed, the actual point of maximum depression will move from before BDC to after BDC as the rpm rises.
The earlier this happens means less overev power and visa versa, so moving the diffuser out further will gain front side power, but loose just as much if
not more in the overev past peak.
Overev power is more important I believe in this application, as hiitting a brick wall with the power graph going to almost vertically downward, will limit the advantage from short gearing.

[RomeuPT]

We are probably loosing something here in translation - what do you mean by narrow pipes.
And also what do you mean by having the steepest diffuser around BDC,the point of maximum bulk flow should be around BDC for sure -
but in reality as the pipe length is fixed, the actual point of maximum depression will move from before BDC to after BDC as the rpm rises.
The earlier this happens means less overev power and visa versa, so moving the diffuser out further will gain front side power, but loose just as much if
not more in the overev past peak.
Overev power is more important I believe in this application, as hiitting a brick wall with the power graph going to almost vertically downward, will limit the advantage from short gearing.


By narrow I mean a pipe that make the engine to have a narrow power band, instead of being a broader pipe.
The steepest part of the diffuser I usually put it at 43/44% to 60/61%. That is what I mean, I though scooters might benefit more from front side power instead of overrev, but ok.

Most or all decent pipes seen here have the stepest angle righ before mid section.

Thanks Wob

[wobbly]

Having the steep diffuser at 40 - 60% is perfectly normal now for any high performance race engine.
It started years ago with the old VSK range of pipes designed for Rotax, and ended up in the final few " tubo 100+ " designs for Aprilia.
This technique does exactly what I mentioned above,the max depression starts to occur BBDC on the front side of the peak, then moves to ABDC in the overev rpm range.
Giving the maximum ,widest, depression for peak Hp centred at your chosen
max Hp rpm.
The real trick for tailoring the Hp curve is creating the conditions for resonance superposition of the outgoing Ex pressure ratio, early in the powerband for
front side power,or later, past peak if overev is your requirement.
Here is an example of extreme superposition in the overev of a WR200 racing quad.
The remnant pressure at EPO adds to the outgoing pressure ratio and the pulse going down the header is off the scale - the max depression in the cylinder occurs well after BDC, all designed
for max overev capability.

[RomeuPT]

Having the steep diffuser at 40 - 60% is perfectly normal now for any high performance race engine.
It started years ago with the old VSK range of pipes designed for Rotax, and ended up in the final few " tubo 100+ " designs for Aprilia.
This technique does exactly what I mentioned above,the max depression starts to occur BBDC on the front side of the peak, then moves to ABDC in the overev rpm range.
Giving the maximum ,widest, depression for peak Hp centred at your chosen
max Hp rpm.
The real trick for tailoring the Hp curve is creating the conditions for resonance superposition of the outgoing Ex pressure ratio, early in the powerband for
front side power,or later, past peak if overev is your requirement.
Here is an example of extreme superposition in the overev of a WR200 racing quad.
The remnant pressure at EPO adds to the outgoing pressure ratio and the pulse going down the header is off the scale - the max depression in the cylinder occurs well after BDC, all designed
for max overev capability.

Would not this still benefit from max depression around BDC?
both cylinders I am working with have 190º of exhaust timing, so I guess superposition is there

[wobbly]

That isnt possible.
The problem is that we have a fixed set of lengths in the pipe that can only develop a depression over a certain period in time, but the rpm is varying
as we accelerate thru the powerband.
Thus as I said above the point of max depression moves in relation to BDC as the rpm varies.
We can bias the efficiency of the diffuser to act at the front side of the curve, by having the max ( widest area below atmospheric ) depression occur later
within the pipe length, or we can design it to create then max power around peak, or we can design the pipe to operate better in the overev.
The max depression part of the equation is confined quite rigidly within the boundary's set by a 32% header and a 68% mid section, but the superposition
resonance effect is governed by the port timing and the pipe tuned length, so is much more able to be "tuned" to a specific end effect.
Here is the same engine trace showing the before peak curve - notice no superposition at EPO, and early peak depression.
Then peak Hp - we have superposition and max depression around BDC.
Then in the overev - we have big superposition and late max depression.
This scenario generates the greatest peak power, and gives a long smooth roll off , of the power into the overev.
It possible to reverse the superposition position, but we will always be fighting the impossibility of stopping the natural movement of the peak depression event
due to the fixed pipe length.
We can change the depression curve shape with clever diffuser design, but it will always move from early to late in the cycle as the rpm changes upward.

[senso]

Excuse my dumbness wobbly, are those traces available in engMod after you run the simulations, or only when viewing the simulation while its running and pausing it?

[RomeuPT]

That isnt possible.
The problem is that we have a fixed set of lengths in the pipe that can only develop a depression over a certain period in time, but the rpm is varying
as we accelerate thru the powerband.
Thus as I said above the point of max depression moves in relation to BDC as the rpm varies.
We can bias the efficiency of the diffuser to act at the front side of the curve, by having the max ( widest area below atmospheric ) depression occur later
within the pipe length, or we can design it to create then max power around peak, or we can design the pipe to operate better in the overev.
The max depression part of the equation is confined quite rigidly within the boundary's set by a 32% header and a 68% mid section, but the superposition
resonance effect is governed by the port timing and the pipe tuned length, so is much more able to be "tuned" to a specific end effect.
Here is the same engine trace showing the before peak curve - notice no superposition at EPO, and early peak depression.
Then peak Hp - we have superposition and max depression around BDC.
Then in the overev - we have big superposition and late max depression.
This scenario generates the greatest peak power, and gives a long smooth roll off , of the power into the overev.
It possible to reverse the superposition position, but we will always be fighting the impossibility of stopping the natural movement of the peak depression event
due to the fixed pipe length.
We can change the depression curve shape with clever diffuser design, but it will always move from early to late in the cycle as the rpm changes upward.

What isnt possible? I think I might not being understood :/, my english is not the best
I understanded what you say before, I had read this all topic once, and read all the important coment's and data several times. :)

I also tested a lot the diffusor position and angles on pipes for several engines. Lately I been varying the baflle inicial percentage to see the effect's.

[wobbly]

What isnt possible is to move the rpm point at which the max depression is seen at,and not have the max depression happen earlyer at lower rpm - then later at higher rpm.
The biggest and widest depression around BDC is seen at the tuned point of the rpm and the pipe length.
The max ( lowest pressure ratio ) point will always move with rpm due to the fixed position of the diffuser.

In answer to seeing the Ex port pressure ratio ( I have the software pressure take off point set a 0 = at the cylinder wall ) yes ,you can see any trace after the run is finished
at any of the rpm points.
Go to Thermo Traces, tick Pressure Traces, load the file, pick the rpm then pick Pex.
This gives you the pressure trace centred on BDC, even easyer to see the differences.

[TZ350]

http://www.pit-lane.biz/f34-gp125-et-250-snif

http://www.pit-lane.biz/t5121-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-4

http://www.pit-lane.biz/t4072-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-3-locked

http://www.pit-lane.biz/t3173-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-2-locked

http://www.pit-lane.biz/t117-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-1-locked

300929

There is more interesting stuff here, more stuff than you can shake a stick at .....

[TZ350]

Then peak Hp - we have superposition and max depression around BDC.
Then in the overev - we have big superposition and late max depression.

This scenario generates the greatest peak power, and gives a long smooth roll off , of the power into the overev.

Thanks Wob, this is great .......

Its taking me a bit to get my head around it all, so far I have not been able to design a pipe that EngMod thinks is better than the std RS pipes we use, but its early days.

[wobbly]

Romeau - interesting that you say that you think a " narrow " pipe would work best with a scooter that allows the engine to be
"in the power " all the time - yes this is true, and is why I believe a design that creates max power and then max overev would be the best.
I say that because if correctly designed the much stronger wave action within the pipe at high rpm, can be used to produce alot more total power under the curve.
But then you say the engine has 190* Ex, this will make it impossible to create anything like maximum power.
No engine can ever be anywhere near max output with that duration, but yes it can have superposition over a wider range than a higher Ex port
can create - and this gives a very wide flat torque output , but it will never be a proper match to run with a "narrow " pipe design for max power output.

[RomeuPT]

Romeau - interesting that you say that you think a " narrow " pipe would work best with a scooter that allows the engine to be
"in the power " all the time - yes this is true, and is why I believe a design that creates max power and then max overev would be the best.
I say that because if correctly designed the much stronger wave action within the pipe at high rpm, can be used to produce alot more total power under the curve.
But then you say the engine has 190* Ex, this will make it impossible to create anything like maximum power.
No engine can ever be anywhere near max output with that duration, but yes it can have superposition over a wider range than a higher Ex port
can create - and this gives a very wide flat torque output , but it will never be a proper match to run with a "narrow " pipe design for max power output.

I see, thanks. I just have to make pipes for what people have and the market offers to them, unfortunely most of the engines I have to make the pipes are oversquare, low timing sometimes, weak transfer port areas or entrance angles, trash designed exhaust ports, bullshit cdi's with fixed timing or change just a little, very confused owners sometimes too. It's what I got :/

By the way, the rotax 122/123 engine that is used on the aprilia rs 125 have supposedly about 182/183º exhaust timing. (some other engines have stock timing like this ex. Banshe 350) In a case like this, will this engines take profit from any superposition with a timing relatively lower than 190º? Would the residual pressure wave that arrives too soon to synchronize with the new exit pulse at exhaust open, but still make any positive/noticible effect?

Thanks

[wobbly]

The low Ex timing makes superposition able to be used over a much wider band of rpm.
In this case there is much more opportunity to design the pipe to adjust the powerband shape you want, as the tuned length resonates with the port
over such a wide range.

[WilDun]

300929

There is more interesting stuff here, more stuff than you can shake a stick at .....

TZ - That looks like me having a go at some Hoons ( from "hoon cam") - they abused me when I was out on my mobility scooter a couple of years ago!!

[wobbly]

Quote " unfortunately most of the engines I have to make the pipes are over square, low timing sometimes, weak transfer port areas or entrance angles, trash designed exhaust ports, bullshit cdi's with fixed timing or change just a little, very confused owners sometimes too. It's what I got "

Sounds like some of the people and the engines here - they are called "bucket racers ", thats why ESE got in a Works Engine Tuner from overseas.

[TZ350]

"unfortunately most of the engines I have to make the pipes are over square, low timing sometimes, weak transfer port areas or entrance angles, trash designed exhaust ports, bullshit cdi's with fixed timing or change just a little, very confused owners sometimes too. It's what I got "

Sounds like some of the people and the engines here - they are called "bucket racers ", thats why ESE got in a Works Engine Tuner from overseas.

"very confused owners sometimes" yes, very true, and more than sometimes too ........... :laugh:

300978

Where it all started, but Thomas did pretty well though, got us to 31rwhp.

Not even Stan Stephan's has done that with an old Suzuki GP125 commuter bike from the 1980's.

301005301002301003301004301001

And with Wobs help we are aiming for the next level, high 30's, maybe 40 .........

[husaberg]

"very confused owners sometimes" yes, very true ........... :laugh:

300978

But Thomas did pretty well though.

Thomas is the tuner? I always thought he was shipped over to be Avalons Mail order bride?

[RomeuPT]

The low Ex timing makes superposition able to be used over a much wider band of rpm.
In this case there is much more opportunity to design the pipe to adjust the powerband shape you want, as the tuned length resonates with the port
over such a wide range.

More about pipes, the stock aprilia RS pipe, for example appears to have two stage baffle, combined angles seem to give more than 14º angle.
What happens when you exceed 14º baffle angle? Does the pressure ratio start to drop more then they raise with that angle?
Is it a thin pipe that needed to begin the baffle at more then 77% to get near 14º a good choice or this narrow's to much the power band even with properly design Diffusor? I know this can be quite dependent on the engine, but in general what can you say about this?

Is quite easy to give 14º baffle to a 125cc with a pipe near 800mm and a belly 120+, but to a 80cc with much thinner belly and a little less lenght needs to start the baffle late at +77% to be near 14º.
I don't know exacly what is late or soon to start the baffle, most of the drawings I have seen and pipes measured seem to be in around 76%.

I did in my nsr tested a pipe with 14,4º instead of 14º, same lenght and belly diameter, felt no diference. Without dyno or bench I am very uncapable to draw conclusions.
Thanks

[TZ350]

300999301000

Here is an oval to round spigot for Robs GP100 with RGV cylinder.
36mm pipe ID, oval shape at the duct exit is 36 wide by 27 high = effective area of a 31mm round..
This nozzle effect doesnt work on single port engines - I have tried.

301009

Re stinger nozzles - if running a 18mm nozzle on a 100cc then you could connect a 20mm stinger tube to it in basically any length and this would not affect the power at all - in fact using the nozzle with a tapered section out to the bigger tube makes more power.
Aprilia/Derby twins do this as the top pipe has a stinger 60mm long, the bottom one is closer to 220, but the effect works on any 2T.

301008301010

Wobs Oval to round Nozzel .....

301007

Frits Overmars stinger nozzle dwg.

[wobbly]

The Aprilia RS123 as it has a powervalve is able to be tuned to a higher level over a shorter range than if the PV wasnt installed.
In general a steep angle rear cone creates a high peak power number in a narrow band with severe roll off of the power after peak.
Something I cant explain is that quite often in a sim having a small steeper section of cone down at the stinger will create more power - like was
used by Aprilia in the RSA / RSW.
But in many dyno tests of this, in reality, it doesnt work any better than a single angle - the same result for a shallow section up at the mid followed by a steeper section.
Both scenarios can be equalled or bettered on the dyno with the correct single cone.
For practical purposes 28* included is about the limit for a single cone,but there are special cases like the RS123 where having a powervalve, and a rev limiter
you get tuners ( like Arrow ) that want a big number to advertise and sell pipes, so they use a REALLY steep angle as it doesnt matter that there is no overev power.
You may get an improvement in power, over a narrow band with a very steep rear cone, but its a special case where running a very low port timing with a severe rear cone
and is not something I seriously want to even think about.
Here is the Arrow design, really dumb with incorrect header length etc, but it gives the result they intended.

[F5 Dave]

Here's my attempt to do something useful in a similar vein TZ

The inner ring is the stub now welded onto the pipe. The oval is 26 by 35 so about 75% of area of the new port welded onto barrel with a triple port. This leaves quite a 6mm step top and bottom I have blended his to about 4mm since pics. Will trial like this, then take the step out to look more like your insert. If it was better with step I can push an insert back in.

it looks a bit prettier once I matched it up when welded on the barrel.

[TZ350]

Hi F5

Looks Good, when I have a few other things out of the way I am going to try making one for the air cooled RGV cylinder.

[2T Institute]

Not even Stan Stephan's has done that with an old Suzuki GP125 commuter bike from the 1980's.



Not sure Uncle Stan and tuner should be used in the same sentence. Don't think many GP125/250's went there ;)

[wobbly]

How the hell did you get a tripple port into a TZ ( old model based on RD cases I mean )

[F5 Dave]

I'm special. No I mean 'Rob' when I said 'TZ' responding to his post.

This is my long suffering MB100. It is a project in itself to 3 port.

[chrisc]

Had the RS125 on the roller at the house of savoured youth tonight. See post here below (click the little blue and white arrow icon next to my user name 'chrisc')



https://farm4.staticflickr.com/3926/15276353165_9d8f6e73f0_c.jpg (https://flic.kr/p/pgVizp)

[RomeuPT]

The Aprilia RS123 as it has a powervalve is able to be tuned to a higher level over a shorter range than if the PV wasnt installed.
In general a steep angle rear cone creates a high peak power number in a narrow band with severe roll off of the power after peak.
Something I cant explain is that quite often in a sim having a small steeper section of cone down at the stinger will create more power - like was
used by Aprilia in the RSA / RSW.
But in many dyno tests of this, in reality, it doesnt work any better than a single angle - the same result for a shallow section up at the mid followed by a steeper section.
Both scenarios can be equalled or bettered on the dyno with the correct single cone.
For practical purposes 28* included is about the limit for a single cone,but there are special cases like the RS123 where having a powervalve, and a rev limiter
you get tuners ( like Arrow ) that want a big number to advertise and sell pipes, so they use a REALLY steep angle as it doesnt matter that there is no overev power.
You may get an improvement in power, over a narrow band with a very steep rear cone, but its a special case where running a very low port timing with a severe rear cone
and is not something I seriously want to even think about.
Here is the Arrow design, really dumb with incorrect header length etc, but it gives the result they intended.

Many Thanks Wob.

I am thinking about build a replica of Honda A-Kit pipe to test on my engine, I did this a couple of years ago, but the pipe is in 1mm mild steel, a litlle longer tuned lenght, shitty welds etc, so I think in build another in 0,8 with all the tools and pactrice I have now.

Looking for the drawing It can be seen a parallel 120 belly, other drawings have a slight increase diameter in the mid section about 1º or so, is this a good thing most of the time? What is the effect on the pressure bench?

Thanks

[wobbly]

The Honda A Kit is VERY old tech, it was basically the design Harold used on the lovely KTM GP efforts and was one ( main ) reason they were never really fast enough.
If you must copy something go with Aprilia Tubo 100+ layout, less the multi angle rear cone.
But using a 800mm tuned length with a very low exhaust port duration is off on a very weird tangent and who knows what result this will give you.
The A kits had 200* duration with that short pipe and needed every ignition trick and electronic powerjets to make that work correctly.

[TZ350]

If you must copy something go with Aprilia Tubo 100+ layout, less the multi angle rear cone.

Hi Wob can you post the dimensions and walk us through the pipes features? Ta ..... :)

[RomeuPT]

The Honda A Kit is VERY old tech, it was basically the design Harold used on the lovely KTM GP efforts and was one ( main ) reason they were never really fast enough.
If you must copy something go with Aprilia Tubo 100+ layout, less the multi angle rear cone.
But using a 800mm tuned length with a very low exhaust port duration is off on a very weird tangent and who knows what result this will give you.
The A kits had 200* duration with that short pipe and needed every ignition trick and electronic powerjets to make that work correctly.

What you think of this pipe in the pic? I did it thinking about front side power, rather then overrev, but still overrev is good, I guess due to the ignitech curve falling fast after peak rpm.
I wanted a pipe to go on drag and use the A-kit pipe I did for overrev and top speed, but the bike is very similiar with both pipes :tugger:

301153

[husaberg]

Hi Wob can you post the dimensions and walk us through the pipes features? Ta ..... :)


Pipe design elements relating to variable with pipes


If I were to explain pipe design I would need to write a book,but in general things are pretty straight forward in relation to the % values.
End of header is always 31 to 33% and end of diffuser is always 62 to 68%.
To see the effect of a silly long header, you can watch the pressure ratio at the Ex port, and thus the effect this has on the depression in the cylinder.
We are looking for the lowest and widest negative ratio we can get around bdc when the transfers are fully open.
A long header delays the beginning of the depression too late in the cycle, when in the power band.
In a race 2T we are always fighting power range Vs peak power.
Shorter diffusers create steeper angles,thus greater wave amplitude, but this narrows the effective band width.
So - in general the best compromise is around 66%.



The % I quoted for header means that portion of the length from piston to rear cone end.
Its from the piston to the beginning of the diffuser, what happens in between isnt relevant.
Unless of course you use a small Ex duct and a bigger header, that makes more power.
And of course same for the diffuser end, that is simply 66% of the length from the piston to the end of the rear cone.
Frits Overmars

A powervalve does not really give you real resonance power; it just prevents the pipe pulses from completely messing up the power curve at low revs. I expect a sliding pipe will make more low-down power.

http://www.pit-lane.biz/t1666p15-technique-rossigrm-2strokes-boat-engine?highlight=twin+rotary[/QUOTE



Imagine the valve passes 60 cc of fuel per minute, but the engine only needs 30 cc. How would you go about that? You could open the valve for 30 seconds and then shut it, but by that time the engine may have drowned.
Open it for one second, close it during one second, open it for one second, sounds more sensible, doesn't it? That is why I quoted the valve's frequency: 13 Hz.
That means it can open and close up to 13 times per second. This again means it could open for 1/13 of a second and close the rest of the second, or open for 12/13 of a second and close during 1/13 s, or everything in between. And of course it can stay completely open or closed; enough possibilities to govern the mixture.

The ignition timing does not have to be changed when you use an electronic power jet. But both the ignition timing and the powerjet timing are means of influencing the exhaust gas temperature. A late ignition and/or a lean mixture both cause a higher EGT, so you can match the exhaust resonance frequency to a rising engine rpm.
And if you have that power jet available, the ignition does not have to do it all by itself anymore, so you can search for a timing that gives a better overall result.



You have to stay within certain length percentage limits for all elements of the exhaust system; you cannot make one part a lot longer or shorter in relation to the others without losing power somewhere.
It is best to concentrate on getting all dimensions correct for maximum power. In the high gears you don't ride low revs and in the low gears you'll have enough low-down power left to pull a wheelie or spin out the rear wheel (I'm not talking about buckets though, so you might want to reconsider your case).
If you have a decent setup for angle*areas, pipe, carburation and ignition, the necessary overrev potential will come naturally; no need to sacrifice maximum power in order to make it rev a little higher.


That old Honda pipe mod drawing is completely useless, it was never used by the factory in any form.The rear cone is insanely steep.
And the so called A Kit pipes were designed to work with high Ex ports - where the customer engines all had 83*ATDC to let them rev without an electric powerjet.
I have much better designs with a ton of dyno time on them, but of course they are all specific to 50Hp 125 cylinders, not 30Hp 100cc designs.
Here is one that has won dozens of 125 kart titles, but again it should just point you in the right direction for the 100.


Here is the A Kit spec RS125 pipe drawing.


Ceramic coating shouldn't cost power; on the contrary. You'd just have to adjust the lengths, like you have to with stainless steel and titanium.
This graph shows the results of three pipes with identical dimensions but different materials on the same engine.
293077

Then try this, Romeu. That should keep you out of the boozer for a couple of evenings :msn-wink:.
293078
The pipe design you have asked for is in the Frits files


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

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

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

Enjoy.

[wobbly]

So there you have it - the A Kit pipe is shit in comparison to that layout.
You have a 2 stage header with the optimum angles of 3.5 and 5.5 * ( even better than Aprilias Tubo designs that to my knowledge never had a 2 stage )
with a 3 stage diffuser,the steepest in the middle with approx equal angled 1st and 3rd stages - all good.
The tapered belly section can be tapered either way, depending upon the engines response to the diffuser action and how much overev it is capable of ( or needed ) via a steep rear cone.
The only element that I have found to work better is the relationships in the header.
In your design the end of the first header is at around 75% = 200/268,but as in the empirical design guides for the whole pipe of 33% header 66% diffuser, the same applies to the header lengths.
End the first 3.5* cone at around 66%, so you would then have two equal headers of 91.5mm ie 60+25+91.5 = 176.5/268 = 66%, thus the second header at 5.5* is 91.5/268 = 34%.
Varying the length of the 1st diffuser changes the shape of the depression curve at and around BDC, thus tailoring to front side or overev power.
I have no idea what the superposition characteristics are of 190* with 800mm TL would be, as such a weird combination has never occurred to me - but as I well know anything I believe
should or should not work at all in a 2T, is very often complete rubbish when you get to analyse it properly in EngMod.

[TZ350]

301160
Thanks Frits and Wob for explaining about pipes

301159

And Husa for showing me where to find the A-Tubo 102 dwg.

301158

[RomeuPT]

So there you have it - the A Kit pipe is shit in comparison to that layout.
You have a 2 stage header with the optimum angles of 3.5 and 5.5 * ( even better than Aprilias Tubo designs that to my knowledge never had a 2 stage )
with a 3 stage diffuser,the steepest in the middle with approx equal angled 1st and 3rd stages - all good.
The tapered belly section can be tapered either way, depending upon the engines response to the diffuser action and how much overev it is capable of ( or needed ) via a steep rear cone.
The only element that I have found to work better is the relationships in the header.
In your design the end of the first header is at around 75% = 200/268,but as in the empirical design guides for the whole pipe of 33% header 66% diffuser, the same applies to the header lengths.
End the first 3.5* cone at around 66%, so you would then have two equal headers of 91.5mm ie 60+25+91.5 = 176.5/268 = 66%, thus the second header at 5.5* is 91.5/268 = 34%.
Varying the length of the 1st diffuser changes the shape of the depression curve at and around BDC, thus tailoring to front side or overev power.
I have no idea what the superposition characteristics are of 190* with 800mm TL would be, as such a weird combination has never occurred to me - but as I well know anything I believe
should or should not work at all in a 2T, is very often complete rubbish when you get to analyse it properly in EngMod.

I am talking about my NSR, that has ~198º exhaust, 190º was a scooter I needed to make a pipe.

From my side, and the tools I have with me I feel a lot uncapable to continue improvment. I have used the 2 stage header and 3 stage diffuser design mostly, sometimes does not seem to be the best, but in average seems to work fine.

Thanks

[husaberg]

I am not sure what model this is but Frits posted it as the last honda pipe.
Actually it appears he posted it for you on pitlane......

He has also posted this pretty extensively

Will fix it later.........

[TZ350]

Making progress with the lighter better handling (I hope) bike.

I am aiming for 21 deg rake, 85mm trail and 40%R & 60%F weight distribution with rider aboard.

Front and rear suspension has pre-load, compression and rebound adjustment.

301172

Now that Beast 2 is coming together it was starting to take up to much space at work, I couldn't hide it under the bench anymore, so I brought it home.

The engine is going to go as far forward as possible to get the weight on the front wheel.

301191

The new head is much bigger than the original Suzuki one and the angle to the airflow should allow for some pretty good cooling.

The original front engine mounts will be used for securing the air cooling ducts.

301171

Of course, there will be copper everywhere on the cylinder and head.

The head is missing from this picture but here is what it looks like.

301173

Copper squish band and toroidal combustion chamber.

The copper plate is bonded to the alloy block with high temperature high thermal conductivity epoxy.

[Frits Overmars]

The engine is going to go as far forward as possible to get the weight on the front wheel. Your rider will love you for it. And take away that front guard. In the dry you don't need it and in the wet removing it will give you hybrid (very wet air) cooling.

Joking apart, even removing something as light as such a small guard from the front forks inertia will noticeably improve the feedback from the front tire contact patch to the handlebars. And it will certainly help cooling. I have no recent figures for aircooled engines (I try to stay away from those) but on a watercooled bike removing the front guard can drop the coolant temperature by as much as 8° C.

[RomeuPT]

I am not sure what model this is but Frits posted it as the last honda pipe.
Actually it appears he posted it for you on pitlane......

He has also posted this pretty extensively

Will fix it later.........

A-Kit pipe is what I called to the middle pipe in that pic. Was posted then as KTM and Honda Pipe used in A-kit cylinders.

My guess is the KTM GP engine is very similiar to the Honda RS

[jonny quest]

Frits beat me too it... but maybe even a beneficial tread pattern for cooling?

[richban]

Well we ran up the new 300 heads. There was a small problem that I didn't have time to fix before race weekend that meant the squish went from .75 to .85. The result was a missing 4 hp. On the up side I gave my old heads to other Richard to try in his 300 and he gained 5hp. I will be pushing the squish to its limit on the next attempt. I think the engine will be ok with .7

[TZ350]

... take away that front guard. In the dry you don't need it and it will certainly help cooling. I have no recent figures for aircooled engines (I try to stay away from those) but on a watercooled bike removing the front guard can drop the coolant temperature by as much as 8° C.


Frits beat me too it... but maybe even a beneficial tread pattern for cooling?

Yes,thanks, making use of the draft off the spinning front wheel for forced fan air cooling is not a bad idea. Especially as it does not cost any extra power to do it, unlike a crankshaft fan or an electric fan or even a large scoop for the air duct would add drag.

[Bert]

Well we ran up the new 300 heads. There was a small problem that I didn't have time to fix before race weekend that meant the squish went from .75 to .85. The result was a missing 4 hp. On the up side I gave my old heads to other Richard to try in his 300 and he gained 5hp. I will be pushing the squish to its limit on the next attempt. I think the engine will be ok with .7

but you still managed to happily beat him :niceone:

it would be interesting to test the squish on a hot engine as I've got a few concerns with 0.7 on a piston that large...

[richban]

I've got a few concerns with 0.7 on a piston that large...

Yeah it will be tight. Richard ran his a .65 with new crank and it didn't touch.

[F5 Dave]

Almost page 1000, a sterling effort.

and a reminder to believe your det sensor:facepalm:

[mr bucketracer]

Almost page 1000, a sterling effort.

and a reminder to believe your det sensor:facepalm:whats happen dave , what did it fell like before!#$@

[TZ350]

301204

Man Cave complete with comfy chair for contemplating motorcycles and the banana box's are full of rock LP's from the 70's for head banging relaxation. The speakers are fastened to the ceiling and the whole shebang is powered by a big valve amp that can only be described as a heater that plays music.

[F5 Dave]

whats happen dave , what did it fell like before!#$@

Pretty good. But there's no water in the rad. That might be an issue.

[TZ350]

Sorry to hear it is still giving you grief....:facepalm:

[bucketracer]

Anything special for page 1000 TZ ?

[TZ350]

Page 1000

On Page 500, Bucket has links to how Team ESE built their 26, 28 and 31 hp engines:- http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page (http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page600)500

And Micks post below is your most useful tool for finding all the other good stuff on the Team ESE (or any) thread, try it.


… some may find this useful. Rather than use the site search, which usually fails.
Use Google to search this site, just use an ordinary search phrase and after it add
site:www.kiwibiker.co.nz (http://www.kiwibiker.co.nz/)
for example
Frits pisa site:www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/ (http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/)
Mick

What F4 or Bucket racing is all about:-


Video from yesterdays F4 cup, filmed from GPR bike no 11


http://www.youtube.com/watch?v=381VSCKmAns


Here is the first 15min of the BOB , Riding with Mr BucketRacer


http://www.youtube.com/watch?v=N5z5hhIWYFo

Here are some other very interesting threads:-
Foundry:- http://www.kiwibiker.co.nz/forums/showthread.php/162399-The-Bucket-Foundry/page29
Team GPR:- http://www.kiwibiker.co.nz/forums/showthread.php/150352-Team-GPR?p=1130775246#post1130775246
Frame and Chassis:- http://www.kiwibiker.co.nz/forums/showthread.php/145224-Race-chassis/page38
Chris C's photos:- http://www.kiwibiker.co.nz/forums/showthread.php/153656-Chris-Bucket-photo-thread-Bandwidth-warning/page5
Old #6:- http://www.kiwibiker.co.nz/forums/showthread.php/68694-6/page49
Bucket Lap Records:- http://www.kiwibiker.co.nz/forums/showthread.php/117354-Bucket-lap-records/page8
Photographic History of Bucket Racing:- http://www.kiwibiker.co.nz/forums/showthread.php/167592-A-photographic-history-of-Bucket-racing/page3
Ecotrons engine management:- http://www.kiwibiker.co.nz/forums/showthread.php/159112-Ecotrons-Engine-Management/page5


2T Engine development software:-

Porting Program http://www.porting-programs.com/

EngMod2T http://www.vannik.co.za/EngMod2T.htm

There is an option in "Thread Tools" to download the complete text off this thread.

There are also over 7000 images on this thread, use "Thread Tools" to view them and then click through to the original post about them.

302136302135


Page 600 is worth a look at:- http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page600

A Link through to Husaburgs vast library of pictures.


NSR500 Porn
I will be adding some more later including
Honda RS125 Aprilia GP bikes YZR500 Swiss auto
Rotax and other Tandem twins RGV500 Kenny Roberts 3's
Cagiva Carbs fuels intakes and stuff


I put together a bit of a photomontage of Neil’s many many projects i haven’t put them in order yet. One word describes Neil ...........Prolific

http://www.kiwibiker.co.nz/forums/album.php?albumid=4864

if you can't see the album don't blame me.

Its worth the visit ......

And there are also over 7,000 images on this thread. Follow the link below and you will find screen shots of the process.


How to view all the images.
Go to Thread Tools at the top of the page and View Thread Images.
Now roll to the bottom of the page.
Here you can sort them from the beginning.
70 to a page, there are 6,000+ images
If you find something interesting just click on the images title and it will take you to the original post.

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

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



Do I understand this correctly, given sufficient blow down and exhaust STA an exhaust duration of 180 deg would be the optimum at any rpm? The short answer is yes. (the long answer is) … the initial pulse starts moving as soon as the exhaust port starts opening. More or less true, but we are not interested in the first weak appearance of the pulse; we want to know when the pulse reaches its maximum amplitude. And that requires a certain amount of open exhaust port area. It turns out that for our desired theoretical exhaust timing of 180° we will need a geometrical exhaust timing of about 190°, depending on the shape of the port: does it open gradually or does it open over its full width all at once.

The obvious question will be: why has the Aprilia RSA125 a geometrical exhaust timing of about 200°? True, at 190° the maximum torque value would be higher, but the engine would not want to rev because the blowdown time area would be too small.

The 200° duration is a compromise: a bit less torque and a bit more revs; as long as the torque decline is smaller than the rpm rise, we gain horsepower.

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

301223
Frits suggested design criteria for a good pipe.

301224

Click on Husabergs link to read about transfer port angles.



301208
I tried to post a little technical story here to help you through the Christmas days, but I could not manage to insert the pictures the way I wanted to...
But in case you're curious, you might want to take a look here: http://www.pit-lane.biz/t3173p657-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-2#134197 Transfer Port Theory

Transfer Ports. Low and Wide is the go….


The lower the transfer timing, the less risk of too-early returning exhaust pulses shoving the cylinder contents back into the crankcase.
In short: lower transfers give a better powerband, all other things being equal (which of course they never are).

The 135mm inlet tract length from tip of reed to carb bellmouth rule of thumb.


I discovered the 135mm inlet rule of thumb on a TM125 MX engine used for 125 class kart shifter racing . That is the length for a reed - the RV needs to be a lot shorter again.

302659 Frits's version of a short carb setup.


The Aprilia's inlet disk diameter. From memory I would say it was 126 mm.

Optimized disk inlets do not generate pulses: you open the disk when the crankcase pressure is equal to the pressure just outside the disk. Opening it any sooner would cause a loss of mixture to the outside world; opening it any later would be a waste of time*area.
You close the disk when the inlet flow has come to a stop. At that moment the pressure at the outside face of the disk will be equal to the pressure in the crankcase, but it will be higher than the atmospheric pressure, so there will be some blow-back, but that does not come out of the crankcase (assuming your closing timing is spot-on); it is just mixture feathering back from the high-density zone outside the disk. For that matter, every conventional inlet system (disk, piston, reed) will show the same blow-back tendency. And it may not be even visible from the outside; maybe the cloud of blow-back moves just a few centimeters and never really exits the inlet tract.
By the way, closing an inlet disk too early (or revving the engine higher than the inlet system's frequency would like to) will generate serious blow-back because then the closing disk interrupts an inward-bound flow which will violently bounce off the disk.
You can observe this very nicely on a dyno: looking into the carburetter you can see the fuel spray exiting the mixing tube and curving towards the crankcase. But rev it high enough and you will see this curving change into a steep front of mixture.


A lot of the decade pages have collections of quotes and links to other interesting things.

Page 990 Blowdown STA, Ex porting plated cylinders, port layout and port angles.
Page 980 No links list but there is talk about spark energy and EGT
Page 970 Fuel - Oil and EGT talk
Page 960 Wob - Fuel and Oil Talk and Crank inertia.
Page 950 Its all about exhaust blow down …..
Page 940 Fixers 50cc adventures – ports & heads – Wob talks about Bad Gas.
Page 930 Frits 50cc pipe – Husburgs large links list, parts books, steering head brgs
Page 920 Big links list, allsorts. Tokoroa GP videos.
Page 910 No links list but the page is about fitting a 12V generator stator.
Page 900 Frits thoughts on O2 sensors – EFI Fueling theory – Wob on EGT
Page 890 DIY Foundry tips – EFI data – Detonation Management (tec paper) – more EFI
Page 880 Big list of Flettners Foundry posts and pictures.
Page 870 YZ & Bighorn Dyno results – Dyno Vids and EFI talk
Page 860 Air cooling and ducting and Carb air inlets, next page Greymouth Race
Page 850 1st run of the EFI Beast
Page 840 Husaburgs big links list on Power Jets – High temp epoxy and Ex port dam.
Page 830 Plugging piston pins – Cyl Heads (no radius) and Plug to Piston distance.
Page 820 Det sensor & Ignitec setup – Exhaust port dam – Boost Bottle – Insulating Paint
Page 810 Links – about Razing the Exhaust port floor
Page 800 Link to dyno graphs for the YZ & BigHorn EFI Bikes & a lot of EFI stuff
Page 790 Car & bike museum pics _ Wobs pipe.
Page 780 Setting up an IgniTec DC-CDI-Race-2 ignition – Big list of links.
Page 770 Wobs views on triple ex ports – first run of the EFI YZ250
Page 760 Port Angles – lots of Pipe design info – Fast model aero engine.
Page 750 Case Com – Basic 2T tuning – BigHorn EFI
Page 740 Case Vol – Deto – Inlet Length – Over rev deto.
Page 730 Pipes – Deto – Lambda – Temp probes – CrankCase CR – Variable headers.
Page 720 Inlet tract length – GP125 service manual – Picture of how to read a plug + Wobs comments
Page 710 Fuel and Power Jets - EGT and CHT - Crank build
Page 700 Talk about wide and low transfers – Case volume and dyno graph – det and Lambda sensors.
Page 690 Pipe talk and ideas about making mufflers.
Page 680 Talk about the Trombone pipe and more of Frits and Wobs views on pipes.
Page 670 Pipes – blowdown STA numbers – Trombone pipe.
Page 660 Lots of links on pipes – Ariel Arrow – and CVT
Page 650 Links – Frits and Wobs views on pipes – CVT transmissions – 30 vis 24 carb dyno graph
Page 640 Links to Wobs views on pipes – crank balance factor – connecting a laptop to the Ignitec
Page 630 More of Wobs views on pipes – Frame & wheel weights – correct O ring grove sizes
Page 620 Links to Cooling Water Flow – Case Comp and Pipes – Setting up 2T carburation.
Page 610 Simulation packages – combustion efficiency – transfer ducts – chamfered exhaust top edge.
Page 600 Books that can be down loaded and Frits talks about why 190 Ex duration is so good.
Page 580 No links but page is about mounting carbs and the 24mm pumper carb & 28hp dyno graph.
Page 570 No links but the page talks about carburation – emulsion tubes and pilot jets.
Page 560 No links, the page is mostly about 96 vis Av gas with dyno test.
Page 550 No links list but the page is mostly about TZ400 build and cranks and rods.
Page 540 No links, the page is mostly about Wobs success with the 400 project.
Page 530 Ignition – setting up det sensors without a dyno – wings inside reed valves – poly quad head
Page 520 Mostly about what some wheels weigh, ATAC valves and crank stuffers.
Page 510 Bucketracers general Links List
Page 500 Bucketracers links list of how to make a mid 20’s hp Suzuki GP125


Page 500 .....

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


Because a few people have asked about the GP engine, to save wading through 270 pages, these links go to the more relevant posts about the 27hp engine. Different link collections can be found on the decade pages 80-90-100.....260 etc.

27rwhp 1978 Suzuki GP125


EngMod2T

For something different Page 400 is going to be the basic info for building a 30+hp Suzuki GP125 taken from the EngMod2T simulation files.

Crank HP. Simulated Dyno Graph from EngMod2T using an early RS125 pipe.

EngMod2T's main screen for developing the model.
Basic engine dimensions.
Exhaust port dimensions.
Transfer port and duct dimensions.
Transfer port cylinder entry design and angles.

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

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

A bit of an index .....

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

pit-lane.biz is another really good thread:-

http://www.pit-lane.biz/f34-gp125-et-250-snif (http://www.pit-lane.biz/f34-gp125-et-250-snif)

http://www.pit-lane.biz/t5121-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-4

http://www.pit-lane.biz/t4072-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-3-locked

http://www.pit-lane.biz/t3173-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-2-locked

http://www.pit-lane.biz/t117-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-1-locked


Go to the NSR site it has a lot of info including the fuel curves I think.
http://nsr-world.com/tuning/250-tuning/carburation-index/carburettors/
http://nsr-world.com/tuning/250-tuning/carburation-index/jetting/
302500302501

NSR250 suspension tuning:- http://nsr-world.com/tuning/250-tuning/suspension/

NSR250 Engine Tuning:- http://nsr-world.com/tuning/250-tuning/engine/

Ed Tuck racing (NSR250):- http://edetuckracing.blogspot.co.nz/...5-pistons.html (http://edetuckracing.blogspot.co.nz/p/fitting-rm125-pistons.html)

http://www.twostrokeracelab.com/

http://www.2strokers.com/index.php?topic=184.0


I thought I'd seen a few photos that looked veglia familiar! :)

I found quite a few photos in this thread (I turned up in a web search for photos of the Scitsu plate frame) that I've copied off to my PC for my future reference.

No need for formality, my name is Michael (not Mike though) so feel free to use it. "Mr." makes me feel so old . . .

For those who aren't familiar with my website this page

http://www.eurospares.com/other.htm

will get you to the various project pages and the pages with links to somewhere around 6000 images of bikes and parts I've found interesting. I started the site nearly 20 years ago and I've retained the largely text-based format that was needed in the low bandwidth days so people have to guess from the descriptions which photos they are likely to want to look at. As you can imagine, going back and adding thumbnails to all the existing links is quite a chore. And I've got plenty of other stuff waiting to go up -- someday.

cheers,
Michael

[TZ350]

The trombone Pipe ...

This graph sticks in my mind ... it had three beautiful overlapping curves. I had to search for this but this was pretty profound, I along with plenty of others had our thinking a little back to front.

Husabergs post is worth a visit, as there are a lot of links to seriously good pipe stuff.


Pipe design elements relating to variable with pipes
Frits Overmars
A powervalve does not really give you real resonance power; it just prevents the pipe pulses from completely messing up the power curve at low revs. I expect a sliding pipe will make more low-down power.
http://www.pit-lane.biz/t1666p15-technique-rossigrm-2strokes-boat-engine?highlight=twin+rotary


The Aprilia RS123 as it has a powervalve is able to be tuned to a higher level over a shorter range than if the PV wasnt installed. In general a steep angle rear cone creates a high peak power number in a narrow band with severe roll off of the power after peak.

Something I cant explain is that quite often in a sim having a small steeper section of cone down at the stinger will create more power - like was used by Aprilia in the RSA / RSW. But in many dyno tests of this, in reality, it doesnt work any better than a single angle - the same result for a shallow section up at the mid followed by a steeper section.
Both scenarios can be equalled or bettered on the dyno with the correct single cone.

For practical purposes 28* included is about the limit for a single cone,but there are special cases like the RS123 where having a powervalve, and a rev limiter you get tuners ( like Arrow ) that want a big number to advertise and sell pipes, so they use a REALLY steep angle as it doesnt matter that there is no overev power.

You may get an improvement in power, over a narrow band with a very steep rear cone, but its a special case where running a very low port timing with a severe rear cone and is not something I seriously want to even think about.

301397

Here is the Arrow design, really dumb with incorrect header length etc, but it gives the result they intended.




I am thinking about build a replica of Honda A-Kit pipe to test on my engine, I did this a couple of years ago, Looking for the drawing It can be seen a parallel 120 belly, other drawings have a slight increase diameter in the mid section about 1º or so, is this a good thing most of the time? What is the effect on the pressure bench? Thanks

The Honda A Kit is VERY old tech, it was basically the design Harold used on the lovely KTM GP efforts and was one ( main ) reason they were never really fast enough.

If you must copy something go with Aprilia Tubo 100+ layout, less the multi angle rear cone.
But using a 800mm tuned length with a very low exhaust port duration is off on a very weird tangent and who knows what result this will give you.

The A kits had 200* duration with that short pipe and needed every ignition trick and electronic powerjets to make that work correctly.


So there you have it - the A Kit pipe is shit in comparison to that layout. You have a 2 stage header with the optimum angles of 3.5 and 5.5 * ( even better than Aprilias Tubo designs that to my knowledge never had a 2 stage )with a 3 stage diffuser,the steepest in the middle with approx equal angled 1st and 3rd stages - all good.

The tapered belly section can be tapered either way, depending upon the engines response to the diffuser action and how much overev it is capable of ( or needed ) via a steep rear cone. The only element that I have found to work better is the relationships in the header.

301344

In your design the end of the first header is at around 75% = 200/268,but as in the empirical design guides for the whole pipe of 33% header 66% diffuser, the same applies to the header lengths.
End the first 3.5* cone at around 66%, so you would then have two equal headers of 91.5mm ie 60+25+91.5 = 176.5/268 = 66%, thus the second header at 5.5* is 91.5/268 = 34%.

Varying the length of the 1st diffuser changes the shape of the depression curve at and around BDC, thus tailoring to front side or overev power.

301345


301346

I am not sure what model this is but Frits posted it as the last honda pipe.


Case com is a very complex subject but a few rules of thumb apply.

The higher the bmep of an engine then the higher the delivery ratio, thus a larger case can store the higher volume of ingested air at a higher pressure and this is then available to the transfer ducts.

But the quality of the duct and port geometry also affects the case com required.

The smaller the case vol (higher ratio) the greater the pressure rise in the case as the piston drops - this suits compromised transfer ducts with little or no inner wall shape, as it helps force the flow around through the ducts quicker.

Good duct/port geometry allows the use of a bigger case as they don’t need a large pressure ratio across the port to initiate good flow.

Lastly is the effect of the pipe geometry, the diffuser sucks like hell on the Ex port around BDC, pulling flow through the transfers, and it is important to match the pipe diameter ( and thus the diffuser included angles) to the transfer port/duct geometry.

Suck too hard on crap transfers and they loose directional control - giving greater short-circuiting out the Exhaust port.

Thus you have a Catch22 in that you need a small case to speed up the flow, but this limits the available stored mixture, and you want to suck on the transfers as much as possible, but not so much as to loose the control of the flow direction - or to speed up the loop velocity excessively thus reducing the trapping efficiency..

One myth that needs busting here is, that the bulk of the flow through the transfers is initiated by the piston dropping. This happens in lawn mowers, not racing engines.

Pipe diffuser suction when the piston is around BDC forces the bulk of the flow volume, NOT the pressure in the case forcing flow up the ducts.

When the transfers open there is more pressure in the cylinder than in the case. Thus we get flow reversal at the initial transfer opening point. This also means that the transfer port that opens first - flows last, as it has the greatest flow reversal affect, down the duct.

In general, high bmep engines that by default will have good port/duct geometry, will like a case com down near 1.3:1, lower performance engines with crap transfer/duct geometry will perform best with the ratio higher, up near 1.4:1.

Thus as you develop an engine, increasing its efficiency with better porting, then this will allow the use of a bigger case, and bigger pipe diameter/vol, to work with that - the two go hand in hand.


Dont get hung up on Bl - STA, thinking its good to get rid of the transfer blip 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 durations 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.
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, alot less and it means the temp/pressure rise in the chamber isnt 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.

Lots more stuff, so little time.



Ignition timing. I have a question re timing. At the moment 300 engine I am working with has plenty of timing at peak power. Like 14 degrees. My question is how much is to much. Is the old thinking of chuck in advance until it stops making power still valid or is there just a place you should not go.



Maybe you should get a detonation sensor, then you will know when too much is to much.
Cheap insurance, cost $68 :- http://www.ebay.com/itm/Knock-gauge-for-detonation-sensor-klopfsensor-NEW-/181309925670?pt=Race_Car_Parts&hash=item2a36e9e926&vxp=mtr
The accepted norm for a race engine with everything well set up is 15* at peak power.
If you cant run this due to getting into deto, then its usually due to low com and or excessive squish velocity.
If it runs fine below this , then its screaming out to be advanced.


You have plenty of com for the fuel at 16:1, and the scavenging is not too bad,so if it likes more than 15* at peak then go looking for something that itsnt optimum. My first guess is the carbs are too small, and or the reed area isnt sufficient for the big cylinder. All mods are aimed at increasing the dynamic com, so getting more air in there will do this and end up limiting what can be achieved with advance.


In a NSR250 using VF3 is worth 4 Hp, and remember that the Aprilias ran 41/42mm carbs.
If the squish is very close and the width is too wide the MSV goes over 40M/Sec, this can and does limit peak and overev power considerably.
I would imagine the effect is caused by very high turbulence in the end gases, and this actually adds up to increased flame speed. This is actually the same as having too much advance. I have tried very high MSV with retarded spark to help make it rev and not deto, but this route looses a lot of power.

302129 302130

[TZ350]

More gold on pipes.

304030


The problem is that we have a fixed set of lengths in the pipe that can only develop a depression over a certain period in time, but the rpm is varying as we accelerate thru the powerband.The point of max depression moves in relation to BDC as the rpm varies.

We can bias the efficiency of the diffuser to act at the front side of the curve, by having the max ( widest area below atmospheric ) depression occur later within the pipe length, or we can design it to create then max power around peak, or we can design the pipe to operate better in the overev.

301408

The max depression part of the equation is confined quite rigidly within the boundary's set by a 32% header and a 68% mid section, but the superposition resonance effect is governed by the port timing and the pipe tuned length, so is much more able to be "tuned" to a specific end effect.

301411

Here is the same engine trace showing the before peak curve - notice no superposition at EPO, and early peak depression.

301410

Then peak Hp - we have superposition and max depression around BDC.

301409

Then in the overev - we have big superposition and late max depression.

This scenario generates the greatest peak power, and gives a long smooth roll off , of the power into the overev.
It possible to reverse the superposition position, but we will always be fighting the impossibility of stopping the natural movement of the peak depression event
due to the fixed pipe length.

We can change the depression curve shape with clever diffuser design, but it will always move from early to late in the cycle as the rpm changes upward.


What isn't possible is to move the rpm point at which the max depression is seen at, and not have the max depression happen earlier at lower rpm - then later at higher rpm.

The biggest and widest depression around BDC is seen at the tuned point of the rpm and the pipe length.

The max ( lowest pressure ratio ) point will always move with rpm due to the fixed position of the diffuser.

In answer to seeing the Ex port pressure ratio in EngMod2T ( I have the software pressure take off point set a 0 = at the cylinder wall ) yes ,you can see any trace after the run is finished at any of the rpm points. Go to Thermo Traces, tick Pressure Traces, load the file, pick the rpm then pick Pex. This gives you the pressure trace centred on BDC, even easier to see the differences.


Romeau - interesting that you say that you think a " narrow " pipe would work best with a scooter that allows the engine to be "in the power " all the time - yes this is true, and is why I believe a design that creates max power and then max overev would be the best.

I say that because if correctly designed the much stronger wave action within the pipe at high rpm, can be used to produce a lot more total power under the curve. But then you say the engine has 190* Ex, this will make it impossible to create anything like maximum power.

No engine can ever be anywhere near max output with that duration, but yes it can have superposition over a wider range than a higher Ex port can create - and this gives a very wide flat torque output , but it will never be a proper match to run with a "narrow " pipe design for max power output.


I see, thanks. I just have to make pipes for what people have and the market offers to them, unfortunately most of the engines I have to make the pipes are oversquare, low timing sometimes, weak transfer port areas or entrance angles, trash designed exhaust ports, bullshit cdi's with fixed timing or change just a little, very confused owners sometimes too. It's what I got :/

By the way, the rotax 122/123 engine that is used on the aprilia rs 125 have supposedly about 182/183º exhaust timing. (some other engines have stock timing like this ex. Banshe 350) In a case like this, will this engines take profit from any superposition with a timing relatively lower than 190º? Would the residual pressure wave that arrives too soon to synchronize with the new exit pulse at exhaust open, but still make any positive/noticeable effect? Thanks


The low Ex timing makes superposition able to be used over a much wider band of rpm.
In this case there is much more opportunity to design the pipe to adjust the powerband shape you want, as the tuned length resonates with the port over such a wide range.

The difference is tuning for breadth of power spread or tuning for ultimate power.


Bottom line here is that as I have stated many times the tuning regime for leaded is completely opposite to that of unleaded pump type gas. To get ANY benefit from a good leaded fuel they need to increase the com, back out the timing and run lean as hell. NFG at all without an egt.

Get some super well proven A747 to run with it at 20:1, but if they are so gun shy of the thing that they wont do the dyno time and do proper back to backs then its probably not going to be much use simply changing fuel and jack shit else.


1300 is too hot. Means that the ignition is ramping out too much timing past peak power.
But just as likely that the com is a bit low at 15:1. Try some more advance past peak, ie flat line it at say 10* ( depends upon what the peak power timing is - it should be around 15* ) then depending upon the result, chuck it some extra com up closer to 16:1. Both things will reduce the temp at high rpm , without having to go richer to stop it.

20:1 is fine for best engine protection. Only issue is that Elf 909 will settle out quite quickly in AvGas, but as we used to do in the old days with Castrol R just add a little Acetone and that problem goes away. I have not actually tried Motul Kart without the Acetone, so that may be OK in AvGas.
A747 is fine in AvGas.


Interesting read from Luc Foekema on spark energy and timing as posted on facebook:
https://www.facebook.com/notes/4223470164094/

Conclusion: More top power as shown in the graph [from decreasing spare energy to 50% from 11K rpm], indicates a not good combination of setup and the exhaust pipe. The setup is optimal for a higher rpm then the exhaust pipe is made for. Just to lower the spark energy, more heat will be available for the exhaust pipe, resulting in a higher rpm and in this case a higher power output.

Conclusion "when there is a gain in toppower by reducing spark energy, the temperature in the exhaust pipe is too low or the exhaust pipe is too long, otherwise a gain in toppower would be impossible".


Roller bearings can take higher loads, but that is not the main reason. When fitted correctly the Aprilia bearings allow for 0,4 mm of axial play. Any less costs power.
You can't do that with ball bearings (unless you use a sloppy fit on the shafts, like many kart tuners used to do).


976 is a full synthetic just like Motul 800,so is OK for unleaded fuel ( as they were designed for ) when run rich to prevent breaking down the oil when it overheats. I did hours of dyno oil testing for a customer using 909 and 976 in a KT100 to establish the best type and ratio.

As soon as you really wind in the needles the superior lubrication of the castor base made more power the hotter the egt got. The 976 started to show marks on the skirts and lost power over around 620* in the header.


i can see why someone would use a high B. allows the aux to be just that much bigger by bringing the floor down a little more. but some engines cant have the aux floor right on top of the A like aprillia because the side piston skirt is cut to high so the aux floor needs to be kept a little higher or you get a short circuit.

On a situation like this do you think the high B would still work better or is its only benefit to allow the aux floor to sit right on top of A ? basically what I am wondering is does a high B only have the benefit on letting the aux floor be very close to the top of A (assuming the piston design will allow it without creating a shortcut) or does a high B also have some kind of scavenging benefit also ?


No - the high B gives more total STA to the transfers, as in a well designed setup it is alot wider than any A port. So you have the B and C ports combining to give a better total STA than is possible with a normal small A and progressively lower B and C ports.

But its always a compromise, it makes no sense to run a high B port with no powervalve, as this scavenging regime favours top end at the expense of below pipe power. As I detailed before I could, and did, make a very good attempt at matching the high A port setup in a KZ2 with the big B port situation - but at the end of the day we needed the high A port to get natural drive off the bottom when passing in traffic.

But this was helped some by the factory catching up on the usual 3 year lag in technology when comparing GP125 with KZ2 and allowing me to grind really big Aux port top edges to gain sufficient blowdown to match the rocket ship big B port engine I did the year before.


rode the bike today and it pulls 1000 times better below the pipe than the last cylinder. probably because the ports are not sky high i suppose. mostly the transfers probably. before it seemed to have 1000 rpm wide powerband. below that and it could not recover without down shifting 1 or 2 gears. now it pulls back to the pipe alot better without down shifting ( in most situations). i left some meat on the bone so i can make more cylinder adjustments if needed. any body got ideas how to get more power without the midrange dropping out, like the last cylinder ?
here is what I got:-
honda T port exh and no powervalve
exh 192 and about 90% width
A trans 128 and 20* upward
B trans 127 and 15* upward. piston dome is 15* also
C 127 and 62* if I recall

I did the best I could with the upward angles. honda had them backwards. 20* on the rear and 15* on the front so I did the best I could with what i had to work with. i even lifted the cylinder up slightly with thicker gasket to try and correct the floor angles.

did not get the spacer installed under the reed stopper yet. should be able to get that done this week and tested next weekend. i think it will help as the current 7mm lift seems really small. still might not be enough lift with the spacer but at least I will know if I am going in the right direction


ive tried 200*. with 132 A and 130 B if i recall. worked ok. but i want to find a good compromise with lower ports. at some point i think the ports get so high you gain nothing but overrev which is useless for me. i ride in sand so there needs to be some power slightly lower in the rpm otherwise the sand can pull the rpm down too easily. maybe 8spd gearbox is the answer


You only need to fill in 3 pages of EngMod to get the full benefit of the STA readout page.
Just having the engine, Ex and transfer inputs will tell you where the ports are in relation to what you think you need.
You , and we, are simply guessing at what is happening until you can give us the STA printout. Do that and we can help.


But best throttle response is had with tons of advance at low rpm/WOT.
If you retard at low rpm/WOT the pipe may get hotter, but it will be very slow responding - due to the low cylinder filling and thus low dynamic com. You have to use so much advance down low it will instantly deto if you run it at part throttle down there. That is where the TPS is good in that you can pull out timing when at part throttle/low rpm,then add a heap when slamming it open to make it drive hard.



Welcome to the piston side.
Below you will find brands such as:
Barikit, Kitaco, Wiseco, Pro-X, Polini, Mahle and others.
I stocks normally pistons that you see below.
, there are other pistons in stock,
which can be a bit odd sizes etc..
If you can not find what you are looking for, write and ask,
so we'll see if I can help you!

304145

http://www.pvlsverige.se/vrm/kolvar/kolvar.html

Rolffe is the Mad Swede who did the Debri cylindered MB50 with a disk valve.
What happened to the piston rod spreadsheet Brent was going to do.:innocent:
this site is a great one in particular as it gives the oclock position of the ring pegs'.

[dark art]

The Aprilia RS123 as it has a powervalve is able to be tuned to a higher level over a shorter range than if the PV wasnt installed.

...

Here is the Arrow design, really dumb with incorrect header length etc, but it gives the result they intended.

First post here, so go easy on me :yes:

I had a aprilia rs 125 model (rotax 123 engine), 2003 model wich arrow pipe was quite different than yours. See below.
Dimentions might not be exact, they was only a rough measurement.

One of the worst things about that pipe was that the PV open sooner than the engine hit the power band, so there was a huge hole around 8-8500 rpm and that was with the cdi mod for the valve to open later. Was very annoying...
Later I mod the pipe on the header to make it slighty longer and that helped but was not perfect. I ended up building a new, longer pipe for the bike.

[dark art]

Anything special for page 1000 TZ ?

Free candys to everyone?:crazy:

[chrisc]

Congrats! I found a photo of the original GP125 on the web.

http://galleryplus.ebayimg.com/ws/web/370843990839_1_0_1/1000x1000.jpg

I spent a considerable amount of time on the ESE thread today. I'm so stoked the resource is here. Thanks!

[Farmaken]

Wow Rob, it's like they say - from tiny acorns...
Seems you planted a seed and have grown a mighty fine resource with the help of some very fine minds
I for one am very grateful to be able to use so much of the information in this mighty collection, long may it continue :yes:

[TZ350]

Yes with the input from Wob and Frits and others it has become a great resource, we could not have got here without their help.

The old Suzuki GP125 is 12-15hp standard, pushed ours out to 31, so pretty happy. Even happier about the good friends we have meet along the way.

[chrisc]

Yes with the input from Wob and Frits and others it has become a great resource, we could not have got here without their help.

The old Suzuki GP125 is 12-15hp standard, pushed ours out to 31, so pretty happy. Even happier about the good friends we have meet along the way.

Today I found these somewhere deep in the ESE thread. Worthy of a repost I think.
Av on Scott's RSGP125 around Mt Welly.


https://www.youtube.com/watch?v=eYEe8gIzs2I

And I had a giggle at Darren inspecting the track conditions.


https://www.youtube.com/watch?v=v1pT-Tt_yMs

[husaberg]

NSR500 Porn
http://www.kiwibiker.co.nz/forums/album.php?albumid=4837
http://www.kiwibiker.co.nz/forums/album.php?albumid=4837

I will be adding some more later including
Honda RS125
http://www.kiwibiker.co.nz/forums/album.php?albumid=4841
http://www.kiwibiker.co.nz/forums/album.php?albumid=4841

Aprilia GP bikes
http://www.kiwibiker.co.nz/forums/album.php?albumid=4839
http://www.kiwibiker.co.nz/forums/album.php?albumid=4839
YZR500

Swiss auto
http://www.kiwibiker.co.nz/forums/album.php?albumid=4833
http://www.kiwibiker.co.nz/forums/album.php?albumid=4833

Rotax and other Tandem twins
http://www.kiwibiker.co.nz/forums/album.php?albumid=4840
http://www.kiwibiker.co.nz/forums/album.php?albumid=4840


RGV500

Kenny Roberts 3's

Cagiva
http://www.kiwibiker.co.nz/forums/album.php?albumid=4842
http://www.kiwibiker.co.nz/forums/album.php?albumid=4842

Carbs fuels intakes and stuff
http://www.kiwibiker.co.nz/forums/album.php?albumid=4844
http://www.kiwibiker.co.nz/forums/album.php?albumid=4844

[andrew a]

Well done Rob and team. I called in last week but Rob was unfortunately out working. Cully showed me around. Great to see your shed. The ESE thread is a great sauce of information.

[speedpro]

Not so good on fish & chips though

[Frits Overmars]

NSR500 Porn
http://www.kiwibiker.co.nz/forums/album.php?albumid=4837

I will be adding some more later including
Honda RS125

Aprilia GP bikes
http://www.kiwibiker.co.nz/forums/album.php?albumid=4839

Swiss auto
http://www.kiwibiker.co.nz/forums/album.php?albumid=4833

Husa, your links give me this:
vBulletin Message
Invalid Album specified. If you followed a valid link, please notify the administrator (http://www.kiwibiker.co.nz/forums/contact.php)

[husaberg]

Husa, your links give me this:
vBulletin Message
Invalid Album specified. If you followed a valid link, please notify the administrator (http://www.kiwibiker.co.nz/forums/contact.php)


Odd it works for me?
Is it the same for others?
There will not be much in there you have not seen before Frits:innocent:

[Muciek]

Odd it works for me?
Is it the same for others?
There will not be much in there you have not seen before Frits:innocent:

I'm too getting this notification

Invalid Album specified. If you followed a valid link, please notify the administrator

:(