ESE's works engine tuner

[adegnes]

Thanks, I think I'll go for something like what TeeZee did, that carbon airbox is sexy though!

[fatbastd]

Dont succumb to the 'varmint theory'..sexy is what works, not what looks good..granted though, they are often they are the same..

[Haufen]

309725

Back several 100 pages are posts where at a Taupo race meet, TeeZee found that he needed to protect the carbs bell mouth from air blowing directly across it and upsetting the carburation so he fashioned this crude but effective wind break from an ice cream container. As an aside, he also posted dyno graphs of 29 rwhp with that pumper carb like it is, without a bell mouth, he said, in back to back tests bell mouths seemed to do nothing for it.

309723309724

He later made a better job of it using stiff rubber sheet. He said he would like to try it the other way around so it scooped air into the carb but was worried that it would just as effectively scoop up road gravel in the event of a crash. The way he has it in the pictures he hoped the rubber would fold over and cover the carb if the bike fell over.

Do you recall what exactly happened to the carburetion? Did it become lean at higher speeds? Maybe the air blowing across the carb bellmouth blew the blowback away thus preventing it from re-entering the carb and thus effectively leaning the carburetion?

[lodgernz]

I vaguely remember that someone, a long time ago, maybe Frits, posted a method of mounting a carb using O-rings rather than a rubber manifold.
I can't remember if it was in this forum or the GP125 one on pit-lane.biz.
Can anyone tell me how to find this post?
I've tried the usual Google searches using the "site:" parameter, without success.

[F5 Dave]

try this, there are some words too. . .hmm, this is what I saved. Problem is all the reed engines I've tried would clash the carb to the case if this short.

. . . . : if the tract diameter has to be small for some reason (rules), you can diminish its negative effect by making it as short as possible. And because it's a lovely day, here is my solution of making it really short.
I slip a plate (P in the drawing) around the carb. The hole in this plate is about 2 mm larger than the carb's outer diameter. Then I slip a thick O-ring O around the carb. Then I slide this composition into a hole in the disk valve cover D and fasten it with two bolts B.
Plate P compresses O-ring O which centers the carb in the disk valve cover so there is no metallic contact anywhere. With this solution I manage to fit the carb at 2 millimeters from the disk valve. It works with reed valves too.

You can play with the O-ring size and the rate of compression to vary the flexibility of the carb mounting. You can also fit a second, smaller O-ring at the bevelled end of the carb, next to the disk valve, to keep the carb from sagging when applying a light rate of compression on the large O-ring.
The ideal would be an O-ring with a sleeve. Maybe you can produce something like that with 'liquid rubber'.

[wobbly]

You can achieve very similar result with using the KZ10B intake.
Here the end of the carb is 2mm from the reed face, as the manifold flange is recessed into the stuffer.

[lodgernz]

Thanks Dave, that's exactly what I was looking for.
Thanks also to Wobbly for further suggestions.

[husaberg]

I vaguely remember that someone, a long time ago, maybe Frits, posted a method of mounting a carb using O-rings rather than a rubber manifold.
I can't remember if it was in this forum or the GP125 one on pit-lane.biz.
Can anyone tell me how to find this post?
I've tried the usual Google searches using the "site:" parameter, without success.


try this, there are some words too. . .hmm, this is what I saved. Problem is all the reed engines I've tried would clash the carb to the case if this short.

. . . . : if the tract diameter has to be small for some reason (rules), you can diminish its negative effect by making it as short as possible. And because it's a lovely day, here is my solution of making it really short.
I slip a plate (P in the drawing) around the carb. The hole in this plate is about 2 mm larger than the carb's outer diameter. Then I slip a thick O-ring O around the carb. Then I slide this composition into a hole in the disk valve cover D and fasten it with two bolts B.
Plate P compresses O-ring O which centers the carb in the disk valve cover so there is no metallic contact anywhere. With this solution I manage to fit the carb at 2 millimeters from the disk valve. It works with reed valves too.

You can play with the O-ring size and the rate of compression to vary the flexibility of the carb mounting. You can also fit a second, smaller O-ring at the bevelled end of the carb, next to the disk valve, to keep the carb from sagging when applying a light rate of compression on the large O-ring.
The ideal would be an O-ring with a sleeve. Maybe you can produce something like that with 'liquid rubber'.
.......................

I vaguely remember that someone, a long time ago, maybe Frits, posted a method of mounting a carb using O-rings rather than a rubber manifold.
I can't remember if it was in this forum or the GP125 one on pit-lane.biz.
Can anyone tell me how to find this post?
I've tried the usual Google searches using the "site:" parameter, without success.


And I am sure I didn't. Quite the opposite in fact: if the tract diameter has to be small for some reason (rules), you can diminish its negative effect by making it as short as possible. And because it's a lovely day, here is my solution of making it really short.
I slip a plate (P in the drawing) around the carb. The hole in this plate is about 2 mm larger than the carb's outer diameter. Then I slip a thick O-ring O around the carb. Then I slide this composition into a hole in the disk valve cover D and fasten it with two bolts B.
Plate P compresses O-ring O which centers the carb in the disk valve cover so there is no metallic contact anywhere. With this solution I manage to fit the carb at 2 millimeters from the disk valve. It works with reed valves too.

You can play with the O-ring size and the rate of compression to vary the flexibility of the carb mounting. You can also fit a second, smaller O-ring at the bevelled end of the carb, next to the disk valve, to keep the carb from sagging when applying a light rate of compression on the large O-ring.
The ideal would be an O-ring with a sleeve. Maybe you can produce something like that with 'liquid rubber'.


Here's some more Helmholtz-encouragement:

Regarding induction systems: build a short induction tract and visit a test bench.
You can forget about calculations. The formulas you find in various books are all based on the Helmholtz resonator. It made me write a simple story, called:
Helmholtz blues
"A Helmholtz resonator consists of a volume connected to a duct". That is what Wikipedia tries to tell you.
But that is a Helmholtz resonator in its simplest form; one that you won't find anywhere in an engine.
What you do find in an engine is an intake tract with a variable cross-sectional area. This tract is from time to time connected to a variable volume (the crankcase) through a very variable window (the intake port / reed valve / rotary inlet).
The crankcase is connected to a number of transfer ducts with variable cross-sectional areas, which are from time to time connected to a very variable volume (the cylinder) through a number of very variable windows (the transfer ports).
The cylinder is from time to time, through a very variable window (the exhaust port), connected to an exhaust pipe with a very variable cross-sectional area who at the same time doubles as a volume. This pipe volume is constantly connected to a big volume (the outside world) through a tailpipe with a constant cross-sectional area and constant entry and exit windows (thank God, finally someting that's not variable).
We call this a compound Helmholtz resonator .
The various papers also tell us how to calculate the resonator's frequency:
" frequency = speed of sound / (2*pi)* Sqr ( cross-sectional area of the neck / ( volume of the resonator * effective neck length ) ) ".
O yes, the speed of sound... It is dependent on temperature, which is not really constant in the intake tract and the crankcase, rather variable in the transfer ducts and very variable in the cylinder and the exhaust pipe.
Now the above frequency formula is not exact; it is an approximation that is usable as long as the volume of 'the' tract is very small compared to the resonator's volume.
So when engines are concerned, that formula goes very far out the window.
Who said gas dynamics is simple dull?
PS:
It's a similar story with acoustics. That is a sub-branch of gas dynamics, simplified with a lot of assumptions that are acceptable as long as the sound pressure does not exceed a certain limit. The wave pressures in a two-stoke exhaust exceed that limit by a factor of thousand. Bye bye, acoustics...


Thanks, I think I'll go for something like what TeeZee did, that carbon airbox is sexy though!


Dont succumb to the 'varmint theory'..sexy is what works, not what looks good..granted though, they are often they are the same..
I found these while i was looking for a case pic. Plus a few more out of the album.
309753309755309754309756309757 309758

[TZ350]

I'm still 1/2 a hp down on the RG at its best but with no over rev. As I review, it's spookily close to the last run on the RG before I put in a new ring. Bah.

Different problem, but I feel your pain Dave. Been working my arse off on this EFI thing. 90% throttle consistently makes more power than a 100%, 80's pretty close to and 70 is not far behind.

309768

I keep making more power but can't get it to come back onto the throttle properly.

I just want it to throttle properly so I can ride it , Bah humbug, and stamp my feet.

[speedpro]

I know it shouldn't, but, I don't suppose it's using or at least being influenced by the VE table? How is your setup being told to only use the TPS table?

I have mine around the opposite way at the moment, VE table up to 95% throttle and then swaps to TPS above that. 4T versus 2T of course and 2T should only be using TPS table. Simple test would be to enter LARGE values in the unused table in the appropriate cells and do a run. If it falls over . . . . .

I think Ecotrons bury it in the software on a system designated for a 2T whereas I have a crossover table I can play with.

[TZ350]

I can see the crossover and VE table but adjustments in them have no effect, Ecotrons has told me that they turn them off for 2T's.

[FastFred]

<iframe width="560" height="315" src="https://www.youtube.com/embed/_eOPv8l-brI" frameborder="0" allowfullscreen></iframe>

Last Sunday, Zayne and Av battle it out for the Super Light TT win at Hampton Downs. The camera is on the front of Zaynes bike, Av in Red & White leathers.

[wobbly]

I mention this as its a pet hate of mine and every bike or kart rider I deal with get told in no uncertain terms about blipping the downchange.
We have speed shifters that give seamless power up thru the box, to then virtually lock the rear wheel on every downchange ( even with using the clutch )
is criminal, not only wreaking the dogs in the box, but upsetting the chassis balance on every corner entry.
Watch another Kiwi doing the job at the TT, at about 1min 6 he drops down the box, blipping every downchange, keeping the rear wheel planted and the chassis straight.
Just trying to help.

https://www.youtube.com/watch?v=UL7P7OkTCDI

[wobbly]

Info for Rich re the NSR300.
Just got the first cylinder back from having the chrome off and boring for the 60mm Wossner piston based on RS125.
Here is pic at BDC.
Also pics of YZ125 bored for the same piston, with rad added to duct entry.

[Haufen]

60mm Wossner piston based on RS125.

Is that part No. 8143D400?

[F5 Dave]

I mention this as its a pet hate of mine and every bike or kart rider I deal with get told in no uncertain terms about blipping the downchange.
We have speed shifters that give seamless power up thru the box, to then virtually lock the rear wheel on every downchange ( even with using the clutch )
is criminal, not only wreaking the dogs in the box, but upsetting the chassis balance on every corner entry.
Watch another Kiwi doing the job at the TT, at about 1min 6 he drops down the box, blipping every downchange, keeping the rear wheel planted and the chassis straight.
Just trying to help.

https://www.youtube.com/watch?v=UL7P7OkTCDI

At Taumarunui Bucket meet at the kart track I mentioned (nicely) that the rear end of a chap was sliding around every downchange into a sweeper with the follow up to be settling the platform, just gentle advice because I'm a nice guy (& also I didn't want him falling off while I was trying to get my 50 around his 150 in the all in races) & was informed that he didn't mind the rear moving around & that he rode his R1 race bike that way, obviously and almost aggressively implying that if you race an R1 you must know it all. Yeah ok, mental note- don't talk to that guy, & always pass on the inside.

[kel]

Last Sunday, Zayne and Av battle it out for the Super Light TT win at Hampton Downs. The camera is on the front of Zaynes bike, Av in Red & White leathers.

It was quite the finish! Zayne had no answer to the extra speed of Av's bike

[fatbastd]

Close racing, though the method of downshifting doesn't make it pretty to watch. I'm with Wobbly on this one.

The engine is not a brake.

Funny how better riders make bikes seem faster.

[kel]

Funny how better riders make bikes seem faster.
In a straight line? Not taking anything away from how well Avalon is riding but she clearly has a few more horse in there

[mr bucketracer]

At Taumarunui Bucket meet at the kart track I mentioned (nicely) that the rear end of a chap was sliding around every downchange into a sweeper with the follow up to be settling the platform, just gentle advice because I'm a nice guy (& also I didn't want him falling off while I was trying to get my 50 around his 150 in the all in races) & was informed that he didn't mind the rear moving around & that he rode his R1 race bike that way, obviously and almost aggressively implying that if you race an R1 you must know it all. Yeah ok, mental note- don't talk to that guy, & always pass on the inside.if we had the time to blip the gas i would loss a second a lap on a small track , you 2 stroke girls have it easy , face it your barrals don't last like are gearbox's so who cares (-;:motu:

[wobbly]

Dont talk utter bollocks, a 125 kart goes down 5 gears into a hairpin in LESS than 1/2 the time you have, with a clean blip into every gear with NO clutch needed.
If your throttle connection is that shit it wont blip fast enough, then stop just ridding it haphazardly, and start doing some meaningful carb testing.
The kart chassis stops straighter with way more rear brake bias and the lap times go down around 6/10s ( yes around Mt Welly ) in a back to back using FULL datalogging running everything from longitudinal and lateral
G force to throttle position and tyre inner edge temp using remote lasers.
You bucket guys do Jack Shit in comparison to the data HAVE we use regularly to win National and World Titles in karts.
Tell me what the difference is between what you are doing and Anstey blipping every change from 320Ks down to 50Ks at the TT.
And funnily enough Moto GP sees fit to use the ECU to lift the revs automatically, so well , on the downchange that it makes a slipper clutch redundant.
Any other relevant excuses - end of rant.

[TALLIS]

Dont talk utter bollocks, a 125 kart goes down 5 gears into a hairpin in LESS than 1/2 the time you have, with a clean blip into every gear with NO clutch needed.
If your throttle connection is that shit it wont blip fast enough, then stop just ridding it haphazardly, and start doing some meaningful carb testing.
The kart chassis stops straighter with way more rear brake bias and the lap times go down around 6/10s ( yes around Mt Welly ) in a back to back using FULL datalogging running everything from longitudinal and lateral
G force to throttle position and tyre inner edge temp using remote lasers.
You bucket guys do Jack Shit in comparison to the data HAVE we use regularly to win National and World Titles in karts.
Tell me what the difference is between what you are doing and Anstey blipping every change from 320Ks down to 50Ks at the TT.
And funnily enough Moto GP sees fit to use the ECU to lift the revs automatically, so well , on the downchange that it makes a slipper clutch redundant.
End of rant.
Settle pettle....:wacko:

[richban]

Info for Rich re the NSR300.
Just got the first cylinder back from having the chrome off and boring for the 60mm Wossner piston based on RS125.
Here is pic at BDC.
Also pics of YZ125 bored for the same piston, with rad added to duct entry.

Cheers Mate. Thats way less piston peaking through at BDC. And yes my stock barrels will be getting a radius in the duct. Need to find time to pull the thing down. Wish I was at the nationals this weekend but work needs to come first. The other 300 will be on track though. It will be interesting to see the straight line speed of that bike. 83 at the wheel and 115kg. It will be quick.

[mr bucketracer]

Dont talk utter bollocks, a 125 kart goes down 5 gears into a hairpin in LESS than 1/2 the time you have, with a clean blip into every gear with NO clutch needed.
If your throttle connection is that shit it wont blip fast enough, then stop just ridding it haphazardly, and start doing some meaningful carb testing.
The kart chassis stops straighter with way more rear brake bias and the lap times go down around 6/10s ( yes around Mt Welly ) in a back to back using FULL datalogging running everything from longitudinal and lateral
G force to throttle position and tyre inner edge temp using remote lasers.
You bucket guys do Jack Shit in comparison to the data HAVE we use regularly to win National and World Titles in karts.
Tell me what the difference is between what you are doing and Anstey blipping every change from 320Ks down to 50Ks at the TT.
And funnily enough Moto GP sees fit to use the ECU to lift the revs automatically, so well , on the downchange that it makes a slipper clutch redundant.
Any other relevant excuses - end of rant.have not seen anstey on any kart tracks lately , big tracks are quite different!!

[TZ350]

Personally I was impressed by Av's slip-streaming sling shot from behind to take the win.

[wobbly]

Bullshit, the 125 karts brake from 132Km/hr at say Tokoroa in 1/2 the distance you do, due to lots of tyre and lots of brakes,and the WINNERS get time to blip EVERY gear on EVERY change down.
How fast are you going at Tokoroa, do you even know.
But the real question is WHY would the lap record holder at the TT bother to blip the changedown at 320 Km/Hr if it was just a fuckin dumb idea, or why would HRC Yamaha/Ducati/Suzuki/Aprilia
use fly by wire servo throttle drive to auto blip the throttle, if it simply didnt work.
Your move.

[mr bucketracer]

Bullshit, the 125 karts brake from 132Km/hr at say Tokoroa in 1/2 the distance you do, due to lots of tyre and lots of brakes,and the WINNERS get time to blip EVERY gear on EVERY change down.
How fast are you going at Tokoroa, do you even know.
But the real question is WHY would the lap record holder at the TT bother to blip the changedown at 320 Km/Hr if it was just a fuckin dumb idea, or why would HRC Yamaha/Ducati/Suzuki/Aprilia
use fly by wire servo throttle drive to auto blip the throttle, if it simply didnt work.
Your move.just run a sliper clutch ( do you even know what one is ):tugger:

[steamroller]

Bullshit, the 125 karts brake from 132Km/hr at say Tokoroa in 1/2 the distance you do, due to lots of tyre and lots of brakes,and the WINNERS get time to blip EVERY gear on EVERY change down.
How fast are you going at Tokoroa, do you even know.
But the real question is WHY would the lap record holder at the TT bother to blip the changedown at 320 Km/Hr if it was just a fuckin dumb idea, or why would HRC Yamaha/Ducati/Suzuki/Aprilia
use fly by wire servo throttle drive to auto blip the throttle, if it simply didnt work.
Your move.

A kart is a kart a bike is a bike for starts:brick: i don't think you have time racing on a kart track on a [ bike] to fuck around blip down gears there are lots of people that win out there just smashing it down gears . never here people fuck there gearbox.:ar15:

[steamroller]

Bullshit, the 125 karts brake from 132Km/hr at say Tokoroa in 1/2 the distance you do, due to lots of tyre and lots of brakes,and the WINNERS get time to blip EVERY gear on EVERY change down.
How fast are you going at Tokoroa, do you even know.
But the real question is WHY would the lap record holder at the TT bother to blip the changedown at 320 Km/Hr if it was just a fuckin dumb idea, or why would HRC Yamaha/Ducati/Suzuki/Aprilia
use fly by wire servo throttle drive to auto blip the throttle, if it simply didnt work.
Your move.

why do karts not use this wire servo throttle to auto blip the throttle becouse its all shit:nya:

[F5 Dave]

You boys ya all on the moonshine early in the week. Keep yer hands off yer sister.
(Or Kerry I guess)

[lodgernz]

Please calm down people, points are made, opinions divided. Let it rest
This is a gentlemanly thread most of the time. All of the time would be good.
This thread is too important for battles. Take them offline.

[mr bucketracer]

only having a laugh with dave , had no idea anyone would have a wobbly over it

[Frits Overmars]

just run a sliper clutch (do you even know what one is)No, never heard of it. Anything to do with a slipper clutch?
Yeah, I know: semantics. But you asked for it; Wobbly already mentioned the device on the previous page so there's no point in asking him if he knows what it is. Besides, if you had read his post you might have noticed how it's spelled.


if we had the time to blip the gas i would loss a second a lap on a small track , you 2 stroke girls have it easy , face it your barrals don't last like are gearbox's so who cares.
i don't think you have time racing on a kart track on a bike to fuck around blip down gears there are lots of people that win out there just smashing it down gears. never here people fuck there gearbox.You guys are missing the point. Blipping is not done to spare the engine (although it does spare the engine) but to prevent the chassis from unsettling. You know, the shaking that hurts laptimes.


Moto GP sees fit to use the ECU to lift the revs automatically, so well , on the downchange that it makes a slipper clutch redundant.And not only redundant; it is better than a slipper clutch. Moto3 only uses a slipper clutch because the rulebook does not allow them the MotoGP-solution of an ECU blipping and feathering the clutch automatically on downshifts.
Slipper clutches are in the wrong place. They should not be between the crankshaft and the gearbox, but between the gearbox and the rear wheel. Then you would have a fixed pre-set maximum engine braking torque at the wheel instead of a braking torqe that varies depending on the gear you're in.


why do karts not use this wire servo throttle to auto blip the throttle becouse its all shit.Because the rulebook says no.

[Sketchy_Racer]

Yep I'm with wobbly on the blip thing no doubt. Some guys make it work on bigger bikes with good slipper clutch setups but as Wob says, it's hard on gearboxes and ultimately excessive back torque makes it hard to manage initial tip in with out the rear trying to overtake the front!

My first year on a 600 without a slipper taught me well that I could never tell that I had a slipper when I got the new bike!

If you're chattering your way into a corner it's because your a munter rider - end of story

[Dutch Fisher]

Here's my response to the blip debate on another forum...

....2001 Suzuka 250 Qualifying Daijiro Katoh onboard.

Skip to 1:40, Katoh downshifts 2 gears into 130R then 3 downshifts into Casio Triangle.

All blipped

https://www.youtube.com/watch?v=WproGBgB4fI


The best riders do make it look easy, that's why they are the best.
Was Katoh one of the best ? YES ....easily

[TZ350]

Edgecumbe Bucket NI 2015 Round 3


309787

Chris C's Edgecumbe photos:- http://www.kiwibiker.co.nz/forums/showthread.php/153656-Chris-Bucket-photo-thread-Bandwidth-warning?p=1130840522#post1130840522

<iframe width="560" height="315" src="https://www.youtube.com/embed/AZ-FUJA3lbc" frameborder="0" allowfullscreen></iframe>

Team GPR Edgecumbe Videos:- http://www.kiwibiker.co.nz/forums/showthread.php/150352-Team-GPR/page125

[mr bucketracer]

Yep I'm with wobbly on the blip thing no doubt. Some guys make it work on bigger bikes with good slipper clutch setups but as Wob says, it's hard on gearboxes and ultimately excessive back torque makes it hard to manage initial tip in with out the rear trying to overtake the front!

My first year on a 600 without a slipper taught me well that I could never tell that I had a slipper when I got the new bike!

If you're chattering your way into a corner it's because your a munter rider - end of storyi say do what suits you . end of story!

[jasonu]

You boys ya all on the moonshine early in the week. Keep yer hands off yer sister.
(Or Kerry I guess)

Yee Haa we all gittin in the pickimup truck and goin on down to the big house!!!!!
309788

[FastFred]

.

the book ... BEING THERE

For anyone who is interested in improving their riding Hugs book is well worth reading, then maybe re reading again to see that ones attitude and what your doing affects how your riding, a little analysis can take you a long way.

You don't get to set the fastest lap at the Isle of Man TT in the fog and survive by luck alone.

It is a real life book by someone who has been there, done that and how they approached things.

http://www.kiwiridernews.com/2014/11/hugh-andersons-book-is-out.html

I am not sure what Hugh Anderson makes of throttle blips but:- In January 2008 riding the same Norton, he has owned from new Anderson beat the current and twice Australasion champion on two occasions and made his fastest ever lap at the Pukekohe race track, when he was 72 years old.

This amazing book takes you inside the mind of one of the toughest, determined and most analytical riders ever to compete in world championships.

BEING THERE is available through this website: www.kiwiclassic.com
Or you can get a copy direct from the man himself: Hugh Anderson, Tel +64 7 853 2711. Or email: hughanderson@clear.net.nz

[F5 Dave]

S`funny I almost bought this yesterday but motomail wanted $10 to send it so I stalled. This site is free post so where's me card I'll buy one, thanks.

[Flettner]

OK, so who out there would have an RZ 350 ish autolube oil pump that is still in working condition but doesn't want it any more? For the 700 twin project, a bit hard to mix the twostroke oil in with the LPG fuel.

[F5 Dave]

They are rebuildable still, ive saved some details. and there's a UK chap doing higher rate conversions, I'll ignore the Aus versions. Still hanging on to mine just in case sorry

[Yow Ling]

OK, so who out there would have an RZ 350 ish autolube oil pump that is still in working condition but doesn't want it any more? For the 700 twin project, a bit hard to mix the twostroke oil in with the LPG fuel.

Pm me your address and ill send one

[wobbly]

Sent him a new one Yow

[Flettner]

Thankyou guys, the heat treated castings will be back tomorrow ready to machine into two 700 twin engines.
Cylinders will be back on Friday and after machining off to NZ cylinders for plating.
Heat Ranger, the heat is on.

[Martin1981]

Wobbly, what is the Topspeed of the 125ccm Shifter Karts on the fastest circuits? thanks

[wobbly]

Fastest I have seen on our data is 134Km/Hr, but we tend to gear for the slowest corner/infield, and use big overev ( 15,000 ) to achieve the terminal speed needed.
So we are well past peak Hp, and could go alot faster in a straight line with taller gear.
Euro tracks are much faster, and regularly see 150K.

[Grumph]

Fastest I have seen on our data is 134Km/Hr, but we tend to gear for the slowest corner/infield, and use big overev ( 15,000 ) to achieve the terminal speed needed.
So we are well past peak Hp, and could go alot faster in a straight line with taller gear.
Euro tracks are much faster, and regularly see 150K.

I hear there's a kart meeting on full track Ruapuna coming up. I'd imagine well over 150K would be achievable there but I'm sure someone will have the data.

[RomeuPT]

Cheking things before next meeting, opsss :tugger:

Honda RS 125 piston.
Too dry underneath? Too much advance? Lean Carburation?

[Reckless]

Kart speeds
Back in the day (20 years ago) we where getting about 100-110mph (170k) out of our methanol powered 125 MX engined open class shifters at Manfield I think?.
Geoff Downs and especially Ian Bias (for many years) the fastest in 125.
I txt a good mate who is currently racing in 250 single and he reckons 195-200k out of that class and the NZ Rotax superkarts are doing about 220k at Taupo last meeting.
Most top speeds are exaggerated but I'd stick by his word. Of coarse the kart doesnt get its lap time from its top speed as we all know.

Superkarts in England have been getting 250k for years. I thought they'd slowly get faster but it seems to be the limit as it has been this for as long as I can remember.
I guess they have maxed out the torque vs gearing vs top speed limit LOL.
Wikipedia
Powered by a 2-stroke 250 cc engine producing 62 hp for an overall weight including the driver of 205 kilograms, Superkarts have a power/weight ratio of 440 hp/tonne (330 W/kg)(c.5 lbs/hp). Superkarts can accelerate from 0 to 60 mph in less than 3 seconds with a top speed of 155 mph (250 km/h).[8] Their low weight and good downforce make for excellent cornering[9] and braking abilities.[10] A Superkart is capable of braking from 100 mph (160 km/h) to standstill in around 2 seconds, and taking corners at nearly 3 g (30 m/s²).[11

Love this thread from the sidelines great read, keep it up lads :)

[twotempi]

Cheking things before next meeting, opsss :tugger:

Honda RS 125 piston.
Too dry underneath? Too much advance? Lean Carburation?

Underside of piston looks fine - ditto the top.

Check your ignition timing.

[wobbly]

There is No heat going into the piston from advanced ignition as there is no darkness underneath.
RS125 ignitions retard shitloads after peak torque to get heat into the pipe and make it rev.
Thus I suspect a combination of not enough static advance to go with the head cc, and running too lean.
All give the end result of alot of heat in the header - too much in this case.
What fuel, what cc, what static advance?
The other possibility is that the later RS125 has the ability to change the powerjet switch rpm, maybe its too low.
But another suspect is maybe the powerjet is too big, and too much fuel is being turned off by the solenoid when in the overev area past 12500.

[speedpro]

There is No heat going into the piston from advanced ignition as there is no darkness underneath.
RS125 ignitions retard shitloads after peak torque to get heat into the pipe and make it rev.
Thus I suspect a combination of not enough static advance to go with the head cc, and running too lean.
All give the end result of alot of heat in the header - too much in this case.
What fuel, what cc, what static advance?
The other possibility is that the later RS125 has the ability to change the powerjet switch rpm, maybe its too low.
But another suspect is maybe the powerjet is too big, and too much fuel is being turned off by the solenoid when in the overev area past 12500.

That narrowed it down :scratch:

[F5 Dave]

In case you aren't following the foundry thread. Check this lot out

Second load of picture of Neil's work.an army of bits

http://www.kiwibiker.co.nz/forums/showthread.php/162399-The-Bucket-Foundry/page57

[TZ350]

309826 Guns in Roses.

Starting to get somewhere with the EFI thing, started again from the beginning, and started working in small steps from the bottom up this time and now it is beginning to come back on the throttle Ok.

[chrisc]

I'll just put this here. The yen is pretty good at the moment!

http://page21.auctions.yahoo.co.jp/jp/auction/j325418660

http://auctions.c.yimg.jp/images.auctions.yahoo.co.jp/image/bi532/users/5/5/7/1/b_tech_japan-imgbatch_1424843690/600x399-2015022300015.jpg

The japanese tuning shop has a blog worth visiting too, click here (http://t2racing.jpn.com/index.html)

[Frits Overmars]

What are you going to do with a 21-year old Honda twofifty? It could become a spare parts nightmare....

[Frits Overmars]

Honda RS 125 piston. Too dry underneath? Too much advance? Lean Carburation?
There is No heat going into the piston from advanced ignition as there is no darkness underneath. RS125 ignitions retard shitloads after peak torque to get heat into the pipe and make it rev.Right, and this late ignition also puts a lot of heat into the piston, particularly weakening the top land where the exhaust flow heats it most.
Maybe the piston ring had too little guidance at the exhaust port bottom and knocked the weakened top land off.

[RAW]

Superkarts in England have been getting 250k for years. I thought they'd slowly get faster but it seems to be the limit


UK Superkarts DO NOT reach speeds of 250 kmh.
Dunlop tyres are tested under duress up to and maintained at 240 kmh for the world market.
Currently the fastest Superkart speeds know in race trim are at the Phillip Island GP Circuit.
2013 Australian Nationl Superkart Championships 2 achieved a speed of 247 kmh, this was the first time such a speed had been attained
Feburary 2015 a new top speed of 248.9 kmh was achieved at Phillip Island with a 1:30 second lap time,
The PI Superkart lap record is 1:28.4 sec
The UK guys can not believe the speeds attained by the Aussies at Phillip Island and as such Russell Anderson & his driver Gavin Bennett organised to come to Phillip Island to compete in the 2014 Championships, a change of race dates after travel bookings were made destroyed there plans.
Good news they may be coming in 2015
309841

[TZ350]

I'll just put this here. The yen is pretty good at the moment!

http://page21.auctions.yahoo.co.jp/jp/auction/j325418660

http://auctions.c.yimg.jp/images.auctions.yahoo.co.jp/image/bi532/users/5/5/7/1/b_tech_japan-imgbatch_1424843690/600x399-2015022300015.jpg

The japanese tuning shop has a blog worth visiting too, click here (http://t2racing.jpn.com/index.html)


What are you going to do with a 21-year old Honda twofifty? ....

Put it in my garage, sit in my comfy chair, drink beer, look at bike, more beer, more look at bike, talk shit with friends.

[senso]

Looks like a good plan TZ.

[adegnes]

Put it in my garage, sit in my comfy chair, drink beer, look at bike, more beer, more look at bike, talk shit with friends.

You don't need a looker to do that...
309842

[wobbly]

Wow man, check that 2T lawnmower in the background - is that what you are looking at ?


Serious note here though, anyone got a late model RD400 cylinder I could have a look at ?
I will be in Auckland on Sunday for the Eagles so could collect if anyone has one there.

[adegnes]

Wow man, check that 2T lawnmower in the background - is that what you are looking at?

Yep, thats my Honda, it deserves the attention, sat for 10 years outside, started first pull on the 10 year old gas! Sadly not a two stroke though.

[F5 Dave]

Put it in my garage, sit in my comfy chair, drink beer, look at bike, more beer, more look at bike, talk shit with friends.
And a track day or two assuming the tyres are up to it.

A mate has a '97 TZ250 in his lounge room, helped him carry it up the stairs. Solid pegs & remove the fairing, piece of piss.

[jasonu]

Put it in my garage, sit in my comfy chair, drink beer, look at bike, more beer, more look at bike, talk shit with friends.

I'm in as long as we can fit in some gun talk.

[F5 Dave]

OK. The woody levery bit goes towards you and the hole end that spits out the hot metal
bits goes towards the person you want to murder.

[fpayart]

But ditch the ram air you won't need it at road speed and it will only serve to bugger the carburation

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=301393&d=1411374076
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=301395&d=1411374076


Hello,
Funny to find his sofa at the other end of the earth:wings:
Francis.

[Frits Overmars]

Bonjour Francis, it's a pleasure to meet you here.

Guys, this L-plate rider is better known as monsieur FPE. Just google FPE Superkart.

[Dutch Fisher]

Bonjour Francis

Welcome.

I've just finished reading about your work on the Veronesi Racing crankshaft for the RGV250 engine.
Very enlightening, especially the revelation that it lacked a centre seal.
Your solution was most elegant. Bravo

[husaberg]

Hello,
funny to find his sofa at the other end of the earth : ailes
Francis.

Hello Francis, A pleasure to have you here. Now I guess I are now going to have to stop referring to you as Mr Paykart.;)
I have posted many many picures of you work here.
They might be considered the breadcrumbs that lead you to here behind the sofa.........

For the few people here that might be unfamiliar with Mr Payarts work
http://www.pit-lane.biz/t875-technique-fpe-superkart?highlight=superkart
309860309861309859



Anyway this was the other find for the evening for the Bucket racer set.
Bloody shame about the 20mm diameter small end but guess it would suit the YZ100 piston for the 100cc
Note the length..........117mm

309856309857
MODEL K-125 W/W
OEM No. -08003
CODE No. BS0290B
B.E.BEARING DIA (mm)：Ａ 26.0
S.E.BEARING DIA (mm)：Ｂ 20.0
B.E.& S.E. PITCH (mm)：Ｃ 117.0
B.E.THICKNESS (mm)：Ｄ 17.0
S.E.THICKNESS （mm)：Ｅ 18.0
CRANK PIN DIA (mm)：Ｆ 20.0
CRANK PIN LENGTH (mm)：Ｇ 49.0
http://www.tkrj.co.jp/goods/m-BS0290B--08003.php
309858

[F5 Dave]

Ahh slinging together parts from obscure 30 year old bikes to race with. This mx85 thing is more appealing by the day. But let's not digress into that debate. Or I'll turn this into an oil thread. I'll do it.

[husaberg]

Ahh slinging together parts from obscure 30 year old bikes to race with. This mx85 thing is more appealing by the day. But let's not digress into that debate. Or I'll turn this into an oil thread. I'll do it.

The Suzuki the rod is designed for is 41 years old, so its actually much younger than you.......
The rod conversely is brand new made the other day using the most modern Wok making materials and metallurgy.
So the answer to the oil debate is therefor sunflower.



Hello,
Funny to find his sofa at the other end of the earth:wings:
Francis.


I wonder if Francis could tell what the diameter of the crankshafts in his Superkart engines.
I note there seems to be a couple of different styles.
From a triangular early Rotax type to a asymmetrical chamfer an the intake side. and I think one for the 125 single
309862309863309864309866

[wobbly]

The high inertia full circle Aprilia style cranks I have designed for PVP - DEA etc are all 94 OD

[fpayart]

Hi,
The outside diameter is 93.5 mm

"I note there seems to be a couple of different styles.
From a triangular early Rotax type to a asymmetrical chamfer an the intake side. and I think one for the 125 single"

Correct, the three left pictures are the last generation and the right one is the first generation, same as the ROTAX one.

The damaged engine is the perfect illustration of the major disadvantage of this type of engine.
The incident occurred at the Sachsenring in the downhill with a beginner driver. A simple seizure can turn into disaster.
The piston has seized heavily in the rear cylinder, the engine continued to run because the other cylinder still working and due to the inertia of the kart launched at very high speed.
The rod ultimately snatch the lower part of the piston, the shaft still attached to the rod strolled into the cylinder, eventually entering in a lateral port and so on ...
The driver finally stopped when the rod penetrated the front case.:first:

[F5 Dave]

Glen what I meant is when you need to do a quick rebuild you won't find one of those in the country. Or ebay. Or on anything other than 4 month special backorder. As opposed to if you were rebuilding a yz. Or even a TS.

[husaberg]

The high inertia full circle Aprilia style cranks I have designed for PVP - DEA etc are all 94 OD


Hi,
The outside diameter is 93.5 mm

"I note there seems to be a couple of different styles.
From a triangular early Rotax type to a asymmetrical chamfer an the intake side. and I think one for the 125 single"

Correct, the three left pictures are the last generation and the right one is the first generation, same as the ROTAX one.

The damaged engine is the perfect illustration of the major disadvantage of this type of engine.
The incident occurred at the Sachsenring in the downhill with a beginner driver. A simple seizure can turn into disaster.
The piston has seized heavily in the rear cylinder, the engine continued to run because the other cylinder still working and due to the inertia of the kart launched at very high speed.
The rod ultimately snatch the lower part of the piston, the shaft still attached to the rod strolled into the cylinder, eventually entering in a lateral port and so on ...
The driver finally stopped when the rod penetrated the front case.:first:

Thanks for both your answers.
Francis you have built a Single also is that correct?
If so are the cranks the same od?
I hope my silly questions are not taking up too much of your time.


Glen what I meant is when you need to do a quick rebuild you won't find one of those in the country. Or ebay. Or on anything other than 4 month special backorder. As opposed to if you were rebuilding a yz. Or even a TS.
By now everyone should know that speed of doing anything is not my forte.
I know what you are saying though Dave because I am looking for a ke125 or similar crank at the moment. I can get them on Ebay but the freight is a killer.

The reason I have become obsessed with using one is not just the small diameter full wheels and correct stroke and pin.

I had actually missed something Frits had posted about the advantage smooth inner wheels until the other day which is something most later cranks lack.
It was from a conversation you and frits were having ;) that I missed.


Good point, Dave; in fact several good points.
Most of the volume is concentrated in the transfer ducts. Then there is the volume inside the piston of course, and the 1 mm shear-avoiding clearance at all surfaces of the crank.
But that is not nearly enough volume. If you take another look at the Aprilia crank below left, you will notice that the space between the crank webs is the same as the space needed for the big end bearing. In other words: the crank webs have flat insides, good for another 60 cc or so, if I remember correctly.Additional benefits: the con rod has an easier time pushing the mixture aside as it moves between the webs, and the big end bearing gets a lot more cooling and lubrication because it is not shrouded in any way.
Because there are no overhung bobweights, the crank webs are stuffed with tungsten to get the balance factor right.In the RSA125, the con rod was lengthened from the RSW's 115 mm to 120 mm to create even more crankcase volume.
309874
The paddling is a mixed blessing; it creates aerodynamical drag but it also greatly improves the homogenity of the mixture.
Smooth, full-circle crank webs have the advantage that there is little mixture hiding in nooks and crannies. An example of it's importance: in a certain engine there were 20 mm spaces between the crankshaft bearings and the seals. these ill-accessible volumes acted as pneumatic dampers on the crankcase pressure fluctuation. Filling those volumes with plastic bushes gave a measurable improvement.
Summary: you need a large crankcase volume. Ideally all of this volume should be situated in the transfer ducts. In real life you will also need to lodge part of this volume between crankshaft and piston, i.e: use a long con rod. Avoid nooks and crannies. Crankshafts should be small and smooth. Big end bearings must never be shrouded by recesses in the crank webs or by stuffers.
.....
Thus my intention if I was to use something like this.
309872
As opposed to say the MB100 (below) With its generic pork chop inner weights.
309873
but alas the recess for the rod is I guess still a shroud I think the GP125 Suzuki is exactly as frits described but some folks have no doubt tucked all spare ones of those away already.
Maybe I are too obsessed with trying to get the inlet straight with a large disk 118mm and small crank 85mm as the Aprilia and other superkarts are it seems a much larger than I thought.
For some reason I thought the RSW crank (with its 20mm pin) od was around 88mm. based on 46mm radius plus 1mm clearance.
In this drawing which was propertied to be a drawing from a RSV250
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=304256&d=1413591175
Which I reasoned, as it was contrary to normal crank design *that Frits had previously posted as having the equivalent half the crankpins diameter as material outside the pin.)



On a more serious note: I just took a look at the crank web + pin you showed above. As a rule-of-thumb the web material around the crank pin hole should have a thickness of at least 50% of the pin diameter. I'm afraid yours hasn't. And I am not even regarding the large bevel....

Let me start by complimenting you on a very clear description plus illustration of the balancing act. But you should not have drilled those holes where you did. As a rule of thumb, a good press fit requires that a big end pin hole should be surrounded by at least half its diameter in material. So for a 20 mm pin there should be at least 10 mm of crank web material everywhere around the hole. As you can see, the large original balancing holes already intrude into this zone, and with the small holes you added there will be little stiffness left.
309933
Removing material in the blue circles would have been a safer approach, although it might not haved raised the balance factor sufficiently.
The best way would be to remove material from the inside faces of the crank webs, around the big end recesses. That would have two additional benefits: it would improve lubrication and cooling of the big end bearing and it would enlarge the crankcase volume.
Now that I am grumbling anyway: big end pins should be massive. The large void in the pictured pin is not exactly promoting a good press fit.

So I reasoned it must have been done on the aprilia's as a compromise in order to achieve more hp.

[Dutch Fisher]

The outside diameter is 93.5 mm


Is that with a 22 or 24mm pin?

[TZ350]

Thus my intention if I was to use something like this.
309872

The KE has lead counter balance weights which will work loose in no time at all at high rpm. Need to replace them with Tungsten (Malory Metal).

[husaberg]

The high inertia full circle Aprilia style cranks I have designed for PVP - DEA etc are all 94 OD


The KE has lead counter balance weights which will work loose in no time at all at high rpm. Need to replace them with Tungsten (Malory Metal).

I was on to that one and tracked down a source of depleted uranium (joke for Jon Key and the GCSB)
309875309876309877309878
Lozza (2Tinstitute) posted a source for not quite Mallory the other day.

http://www.ebay.com.au/itm/Woodland-Scenics-PINP3919-Pine-Car-Derby-Weights-Tungsten-Center-of-Gravity-2-O-/281600524563?pt=LH_DefaultDomain_0&hash=item4190b30113

Here are some screw in tungstens 14g/ half oz each net add should be 11g

http://www.ebay.com.au/itm/Pinecar-Tungsten-Weights-3-oz-Cylinder-Pinewood-Derby-/391052179714?pt=LH_DefaultDomain_0&hash=item5b0c86b902
http://www.maximum-velocity.com/tungstencylinders.htm
http://www.abs-products.com/heavy-metal/net-gain-chart.shtml
http://www.abs-products.com/heavy-metal/price-sheet.shtml

[wobbly]

If you really want to do it properly make your own.
Ive done a heap of them as home jobs with a local CNC shop, and as long as you have the rod and piston you will be
using, dong the balance is easy.
The KE crank is holes in it - these will need to be filled with alloy, so the balance will need to be redone with Mallory anyway.

[husaberg]

If you really want to do it properly make your own.
Ive done a heap of them as home jobs with a local CNC shop, and as long as you have the rod and piston you will be
using, dong the balance is easy.
The KE crank is holes in it - these will need to be filled with alloy, so the balance will need to be redone with Mallory anyway.

I know what you are saying Wob and I was expecting the same from Neil, but the cost is likely more than a complete FXR150.
A custom made case and a cylinder is enough. plus it looks highly likely I will have to do a custom (cha-ching) primary gear now too.
Cause I still want to fit in that water cooled case.

Simply put by compromising on the crank it allows for less compromises to be made elsewhere....

[RomeuPT]

There is No heat going into the piston from advanced ignition as there is no darkness underneath.
RS125 ignitions retard shitloads after peak torque to get heat into the pipe and make it rev.
Thus I suspect a combination of not enough static advance to go with the head cc, and running too lean.
All give the end result of alot of heat in the header - too much in this case.
What fuel, what cc, what static advance?
The other possibility is that the later RS125 has the ability to change the powerjet switch rpm, maybe its too low.
But another suspect is maybe the powerjet is too big, and too much fuel is being turned off by the solenoid when in the overev area past 12500.

The piston and cylinder are from Honda RS, but they are running in my NSR 125 engine with ignitech :)

Last change was lowering the cylinder and also squish clearance from 1mm to around 0.7mm. Didn't seem to run lean, but iridium plugs fool me :/.
Before this change runned alot at high rpm with no problem. So I guess either the compression is on the limit for fuel and I was running a little lean.

[F5 Dave]

Yes reducing the pork chop on the MB is a written down evolution (thanks to that very post from about a year or more back).

Incidentally thinking about the volume in the transfers, I dropped the vinamold of my modified MB into some water (all 5) and got an increase of less than 80cc. I wonder how much is in a proper performance engine.

[wobbly]

Be carefull about what you measure when considering transfer ducts.
In Engmod the duct is defined as follows - not what many would think.

[TZ350]

Be carefull about what you measure when considering transfer ducts.
In Engmod the duct is defined as follows - not what many would think.
309922

Yes, I had wondered about that too, makes sense, thanks Wob.

[TZ350]

Page 1140 .....


TZ, Hp is not directly proportional to cylinder capacity in two-stroke engines. It actually follows a 2/3 rds power law.

Hence for a 70cc v's a 50cc at 24hp you have 24 * (70/50)^0.6667 = 24 * 1.251 = 30.0 hp for the 70

Basically hp is directly proportional to cylinder bore surface area - hence the reason over square 2 strokes are so poor.



I tried ceramic coated pistons some years ago and that's what they did , get hot and help detonation. I wonder about these modern metal sintering ( laser welding metal layer by layer ) apparently you can change the metal as the component is built up. A piston could start off aluminium alloy and end up with say a copper finish layer on top, flash chrome over that. Perhaps?
Absolutely. Aprilia GP piston heads were polished to a mirror shine; piston heads for four-stroke competition engines are sometimes chromed. I don't know whether this chroming can be done by selective laser melting, but chroming the piston head in the conventional way has given good results.
If you want to protect the piston from combustion heat, covering its head with a heat barrier is not the way to go because of the detonation this will cause.
The only safe way I can think of is to reflect the heat. That way it won't get into the piston material and as soon as the combustion is gone, so is that heat reflection; fresh mixture won't be heated.


Wobbly Re:Ignitech .. What's your take on this reported problem http://www.pit-lane.biz/t3652p20-2-stroke-twin-350cc-development > post no.2


There are several issues that I have worked thru to get the Ignitech to work its best.
Firstly is that they like low impedance coils - that is low DC resistance ( 0.2 ohm or less ) primary and a high inductance secondary.
The Suzuki RGV or Aprilia RS125/250 are the best common coils available, but I have used Crane PS92N cdi coils on Methanol burning Hydros where spark power is super important.
Stock Honda RS125/250 and CR250 coils are way too high resistance/low inductance to work well with this type of DC CDI.
Using both cdi to drive one coil doubles the effective energy available at the plug, and this is the way to get more power from say a RS125 Honda, especially if you swap out the coil.
Lastly using simply a battery alone isnt the go at all.
The voltage drops quickly under load with this setup, the DC CDIs work best when run with a battery that is being charged by the alternator at 14.2V continuously.
There is only one setup of MX rotor and stator that will drive sufficient current into an Ignitech for it to work best when using a cap instead of a battery.
The stator must have a 2 ohm winding and the rotor must be the later type with super strong magnets - you can feel them " clunk " over each pole as you rotate the rotor by hand.
You can see the voltage at the CDI drop ( on the computer screen ) during a dyno run - if the power supply isnt working as it should.
And as usual, the posts reveal that they werent using a resistor plug and cap as Seb4LO also pointed out, along with using the proper NGK race plugs.
So the spark would be all over the shop, not at the correct time to make power.
I dont know the exact calculation sequence the software uses, but I have found by trial and error that the best setup if possible,is to ensure that the addition of the base advance to the lobe duration
should be around the max advance used in the curve.
Having said that I have built several CR250 kart engines that have stock 6* of base and around 15* of lobe length, but the engine strobed exactly showing the 32* max advance as programmed.
And lastly I found that a lobe longer than around 20* length makes the calculations go haywire, and it will misfire badly at one rpm, then go perfectly well everywhere else.
There is a software button that says " wide lobe " and also one that says " no lobe length check ", but trying to translate from Czech what these actually do is impossible.
I simply cut the lobe length in 1/2 and it worked perfectly.


Answering the first question - you can use twinfire as I call it, dumping 2 cdi into 1 coil in a twin - by purchasing a DC CDI P4.
This has 4 cdi in one box ( twice the size ) and uses a rather older version of TCIP4 software, but does everything you would need.
You will need some serious power supply capability to keep that system from pulling down the voltage.
Im doing exactly that in the new TZ400 im building with two of the huge Crane coils.

Re the header dimensions, the reason for the latest configurations is to try and get the best, widest spread of lowest depression in the cylinder, from the diffuser sucking on the Ex port
around BDC.
Initially the diffuser is actually too close to the port at the bottom of the powerband, and the depression max is too early in the cycle ( transfers not fully open for best bulk flow )
Then into the overev the max depression point is too late, as the transfers are closing.
So the header end point can be moved around a little to tailor the shape, and peak intensity point where we want max depression in the cylinder for best power at a certain rpm.


Thanks Wob.

I have a DC CDI-P running for over a year now. Pretty nice. Hope that ignitech will update software or change the hardware to tune the spark plug energy, as seen it could increase top end power...

On header entrance as example, if I remember, NSR 125 exhaust round exit is 37, and exhaust header is 38. DTR 125 round exit leaves at 32mm and the header in a famous aftermarket exhaust is 33. I am wondering if this is the rule of thumb to follow, or if it would be better to go 1,5 or 2mm wider instead of just 1mm that is sometimes the tolerance needed to eleminate outward kinks. Maybe I will try to go with a 25mm lenght round transition from 32 to 34 for example without any kinks.

If is was oval, then I would be wheel advised :)

Sorry if I am posting too many hard questions.

Thanks


The twin fire setup does not add any voltage at the plug.
The two cdi output capacitors in parallel,simply doubles the available stored energy.
This translates into exactly the same arc over performance but increases the burn time duration, as the caps energy is drained into the ionised gap.
The only other way to increase burn length is to increase the inductance of the coil.
Using a PC based oscilloscope with an ignition analysis app,I saw the burn duration at x4 using twinfire and a Crane coil, over a standard single cdi and RS125 coil.

Re headers, at this stage the duct exit, and header entry I can only define in relation to the port effective area.
For a racing T port or tripple port setup the header should equal the whole effective area, and the duct exit = approx 75% of the area.
A CNC transition from oval to round makes the best connection between the two areas, with the oval width the same as the header diameter.

For a single racing Ex port ( that is - 72% and around 200* ) the duct exit and the header entry should both be around 90% of the Ex effective area.

Frits has pointed out, and I completely agree that the relationships should be based on the Blowdown capability, but that would need some time to find the correlation.



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.

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.


I also believed what I had been told previously ,that large changes in initial diffuser angle would cause flow separation and massive turbulence due to choking.
I built a heap of pipes to come up with a new design for CR125 Moto in SKUSA racing.
One of the tests was to try a design similar to the older Aprilia, with a very steep diffuser directly after the header.
This pipe made good power, but i was sure that if I added a short 25mm section ( the length of a bend segment in the U bend ) between the header and the main diffuser, with
only 1/2 the angle change - it would make more power.
Sadly no free lunch, it was worse by a small margin - bugger, another wives tale down the dunny.
I went on to discover the relationship of best power production, to the shape of the depression waves amplitude around BDC - was super critical to where the main diffuser started.

<iframe width="560" height="315" src="https://www.youtube.com/embed/mvV4xbFKs0g" frameborder="0" allowfullscreen=""></iframe>

Trombone pipe


I am very taken with the Trombones possibilities and after using EngMod2T to simulate it.

oh got that wrong more than usual.......:clap:
can't find the post either ROB but found these.........

[Martin1981]

Be carefull about what you measure when considering transfer ducts.
In Engmod the duct is defined as follows - not what many would think.

the centerline wobbly. of course. wouldn`t think anything else.

[F5 Dave]

Be carefull about what you measure when considering transfer ducts.
In Engmod the duct is defined as follows - not what many would think.
That would be a fail on my part, but it was easy to measure with the rubber to hand

[seattle smitty]

Wait a sec, back one page, Husaberg quotes Frits talking about crevice volumes, about nooks and crannies, and citing an engine that had 20mm spaces between crank bearings and seals that "acted as pneumatic dampers on the crankcase pressure fluctuation," etc..

Come on, you're also talking about opting for longer rods and flat-sided crank throws and substantially increasing total crankcase volume . . . which would appear to constitute a "pneumatic damper" so large that these crevices amount to nothing by comparison. If the ancient practice of crankcase-stuffing has been obsoleted by the enormous crankcase clearing action of modern expansion chambers, what's this about "pneumatic damping"?? Slow-witted members like me need extra explanation.:scratch:

(Seems to me Dave's method of measuring port volume would have more validity than a centerline measurement {a difficult measurement to make accurately, isn't it?}, even if it doesn't work with the particular program . . . ).

[husaberg]

Wait a sec, back one page, Husaberg quotes Frits talking about crevice volumes, about nooks and crannies, and citing an engine that had 20mm spaces between crank bearings and seals that "acted as pneumatic dampers on the crankcase pressure fluctuation," etc..

Come on, you're also talking about opting for longer rods and flat-sided crank throws and substantially increasing total crankcase volume . . . which would appear to constitute a "pneumatic damper" so large that these crevices amount to nothing by comparison. If the ancient practice of crankcase-stuffing has been obsoleted by the enormous crankcase clearing action of modern expansion chambers, what's this about "pneumatic damping"?? Slow-witted members like me need extra explanation.:scratch:

(Seems to me Dave's method of measuring port volume would have more validity than a centerline measurement {a difficult measurement to make accurately, isn't it?}, even if it doesn't work with the particular program . . . ).

The crevice Frits referred to was inaccessible next to the mains, thus was not easily accessible. (Likely just stayed where it was.) between the bearing and the seal
The volume between the webs had to be paddled through, with those pork chop flywheels paddling it around, which is a loss. when compared to a smooth crankshaft just slicing through it.
Friction loss is why there should be a minimum of 1mm clearance all around the crankshaft faces to alleviate the boundary friction shear?(I understand it can be larger but there is little to be gained from any larger clearances)
The most useful place for the large volume is in transfers and directly under the transfer's. Ie where it can be readily accessed and passed into the cylinder.
Remember The longer rod has other benefits such as dwell.
Of all the ports in a two stroke engine the transfers are open for the shortest duration.
It also proves space for a nice large port on a disk valve engine under the cylinder ;)

Anyway My take on what has been said by others....
The more clever wity one's will be along later to fill in the gaps.:dodge:

I seem to remember something along the lines of there was more than a revolutions worth of mixture just in the transfers alone.
It was around total of 650cc in the crankcase and transfers for the RSW125, 675cc for the RSA125, but most of it is near or in the transfers.

[fpayart]

Is that with a 22 or 24mm pin?

20 mm only

[seattle smitty]

The crevice Frits referred to was inaccessible next to the mains, thus was not easily accessible. (Likely just stayed where it was.) between the bearing and the seal.

I get that it was unusable A/F mixture (probably mostly oil anyway), but why is it any more of a "pneumatic dampener" than any of the rest of the volume (of the transfers, the volume under the piston, between the crank-wheels, all of it)?? Compared to the total volume, I'd think that whatever the theoretical effect is supposed to be (and what is that, again???), the actual effect of that itty bitty space would be undetectable. Wakaranai, so far.

[Muciek]

Question about carbs and airboxes.
Sorry for hijacking the thread but there is question that bothers me lately.
Is there any rule of thumb of minimal length carb face- airbox wall that's not restrictive to inlet? Looking few pages back we can see airbox of NSR300 (that one which sucked into little bird) and it's huge , on the other hand there is Aprilla airbox which looks like there is very little space between carb face and wall of airbox.

[richban]

Question about carbs and airboxes.
Sorry for hijacking the thread but there is question that bothers me lately.
Is there any rule of thumb of minimal length carb face- airbox wall that's not restrictive to inlet? Looking few pages back we can see airbox of NSR300 (that one which sucked into little bird) and it's huge , on the other hand there is Aprilla airbox which looks like there is very little space between carb face and wall of airbox.

If you don't have much room. The polystyrene and acetone method looks to be very simple and quick. Just carve a block polystyrene to the shape you need. Rap it in fibreglass. Then just pour in some acetone and watch the poly disappear. Boom! Custom air box. It will not be super pretty but it will work. If you want a pretty one then you could then turn the fibreglass box into a mould.

This is how I was planning to do my 300 ram air. Still not got around to it.

[TZ350]

309935 309937

Chambers RG50 full reed valve inlet conversion.

309936

Plenty of openings into the crankcase and cylinder.

309934309938

Curved flow guide to aid air flow around the bend in the inlet tract.

Also if the dyno does not like the carb with a curved inlet approach Chambers can go to a straight shot pumper carb setup without the curved manifold. so plenty of options that can be explored on the dyno.

309939

My more conventional setup looks positively restricted by comparison.

[TZ350]

309940309941

To get my reed valve inlet lower I cut the back out of the cylinder so the bottom edge of the reed block housing will seal on the crankcase.


309942

Both motors will be filled in where the original case reed was.

[wobbly]

Did the work on the dyno at ZipKarts for testing seat proximity on the LH drive Superkart.
The 256 Rotax at full noise with a 300mm square alloy plate just 8mm from the carb face - no difference in power at all.

Re the RG reed conversion, many 50cc racers in Euro use 30mm HV Lectrons, you can run these very steep due to no pilot circuit in the front of the carb.
I have a SmartCarb on one as per the pic I posted before about the short intake.

[F5 Dave]

TZ, Well you've got two weeks till the GP, plenty of time.


I made my RZ airbox with polystyrene, with a smear of plaster over it. Took a little bit of time to melt & dig it out but all doable in a morning.

[wobbly]

What Frits refers to re the volumes " hidden " behind bearings, and more relevantly those volumes contained within flywheel balance holes
is that even in my minds eye I can see that there is no way that these volumes can " flow " from these cavities into the transfer duct entry area.
Thus all they do is expand or contract due to the varying pressure ratios experienced within the case - thus are " dampers " contributing nothing but
to increase the overall measured volume.

Re the centreline duct measurement, most people seem to think that the transfer duct length ends where the septum divider is, and this is usually situated at the case/cylinder deck line.
Whereas the real duct begins around the corner under the piston/cylinder cutout - quite a bit longer in length, and way bigger in volume.
This is obviously anecdotally true in that a ball nose radius on the cylinder edge at the beginning of this real duct entry, can and does increase power.

[husaberg]

I get that it was unusable A/F mixture (probably mostly oil anyway), but why is it any more of a "pneumatic dampener" than any of the rest of the volume (of the transfers, the volume under the piston, between the crank-wheels, all of it)?? Compared to the total volume, I'd think that whatever the theoretical effect is supposed to be (and what is that, again???), the actual effect of that itty bitty space would be undetectable. Wakaranai, so far.


What Frits refers to re the volumes " hidden " behind bearings, and more relevantly those volumes contained within flywheel balance holes
is that even in my minds eye I can see that there is no way that these volumes can " flow " from these cavities into the transfer duct entry area.
Thus all they do is expand or contract due to the varying pressure ratios experienced within the case - thus are " dampers " contributing nothing but
to increase the overall measured volume.


Smitty What Wob said plus what I guess may have you missed Frits said


. Filling those volumes with plastic bushes gave a measurable improvement.

I see it as to draw these inaccessible volumes requires energy, This energy that could actually be better used drawing in more accessible volumes in the crankcase or transfers.
The fact this is likely repeatedly accelerated and then decelerated without likely being drawn into the transfers actually makes it criminally wasted energy.
These voids are not contributing anything much at all but simply adding inaccessible volume just makes it harder to draw in the more accessible and therefore useful volumes.
Hence why as Frits suggested he has done, When these voids were filled power goes went up.
Its not a question of the actual volume, but the usefully accessible volume.

[seattle smitty]

I read that about the spacers and the "measureable improvement." There's not much point in repeating the argument that the amount of space those spacers occupied is so small as to be irrelevant when measured against the entire volume. Hard to argue with Frits, but also hard not to suspect that something else occurred, unnoticed, during the rebuild to give that measureable improvement. Engines have been known to mysteriously gain, or lose, a little power even during rebuilds in which nothing was modified. Maybe that doesn't ever happen to the masters. Well, whatever.

[F5 Dave]

I've tried to use pistons with short distance from pin to crown, I'd see ideally the pin was in the crown to reduce all that volume there. Obviously this is impracticable.

. . . Sometimes that does happen but the engine doesn't run afterwards.

[wobbly]

Well, as always I have done the repeatable back to back tests.
Rotax 256 with porkchop cranks, and 110 rods.
Replace that with full circle cranks, no cavities and long 118 rods ( before 120 were available off the shelf )so plates needed under the cylinder.
This made the crankcase vol larger, changing it from 1.31, to 1.27.
Of course we have side the issue of less rod angularity, and the larger case, plus increased crank inertia by way of a heap of Mallory to balance the assembly.
But the final result was near on 3 Hp all the way to peak, then a much flattened drop off that gave near 8 Hp at 13,500.
Conclusion, long rod, big case , hight inertia, who cares, the dyno does not lie,when you have repeatable results from adequate weather correction, on an inertia based measuring system, as I do.

[koba]

Husa, it almost seems like you are looking for ways to draw this build out for longer...

[husaberg]

Husa, it almost seems like you are looking for ways to draw this build out for longer...

Actually aiming for a internet record............

[koba]

Actually aiming for a record............

Must spread rep... :lol:

[Bert]

Husa, it almost seems like you are looking for ways to draw this build out for longer...

Actually aiming for a record............

Must spread rep... :lol:

I can't spread more rep either... Husa just wants to have this ready for his eldest child...

[husaberg]

I can't spread more rep either... Husa just wants to have this ready for his eldest child...

But he's 11 soon, will you accept for my daughter?
309964

[koba]

But he's 11 soon, will you accept for my daughter?

Does that buy you another decade?

[husaberg]

Does that buy you another decade?

I wish.... she's already 7....... perhaps I could adopt a younger one?

okay this is the premise.
I could faf about some more (if thats possible)trying to get a NSR125 to be a 100 but even then I have to hack about the RS125 frame and engine to get it anywhere near fitting.
Its not impossible its been done before.
Or I could just do something more fun.
By me attempting to design something I have figured out so much more about why some engines are actually like they are.
So theses are the things I consider worthy.
it has to have a water cooled case even just cooling the septum's on the later Aprilia's was worth .5 hp so the full cases I am picking are worth plenty more.
The Disk valve is worth 10% extra HP. over a reed.
None of the std legal cases have what I are looking for in either stud spacing or inlet layout or decent gearbox.
The cylinder I have out to be good for nearly 40 (internet) hp. Measured at the usb port
It seems criminal to sling it on a Suzuki RG125.
I want a high mounted balancer or at least an allowance for one.
I want the ignition mounted on the Primary drive side. Out of the way of the Rotary valve
I considered mounting the stator on the balance shaft but I think its not needed it should still be narrower than the frame rails.
Because I am neither talented and I am lazy and cheap I want to use as many std parts as possible.
That's were it gets tricky.
To do a water cooled case it needs a big clutch gear I thought I had that solved with the VT250 tranny but the gear is pretty odd tooth pattern by small Honda stds and its taken a bit of nutting out.
I want a smooth crank I will I guess have to work with what I can find what I wanted to use and have won't work.
I want a square engine around 50.5mm x50.6mm bore and stroke because it has been proved to be the best compromise
I want to use a bloody long rod and I can't see the point in anything bigger than a 20mm crankpin and a 14mm gudgeon for a 100cc
Anyway enough of me blabbering on as in the time I have taken to type this Flettner has made 3 complete engines already from scratch.
The idea is to borrow a shit load of Aprilia tech that Jan and Frits and Wob and others have freely disseminated over the web.

Insert obscure crank pic the result of many misspent hours trolling the net. its obscure yet legal.
Then child like rendering of a backwards mirrored RSW with the balance shaft placed in a more appropriate position
309969309970

A good place to add the NSR500 crank
I actually never noticed the detail before.
309986

[Sketchy_Racer]

So I've dug out my old MB100 and ran it at kaitoke last weekend. Went really well so I've decided to chuck a little bit of development at it. Starting with a water cooled head.

I've had a quick play around tonight at a insert style head, but am after some constructive criticism of the design.

It's based around the theory of easy to manufacture with only 2 real setups in the mill, and out of 100X100 Solid square or 30mm thick plate.

I've tried to get as much water onto the face of the barrel to try get as much heat out of the barrel as well as focusing on trying to get heat away from the spark plug in the insert but keep more head in the combustion chamber.

There's plenty of space to play with on the spark plug heights for different cylinders (such as mine which has a 2mm positive deck height)

Any way go nuts with pointing out my short comings!

309965309966309967

[lodgernz]

better plug cooling than VHM inserts. Gotta be good

[Frits Overmars]

it has to have a water cooled case.... I want the ignition mounted on the primary drive side. Out of the way of the rotary valveThese seem to be the two biggest stumbling blocks on your wish list, Husa. But maybe we can remove both of them.
Water cooled cases are fine, but another option is insulating the inside of the cases, where the mixture comes in contact with the case walls.
My mate Martijn Stehouwer of Emot.nl offers an amazingly effective heat insulation lacquer. He became twice European champion using the stuff.
309968

Next: your ignition. You can put the ignition pick-up on the primary drive side, but you can also go for the Aprilia RSA solution and put it in the outer crankcase wall where it is triggered by a notch in the crankshaft circumference.
309971309972309973309974

Or you can put the ignition opposite the primary drive side anyway: converting a non-rotary engine to the 24/7 inlet system is simpler than converting it to rotary....

[speedpro]

Handy, you've already smashed the ceramic off the plug. Drawn with B8ES size rather than B8HS? A better option I think. Though if going to the trouble I'd probably check if a smaller diameter plug has advantages. I "know someone" who would be interested in a couple. 52mm bore and profiled for a KSI KT100 piston, 50% squish, 0.65 squish clearance, and 14.5:1 compression so about 7.3cc trapped volume.

[speedpro]

Also, what method are you using to locate the head to stock cylinders? With your skills it would be an idea to get the cylinders and match head to cylinder with whatever method you use.

[husaberg]

These seem to be the two biggest stumbling blocks on your wish list, Husa. But maybe we can remove both of them.
Water cooled cases are fine, but another option is insulating the inside of the cases, where the mixture comes in contact with the case walls.
My mate Martijn Stehouwer of Emot.nl offers an amazingly effective heat insulation lacquer. He became twice European champion using the stuff.
309968

Next: your ignition. You can put the ignition pick-up on the primary drive side, but you canalso go for the Aprilia RSA solution and put it in the outer crankcase wall where it is triggered by a notch in the crankshaft circumference.
309971309972309973309974

Or you can put the ignition at the rotary disk side anyway: converting a non-rotary engine to the 24/7 inlet system is simpler than converting it to rotary....

Thank's Frits you are to kind, my biggest stumbling block is my lazyiness and my chronic procrastination and general lack of talent.
I have raided Emot site already. The paint was Russian if memory serves me right and used for stuff as diverse as missiles or rockets and houses.
I are wanting to have a go at making cases. just to do something different. That way I can fit everything on the whish list in.
I are pretty sure Honda will have used the same tooth pattern elsewhere, I will find it. After all I only have 10 more years to get it finished now.
To fit it on a std primary drive side I need a long snouted crank I think I found one last night in the edit above.
oh well here it is for those unwilling to go back a page
309975
Its not perfect its bloody obscure but I think it will work.

The idea in my mind for mounting the stator on the clutch side was because the clutch was already poking out that side anyway so it wouldn't make it any wider.
Wob hopefully still has the Cr ignition and the ignitec tucked away in his emporium which although it is ino where as neat as the Aprilia's Selecta, it should do the job.
The 24/7 is something that does interest me very much but I think Flettner was doing something along those lines last week, he's likely finished it already.

Any idea what a water cooled case is actually worth in HP terms.
Also if I way ask why was the balance shaft mounted so low on the RSW was it mealy a Rotax carry over?
The ignition pick up on the crank wheels was for accuracy is that right? as the shafts flapped about to much?

[Sketchy_Racer]

Handy, you've already smashed the ceramic off the plug. Drawn with B8ES size rather than B8HS? A better option I think. Though if going to the trouble I'd probably check if a smaller diameter plug has advantages. I "know someone" who would be interested in a couple. 52mm bore and profiled for a KSI KT100 piston, 50% squish, 0.65 squish clearance, and 14.5:1 compression so about 7.3cc trapped volume.

Plug is just in there for a indicative thread length. That chamber profile is what's in my motor at the moment. Makes the same power as the RM85 (before it gets hot)

I have a model for Yamaha KT piston dome but not the KSI ones, are the domes different?

I'll be putting alignment dowels into accurately align the head to the barrel.

[Peter1962]

On page 962 and 963 Frits talked about a Zabel engine he was working on. Incredible engine used in sidecar MX .
I found this article about a guy who mounted a zabel in a motocross bike. Quite interesting and very impressive to say the least. The exhaust is a work of art.
http://www.sidecarcross.de/hofmann/news/Devil%20007.pdf

[Frits Overmars]

Any idea what a water cooled case is actually worth in HP terms.I haven't got the old Rotax129-data at hand but I guesstimate: about 5 % (HP figures must always be seen in relation to the total engine power; percentages are universally usable).


why was the balance shaft mounted so low on the RSW was it mealy a Rotax carry over?Yep. And you're too kind calling it a balance shaft. It was grossly offset to the left so it turned the engine vibration into a rocking couple.
Moreover, it is a cross between a cream whipper and a gear pump; running so low, immersed in gearbox oil and in such tight casings, it absorbs a lot of power.
Not the sort of solution I would normally expect from a clever company like Rotax. Must have been a quick-and-dirty 'improvement' on the shaft-less Rotax124-engine.
309976


The ignition pick up on the crank wheels was for accuracy is that right? as the shafts flapped about to much?Yep again.

[wobbly]

Re the head insert Sketchy.
Get rid of the stress raiser corners with rads, will make the insert much stronger and able to transfer some of the combustion load up to
the cover for support.
As you appear to have the water inlet and outlet in the head, put a blanking wall across the head cover that fits closely to the chamber, only allowing water to flow
across the head thru the small gap close to the plug.
This will force most of the water down into the cylinder, so you will need to blank off the holes on each side of the head, so the flow within the cylinder has
to go across the transfer outer walls, then travel up from around the EX port into the head,and exit.

Sorry dribbling again, didnt read properly that the cylinder was aircooled - dumbarse.

[RAW]

Yep. And you're too kind calling it a balance shaft. It was grossly offset to the left so it turned the engine vibration into a rocking couple.
Moreover, it is a cross between a cream whipper and a gear pump; running so low, immersed in gearbox oil and in such tight casings, it absorbs a lot of power.
Not the sort of solution I would normally expect from a clever company like Rotax. Must have been a quick-and-dirty 'improvement' on the shaft-less Rotax124-engine.
309976

Frits I'm about to machine up a couple of them there ice cream whips for Lozza, best we rethink this and improve things rather than just copy a poor mistake. Any chance yourself or perhaps Wobbly would take myself & the readers through the process of how to work out the balance shaft. using the RSW shaft as pictured & how to design a new full circle unit with tungsten weights to retrofit in replacement of the original unit ?

[Frits Overmars]

Frits I'm about to machine up a couple of them there ice cream whips for Lozza, best we rethink this and improve things rather than just copy a poor mistake. Any chance yourself or perhaps Wobbly would work out the weights & positions if we were to build a full circle one to retrofit in replace of the original unit ?That would take more time than I have available right now. What you can do is fit a sleeve around it. It won't do much good for the viscous drag but at least you won't have a cream whipper any more.
Inserting mallory slugs may allow you to reduce the outer diameter; that would reduce the drag. But it won't reduce the rocking couple. For that you would need a shaft running across the engine, with bob-weights left and right, like on the RSA125

[RAW]

Thanks Frits. You've made it easy again.

[lodgernz]

... But it won't reduce the rocking couple. For that you would need a shaft running across the engine, with bob-weights left and right, like on the RSA125

...or a single weight running right across the engine, like the Honda Mission engines (NSR50, 75, 80 etc)

[husaberg]

The CRF150R and the NSR125/150 has a two sided balance shaft with one side built into gears.
http://i.ebayimg.com/00/s/NDgwWDY0MA==/z/XAAAAOxyYTRSZtY3/$(KGrHqV,!qsFJgQY7TsZBSZtY2rVZQ~~60_35.JPGhttp://i.ebayimg.com/04/!Bwmg)z!!Wk~$(KGrHqMOKnIEvyFryDd0BMJyuQQ++Q~~_35.J PG
Other Hondas use a one lobe design in the middle Yamaha and Suzuki also do the same.
309978309979
The first one I seen with a gear build into the balance shaft was the NS500/RS500
309982309983
The MB50 NSR75 MB100 etc is clever in that it is driven from the clutch.
309980
Various others
309981
The latest KTM used a combined water pump balance gear set up
http://www.kiwibiker.co.nz/forums/album.php?albumid=4896&attachmentid=307181

[wobbly]

Rethinking the aircooled cylinder with water cooled head - is it possible to cut a couple of side trenches in the cylinder top deck, between the studs and force some water
into the hottest area at the top of the bore.

[F5 Dave]

I've just disabled balancer on a Derbi 50 as an experiment. Didn't notice an increased vib at racing speeds. Might leave it off. Unless can be convinced otherwise. Engine obviously spins somewhat faster than road bike it was designed for.

[ken seeber]

Frits I'm about to machine up a couple of them there ice cream whips for Lozza, best we rethink this and improve things rather than just copy a poor mistake. Any chance yourself or perhaps Wobbly would take myself & the readers through the process of how to work out the balance shaft. using the RSW shaft as pictured & how to design a new full circle unit with tungsten weights to retrofit in replacement of the original unit ?

Rick,
Maybe this article can be of some help309984
Ken

[husaberg]

Seen this when I was looking for crankseals
Dimensions of the Koing Flying web crank.
http://konny.cz/price_b/2s.htm
309987309988309989309990309991309992

[Sketchy_Racer]

Rethinking the aircooled cylinder with water cooled head - is it possible to cut a couple of side trenches in the cylinder top deck, between the studs and force some water
into the hottest area at the top of the bore.

Yep possible, only problem to overcome on my cylinder in particular is casting porosity. Im not sure about other MB100 cylinders but mine is swiss cheese. I'll look into it and see if it might just be a case of sealing it up with some epoxy after milling pockets.



On a side note, had another play on the dyno tonight, picked up a couple more HP up top and 3 right in the middle of the "two peaks"
Dynos are always interesting, turns out I fluked the ignition timing to spot on for best power, any way than where it was lost power. And taking off the boost bottle picked up the 3HP in the middle of the two peaks, so whilst still not good, the mean average through the spread of power now is much much better.

So comparing the best run from the RM85 cheater bike and this rooted old MB100 the MB wins the dyno war at the moment!

309994

[senso]

I've just disabled balancer on a Derbi 50 as an experiment. Didn't notice an increased vib at racing speeds. Might leave it off. Unless can be convinced otherwise. Engine obviously spins somewhat faster than road bike it was designed for.

Did the same in my crm 50 engine, the engine was much more responsive, but vibrated a bit, some screws fall off, all the plastics(fairings?) have broken, the gas-tank supports have broken off, but it revs better, so I left it out.

[F5 Dave]

If its in the rev range you use it is vibrating you should consider some rebalancing of the crank itself. My MB100 has a couple of 10mm holes drilled either side of the pin & it is fine at race revs, if a little vibey at say 5000, but who cares?, only notice that warming it up.

[TZ350]

310000

More progress with the EFI tonight. Sure the graphs look ugly but the interesting thing for me was that 75-80-85-90-95 and 100% throttle position gave pretty much the same curve and power, these curves are from 25% to 70 and the last one at 100%

A while back Frits pointed me to the EFI's equivalent of an accelerator pump. It has taken me a while to learn how to use it, there are two parts, the first is selecting how much change in throttle position there needs to be before the accelerator pump kicks in and then the second part is the delivery curve of the pump itself. It seems I had it coming on to soon and far to rich. Now the bike is starting to respond to the throttle much better after closing it at high rpm then opening it up again, its still messy but I am confident I am on the right track.

[Flettner]

On my Kawasaki I turned the accelerator pump to off, much easier to tune.

[senso]

If its in the rev range you use it is vibrating you should consider some rebalancing of the crank itself. My MB100 has a couple of 10mm holes drilled either side of the pin & it is fine at race revs, if a little vibey at say 5000, but who cares?, only notice that warming it up.

I will try to do that, now that Frits has explained in a way that I can understand.
There is still one thing that I don't understand, are the holes made symmetric in relation to the crankpin, or are they made with different angular positioning?

[SwePatrick]

When mapping electronic systems om 4 strokes,, you should never have any throttle enrichment active until you stumbles into problems with response that can´t be solved any other way.
Then it might help solve that problems, best is if you manage to run without.

I figure it´s the same on twostrokes.

Rgds.

[speedpro]

I don't see the reason 4Ts with port injection need enrichment at throttle position change happening in a case injected 2T

[TZ350]

There is still one thing that I don't understand, are the holes made symmetric in relation to the crankpin, or are they made with different angular positioning?

Some are some aren't, Suzuki's had different sized holes either side of the crank pin on a lot of their early off road bikes (farm, trail and MX) and road bikes were symmetrical. Depends on how you want the vibration to go I guess. The norm nowdays seems to be symmetrical, maybe asymmetrical was too clever to be useful.

[TZ350]

On my Kawasaki I turned the accelerator pump to off, much easier to tune.


When mapping electronic systems om 4 strokes,, you should never have any throttle enrichment active until you stumbles into problems with response that can´t be solved any other way.
Then it might help solve that problems, best is if you manage to run without.

I figure it´s the same on twostrokes.

Rgds.


I don't see the reason 4Ts with port injection need enrichment at throttle position change happening in a case injected 2T

Good points, thanks.

Its set on by default, I will turn it off, I was trapped for a long while thinking the engine was stalling because it appeared to go lean when I closed then opened the throttle but it now appears the fire is just getting blown out by the over rich mixture from the accelerator pump. Frits had also warned me about to rich to fire means excess oxygen in the exhaust fooling the O2 sensor into thinking its running lean.

Speedpro had earlier suggested turning the warm up fuel off because it can confuse things, a bit harder to start and warm up but much easier to tune.

[wobbly]

I have seen several cranks with the holes each side of the pin asymmetric as well a several with the balance weight not quite opposite
the pin.
Does anyone have a rational explanation of this,I can see it would generate a peak reaction force offset from the TDC force of the piston
but what effect does this have on the overall balance, ie why do it.

[Frits Overmars]

I have seen several cranks with the holes each side of the pin asymmetric.They can't have been Aprilia racing cranks then, as these have no holes at all, just a lot of slugs. But some are tungsten, some are very light.
The color difference in the picture below shows the asymmetrical distribution of light and heavy slugs. This is a give-away that these are crankshafts from the 90°-twin engine; their balance mass center of gravity has a 45° offset whereas the crankshafts of the Aprilia singles have no balance mass offset.

You (not you, Wobbly) may also wonder why there are so many slugs; couldn't it have been done with a much smaller number? Yes, but the large number serves a second purpose, apart from balancing. Putting light slugs near the center and heavy slugs near the circumference of the crank webs increases the crankshaft inertia without increasing its weight.
310031

[Frits Overmars]

You may have noticed that I did not call the Aprilia 90°-twin a V-twin. The Aprilia twin engine is sometimes called a W-twin because of its two counter-rotating cranks whereas a V-twin usually means: two cylinders on one common crankshaft. Both the V-twin and the W-twin can be balanced pretty good (they're only beaten by the boxer twin; balance-wise you can hardly do anything wrong with a boxer). Below you'll find the balance theory behind the common 90° V-twin (courtesy of Tony Foale).
310032

[F5 Dave]

Look at those Beautiful rods.
My, what large eyes you have.

[senso]

No, not Aprilia cranks, but cranks made and/or designed by some portuguese tuners and also some from the internet, sometimes they are really just holes, some times they fill them with aluminium or lead(poor mans tungsten, also prone to becoming loose in the bore), there is also on crank that I know that has a 5-6mm thick ring of bronze on the outer diameter, in part to increase the weight of the crank and in part to be able to re-use a crank made for a nsr/crm 50 engine in an nsr/crm 75 engine that uses a larger crank from factory, so hey, slap some bronze, hammer some pins and call it ultra racing.

A long time ago(more than 7 years ago) I bought my first two stroke related book:
The High-Performance Two-Stroke Engine by John Dixon
http://www.amazon.com/High-Performance-Two-Stroke-Engine-John-Dixon/dp/1844250458

At the time it only costed 50€, and for me it was a great book, not because it has recipes that say grind here and there and gain lots of horse power, its a more mathematical/physical approach to an engine, and in half a page he talked(wrote?) about crank positivity, has being a crank that has more weight on one side of the crank(considering that the wrist-pin is the center of the parting line) than on the other, so that when the piston is at TDC there is a slight bit more inertia to rotate it down, and on BDC there is the tendency to go up, it was finally a real explanation of a mythical thing that was talked in portuguese forums, but those who didn't know just tried to understand, those who understood the concept keep it to them.

But still today, I have some doubts its really helpful given how real racing cranks are made, but now those Aprilia cranks in fact have more mass in one side than on the other, fascinating.

[Frits Overmars]

.. a crank that has more weight on one side of the crank than on the other, so that when the piston is at TDC there is a slight bit more inertia to rotate it down, and on BDC there is the tendency to go up... I have some doubts its really helpful given how real racing cranks are made, but now those Aprilia cranks in fact have more mass in one side than on the other, fascinating.The mass asymmetry in those Aprilia cranks is there purely for balancing reasons; it has nothing to do with 'rotating up' or 'rotating down'.
For all I know rotating means going round, not up or down :oi-grr:.

[wobbly]

So looking at a single crank - end on that spins clockwise, you would bias the balance mass ( if using Mallory opposite the crank )
slightly clockwise of the vertical centreline thru the pin.
Or if using holes each side of the pin, there would be a smaller hole to the right, and a bigger hole to the left of the pin ( irrelevant if they are alloy filled or not for this discussion ).
And the purpose of the bias is to advance the cranks rotational inertia such that this aids acceleration away from BDC and TDC - right?
But what advantage would this give - I will have to go read Dr Dixon to see if he mentions some perceived benefit.

[senso]

My up and down are regarding going to TDC or to BDC, the piston goes "up" and "down".

I don't have the book here, but its just a short paragraph, its basically explaining the term, and nothing more if I remember correctly.

[TZ350]

310045

I love these original moped race builds and the ideas that go into them, very Bucketerish.

http://garage.1977mopeds.com/build/Bad+Attitude+-+Old+iezer+v3.0

Sometimes more art than function:- https://youtu.be/LYfzI5nLC2w

And

http://garage.1977mopeds.com/build/Mono+Maxi


Other interesting builds here:- http://garage.1977mopeds.com/browse/builds/?product=3220

[F5 Dave]

Those tyres look like they could kill, as could the front brake line.

[seattle smitty]

I have seen several cranks with the holes each side of the pin asymmetric as well a several with the balance weight not quite opposite
the pin.
Does anyone have a rational explanation of this,I can see it would generate a peak reaction force offset from the TDC force of the piston
but what effect does this have on the overall balance, ie why do it.

One explanation from long ago was that a single was going to be a shaker in any case, and that the factory might choose to move the direction of the shaking to where it was easier on motor-mounts or the frame or the rider's hands or whatever.

[adegnes]

310045

I love these original moped race builds and the ideas that go into them, very Bucketerish.

http://garage.1977mopeds.com/build/Bad+Attitude+-+Old+iezer+v3.0

Sometimes more art than function:- https://youtu.be/LYfzI5nLC2w

And

http://garage.1977mopeds.com/build/Mono+Maxi


Other interesting builds here:- http://garage.1977mopeds.com/browse/builds/?product=3220

How about this for range - four variable pulleys.

http://garage.1977mopeds.com/assets/images/builds/2900/c743c1e26feb4a9b8ecef06d2b15c481.jpg
http://garage.1977mopeds.com/assets/images/builds/2900/77d8e50d5f10200fa9621031e0780e33.jpg
http://garage.1977mopeds.com/build/Black+Betty+aka+VX4

[RAW]

Re crank weight offsets
Frits if I recall correctly. upon the pit lane thread you described the differing rotational speeds as a crankshaft moves through 360 degrees along with the crankshaft pulling the piston away from TDC in the overrev. Would this offset balance benefit in assisting the crank to rotate at a more even speed throughout a & each subsequent revolution along with stabilising the spark signal from the ignition rotor upon the crankshafts end ?
I hope I've recalled this correctly.

[Dutch Fisher]

So looking at a single crank - end on that spins clockwise, you would bias the balance mass ( if using Mallory opposite the crank )
slightly clockwise of the vertical centreline thru the pin.
Or if using holes each side of the pin, there would be a smaller hole to the right, and a bigger hole to the left of the pin ( irrelevant if they are alloy filled or not for this discussion ).
And the purpose of the bias is to advance the cranks rotational inertia such that this aids acceleration away from BDC and TDC - right?
But what advantage would this give - I will have to go read Dr Dixon to see if he mentions some perceived benefit.

The only thing i can think of re: asymmetric balance mass is to slow the instant crank velocity close to BDC to give more transfer "Time" without an increase in degree opening. If the single cylinder is near vertical then the bigger weighted hole would have to be to the right of the pin so its interaction with gravity 'could' be allowed to slow the crank.

Maybe.

[TZ350]

How about this for range - four variable pulleys. http://garage.1977mopeds.com/build/Black+Betty+aka+VX4

That is clever, I like it.

[ken seeber]

My take is that, irrespective of where the counterbalance weights/holes are and even if they are asymmetric, will make no difference at all to the overall flywheel effect of the crank. All the crank is a lump of metal, which apart from its other functions, is a flywheel with a 2nd moment of mass around the crank axis.
However, it is possible that any asymmetry could provide an out of balance force vector that could oppose some (higher) connecting rod force acting on the crankpin, thereby minimising the force on the main bearings at a certain time over the cycle, maybe reducing friction. Could be crap though.

[speedpro]

Do people REALLY think that having the holes asymmetric is going to change the rate of change of crankshaft rotational velocity depending on crankshaft position, REALLY? The crank rotational inertia will remain constant irrespective of where the holes are, as long as the holes are the same size and the same distance from the centre of rotation, i.e. - the centre of the mainshafts. Their position about the circumference of the crank is not going to have an effect on the inertia and therefore the crankshaft speed changes that occur within a single revolution. Gravity will have an effect but good luck measuring that. The motorcycles rate of acceleration would have a similar effect but at 90degrees.

There might be a case for the asymmetry based on changes in crankshaft speed within a single revolution but I don't know how much a crankshaft changes speed from the compression to the power stroke. Obviously a bit or there would be no need for cush drives

[Frits Overmars]

My take is that, irrespective of where the counterbalance weights/holes are and even if they are asymmetric, will make no difference at all to the overall flywheel effect of the crank. All the crank is a lump of metal, which apart from its other functions, is a flywheel with a 2nd moment of mass around the crank axis.
However, it is possible that any asymmetry could provide an out of balance force vector that could oppose some (higher) connecting rod force acting on the crankpin, thereby minimising the force on the main bearings at a certain time over the cycle, maybe reducing friction.

Do people REALLY think that having the holes asymmetric is going to change the rate of change of crankshaft rotational velocity depending on crankshaft position, REALLY? The crank rotational inertia will remain constant irrespective of where the holes are, as long as the holes are the same size and the same distance from the centre of rotation, i.e. - the centre of the mainshafts. Their position about the circumference of the crank is not going to have an effect on the inertia and therefore the crankshaft speed changes that occur within a single revolution. Gravity will have an effect but good luck measuring that. The motorcycles rate of acceleration would have a similar effect but at 90degrees.Ken and Speedpro, I'd say you both nailed it.


I don't know how much a crankshaft changes speed from the compression to the power stroke. Obviously a bit or there would be no need for cush drivesThe rotational speed variation is quite small, as is the angular position variation. The actual crankshaft position will never vary more than 0,5° compared to a truly uniform rpm, so its influence on port and ignition timings is just about negligible.
The cush drive is not there to smooth the rpm fluctuation but the torque fluctuation. The torque fluctuation can be ten times the nominal torque and if you don't do something about it, you will be forced to construct the whole transmission much heavier than necessary.
310107

[senso]

Here is one extreme example of asymmetric holes, its a crank for a sachs engine, with 48mm stroke(the original engine has 44mm stroke).
310108

[TZ350]

Their position about the circumference of the crank is not going to have an effect on the inertia and therefore the crankshaft speed changes that occur within a single revolution. Gravity will have an effect but good luck measuring that.

I once spent quite a bit of time as a Technician working on a prototype vertical cyclotron at ANAC (1980's) and gravity did have a measurable effect on the particles being spun around. Gravity would detract energy on the up side and added energy (speed) on the down side. Talking with the Physicist in charge, the challenge was timing the pushes and pulls of the accelerating plates to coincide with the particles passing, it wasn't symmetrical.

[Grumph]

I once spent quite a bit of time as a Technician working on a prototype vertical cyclotron at ANAC (1980's) and gravity did have a measurable effect on the particles being spun around. Gravity would detract energy on the up side and added energy (speed) on the down side. Talking with the Physicist in charge, the challenge was timing the pushes and pulls of the accelerating plates to coincide with the particles passing, it wasn't symmetrical.

Interesting...Having watched with some amusement the theorists speculating about balance, can i pose a question ?

What balance factor would you use for a vertical shaft engine ?

Given that in a motorcycle application where the cylinder is vertical or nearly so, the balance factor tends toward greater than 55% and where the cylinder is horizontal or nearly so, it is usually the reciprocal or less than say, 45%. This in order to have the out of balance forces acting vertically in relation to the ground as this plane has historically been shown to be more acceptable in use.

And Smitty, yes, I know a lot of your outboards are horizontally opposed twins and therefore sidestep the issue...

[Dutch Fisher]

310107

Calculated or direct measurement?

No. of cyls (if >1, degrees of combustion separation?)?

[Frits Overmars]

Calculated or direct measurement? No. of cyls (if >1, degrees of combustion separation?)?Calculated, 1 cylinder. Two cylinders with 90° combustion separation run much smoother. With 180° separation they only sound smoother but the torque fluctuation is almost as bad as in a single.
310115310116310117310118

[seattle smitty]

[QUOTE=Grumph] Interesting...Having watched with some amusement the theorists speculating about balance, . . . . (end quote)

And it's not like these assymetrically balanced engines are some factory race-team secret. I have an ordinary 1973 Yamaha 125 MX engine, thousands and thousands made, and it has one balance hole quite markedly bigger than the other one. I always supposed that it had nothing at all to do with engine performance, and was that way because after testing Yamaha found that moving the direction of the shakes was less likely to break welds, or made the carburetor float-needle meter better, or something like that.

If that was true, then with a vertical shaft or any other arrangement, I would speculate (it's free!!) that rather than there being a formula, you test the engine, and if it is shaking itself apart, or if the carburetion gets weird at certain places, you cut-and-try different balance combinations. There undoubtedly are some rough guidelines used by the factories. Industrial plant maintenance techs have been using vibration measuring equipment for decades, and surely these have been adapted to factory engine development for almost as long.

[husaberg]

Reading some of the posts with th physics involved made my head hurt....just me?

This I do know different bikes with the same engines sometimes have different balance factors depending on the frame design and inclination.
Ie Nortons in Featherbeds or STD frames even I understand slimline featherbed vs Wideline.
I am referring to old pommy shitters here these were arrived at by trail and error to what was acceptable to the rider (what the pommies thought was acceptable at the time)
A cr500 vibes far more in an alloy frame than in a steel frame

I know for a fact that a old pommy shiiter I had (8e Villers FB Falcon) was un-ride able without a head stay (which was a piece of pipe crushed on the ends that tied the frame to a head bolt.)
With this silly head stay made and fitted on, it was fine. (By old pommy shitter standards.) the vibes I guess did not disappear but were transferred to somewhere else. Likely the flexible frame.
So I guess it was tuned out resonance wise or something?

[speedpro]

The asymmetrical balance holes could also be due to asymmetrical piston acceleration either side of TDC & BDC. Remember the gudgeon pins are not in the centre of the pistons but offset. This affects rod geometry and therefore piston acceleration approaching TDC and departing TDC, and BDC. If the acceleration is affected then so is the resultant force/reaction.
It'd be interesting to see a graph of forces with the usual offset gudgeon pin versus with a pin central in the piston.

[breezy]

:clap:"old pommie shitters", .... charming:bash:

[Grumph]

:clap:"old pommie shitters", .... charming:bash:

A technical term much used in the ex colonies.

Can also refer to elderly freedom campers of British origin....

[husaberg]

:clap:"old pommie shitters", .... charming:bash:

I didn't want to confuse anyone that I was referring to cutting edge two stoke design.
So to clear it up for our British overloads I will hence force refer to them as "shitters":bleh:
http://www.villiersparts.co.uk/20motor.jpg

Although it looks like you can get decent crankshafts for them now
http://www.feked.com/villiers-crankshaft-and-conrod-197cc.html
http://images.classicbikepartscheshire.com/images/products/1346318805-36782800.jpg
As opposed to what they had.
http://thumbs2.ebaystatic.com/d/l225/m/mU_jKfmG3zn88hlUszqy8qg.jpg
With bushed big end and little end.

[breezy]

I didn't want to confuse anyone that I was referring to cutting edge two stoke design.
So to clear it up for our British overloads I will hence force refer to them as "shitters":bleh:
http://www.villiersparts.co.uk/20motor.jpg

Although it looks like you can get decent crankshafts for them now
http://www.feked.com/villiers-crankshaft-and-conrod-197cc.html
http://images.classicbikepartscheshire.com/images/products/1346318805-36782800.jpg
As opposed to what they had.
http://thumbs2.ebaystatic.com/d/l225/m/mU_jKfmG3zn88hlUszqy8qg.jpg
With bushed big end and little end.

:niceone: bring on the world cup:third:

[husaberg]

:niceone: bring on the world cup:third:

Yeah past history suggests they always go so well for old blighty............:nya:

Cricket
Third may be a tad optimistic old chap where did you guys finish again......
2 wins from six matches. VS NZ undefeated in 6 thus far.
http://www.mirror.co.uk/sport/cricket/england-finish-miserable-world-cup-5325955

Unless you mean the rugby.
NZ VS England Overall games 40 allblack wins 32. 1 draw:whistle:

A century of New Zealand dominance has been punctuated by remarkable England victories. The 17 point margin in 2012 eclipsed the 13-0 win in 1936. Out of the blue England visited NZ in 1973 and won the test match 16-10, their first win in New Zealand. Ten years later they pulled off the first home win in 48 years by 15-9 and repeated the feat ten years later by the same score. They won twice in 2002 and 2003.
One of the 1997 matches resulted in a 26 all draw.
The rest of the matches have been won by New Zealand. The highest margin was 42 points in 1998 in Dunedin when England sent a depleted touring side to New Zealand.
The teams have met three times in World Cups, with New Zealand winning all three matches.
Soccer surely not..........


16 - New Zealand All Whites soccer team undefeated in World Cup
During the 2010 World cup in one of those strange statistical quirks the All Whites were the only unbeaten team in the competition with a series of three exceptional draws — including one against defending world-champions Italy.

Pretty sure you wouldn't have meant League either.
https://www.youtube.com/watch?v=jTwYICJ-nPc

Netball unlikey seeing as as well as NZ and er Trindad and Tobago have won more world cups than England as well.

What sports are left? yachting and rowing lol.
I understand NZ pretty dire at those.........
Although its astounding to consider Engand have been trying to win an Americas cup since 1851 and we managed on our what third go..........

[cotswold]

Thanks Tee Zee for letting me put the 50 on your Dyno, shame things went pear shape but fairly happy with the nearly 14, could you post the graph for me as I forgot to take a photo in my haste to get home and strip the bee atch.

[TZ350]

Sure, but it will have to be tomorrow when I get back into work.

310162

There you go.

[breezy]

Yeah past history suggests they always go so well for old blighty............:nya:

Cricket
Third may be a tad optimistic old chap where did you guys finish again......
2 wins from six matches. VS NZ undefeated in 6 thus far.
http://www.mirror.co.uk/sport/cricket/england-finish-miserable-world-cup-5325955

Unless you mean the rugby.
NZ VS England Overall games 40 allblack wins 32. 1 draw:whistle:

Soccer surely not..........


Pretty sure you wouldn't have meant League either.
https://www.youtube.com/watch?v=jTwYICJ-nPc

Netball unlikey seeing as as well as NZ and er Trindad and Tobago have won more world cups than England as well.

What sports are left? yachting and rowing lol.
I understand NZ pretty dire at those.........
Although its astounding to consider Engand have been trying to win an Americas cup since 1851 and we managed on our what third go..........

:weep::weep::weep::weep: :not::beer:

[peewee]

hey guys has anyone attempted to move the piston rings locating pegs with any sucess ? i heard people do it but it failed. surely there must be a way

[speedpro]

hey guys has anyone attempted to move the piston rings locating pegs with any sucess ? i heard people do it but it failed. surely there must be a way

I used to get Pete Sales of Total Motorcycles in Palmerston North to do it all the time. I probably wouldn't bother now. The KT pistons have a ring peg in the middle of the boost port and no problems, with that anyway.

[peewee]

the pistons i have use the peg at the 5 oclock position but i want to relocate it to the 6oclock. i was going to call wiseco and see if they will do it. any other idea who has experience with this ?

[FastFred]

the pistons i have use the peg at the 5 oclock position but i want to relocate it to the 6oclock. i was going to call wiseco and see if they will do it. any other idea who has experience with this ?

310158

Kel has some experience with relocating the ring peg.


Well things didn't go to plan today, after practice and prelim races, engine failure and a masive high side that slam dunked Kel.

[F5 Dave]

Well they aren't cast in there so the manufacturers manage it. Talk to a toolmaker.

[speedpro]

Pete used to tap the original pin into the piston so it didn't interfere with the ring and then drill another hole in the new position and insert a pin he'd retrieved from an old piston. You just have to make a hole with the desired press fit for the pin, OR, do like others do and press it in from on top into a 2nd larger hole below the ring land and bend the end of the pin so it can't come out. Depending on the method you will need to get the right rings.

[jasonu]

hey guys has anyone attempted to move the piston rings locating pegs with any sucess ? i heard people do it but it failed. surely there must be a way

We have had to do that to MB100 pistons when used in an RG400 cylinder. Never had one fail.

[jasonu]

"old pommie shitters", .... charming.

No they're not...

[ken seeber]

Below are pics of port mouldings of a TM 10B cylinder. These are located and glued on to the steel “bore” mandrel to maintain their correct relationship. Without having looked at lots of cylinders though, they seem to be pretty much the current norm.
So, looking at the B port/passage, it just gets me wondering if the complex twisting of the passage is a product of having to work around the existing crankcase stud spacing pattern. The cylinder entry is strongly influenced by the casting wall thickness surrounding the ring spanner clearance for the cylinder nut. The final entry to the cylinder is in fact almost on the stud centre. Recalling my failed kindergarten skills, I made up a rough passage shape in plasticine (painted blue), with essentially a vertical shape. I know it doesn’t have the exact same leading entry angle, but it is there as an example of an alternative to the current complex shape.
Is it time to review the traditional stud spacing and number thereof?
Funnily enough, if one duplicated the exhaust port plan over the suggested B & the C ports, it would start to look like another scavenging system. Frits, I am sure that this must give you a warm and fossy feeling. NOTE: fossy is probably Kiwi for fuzzy. :niceone:
310168310169

[peewee]

310158

Kel has some experience with relocating the ring peg.

who is KEl ? who is pete ? do they have contact info ? problem is im on the other side of the globe but if thats what it takes to get the job done then ill send some pistons over. or better yet maybe they can source the pistons locally and relocate the peg then send them to me. hell i dont know what would be cheaper/easier. it seems doubtful wiseco would be willing to do this procedure but ill call tomorow. other wise i dont know who else to call in the usa.

i asked this question before but i want to ask again and get a clearer answer. has anyone installed roller bearings on the banshee style crankshaft that originally used ballbearings ? im about to pull the trigger on the bearings (all 4 ball bearings will be replaced with roller style) but i need to know exactly which style i need.

i called crankworks to ask which ones i need, because im going to have them do the job but the phone answering guy wasnt much help. he said they use koyos with metal cage, possibly brass, (but didnt offer any more info than that) and then they machine a groove in the circumference of the outer race, presumably for the circlip, then they machine a groove in the center and flywheel side bearing valley of the lower crankcase, so each bearing has a circlip or half a circlip to hold it in place in the lower case half. i was thinking to use skf NJ 305 ECP with polymer cage, but of course they have no groove in the outer circumference. can the rollers and cage be removed without damage, to machine a groove, then reinstalled ?

theres another option but i dont know if its a good choice or not. theres a skf NUP 305 ECNP. which has a outer clip groove already machined but it uses a collar on the inner race. seems like the collar would be of no value in this situation. first pic is NJ305ECP. second pic NUP305ECNP

[husaberg]

who is KEl ? who is pete ? do they have contact info ? problem is im on the other side of the globe but if thats what it takes to get the job done then ill send some pistons over. or better yet maybe they can source the pistons locally and relocate the peg then send them to me. hell i dont know what would be cheaper/easier. it seems doubtful wiseco would be willing to do this procedure but ill call tomorow. other wise i dont know who else to call in the usa.

i asked this question before but i want to ask again and get a clearer answer. has anyone installed roller bearings on the banshee style crankshaft that originally used ballbearings ? im about to pull the trigger on the bearings (all 4 ball bearings will be replaced with roller style) but i need to know exactly which style i need.

i called crankworks to ask which ones i need, because im going to have them do the job but the phone answering guy wasnt much help. he said they use koyos with metal cage, possibly brass, (but didnt offer any more info than that) and then they machine a groove in the circumference of the outer race, presumably for the circlip, then they machine a groove in the center and flywheel side bearing valley of the lower crankcase, so each bearing has a circlip or half a circlip to hold it in place in the lower case half. i was thinking to use skf NJ 305 ECP with polymer cage, but of course they have no groove in the outer circumference. can the rollers and cage be removed without damage, to machine a groove, then reinstalled ?

theres another option but i dont know if its a good choice or not. theres a skf NUP 305 ECNP. which has a outer clip groove already machined but it uses a collar on the inner race. seems like the collar would be of no value in this situation. first pic is NJ305ECP. second pic NUP305ECNP

I have already relayed I once ages ago watched my father do it, then again it was part of a repair of an that consisted of him put some welding a ring land and top edge of a piston and re-machine a groove as well.
After I chipped the top of a piston (on a old shitter 197 James Captain on a 215cc oversize) Incidentally likely the worlds loudest James 123db at Levels 1993.
What he did was after drilling a hole with a numbered bit was make up a peg out of a fine brass threaded bolt likely out of a electronic do-dad or something.(he's a world class Hoarder)
No idea if he peened it over or used some locking compound or anything.
He then filed it off flush. This was only done because the piston was unobtainable at the time. I doubt it consists of best practice.


Note Pewee Ken Seebler here manufactures pistons. Pretty sure he could sort you out. For the peg, info at least
He has the post above yours........

There are also plenty of small crowds that do custom pistons.
Bigger operations like would likely not be interested.
I think though Woosner still will do custom stuff to order.

[F5 Dave]

Your location of 'everywhere' no doubt confused a few.

Go take I piston to a toolmaker or some small engineering shop (there must be a gazillion of them hiding in industrial areas) used to working with precise tolerances and look for an older chap with grey hair who looks like they would know about interference fit & wave the piston in front of him. Ideally you retrieve some pins from scrap pistons to use to push into a precise hole. A drill bit end can be used in a pinch.


The redundant one might be able to be tapped in, or carefully ground with a dremel cut off wheel

[husaberg]

Your location of 'everywhere' no doubt confused a few.

Go take I piston to a toolmaker or some small engineering shop (there must be a gazillion of them hiding in industrial areas) used to working with precise tolerances and look for an older chap with grey hair who looks like they would know

Dave is of course right but the old chap will have the dirtiest overalls in the workshop and preferably a beard and ill fitting glasses. Also if you go there with some Beer on a Friday afternoon.
Magic can happen.
Never trust someone who is an engineer yet is without a beard.......:msn-wink:

[mr bucketracer]

Dave is of course right but the old chap will have the dirtiest overalls in the workshop and preferably a beard and ill fitting glasses. Also if you go there with some Beer on a Friday afternoon.
Magic can happen.
Never trust someone who is an engineer yet is without a beard.......:msn-wink:me at 17 was cutting pins out of old pistons and setting them up in rg50 pistons for my rd50 , never had a promblem , get a old piston and get some practice in

[wobbly]

The whole question re fitting rollers to a Banshee/RZ style crank all depends upon the primary drive gears.
If using a helical set then you must use a ball on the drive end and this can be replaced by a high capacity, extra ball unit called BL305NRC3.
But if you are going straight cut, then you can use balls in the centre ( HiCap if you feel like it ) and rollers on the outer ends.
These are NJ305EWC3 with the step on the inner race facing the web.
Both these bearings have a clip groove.
There is NO advantage to using rollers on the inners, all the loads are on the drive end from the gear force pushing the shafts apart , and on the
ignition end from the flywheel trying to rip the crank snout off due to precession.
If you fit a roller on the ignition end you will need to cut a groove in the bottom case, as the crank can float left and right, and the inner bearings
only have O rings in the outer races that dont prevent sideways movement.
You could if really keen put rollers in the middle, and set up the outer race positions so that the crank floats 0.3mm in the case, but again as I said
this then would need another groove cut on the ignition side for retention in both directions.

[peewee]

thnx for the help on the ring pegs. i sent some pm's so hopefully i can get it sorted out.

about the bearing question. anybody transformed one of the inline twin cranks with ballbearings to all roller bearings ? wobbly mentioned something about it a while back but i dont recall any mention of the style of bearing, other than it was a roller. im new to all this and havent personally seen a ballbearing crank turned into a roller bearing crank. whats throwing me off is the machining of the groove on the outer circumference. i realize the groove is so the clip will hold the bearing from sliding around but i didnt know the rollers and cage could be removed to machine the groove.

looks like i was posting this at the same time as you wobbly. LOL. anyways ya ill be using straight cut primary gears. i have to pull the crank completely apart anyways, the center ball bearings are the cheapest shit from taiwan, i dont trust them as far as i can throw em. so may as well use rollers there also, the case will have grooves cut for all 4 bearings. NJ305EW c3, ok ill look into them. thnx for the help

[FastFred]

... has anyone installed roller bearings on the banshee style crankshaft that originally used ballbearings?

Look at the Yamaha TZ's from the 70's they have a similar (cruder) crank to the RZ, the TZ used roller brgs on the outside and ball races for the inner two brgs, some factory race bikes I think used rollers all round. The outer roller TZ brgs had brass cages and groves on the outside of the race which were located by half circlips to keep the outer shell in the right place. The inner ball brgs had plastic cages and there was a labyrinth seal between them and half clips each side between the seal and brg, these located the crank central in the crankcase. All the brgs had little dowels to stop them spinning in the case, all the half circlip groves were in the bottom case half.

I have seen TeeZee grove std roller brg outer shells by spinning them in a lathe and using a 4" angle grinder and a very thin cutoff blade.

Road RD cases were converted to racing TZ ones by mounting the lower case against a lathe face plate and with a suitable parting tool in the end of a boring bar. TeeZee would swing the lower crankcase half back and forth by hand and carefully wind the the cross slide in to cut a very nice half circlip grove. To stop the brgs spinning in the cases he cut a second set of smaller half circlip groves for pieces of 1.5mm O ring, these griped the brg and held it firmly enough to stop the outer race spinning.

There you are, some of the best kept race prep secrets from the 70's.

If you ask me very nicely I will tell you what he did to TZ cylinders to make them Fast Reliable and above all, Easy to Ride without that all or nothing light switch effect out that of the box TZ's were known for.

[peewee]

hey wob the only thing i find on the nj305EW is its just a nj305 with one piece steel cage. maybe theres a missing letter. nj305EWN perhaps ? the letters EW seem to be specific to NSk but im not finding a nj305EW with clip groove on their site.

[wobbly]

Ive got plenty of them, send a PM.

[peewee]

If you ask me very nicely I will tell you what he did to TZ cylinders to make them Fast Reliable and above all, Easy to Ride without the light switch effect out of the box TZ's were known for.

i wouldnt mind some more info on that crankshaft in the pic :clap:. never seen one like that before

[FastFred]

i wouldnt mind some more info on that crankshaft in the pic :clap:. never seen one like that before

Google TZ350 crank

TZ cranks are old technology dating from the very beginning of racing 2T's, and invariably cracked and/or spread the big end pin holes. RZ cranks with their forged pins are much better ...

[Dutch Fisher]

Calculated, 1 cylinder. Two cylinders with 90° combustion separation run much smoother. With 180° separation they only sound smoother but the torque fluctuation is almost as bad as in a single.
310115310116310117310118


Calculated ! I'm intrigued

If you don't mind a bit of peer review Frits, pls feel free to publish your variables and their values.

[Frits Overmars]

Pete used to tap the original pin into the piston so it didn't interfere with the ring and then drill another hole in the new position and insert a pin he'd retrieved from an old piston. You just have to make a hole with the desired press fit for the pin, OR, do like others do and press it in from on top into a 2nd larger hole below the ring land and bend the end of the pin so it can't come out. Depending on the method you will need to get the right rings.Pressing the pin in from above and then bending the lower end is the tried-and-trusted Yamaha method. But it requires a rather soft steel for the pin, or the bending force might cause loss of press fit in the vertical bore.
310193310194

Emot recently developed a variation on the theme: the pin is pressed in from above, after which the top of the vertical bore is closed by welding.

[husaberg]

Google TZ350 crank

TZ cranks are old technology dating from the very beginning of racing 2T's, and invariably cracked and/or spread the big end pin holes. RZ cranks with their forged pins are much better ...

Best place to see the TZ and RD crank stuff is here I have posted it before. Wob has mentioned before the old RD cranks are better balanced that the later stuff.
Certainly more rebuildable that the LC stuff to. They do also have different bore centres.
http://www.t20suzuki.com/racing.htm#TZcrank.
this is interesting
http://www.2strokeworld.com/forum/index.php?topic=3262.15

[Frits Overmars]

looking at the B port/passage, it just gets me wondering if the complex twisting of the passage is a product of having to work around the existing crankcase stud spacing pattern. The cylinder entry is strongly influenced by the casting wall thickness surrounding the ring spanner clearance for the cylinder nut. The final entry to the cylinder is in fact almost on the stud centre....Is it time to review the traditional stud spacing and number thereof?I think so, Ken. Stud spacing is the very last thing that should be established when designing a cylinder.


Funnily enough, if one duplicated the exhaust port plan over the suggested B & the C ports, it would start to look like another scavenging system. Frits, I am sure that this must give you a warm and fossy feeling. NOTE: fossy is probably Kiwi for fuzzy. :niceone:A warm and fossy feeling as in wetting your pants?
Anyway, duplicating the exhaust plan reminds me of a cylinder constructed by a certain Ken Seeber...
310195310196

[fatbastd]

Minor additions to the TZ crank discussion above: the crank pictured (not in the cases) is a 350G - male thread on the ignition end, which removed the problems associated with the female thread being very close to the rotor keyway, sometimes resulting in the end of the crank braking off...

The TZ250/350 cases of that generation also had rubber forward engine mounts, which th RD's did not.

Standing by, FastFee, for your words of wisdom on how to make an old TZ 'fast and reliable' and 'easy to ride'. The 6 port 350 F/G cylinders (no reed valves) were much better in both these respects than the the twinshock sh!tters that I suspect TeeZee was fiddling with..

Ling the dream..living in the past!

[wobbly]

Another thing to add on the RD/TZ cranks is that the aftermarket RZ cranks that are rebuildable can easily be made to fit into
the TZ cases, with some web machining and an offset retaining clip.
Even the 115 long rods will fit to increase the case volume.

[twotempi]

Pressing the pin in from above and then bending the lower end is the tried-and-trusted Yamaha method. But it requires a rather soft steel for the pin, or the bending force might cause loss of press fit in the vertical bore.
310193310194

Emot recently developed a variation on the theme: the pin is pressed in from above, after which the top of the vertical bore is closed by welding.

I have relocated pins without problems. I used the same method as EMOT. Just ensure that the top end of the pin is 1- 2 mm below the piston crown.

The pin was a needle 1.5mm dia out of a little end bearing into a 1.45mm ish hole. You may need to use a mill file to dress off the outside of the piston at the position of the pin after fitting the pin .

[Frits Overmars]

The pin was a needle 1.5mm dia out of a little end bearing. No need to demolish bearings or old pistons in order to obtain pins. One piano or guitar string will provide you with hundreds of pins in any diameter you want.

[peewee]

heres my next question. the yamaha bearings use a small nub on the circumference of the bearing to keep it from spinning. most aftermarket cranks use a oringed bearing to accomplish the same. if roller bearings with a clip in the lower case half are used instead of ballbearings, will the clip and clamping pressure of the cases be enough to keep the bearing from spinning or would each bearing need a clip and a oring ? all my experience has been with single cylinders that use interference fit of the bearing and case. these horizontaly split cases are new to me

[wobbly]

Simple answer is that its easy to fit the clip in the lower half, and a cut O ring piece in the top - problem solved.
Its not so much outer race rotation, its the case fretting caused by cranks that are not dead true that cause all the problems.
If you are not under 0.015mm on all the bearing journals then the crank is a shitter, and should not be used in a race engine.
Over 90% of RD/RZ cases are shagged on the main tunnels due to ( shop ) wankers rebuilding the cranks.
Now you know why Honda refused to sell crank parts for two strokes.

[seattle smitty]

All of you guys will probably know about this. Maybe about 1980 I read an article in "Cycle World" about a wildly exotic (to us) European grand prix roadracer, the water-cooled Morbedelli 125cc twin. As I recall, our 125 racers were pretty much all still using air-cooled Yamaha TA125s (my buddy held a national drag racing record with his TA), and that the Honda single had not yet appeared. How does the Morbedelli compare as a piece of engine technology to the best of today's engines? I remember the chief engineer was named Jorg Muller. The article said that he was on his way to Minarelli. What happened to Muller, is he still active? What became of Morbedelli and Minarelli, and Derbi and the other carriers of the 2-stroke touch? Have many of the old-timers who developed these machines had a hand in designing the new 2-stroke motocrossers from Ossa and KTM and others? Or got into superkarts or sleds or anything? Frits, I expect you knew/know all those guys personally.

[F5 Dave]

Kevin Cameron was the author, you can find his writings in a couple of books TDC & they are a good yarn. Most of the Euro small companies went away with the change to single cyl 125s & the loss of the 50 & 80cc class. More Honda influence if you are a conspiracy theorist (we meet on Thursdays). Derbi of course lives on & almost won a championship with Youichi Ui in about 2000 (to what extent a Derbi. . . but they make small roadbikes for Spanish/Euro market).

[husaberg]

All of you guys will probably know about this. Maybe about 1980 I read an article in "Cycle World" about a wildly exotic (to us) European grand prix roadracer, the water-cooled Morbedelli 125cc twin. As I recall, our 125 racers were pretty much all still using air-cooled Yamaha TA125s (my buddy held a national drag racing record with his TA), and that the Honda single had not yet appeared. How does the Morbedelli compare as a piece of engine technology to the best of today's engines? I remember the chief engineer was named Jorg Muller. The article said that he was on his way to Minarelli. What happened to Muller, is he still active? What became of Morbedelli and Minarelli, and Derbi and the other carriers of the 2-stroke touch? Have many of the old-timers who developed these machines had a hand in designing the new 2-stroke motocrossers from Ossa and KTM and others? Or got into superkarts or sleds or anything? Frits, I expect you knew/know all those guys personally.

I was looking at pics of its cranks the other day.
They look exactly like a KE125 crank doubled up.
The disks seem huge
The Morbidelli from memory had huge disks for the engine size as written in the bell book.
Someone post the Cameron article?

Oh it was the GARELLI 125GP - Angel Nieto 1982
I was looking at.
https://www.facebook.com/media/set/?set=a.296967340505091.1073741929.254890808046078&type=3
Some random's lol
http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=310217&d=1427265013

[Frits Overmars]

about 1980 I read an article in "Cycle World" about a wildly exotic (to us) European grand prix roadracer, the water-cooled Morbedelli 125cc twin... I remember the chief engineer was named Jorg Muller. The article said that he was on his way to Minarelli. What happened to Muller, is he still active? ... Frits, I expect you knew/know all those guys personally.Yes, I know Jörg Möller, the Morbidelli 125 / 250 / 500 cc bikes, and the Minarelli that finally evolved into the 125 cc Garelli twin.
Jörg owns a block of flats in Italy from which he collects the rent. The last time that he was involved with engines lies some years back (the 125 cc CRS kart engine).
I could go on telling stories for days and plaster you guys with pictures; I just don't know where to start. Maybe with a couple of pictures.
310199310200310201310202

[2T Institute]

All of you guys will probably know about this. Maybe about 1980 I read an article in "Cycle World" about a wildly exotic (to us) European grand prix roadracer, the water-cooled Morbedelli 125cc twin. As I recall, our 125 racers were pretty much all still using air-cooled Yamaha TA125s (my buddy held a national drag racing record with his TA), and that the Honda single had not yet appeared. How does the Morbedelli compare as a piece of engine technology to the best of today's engines? I remember the chief engineer was named Jorg Muller. The article said that he was on his way to Minarelli. What happened to Muller, is he still active? What became of Morbedelli and Minarelli, and Derbi and the other carriers of the 2-stroke touch? Have many of the old-timers who developed these machines had a hand in designing the new 2-stroke motocrossers from Ossa and KTM and others? Or got into superkarts or sleds or anything? Frits, I expect you knew/know all those guys personally.

Look up Carlo Mattrozzi on FB he has been making reproductions of MBA 125/350/500 unfortunately just for his own pleasure:niceone:

[peewee]

Simple answer is that its easy to fit the clip in the lower half, and a cut O ring piece in the top - problem solved.
.

thats exactly what ill do. dont know why i cant ever think of this stuff :laugh:

not sure if i showed this pic yet but i had a dummy set of cases and used that brazing rod the fill in the trench then i can redrill the oil hole, just in case theres a problem i wont ruin my good cases. i think its somewhere around 730F to melt that stuff. do you see any problems i may have from doing this ? i wouldnt think it would cause any warp but then again im not sure. i have a dummy crank i can put in the cases and tighten them up to see if it still clamps down fine. what about any problem with the aluminum annealing ? im hoping it will work fine because its far more permanent than epoxy

with the spacer ill be around 1.32 :2thumbsup

[chrisc]

I could go on telling stories for days and plaster you guys with pictures; I just don't know where to start. Maybe with a couple of pictures.

Please do!

Here's an interesting story: First Ever Win for a Japanese Rider the 1963 50cc TT
http://www.2116680.contentys.com/1963-50cc-tt-jap-win.html

Interestingly, in 1962 there were 57 50CC race entries and in 1963 there were only 34, of which only 18 started the race. Noted in that article as being due to the much faster Japanese and German bikes. Hugh Anderson (another brilliant New Zealander) was there on a Suzuki 50. What a cool era of racing that was.

[wobbly]

Trust me, welding the cases the main tunnels will be miles out of round and the deck will be warped to buggery.
Just use Devcon F and score the surface and bead blast clean, the stuff will never come out.
If you are really worried you can wind in several self tapping screws that sit up into the epoxy so it cant move even if the surface grip is lost.

[husaberg]

Trust me, welding the cases the main tunnels will be miles out of round and the deck will be warped to buggery.
Just use Devcon F and score the surface and bead blast clean, the stuff will never come out.
If you are really worried you can wind in several self tapping screws that sit up into the epoxy so it cant move even if the surface grip is lost.

That's how they used to stuff those old Villiers engines crankshaft bobweights.
Skeletons from the closet Wob?

[Grumph]

Yes, I know Jörg Möller, the Morbidelli 125 / 250 / 500 cc bikes, and the Minarelli that finally evolved into the 125 cc Garelli twin.
Jörg owns a block of flats in Italy from which he collects the rent. The last time he was involved with engines lies some years back (the 125 cc CRS kart engine).
I could go on telling stories for days and plaster you guys with pictures; I just don't know where to start. Maybe with a couple of pictures.
310199310200310201310202

thanks for those Frits. Can we assume the barrel marked "campione" was the best ? Practically every combination of transfer ports known to man amongst that lot. Is there an evolution sequence ?
I'm looking at the side on pic of the motor and trying to work out how I can make a similar side cover setup for the Kawasaki....

We actually had a Morbidelli racing in NZ. Dave Moore from Christchurch had it. It was looked after by the well known Dr Bob who produced some very quick kawasaki buckets which probably had Morbo copy porting...Dave took it with him when he moved to Australia and when i saw Bob a few months ago he reported it's in the Aussie National Bike Museum at Bathurst.

[husaberg]

thanks for those Frits. Can we assume the barrel marked "campione" was the best ? Practically every combination of transfer ports known to man amongst that lot. Is there an evolution sequence ?
I'm looking at the side on pic of the motor and trying to work out how I can make a similar side cover setup for the Kawasaki....

We actually had a Morbidelli racing in NZ. Dave Moore from Christchurch had it. It was looked after by the well known Dr Bob who produced some very quick kawasaki buckets which probably had Morbo copy porting...Dave took it with him when he moved to Australia and when i saw Bob a few months ago he reported it's in the Aussie National Bike Museum at Bathurst.

One thing i do know from Google Greg is The covers were bronze because bronze and steel are old mates.
I started to raid the Cameron article from TDC2 but googles is on to me and it doesn't have all the pics in the preview.
Can anyone post up the original Cycleworld article or what issue it was in or the TDC2 article?

Frits will fill us in but I think from memory there was a photo description tucked away on Pitlane.

[senso]

Were Mr. Jörg Möller, Mr. Voskamp and Mr. Jan Huberts all friends?
Their cylinders look like they all came from the same castings.
This was mine a long time ago, its a portuguese copy from the original HuVo kits:

310224

310225

310226

And probably a works pair:

310223

[Frits Overmars]

thanks for those Frits. Can we assume the barrel marked "campione" was the best ? Practically every combination of transfer ports known to man amongst that lot.
Is there an evolution sequence ?Italian is generally an easy language, but not always: campione can indeed mean champion but it can also mean sample, which was probably the case here.
Evolution sequence: not really; most versions are shown, but not in any particular order. The bottom row shows both the first and the last versions.
Bottom left is the original cylinder, and if I'm not mistaken the second-from-right cylinder is the ultimate version. Both are marked 'S' for 'sinistra' but there's nothing sinister about that; it simply means 'left'.

I'm looking at the side on pic of the motor and trying to work out how I can make a similar side cover setup for the Kawasaki.Looking at the past is a good idea but then you'd better look at the best of the flock: Jan Thiels Garelli 125-twin with a straight run of six world titles: 1982-83-84-85-86-87.
310227310228310229310230310231310232

[Frits Overmars]

Here are some drawings to complement the above picture series. Left is the ultimate Garelli 125-twin pipe, right is a dyno comparison between the Garelli 125-twin (yellow) and its descendant, the thirty years younger Aprilia RSA125 single (blue). Solid lines show power, dotted lines show torque.
What made the Garelli invincible was not just the power but just as much the tractor-like torque. Jan Thiel accomplished this without a power valve, without a power jet and without a programmable ignition (we started testing with programmable ignition after the 1987 season).
310233 310234

[Frits Overmars]

Were Mr. Jörg Möller, Mr. Voskamp and Mr. Jan Huberts all friends?
Their cylinders look like they all came from the same castings. This was mine a long time ago, its a portuguese copy from the original HuVo kits.Yes they were. Jan Huberts used to be a works Kreidler rider, Jaap Voskamp and Jörg Möller worked together at Van Veen Kreidler.
Jörg then went to Morbidelli, and Jan and Jaap started the HuVo (Huberts-Voskamp) company. Jörg kept visiting HuVo and prepared engines for his friends.

[senso]

Fantastic information Frits.

Makes me wish there was a book, keeping all that history for future generations, not just about the engines, but the people behind them.

[fatbastd]

Interesting stuff...

Was in a shed of a well-known collector in the UK a month or three ago, and he led me into a little room where he had about half a dozed Morbidellis and a grail twin...plus a set-meatl monocoque early TZ350 (ex-=Tony Rutter and nearly won the Junior TT one year, only to break down close to the finish), several 750's - TZ (several) and TR (2), other small stuff and his favourite - a ROC 500 Yamaha..

Not meany people get into that shed, so I was a bit shy of taking photos..

FB

[Frits Overmars]

Not many people get into that shed, so I was a bit shy of taking photos.Taking photos without asking first is always a bad idea. And I can understand that people do not want it known to the world when they have a valuable collection.
But there won't have been many technical secrets around in that shed anymore, so that would not have been a problem.

In the previous century (and it feels like a century ago) I was a technical editor, always on the look-out for scoops in the GP-paddocks. The Japanese engineers of that era had strict instructions not to let anybody photograph their works machines, so they were understandably nervous when they saw people with cameras.
Once I walked into the Yamaha pit box and the first thing I did was to hand my camera over to the engineer in charge, for him to stow it away so he could have peace of mind.
One day later he called me and I was the only person allowed to photograph the machines without fairing. That is how friendships can start.

[seattle smitty]

Whenever you run into any of those old-timers, tell them that they have a little fan club that stretches around the world, and that we are asking about them and what they are up to these days. And urge them to join this site and tell us about their glory days.

[peewee]

now days im sure its impossible to keep anything a secret. for $35 you can get some glasses with hidden camera :bleh:

http://www.ebay.com/itm/8GB-Mini-HD-720P-Glasses-Spy-Hidden-Covert-Camera-Eyewear-DVR-Video-Recorder-Cam-/151172809018?pt=LH_DefaultDomain_0&hash=item23329a013a

[ken seeber]

NEW FOUR STROKE INNOVATION

A new variable squish, spherical skirt & lightweight piston design


I hope this doesn't mean an end to two strokes !!


310259

[Ocean1]

NEW FOUR STROKE INNOVATION

A new variable squish, spherical skirt & lightweight piston design


Obviously an electrical fault...

[RomeuPT]

Here are some drawings to complement the above picture series. Left is the ultimate Garelli 125-twin pipe, right is a dyno comparison between the Garelli 125-twin (yellow) and its descendant, the thirty years younger Aprilia RSA125 single (blue). Solid lines show power, dotted lines show torque.
What made the Garelli invincible was not just the power but just as much the tractor-like torque. Jan Thiel accomplished this without a power valve, without a power jet and without a programmable ignition (we started testing with programmable ignition after the 1987 season).
310233 310234


125 twin with 47cv at 13600RPM, should have been such a fun little monster :), is there a video anywhere?

[husaberg]

Obviously an electrical fault...

I pick it as being a loose oil fitting just like Raymond Roches at Mansfield that year.:laugh:

[TZ350]

Garelli 125-twin ... What made the Garelli invincible was not just the power but just as much the tractor-like torque.

I hear 2Tempi was poking around in his shed the other day and stumbled across a complete Garelli 125-twin engine. The things that turn up in that blokes shed.:laugh:

[fatbastd]

That shed only has a one way door though!

[F5 Dave]

I pick it as being a loose oil fitting just like Raymond Roches at Mansfield that year.:laugh:

No 's' you plonker.

I was flagging and that happened out of the hairpin just approaching us.

[husaberg]

No 's' you plonker.

I was flagging and that happened out of the hairpin just approaching us.

Would have loved to have seen it that close he carried on for what seemed like a full lap after as well.
He was riding like a man possessed that race.

[senso]

More funny doubts, this time regarding the port-map of an aprilia rs 125(rotax engine) cylinder, this one is the cylinder without the boost ports, I have made a port-map and the single exhaust port measures 42mm maximum width, but going by the 75% convention, 75% of a 54mm bore is just 40.5mm, maybe this explains why so many of this cylinders always seize in the same way, the piston tries to escape through the exhaust port.

I have measured and eye-balled and both the boost + oval exhaust port and the single oval exhaust port cylinder share the same casting, the boost ducts are made with very little space, and in some points they can't have more than 2mm of wall between them and the water jacket.

The port map is attached below, if some one wants to print it, just print at 300dpi and it will have the real size:
310263

[senso]

And some photos, first are the dreaded water circulation holes under/around the exhaust duct, as warned by Frits they have already been drilled to 7mm, much better now(no photo of that yet):
310266

How little room there is to make some big boost port ducts, they use the boss for the screw as extra room, done is casting is easy, but hogging the ducts in a non boost ported cylinder seems like a challenge:
310264

And finally boost port cylinder vs single oval:
310265

310267

[twotempi]

I hear 2Tempi was poking around in his shed the other day and stumbled across a complete Garelli 125-twin engine. The things that turn up in that blokes shed.:laugh:


Not quite true !!

It is a MBA Morbidelli 125 twin but with some important parts missing.

I have a Sanverno gearbox "kitset" but have not confirmed if this will fit. does Frits know if it is the same ??

Also the primary gears are missing. I can reverse engineer this but if any one has any drawings that would help immensely.

[fatbastd]

'Manfeild' would also have 'e' before the 'i', as the name is a contraction of 'Manawatu - Fielding' and that's the correct spelling of Fielding..

[husaberg]

'Manfeild' would also have 'e' before the 'i', as the name is a contraction of 'Manawatu - Fielding' and that's the correct spelling of Fielding..

lol
I found this when trying to find the clip Hailwood.

https://www.youtube.com/watch?v=iyx3FnWK2eM

[Frits Overmars]

It is a MBA Morbidelli 125 twin but with some important parts missing. I have a Sanverno gearbox "kitset" but have not confirmed if this will fit. does Frits know if it is the same ? Also the primary gears are missing. I can reverse engineer this but if any one has any drawings that would help immensely.In case you want to google it, the correct spelling is Sanvenero. And although it's a 125 cc parallel twin, it differs from the Morbidelli, MBA, Minarelli and Garelli twins.
For example the Sanvenero crankshaft is bolted to the upper crankcase half by means of saddles (a bad solution, as it turned out).
But if you need Morbidelli gearbox parts, you don't need to look very far: try Yamaha TZ 250/350 parts; most of those will fit.

[breezy]

Not quite true !!

It is a MBA Morbidelli 125 twin but with some important parts missing.

I have a Sanverno gearbox "kitset" but have not confirmed if this will fit. does Frits know if it is the same ??

Also the primary gears are missing. I can reverse engineer this but if any one has any drawings that would help immensely.

http://www.bonhams.com/auctions/20924/lot/467/

[Dutch Fisher]

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=310107&d=1426766350&thumb=1


Calculated, 1 cylinder.



Calculated ! I'm intrigued

If you don't mind a bit of peer review Frits, pls feel free to publish your variables and their values.

Frits, did you miss my post. You might be interested, I spotted an error (or two)

[Frits Overmars]

If you don't mind a bit of peer review Frits, pls feel free to publish your variables and their values.
Frits, did you miss my post. You might be interested, I spotted an error (or two)Do I mind a bit of peer review? Not at all.
Did I miss your post? No.
Am I interested? Yes.
Can I find the time to discuss the subject? Alas; the racing season has broken out....

[twotempi]

That shed only has a one way door though!

The door opened both ways when you had the use of one of the bikes !!

[TZ350]

Page 1150 .....



But if the engine NEEDS the smaller crankcase volume? And the rsa engine also has smooth crankwebs that do not help stirring?:confused:Edit: okay, if ANY engine needs the smaller crankcase volume? the banshee engine obviously doesn`t need it.

With the RSA/ RSW Most of the volume is concentrated in the transfer ducts. Then there is the volume inside the piston of course, and the 1 mm shear-avoiding clearance at all surfaces of the crank.
But that is not nearly enough volume. If you take another look at the Aprilia crank below, you will notice that the space between the crank webs is the same as the space needed for the big end bearing. In other words: the crank webs have flat insides, good for another 60 cc or so, if I remember correctly.
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Additional benefits: the con rod has an easier time pushing the mixture aside as it moves between the webs, and the big end bearing gets a lot more cooling and lubrication because it is not shrouded in any way.
Because there are no overhung bobweights, the crank webs are stuffed with tungsten to get the balance factor right.
In the RSA125, the con rod was lengthened from the RSW's 115 mm to 120 mm to create even more crankcase volume.

The paddling is a mixed blessing; it creates aerodynamical drag but it also greatly improves the homogenity of the mixture.
Smooth, full-circle crank webs have the advantage that there is little mixture hiding in nooks and crannies. An example of it's importance: in a certain engine there were 20 mm spaces between the crankshaft bearings and the seals. these ill-accessible volumes acted as pneumatic dampers on the crankcase pressure fluctuation. Filling those volumes with plastic bushes gave a measurable improvement.

Summary: you need a large crankcase volume. Ideally all of this volume should be situated in the transfer ducts. In real life you will also need to lodge part of this volume between crankshaft and piston, i.e: use a long con rod. Avoid nooks and crannies. Crankshafts should be small and smooth. Big end bearings must never be shrouded by recesses in the crank webs or by stuffers.

The picture below shows, wait for it, an RSA125-crank with stuffers...
After Jan Thiel went into retirement in 2008, some geniuses at the factory grabbed their chance to 'correct' the errors that Jan left behind, without even testing the result because 'everybody knows the smaller the crankcase volume the better'. But they never could understand why a 2011 RSA125 was slower than a 2007 model (just look at the 125 cc top speeds on any GP-track). O, the joy of working with Italians.....
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Frits Overmars 2012


In theory enclosed cranks are good. Jan Thiel did some experiments at Aprilia with a kart engine that had its reed valve at the front: the incoming mixture had to move against the direction of crank rotation. And although the crankcase stretched over the crank webs, reversing the direction of rotation brought another HP. So the crankshaft does have an influence.
But in practice, if you reduce the distances between crankshaft and crankcase walls to less than 1 mm, the viscous friction of the mixture between the surfaces really costs power at high rpm. And if you make the clearances so tight that lubricating oil can no longer reach the big-end and crankshaft bearings, it will also cost engines
Another negative aspect: any volume with a narrow 'entrance' between the crankshaft and crankcase surfaces acts as an hydraulic damper on the Helmholtz-resonance in the crankcase.
Aprilia has avoided this by making the space between the crank webs as wide as the big-end bearing. As a result the crankcase volume of the 125 cc RSA engine at TDC is about 650 cc,(or 675 maybe) so the exhaust pipe really has some volume to breathe from.


Crank stuffers? An Aprilia RSW125 has a TDC crankcase volume of 650 cc. An RSA125 has 675 cc and a bit more power. See where this is going?

So much for the fairy tale of high crankcase compression

I remember Jan saying that the crankcase volume of the Derbi reed valve engine was even larger than that of the rotary engine. And after Jan had laid his hands on it, that reed valve engine was the strongest 125 cc reed valver ever.
You see, the volumes of the transfer ducts and the volumes between the crank wheels and inside the piston are largely equal, and the volume of the reed cavity is a lot larger than the volume of a rotary inlet duct.

Frits has also mention previously that the Reed Valve Derbi that produced 49 (I think) HP after some work by Jan had an even larger crankcase volume than the RSW and RSA.


A technical explanation? Nah, too much to do today. But since you were kind enough to post that picture of your sex six sisters, I will show some curves of my own.
When Jan Thiel went to Derbi to design the bike we now know as the Aprilia RSA125, he encountered the 125 cc reed valve Derbi ridden by Lorenzo the previous season. Jan played around with the reed valver as well, because he wanted to find out the differences between reed valve and disk valve power. He managed to extract 2 HP more from the reed valver than anyone else had ever done before (never mind the fairy tales of reed valve 125s producing over 50 HP; those Horses must have been Shetland ponies, probably measured at the piston ring).
My graph shows the power curve for the Aprilia RSA, the Aprilia RSW and that best-ever reed valve Derbi. It's not quite in the same league as the rotaries, hmm?

EDIT: Shame on me; I discovered that I posted a wrong graph (and I do not have the correct one at hand here in Holland). Power curve DERBILOR shows the reed valve Derbi as Lorenzo rode it. After Jan finished playing with it, it had 49 HP. Still, the best-ever disk valver produced 10 % more power than the best-ever reed valver.

Well 41 or so of the words are mine. I wonder if there is any job opening for a Physicists secretary. Click on the pics to make them bigger


Husa, thanks for your post. a rotary valve engine needs a big crankcase volume, i know that jan thiel and frits told us many times. but ask wobbly if a reed valve engine also needs the bigger the better crankcase. and the banshee engine IS a reed valver.


For sure bigger case volume is better,but I think Jan Thiel said on pitlane that you need the most of the volume to be on the transfer ducts on the cyl and case transfers,will bigger volume between the crank webs help on BDC??
Plus,can tranfers like the RZ's handle a very big volume in the cases and also a fat Aprilia type exhaust?
Cheers


It has been my experience with many reed engines that do NOT have any where near all the design elements correct ( like the Derby did after Jan )
for making big bmep numbers - that going under 1.3 CCR yields no better power.
As always there is alot more to this than meets the eye, as I have recently done a little more work on a KZ10B kart engine.
I spent hours stripping and machining 5mm off the reed face on the case and enlarged the trenches for the reed block screws to make it fit.
Now this ( my ) engine makes 47 Hp at 13,000 so must have most of the ducks in a row - but it now has a 5 mm spacer behind the reed.
So a blanket statement that claims big cases make more power in reed engines is over simplifying rubbish.
But as part of that test session I fitted some experimental plastic plugs to the piston and ground the Aux around to bore centre with
nice radial pockets on the rear entry walls.
This added 3.8 Hp at 14,000, a 10% increase in power over the stock setup at that rpm - now thats a result.
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Off the pipe you want a reasonably small crank case, on the pipe it almost can't be too big. Assuming a good pipe and port design.
You kind of need dual cankcases volumes.


ok and that spacer BEHIND the reed keeps the intake tuned length correct?


Jan did not enlarge the crankcase volume on the Derbi reed valve engine; it was already big; a reed case has a lot more volume than a rotary valve duct.


True, Neil. Off the pipe you need a pump with the minimum amount of dead volume; on the pipe you'll want the engine to breathe directly from open air (mixed with a bit of fuel and oil). But that oil has to pass through the crankcase to keep the bearings happy. Hence my 24/7-setup


There are several issues involved with the reed engine and its case volume - that has effects not seen in an RV setup.
The bigger the case the less are the pressure swings from piston movement and the pipe action ( assuming the same depression at the Ex port created by the pipe )
around BDC.
This changes the tuned frequency of the case vol, but this also requires thinner reeds to get them open fast and far enough.
Of course changing the reed stiffness then changes the intake tuned frequency,they then hit the reed stops and flutter uncontrollably - and so it goes on and on.
I tried machining the KZ10B case back to make the volume smaller as I already had the 5mm laser cut spacer from a test making the case bigger by pushing the reed block outward.
This failed miserably, so of course you then go the other way - this also failed,but only partially in that I did not then try differing reeds to compensate as I should have.
Adding a spacer behind the reed block HAS NOTHING to do with the intake length, this is already as short as it can be, with the rubber manifold recessed into the reed stuffer.
All I can say is that from a huge amount of sims and real world reed engine testing, that a very well tuned engine with good power capability ( bmep ) likes the case down near 1.3.
An engine with less power ( bmep ) capability ( for whatever reason ) tends to respond better to the case closer to 1.4.
When you are making 8 Bar and or 14 Bar BMEP of course these exceptions to the norm tend to prove the rule of thumb.


Might get to try that soon, the sleeve engine cases are not too far off finished. First I will be running just normal reeds.
You may have seen earlier, LM13 plates well. I've had all my Heat Ranger cylinders done. I sent them an offcut from the casting process to test first. FOS pattern has stalled due to having to get these Heat Ranger engines out.


this is why i was thinking you could stuff the voids near the big end pin (but not shroud the big bearing) on these twin cylinder cranks like the pic i posted, either with carbon fiber, the material that wobbly suggested or simply using plastic like ktm has done for years, then of course just screw the stuffer into the side of the cheek. then the lost volume from stuffing the voids, you can gain that volume back via longer conrod. if my thinking is correct, this would now put all your volume above the crank cheeks and at the transfer entry, rather than have voids down low in the crankcase during the transfer phase. maybe the performance difference wouldnt be much but atleast you would end up with a rod ratio probly around 2.15-2.2 ( just guessing as i havent calculated it), which doesnt seem like a bad thing for high rpm


But by adding the stuffers into the crank you loose more volume than you gain by adding 115 long rods ( that fit straight in )


from my calculations i think your right but who said anything about using 115 rods :cool:. theres even longer rods that fit right in :cool:. might even be something around +120mm that would fit right in, or require just a alittle machine work, i havent looked into this option yet though. just eyeballing the size of the stuffers needed, im guessing somewhere around 120mm is what would be needed to be at 1.33ish, this is just a guess though. i had it written down somewhere but with 64 bore,58 stroke, 118 rod and 513 series piston (standard wristpin location), it was 1.31 if i recall, ill try and find my notes. i do have a crank sitting around i could check the volume of the voids and get a pretty good idea what length of rod would be needed to recoup the stuffer volume, based off my previous calculations. ill have a answer in the next few days as im curious to this


Something Wob I think and Grumph had said about the Reed valve Hondas having the shorter rods with the reed valve engines.

Long vs Short rods

I think (if I have got this right if I haven't the panel will fix it and burn me later at the stake)

Short rods have a higher acceleration rate away from and until about 90 degrees either side of TDC and BDC. This could be an advantage with a reed valve engine.
Conversely after 90 degrees either side of TDC or BDC the longer rod then actually accelerates more but then slows again nearing either side of TDC or BDC. Dwelling for longer.

Honda stuck with shorter rod despite huge amounts of R&D money with I guess was thrown about.
I don't know the rod length of of the Yamaha and Suzuki Cagiva GP500's but none of them seem that long either

Note I believe The longer rod should have less thrust friction as most of the this acceleration occurs with the piston and rod in a more parallel position though.

I note RAW on a Superkart has noticed the carburation is very different when he went to longer rods but I guess the burn will be different and so would be the optimum carb and especially the ignition timing.


I'm sure you've grasped it Husa, but the way it comes out of your keyboard indeed deserves burning. And your and is simply wrong. You might damage the younger brains here!
Short rods have a higher acceleration rate approaching and leaving TDC but a lower rate approaching and leaving BDC. That is all there is to it.
I posted the graph hereunder before, but it may not have sunk in with everybody, so I made an additional sketch.
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When the crankshaft rotates away from TDC, the big end pin pulls the con rod downward. But because the rod also has to sway sideways, the small end drops more than the big end. The sketch (made with MS-Paint, so everyone can understand) shows a crankshaft with a 100 mm stroke, rotated through an angle alpha of about 70°.

On the right there is a 220 mm rod. Because of the swaying the small end has dropped an additional 4,8 mm.
On the left there is a 110 mm rod. Because of the swaying the small end has dropped an additional 9,9 mm, although the angle alpha is the same on both sides of the sketch. It's as simple as that.


Frits, you said that the best rotary valve engine has 10% more power than the best reed valver.

can you also tell us how much better is a case reed engine than a cylinder reed engine (in%)?


Nope. The 10% was not a calculated but a measured value; it was based on Jan Thiel's work with the reed valve and rotary valve Derbis.
I doubt if we can persuade Jan to come out of retirement and start tuning a cylinder reed engine for us (he doesn't like reed engines anyway).


Long rods that affect the case volume then influence the carb tuning dramatically as well.
I did a Rotax 257 single years ago for sprint kart racing, filling the crank webs with that UHWMP stuff.
This raised the case com form down near 1.3 up to about 1.35.
It needed complete rejetting and the main dropped from a 185 to a 165 due to the much stronger signal across the jets.
Going the other way on a 250 tandem twin by fitting long ( 120 ) rods and making full circle ( no pockets ) cranks, the jets then need to be huge
in size by comparison.
Honda used the short rod for years in the customer engines, but when push came to shove the final version used to win the last 250GP title used a long rod, for a reason obviously.
The big reed boxes that design had from day one, gave a relatively big case volume by default.

In my experience if a case reed is done as well as it can be ( look at a TM - KZ10 ) then there is very little difference in power if a cylinder reed
is also done properly with plenty of intake STA via piston cutouts and big Boyesens or floor ports.
The only real difference is that the boost port duct does not have a proper inner wall, and thus the flow regime is not as well controlled.


Nowadays an engine needs a large crankcase volume, all the port area you can cram into the cylinder circumference, good ducts for efficient flow and directional control, an exhaust that sucks and blows hard at the appropriate moments, and cooling, cooling, cooling.

[TZ350]

Well, that was the F4 and F5 Gp and the Tokoroa cup. Lots of great people from all parts of the North Island. Good weather for Saturdays practice, Wild Partying Saturday Night, Rain all night and Sunday morning, drying track late morning with more rain forecast in the afternoon making tyre choice a tricky gamble. Some very brilliant riding, with a spot of bad luck followed by a controversial re-interpretation of what was a pretty clear safety rule, all the drama you could wish for.

All in All a brilliant weekend of racing at a great track.

[NSR143]

Well, that was the F4 and F5 Gp and the Tokoroa cup. Lots of great people from all parts of the North Island. Good weather for Saturdays practice, Wild Partying Saturday Night, Rain all night and Sunday morning, drying track late morning with more rain forecast in the afternoon making tyre choice a tricky gamble. Some very brilliant riding, with a spot of bad luck followed by a controversial re-interpretation of what was a pretty clear rule, all the drama you could wish for.

All in All a brilliant weekend of racing at a great track.

Not sure what the re-interpretation was, none of the officials on the day changed the rule in any way? Damn good weekend though!

[kel]

Not sure what the re-interpretation was, none of the officials on the day changed the rule in any way?
You are taking the piss. The rule was clear, but it seems rules no longer apply. Its now open season in buckets!!!!!!
Your post really pisses me off Steve. The call was bullshit and you know it!

[seymour14]

Not sure what the re-interpretation was, none of the officials on the day changed the rule in any way? Damn good weekend though!

I thought most of us were told in no uncertain terms that bikes would need to be scrutinized if they hit the deck, and we would be marched if we failed to follow those very explicit rules. Not sure that a "made up" penalty was a good result for a blatant mistake. Pretty sure if Regan had hit the deck and then got up and carried on, that the shit would have hit the fan.

It's history now, but plenty more will be said about this I'm sure.

[NSR143]

You are taking the piss. The rule was clear, but it seems rules no longer apply. Its now open season in buckets!!!!!!
Your post really pisses me off Steve. The call was bullshit and you know it!

well well well... out of the frying pan and straight into the toilet. If I(we) thought it bullshit we would not have called it that way would we? I suspect a few people do not have the full facts to hand have misunderstood the situation. I would be happy to explain the full situation if you are interested in listening to it carefully and thoughtfully.

[kel]

well well well... out of the frying pan and straight into the toilet. If I(we) thought it bullshit we would not have called it that way would we? I suspect a few people do not have the full facts to hand have misunderstood the situation. I would be happy to explain the full situation if you are interested in listening to it carefully and thoughtfully.

Toilet or fry pan I couldn't care.
You don't need to explain it, I was there. I saw him go down, I saw him choose not to come in, I saw you guys hand him the trophy. You called it wrong, he should have been black flagged.
Its supposed to be one rule for all Steve. Bad call, very bad call.