ESE's works engine tuner

[Lightbulb]

The latest thing I have been doing is making my own Magneto bearings from standard bearings and using near full complement ceramic balls. A bit trick to get the total end float correct and also getting the correct sized ceramic balls and diameter for the races. The bench testing shows a slight improvement in engine torque as compared to using the regular bearings with cages. Flight testing will be the real tell tail for sure. Also the crank is very free in the case, similar to the restored old engine I did. The case can be rotated, and the crank shaft stays radially stationary. so very happy with that.
Neil

[Frits Overmars]

In reality Mr Hintz is the Da Vinci of our time. Not only does he have the ability to come up with ideas, assemble a group of ideas, then reapplies it to a 2 stroke engine, then he makes it. Some have had their short comings, but by and large Neil has delivered and shown that it is all possible, on a very limited budget and gets results. I think we should be crowd funding Neil as a group. It will be well worth it, even just for the ideas he shares on this forum. If most of us had 1/2 of Neil's enthusiasm for what he is doing , absolutely great things could be achieved.
I would really like to publicly thank Neil for his many contributions and insights to what he is doing, proposes to be doing, and the numerous videos and links he has shared with us all and free of charge I might add. Many people have paid substantially to learn less than what Neil has shared.
Neil Lickfold another engine enthusiast.
+1
And I don't think his knees are all that ugly, Wob :p.

[nasone32]

Frits did you have the resources to develop the FOS system further? (time is a resource too :) )
or, do you know of someone who had some interesting results?

[Muciek]

Here's one video (even Frits is there :D )
(go to 4:38)

https://www.youtube.com/watch?v=uj-DqT0l7O0&feature=youtu.be&t=278

I have seen other video from that event and engine had like 14 15hp (video was taken down later). Frits does the owner made any more power with it? We also have onboard LucF and he's also working with system like this maybe he can share some info?

[husaberg]

Here's one video (even Frits is there :D )
(go to 4:38)

https://www.youtube.com/watch?v=uj-DqT0l7O0&feature=youtu.be&t=278

I have seen other video from that event and engine had like 14 15hp (video was taken down later). Frits does the owner made any more power with it? We also have onboard LucF and he's also working with system like this maybe he can share some info?

They like their Beer cold i am guessing.........
It was 39C degrees here on Sunday.;)

[Frits Overmars]

Frits did you have the resources to develop the FOS system further? (time is a resource too :)) or do you know of someone who had some interesting results?You're damn right about time being a resource Nasone. Other projects got in the way. Among the persons occupying themselves with the FOS system at the moment I think Flettner is the one to watch. He has enhanced it (or bastardized it, as he calls it) with variable timing for both the transfer ports and the exhaust ports. It might remedy the typical two-stroke torque dip.

[Frits Overmars]

As you will know, A Non Disclosure Agreement prohibits me to comment on the Ryger situation.
All I can say is: thank you for the heart-warming reactions on the previous pages :niceone:.

[breezy]

Frits, ive just re-read a facebook article by Luc Foekema about reducing ignition spark energy( by 50%) at high rpm (11,000 rpm) showing an increase in rpm . He surmised that this showed the exhaust system was not optimised for the tuning of the engine. This i assume would be a good test for the exhaust system?. Would you think that having an exhaust system that was optimised for 15000rpm attached to an engine with was tuned for optimum power at 18000rpm could therefore still be used by being able reduce the power to the ignition system at high rpm bringing the exhaust up to the engine design rpm. i wonder if the ignition could in fact be turned off completely to enable this. perhaps even a sliding exhaust sysyem used..

[Frits Overmars]

Luc is part of the Ryger organisation, so no comment.

[Muciek]

I was talking about FOS/FST not Ryger. About that ignition power there was also talk here or pitlane (can't remember) , someone got flat battery in TZ250 and on lower voltage there was power gains.

[breezy]

I was talking about FOS/FST not Ryger. About that ignition power there was also talk here or pitlane (can't remember) , someone got flat battery in TZ250 and on lower voltage there was power gains.

i think that it was a good indicator as to the incorrect exhaust design for the engine, tuned length to long i think was discovered.

[MotleyCrue]

seems your the only one talking. wobbly, tz350, me and a lot of other folks been working on all kinds of projects. plenty of photos around in case your memory needs refreshed

I don't mind looking at pics and hearing about projects, but I didnt realize that show and tell was a prerequisite to participation in this thread. I thought discussion of ideas in a nonoffensive manner would suffice. Not everybody has the same background or life situation, I cant race because of health reasons and I very rarely have a moment to work on a 2 stroke currently because my life is currently fully consumed with other work. Doesnt make 2 strokes any less interesting and the day will come when I either have time to devote to it or time will have run out.

[WilDun]

I don't mind looking at pics and hearing about projects, but I didnt realize that show and tell was a prerequisite to participation in this thread......... I very rarely have a moment to work on a 2 stroke currently because my life is currently fully consumed with other work. Doesnt make 2 strokes any less interesting and the day will come when I either have time to devote to it or time will have run out.

I can understand that, only time, health and financial constraints stop me from doing the things I really want to do, but as you say I shouldn't be put in the bin because I don't produce anything tangible -
I have been interested in two strokes since the MZ racers came on the scene and have been interested ever since, I am also interested in the associated engineering involved with them and have a lot of years experience in machining.
Many of us have ideas (some impossible of course) which we would like to share, seeing that time is running out for us.
Any ideas, which might inspire others should be encouraged in this thread, rather than be rejected.
We like two strokes and like to take part in (or read) discussions about them as well but it seems that some (at least 3) people would like to see us excluded because we don't contribute something in metal.

For you you anti guys ..... will come the day!

[peewee]

your correct. I don't believe the rules state that photos are required to join. but if this place isn't meeting your expectations and theres to much talk, why bother hanging around. surely there must be a hundred or more other 2t sites out there

[WilDun]

your correct. I don't believe the rules state that photos are required to join. but if this place isn't meeting your expectations and theres to much talk, why bother hanging around. surely there must be a hundred or more other 2t sites out there

No need to go that far!
Best if everyone can share views as well as photos.
Criticism of others' views needs to be kept in check though, if you have got any sound and logical reason to disagree with someone, then state what it is and the other posters can be the judge ...... or perhaps better just to leave it and it will sort itself out.

[MotleyCrue]

but if this place isn't meeting your expectations and theres to much talk, why bother hanging around. surely there must be a hundred or more other 2t sites out there

Ummm... what you have written there makes little to no sense.

This place has always met my expectations, and then some, but from your earlier comments it is clear that I AM NOT MEETING YOUR EXPECTATIONS.

And as for "too much talk", whoever said there was too much talk, certainly not me, I want to talk, and listen, I just have nothing worthwhile to add in the way of pictures, currently.

Cant get much simpler or clearer than that.

[wobbly]

The real issue is that those who have perfectly sound and logical reasoning behind a belief or statement that is published on here,find quite quickly that most of
those who then disagree, simply cant provide a sound and logical reasoning for THEIR position.
So what do they do - invoke a validation of themselves by promulgating a personal attack.
There is no real defense against this " flaming " as its called, except to lower oneself to that level, or walk away.
I tried both a while back, and got no satisfaction from either.
What do we do then - TeeZees wisdom sorted my shitfight out, but he cannot be responsible for everyone on here can he ?
Narcissistic as I undoubtedly am,I dont even begin to have an answer in this case.

[WilDun]

The real issue is that those who have perfectly sound and logical reasoning behind a belief or statement that is published on here,find quite quickly that most of those who then disagree, simply cant provide a sound and logical reasoning for THEIR position.

....... except to lower oneself to that level, or walk away.
I tried both a while back, and got no satisfaction from either.

....... I dont even begin to have an answer in this case.

Walking away from an argument takes guts and is the lesser of the two evils!

Think I need to start plodding on in my workshop again, it has been silent for some time! :bye:

[MotleyCrue]

As far as I am concerned:

1) I made a suggestion for discussion a page or two back

2) Wobbly gave me his polite and detailed technical response

3) The OP indicated he didn't really want the discussion to happen in this thread

4) I indicated to the OP why I thought the discussion would be fine but agreed to stand down as it was of course the OP's thread

End of story.

[peewee]

hey wob I did a bunch of welding recently and wondered if you've found a way to keep distortion to a very minimum ? my machine has pulse function but I haven't bothered to try it yet but I wonder if that may help. ive put items in the oven after I was done welding so they didn't cool rapidly but I cant say for sure if this helped or not. also I heard pinging the weld with a small hammer could help but I haven't tried it yet

[F5 Dave]

Have you tried dirty big torque plates? Will suck heat out till they warm up. Erm, citation needed as they say on wiki. Let's see if I can repost an old pic using the tablet.

Ahh crap, didnt work. - big chunks of steel bolted top and bottom of barrel clamping together. Might help integrity.

[peewee]

I use clamping fixtures when ever possible as they help hold its shape and can provide some what of a heat sink but its not always possible to use such fixtures. I think this weekend ill give the pulse a try as ive heard quit a few times that it can help with distortion.

welded some alloy bungs not long ago and they ended up like eggs afterwards :facepalm:. I think what I did wrong is I tried to weld continuously around the circumference. what I probly should of done was put four tack welds at 3-6-9-12 oclock positions then just weld alittle at a time . going from 12 to 6 to 3 to 9 if that makes sense. then maybe the pulling force from each side of the bung would be more evened out

[Lightbulb]

This has got to be one of the best threads about engines. There have been some really good thought provoking conversations.
There have also been some of the dumbest shit posted as well. But lucky for me, I can ignore that stuff and then concentrate on the
good oil that is being freely shared by so many.
Photo's and other things that are posted are just as valuable as someone's insight to some theory that could be the difference in winning
or being an also ran.

[jasonu]

hey wob I did a bunch of welding recently and wondered if you've found a way to keep distortion to a very minimum ? my machine has pulse function but I haven't bothered to try it yet but I wonder if that may help. ive put items in the oven after I was done welding so they didn't cool rapidly but I cant say for sure if this helped or not. also I heard pinging the weld with a small hammer could help but I haven't tried it yet

You can get good results by 'pulsing' the pedal (I am assuming you are tig welding). If done correctly your weld will look like a stack of pennys pushed over.

[F5 Dave]

I probably qualified as at least equal smartest guy on page 1 of this threat. Think I've been relegated to dumbshit by now, but we're all enjoying where this goes.

[wobbly]

Pulsed TIG will do nothing much to help distortion.
What it does do is allow you to use a higher base amperage to speed up the M/min welding rate and not create holes or
a big lumpy mess on the inside of a pipe for example.
The jump in amps allows you to move quickly, then the amps drop off, stopping the weld pool from getting to large.
It creates the scallop effect without you having to pulse the pedal, or move the tungsten back and forth to make a "pattern ", that looks nice.
Cold wire over TIG is by far the best method to weld thin sheet, but is idiotically expensive, and takes alot of slow practice to master.

[chrisc]

I probably qualified as at least equal smartest guy on page 1 of this threat. Think I've been relegated to dumbshit by now, but we're all enjoying where this goes.

Agreed. Feel like a 12 year old when reading some of these posts haha. However, I feel like after reading this thread more times than I'm embarrassed to say, I feel like I have a really strong theoretical knowledge of race 2 strokes. But I have stuff all practical modifying experience so far. Hoping my RSGP125 bucket will teach me more practically. For now I'm just hyped to be a part of one of the best lectures on tuning on the internet!

As one of the many side discussions going on in this thread:
Suggestions on a very good base motor for a freetech 50 bike? The Derbi 50 and AM6 are common but there has to be better alternatives?
50cc, 6 gears, unleaded fuel, no super to turbos, pretty simple rules really. Maybe a MX engine?
Frits, Wob any suggestions?

[seattle smitty]

Peewee, you asked about peening the bead (you wrote "pinging" but I assume you meant what I know as peening), and yeah, that's always a stress reliever (though it is unlikely to remove visible distortion). The metallurgists say you want to mostly concentrate on the outer edges of the bead, more than the center of it. There's a device called a needle-scaler, usually air-powered though sometimes electric, which is ordinarily used mainly for fast removal of slag during stick-welding. But if you take the needles out and round off their working ends, the tool then becomes good for bead-peening.

You're right about sequencing the weld, and dividing the circle into four (eight, if there's room) segments and welding them criss-cross fashion, another technique worked out long ago by the metallurgists.

You're having a blast with that new TIG machine; cool!!!! I can't say anything from personal experience about pulse and so forth, because my poor old transformer TIG welder pre-dates not only inverters but square-wave, too. :oi-grr:

[husaberg]

I probably qualified as at least equal smartest guy on page 1 of this threat. Think I've been relegated to dumbshit by now, but we're all enjoying where this goes.

threat?:killingme

[adegnes]

Suggestions on a very good base motor for a freetech 50 bike? The Derbi 50 and AM6 are common but there has to be better alternatives?
50cc, 6 gears, unleaded fuel, no super to turbos, pretty simple rules really. Maybe a MX engine?
Frits, Wob any suggestions?

Newer Ktm sx50 has a great engine, probably expensive.

[adegnes]

threat?:killingme
:killingme A 1500 page long threat

[F5 Dave]

Ahh shit, hp tiblet spill chucker.

[husaberg]

Newer Ktm sx50 has a great engine, probably expensive.


:killingme A 1500 page long threat

There is quite a few around, they will be cheaper here when they bring in a new updated design. The SX50 cylinders bolt on to KTM65 bottom end giving you a triple port case reed in a modern configuration. The Std KTM50SX is a slipper clutch one speed. (It would probably faster around a Kart kart as an slipper auto though)

[cotswold]

Newer Ktm sx50 has a great engine, probably expensive.

the combo getting a bit of a fan base in the UK freetech is KTM65 bottom end with KTM50 cylinder, lots of easy horsepower to be had.

Beaten by Husa as usual

[husaberg]

the combo getting a bit of a fan base in the UK freetech is KTM65 bottom end with KTM50 cylinder, lots of easy horsepower to be had.

Beaten by Husa as usual

I forgot to add the earlier KTM50's 2002-2008 cylinders mount onto the corosponding earlier (BETA) engines KTM65 as well, there are plenty of them about as they are not the latest model anymore.
They both have the neatest tiny sellectra ignition.
319495319496

[RAW]

Things to minimise ( not stop distortion )
Pre-heating of the base item / items - this minimises the heat differential between the base & weld metals, thus the shrinkage upon solidification of the weld is reduced along with a massive reduction in shrinkage stress, the stuff that make thing break for no apparent reason.
Jigs & fixtures, these restrain the job / items in place whilst the shrinkage of the solidifying weld / welds attempt to pull / distort the job
Small size weld beads - ie use a 3mm width weld instead of a 6mm wide weld bead, this benefits in several ways,
smaller weld beads = less heat, less distortion, yes you will need to do more weld passes but, each subsequent weld will have a nornalizing / stress relieving effect upon the previous weld if performed correctly. such as heat input, wait until the item has returned to you're initial preheat temperature before you run your next weld, before this next weld you should peen along the toes of the preceding weld bead, this is the area of most joint restraint/ shrinkage stresses
Slow cooling - preferably in a controlled manner / oven. If you have not completed the job but intend to take a break it goes in the oven to either cool out slowly or be held at the chosen preheat temperature for works to continue on.
These are the easy bits. The hard parts are how shapes, differing thicknesses, ambient temperature, draughts, etc etc effect the process / all of the above, this can not be explained here & only a really good operater even acknowledges this stuff & caters for it,
A back yarder just dose not have the EXPERIENCE, however nor does most others.
Just one more thing to think about.
Distortion or Shrinkage Stresses, what is the greater evil & how do you manage it to your advantage
Hope this helps.

[TZ350]

Page 1470 ...... there has got to be some stuff in the last ten pages worth collecting here.



As it stands I wouldnt use a Wiseco if they gave them away.
I've heard this a million times from different sources but I haven't heard a good explanation. What is the reason they suck ? They have been in business a long time and still sell lots of pistons, is it just certain applications they aren't good for ?


I used to buy a Wisco piston for my 350 Kawasaki, it was a prolite type, cost a bit too but it did the job. After a few pistons used (ordered on the same part number), a standard pistons turned up, not prolite, same price. Wisco said "get stuffed" thats all we will supply now and you will have to pay the same price, to bad. So I turned them into prolite myself with the milling machine. Then I find Wossner, only make prolite type, cheaper, available without waiting and seem to work well. I can order them from the factory in lots of ten, even cheaper still! Won't catch me dealing with Wisco again until they change their attitude, and make a decient product again.


The Wiseco Prolite range was a big step forward for the company, where they finally changed the forging material.
But the bottom line still is that they will 4 corner seize instantly if run at the minimum clearance recommended, and if run even slightly loose
they rock badly in the bore ( alot of taper,top to bottom ) then shrink insanely.
This then of course doesnt help the ring stay true in the bore and you quickly get blowby darkening the area under the groove.
Recently ( last 18 months ) the company has been groomed for corporate takeover.
The cash its worth comes down to the bottom line profit margin on sales, so they have deleted nearly all CNC ops on the basic forging.
The pistons are now way heavyer,more expensive and still have the issues explained above.
They used to do small run specials,but are now not interested.
Not even close to a Wossner in any respect.


Whilst I respect Wob's experience with Wiseco pistons, and agree broadly with what he's saying, I suspect the target market for Wiseco now is mainly 4T pistons. I've used a lot of their 4T forged pistons over the years and will continue to use them as long as the price stays reasonable.

I'd also suspect that Wossner and others have seen a vulnerability in the 2T market where Wiseco is concerned and jumped in with a more up to date product.
Fair enough, that's the American way of business. As consumers we should be aware of it and take advantage.


Are there any extra requirements (for a basic TIG welder) to enable aluminium welding to be done?
eg I remember being told way back that the old welders required a high frequency unit (AC I guess) and it was necessary to use a flat tip on the tungsten electrode, but I never see any of that mentioned these days, - I've really got behind here!


Over the years, I have funded my addiction (hydroplane racing) by welding. A few hints for welding aluminum that may or may not help...

In the US they sell an automotive cleaner called Superclean. Purple squeeze bottle. I run the hot water in kitchen sink and get it as hot as it will go. Shut the water off, put the part in the sink and spray it down with Superclean. Only let is soak for a minute or so. Then spray it with the hottest water you can. Works great. Do not ever use brake clean / carburetor cleaner to clean parts prior to welding. Bad gasses are created and bad things happen to the guy welding.

Complex casting repairs / additions are going to warp. Simple fact of life. If you are building parts to add on, leave stock to machine off. If you are going to have to machine a surface near where you are welding, run a bead on it.

Peening the weld makes the weld material denser / stronger. More like billet than cast. One of the places I use this is, is on cracked lower units on outboards. I have found that by peening the weld on both sides of the skeg, the repair lasts far longer. I use a simple air chisel set up like used for cutting off automotive mufflers. I cut up one of the chisels and sanded a big radius on it. The other place I use it is when the weld bead is on a mating surface. Machines much better.

Most aluminum repairs that require structural strength, you just have to preheat the whole thing, weld it and let it cool off slowly. I have used my wife's oven for years, but recently have switched over to using our gas grill on our back deck. Put the part in, turn it on and when it gets up to 350-400 F pull it out and weld it. Then throw the part back on the grill and turn it off.

DC straight polarity and medical grade helium works. All the Top Fuel Dragster blocks are repaired with this set up. No pre heat and you can penetrate over 1/2" with no weld prep. The helium and regulator is not cheap, but it works.

Take an HW-20 torch and using silicon carbide wheel (green) on a bench grinder, shorten the gas lens as much as you can. Then take the shortest "tail" and cut it down to about 1/4" long. Use some good 2 part epoxy to fill in the hole where the tungsten goes. Use about 1" long tungsten and you can get down inside a 125 cylinder. Not an easy job, but worth the effort.

Heat treating aluminum works. Most billet is heat treated to a T-6 condition. After you weld it, it goes back to T-0 (dead soft / weak) Having it heat treated back to T-6 is huge. In the US it is very expensive to have a single piece heat treated because of the time it takes. I have found that by going to a foundry that does their own heat treating, you can get parts done for far less money.

Steel, stainless and titanium you can get away with welding "cold". Weld a short bead (1/2") and let it cool back to room temperature. I even use compressed air to cool then off between beads.

Hope this helps a few of you. Again, this just a great thread / website for two stroke races.


Thanks Yow Ling / Wobbly, for the info, video etc. I will have to spend some time digesting it all.
A whole new world for me, I bought a small 160 welder about 2 years ago but had no idea of the cost of Argon (it was a bargain and that's all I could see at the time!) - now I have Argon I'm just setting up to learn it all from scratch, but I'm a pensioner and it will be a limited effort of course. I do want to try my hand at pipes as well as casting ally + machining (which I know) - no need to specialise in anything anymore as it's all a hobby and not for profit just very interested in all the processes. - still trying your hand at casting Yow Ling?

It's all learning at the moment, no particular project to work on but that's not the way I want to be in the future.
Good thread and I am learning - well at least as much as I am able to digest, much of it goes over my head! :laugh:


Yes, cold wire over TIG has a small wire feeder that runs a spool of the filler thru a sheath that clamps to the top of your torch.
The normal TIG tungsten heats the weld pool and then the wire is fed into this pool.
Thus if you run the spool very slowly a tiny seam of weld is created, and this will easily fill small gaps,or ripples in the segments where they are not
aligned well.
Here is a pic of a stainless pipe I did with that gear.
The segment seams are normal tig, with the cut joints you can see the tiny raised bead.
I sold the setup, as I only really got the feeder to do Ti pipes for the factory teams I worked for, and both Ti and stainless take so long to roll/form/hand work
into segments that its impossible to charge out the time and make any money from the exercise ( unless you work for a cup of rice a day in Thailand ).
Also you MUST use Argon purge inside the pipe as its made ,and Argon isnt cheap enough now to use huge amounts of it.
The factory team engineers use an argon filled chamber, and weld the pipes inside this box with sealed gloves thru the front and a plexiglass lid.


Hi Will , it seems to be TIG with a wire feeder
In the case of an automatic supply a distinction is made between hot wire feeding and cold wire feeding. When feeding cold wire, the filler material is led to the welding spot without current and molten in the arc of the main process. So the TIG process creates very high-quality, spatter-free weld seams.

https://www.youtube.com/watch?v=Lvi8nyXEsCU


ya i have a oven for cylinders and small stuff. yesterday i seen a video and distortion on a flat plate was reduced alot by increasing travel speed


Wobbly,
What is the "cold wire over TIG" you mention?
Just starting out on TIG and need to understand the different processes etc.


Things to minimise ( not stop distortion )
Pre-heating of the base item / items - this minimises the heat differential between the base & weld metals, thus the shrinkage upon solidification of the weld is reduced along with a massive reduction in shrinkage stress, the stuff that make thing break for no apparent reason.
Jigs & fixtures, these restrain the job / items in place whilst the shrinkage of the solidifying weld / welds attempt to pull / distort the job
Small size weld beads - ie use a 3mm width weld instead of a 6mm wide weld bead, this benefits in several ways,
smaller weld beads = less heat, less distortion, yes you will need to do more weld passes but, each subsequent weld will have a nornalizing / stress relieving effect upon the previous weld if performed correctly. such as heat input, wait until the item has returned to you're initial preheat temperature before you run your next weld, before this next weld you should peen along the toes of the preceding weld bead, this is the area of most joint restraint/ shrinkage stresses
Slow cooling - preferably in a controlled manner / oven. If you have not completed the job but intend to take a break it goes in the oven to either cool out slowly or be held at the chosen preheat temperature for works to continue on.
These are the easy bits. The hard parts are how shapes, differing thicknesses, ambient temperature, draughts, etc etc effect the process / all of the above, this can not be explained here & only a really good operater even acknowledges this stuff & caters for it,
A back yarder just dose not have the EXPERIENCE, however nor does most others.
Just one more thing to think about.
Distortion or Shrinkage Stresses, what is the greater evil & how do you manage it to your advantage
Hope this helps.


Peewee, you asked about peening the bead (you wrote "pinging" but I assume you meant what I know as peening), and yeah, that's always a stress reliever (though it is unlikely to remove visible distortion). The metallurgists say you want to mostly concentrate on the outer edges of the bead, more than the center of it. There's a device called a needle-scaler, usually air-powered though sometimes electric, which is ordinarily used mainly for fast removal of slag during stick-welding. But if you take the needles out and round off their working ends, the tool then becomes good for bead-peening.

You're right about sequencing the weld, and dividing the circle into four (eight, if there's room) segments and welding them criss-cross fashion, another technique worked out long ago by the metallurgists.

You're having a blast with that new TIG machine; cool!!!! I can't say anything from personal experience about pulse and so forth, because my poor old transformer TIG welder pre-dates not only inverters but square-wave, too. :oi-grr:


Pulsed TIG will do nothing much to help distortion.
What it does do is allow you to use a higher base amperage to speed up the M/min welding rate and not create holes or
a big lumpy mess on the inside of a pipe for example.
The jump in amps allows you to move quickly, then the amps drop off, stopping the weld pool from getting to large.
It creates the scallop effect without you having to pulse the pedal, or move the tungsten back and forth to make a "pattern ", that looks nice.
Cold wire over TIG is by far the best method to weld thin sheet, but is idiotically expensive, and takes alot of slow practice to master.


You can get good results by 'pulsing' the pedal (I am assuming you are tig welding). If done correctly your weld will look like a stack of pennys pushed over.


I use clamping fixtures when ever possible as they help hold its shape and can provide some what of a heat sink but its not always possible to use such fixtures. I think this weekend ill give the pulse a try as ive heard quit a few times that it can help with distortion.

welded some alloy bungs not long ago and they ended up like eggs afterwards :facepalm:. I think what I did wrong is I tried to weld continuously around the circumference. what I probly should of done was put four tack welds at 3-6-9-12 oclock positions then just weld alittle at a time . going from 12 to 6 to 3 to 9 if that makes sense. then maybe the pulling force from each side of the bung would be more evened out


hey wob I did a bunch of welding recently and wondered if you've found a way to keep distortion to a very minimum ? my machine has pulse function but I haven't bothered to try it yet but I wonder if that may help. ive put items in the oven after I was done welding so they didn't cool rapidly but I cant say for sure if this helped or not. also I heard pinging the weld with a small hammer could help but I haven't tried it yet

[lodgernz]

Aren't the KTM SX65 and SX50 motocross bikes? That would invalidate them from buckets. I don't know about Freetech50 though. Might be legal there.

[Frits Overmars]

Those who have perfectly sound and logical reasoning behind a belief or statement that is published on here, find quite quickly that most of those who then disagree, simply cant provide a sound and logical reasoning for THEIR position. So what do they do - invoke a validation of themselves by promulgating a personal attack. There is no real defense against this " flaming " as its called, except to lower oneself to that level, or walk away. I tried both a while back, and got no satisfaction from either.Wob, I don't feel that 'most of those who then disagree' resort to flaming. But I agree that it can be annoying, although I have nothing to complain about, compared to what you have to put up with.
Whatever your approach, there is no satisfaction to be found in the way you handle the situation. But I try to look upon it as an opportunity to work on my character. Walking away or ignoring the aggro can be considered Zen. Lowering oneself to the level of the flamers would be like barking back at a dog that barks at you: daft.


Aren't the KTM SX65 and SX50 motocross bikes? That would invalidate them from buckets. I don't know about Freetech50 though. Might be legal there.[/Yes, those KTMs are MX-bikes. By the way, KTM prefers to mention an engine's cylinder capacity first and its intended use second: 65SX instead of SX65.

A KTM 65SX with a 50SX-cylinder (smaller bore, same stroke) is a good tool for 50 cc racing. One drawback: it has no balance shaft, so the way you mount the engine will influence the life span of the frame, the functioning of the carburettor and the amount of numbness in the rider's hands and feet.
The latter may sound futile, until you've experienced the difference between engines without and with a balance shaft. Vibration costs concentration.

Freetech is like the name says: almost anything goes. Nitro is a no-no but if you want to play with a 50 cc V-8, a 40 mm carburettor, a twelve-speed gearbox, a variomatic or a turbo, go ahead. For a turbo the total cubic capacity should not exceed 25 cc though.
But if you look at ancient Formula 1 engines (1500 cc BMW 4-cylinder with 1350 hp during qualifying) a blown 25 cc foul-stroke could become a real thread. Eh, threat.

[WilDun]

Cold wire over TIG is by far the best method to weld thin sheet, but is idiotically expensive, and takes alot of slow practice to master.

Wobbly,
What is the "cold wire over TIG" you mention?
Just starting out on TIG and need to understand the different processes etc.

[peewee]

Things to minimise ( not stop distortion )
Pre-heating of the base item / items - this minimises the heat differential between the base & weld metals, thus the shrinkage upon solidification of the weld is reduced along with a massive reduction in shrinkage stress, the stuff that make thing break for no apparent reason.
Jigs & fixtures, these restrain the job / items in place whilst the shrinkage of the solidifying weld / welds attempt to pull / distort the job
Small size weld beads - ie use a 3mm width weld instead of a 6mm wide weld bead, this benefits in several ways,
smaller weld beads = less heat, less distortion, yes you will need to do more weld passes but, each subsequent weld will have a nornalizing / stress relieving effect upon the previous weld if performed correctly. such as heat input, wait until the item has returned to you're initial preheat temperature before you run your next weld, before this next weld you should peen along the toes of the preceding weld bead, this is the area of most joint restraint/ shrinkage stresses
Slow cooling - preferably in a controlled manner / oven. If you have not completed the job but intend to take a break it goes in the oven to either cool out slowly or be held at the chosen preheat temperature for works to continue on.
These are the easy bits. The hard parts are how shapes, differing thicknesses, ambient temperature, draughts, etc etc effect the process / all of the above, this can not be explained here & only a really good operater even acknowledges this stuff & caters for it,
A back yarder just dose not have the EXPERIENCE, however nor does most others.
Just one more thing to think about.
Distortion or Shrinkage Stresses, what is the greater evil & how do you manage it to your advantage
Hope this helps.

ya i have a oven for cylinders and small stuff. yesterday i seen a video and distortion on a flat plate was reduced alot by increasing travel speed

[Yow Ling]

Wobbly,
What is the "cold wire over TIG" you mention?
Just starting out on TIG and need to understand the different processes etc.

Hi Will , it seems to be TIG with a wire feeder
In the case of an automatic supply a distinction is made between hot wire feeding and cold wire feeding. When feeding cold wire, the filler material is led to the welding spot without current and molten in the arc of the main process. So the TIG process creates very high-quality, spatter-free weld seams.

https://www.youtube.com/watch?v=Lvi8nyXEsCU

[wobbly]

Yes, cold wire over TIG has a small wire feeder that runs a spool of the filler thru a sheath that clamps to the top of your torch.
The normal TIG tungsten heats the weld pool and then the wire is fed into this pool.
Thus if you run the spool very slowly a tiny seam of weld is created, and this will easily fill small gaps,or ripples in the segments where they are not
aligned well.
Here is a pic of a stainless pipe I did with that gear.
The segment seams are normal tig, with the cut joints you can see the tiny raised bead.
I sold the setup, as I only really got the feeder to do Ti pipes for the factory teams I worked for, and both Ti and stainless take so long to roll/form/hand work
into segments that its impossible to charge out the time and make any money from the exercise ( unless you work for a cup of rice a day in Thailand ).
Also you MUST use Argon purge inside the pipe as its made ,and Argon isnt cheap enough now to use huge amounts of it.
The factory team engineers use an argon filled chamber, and weld the pipes inside this box with sealed gloves thru the front and a plexiglass lid.

[WilDun]

Hi Will , it seems to be TIG with a wire feeder
So the TIG process creates very high-quality, spatter-free weld seams.


Yes, cold wire over TIG has a small wire feeder that runs a spool of the filler thru a sheath that clamps to the top of your torch............
Also you MUST use Argon purge inside the pipe as its made ,and Argon isnt cheap enough now to use huge amounts of it.


Thanks Yow Ling / Wobbly, for the info, video etc. I will have to spend some time digesting it all.
A whole new world for me, I bought a small 160 welder about 2 years ago but had no idea of the cost of Argon (it was a bargain and that's all I could see at the time!) - now I have Argon I'm just setting up to learn it all from scratch, but I'm a pensioner and it will be a limited effort of course. I do want to try my hand at pipes as well as casting ally + machining (which I know) - no need to specialise in anything anymore as it's all a hobby and not for profit just very interested in all the processes. - still trying your hand at casting Yow Ling?

It's all learning at the moment, no particular project to work on but that's not the way I want to be in the future.
Good thread and I am learning - well at least as much as I am able to digest, much of it goes over my head! :laugh:

[mike schmidt]

Over the years, I have funded my addiction (hydroplane racing) by welding. A few hints for welding aluminum that may or may not help...

In the US they sell an automotive cleaner called Superclean. Purple squeeze bottle. I run the hot water in kitchen sink and get it as hot as it will go. Shut the water off, put the part in the sink and spray it down with Superclean. Only let is soak for a minute or so. Then spray it with the hottest water you can. Works great. Do not ever use brake clean / carburetor cleaner to clean parts prior to welding. Bad gasses are created and bad things happen to the guy welding.

Complex casting repairs / additions are going to warp. Simple fact of life. If you are building parts to add on, leave stock to machine off. If you are going to have to machine a surface near where you are welding, run a bead on it.

Peening the weld makes the weld material denser / stronger. More like billet than cast. One of the places I use this is, is on cracked lower units on outboards. I have found that by peening the weld on both sides of the skeg, the repair lasts far longer. I use a simple air chisel set up like used for cutting off automotive mufflers. I cut up one of the chisels and sanded a big radius on it. The other place I use it is when the weld bead is on a mating surface. Machines much better.

Most aluminum repairs that require structural strength, you just have to preheat the whole thing, weld it and let it cool off slowly. I have used my wife's oven for years, but recently have switched over to using our gas grill on our back deck. Put the part in, turn it on and when it gets up to 350-400 F pull it out and weld it. Then throw the part back on the grill and turn it off.

DC straight polarity and medical grade helium works. All the Top Fuel Dragster blocks are repaired with this set up. No pre heat and you can penetrate over 1/2" with no weld prep. The helium and regulator is not cheap, but it works.

Take an HW-20 torch and using silicon carbide wheel (green) on a bench grinder, shorten the gas lens as much as you can. Then take the shortest "tail" and cut it down to about 1/4" long. Use some good 2 part epoxy to fill in the hole where the tungsten goes. Use about 1" long tungsten and you can get down inside a 125 cylinder. Not an easy job, but worth the effort.

Heat treating aluminum works. Most billet is heat treated to a T-6 condition. After you weld it, it goes back to T-0 (dead soft / weak) Having it heat treated back to T-6 is huge. In the US it is very expensive to have a single piece heat treated because of the time it takes. I have found that by going to a foundry that does their own heat treating, you can get parts done for far less money.

Steel, stainless and titanium you can get away with welding "cold". Weld a short bead (1/2") and let it cool back to room temperature. I even use compressed air to cool then off between beads.

Hope this helps a few of you. Again, this just a great thread / website for two stroke races.

[WilDun]

Are there any extra requirements (for a basic TIG welder) to enable aluminium welding to be done?
eg I remember being told way back that the old welders required a high frequency unit (AC I guess) and it was necessary to use a flat tip on the tungsten electrode, but I never see any of that mentioned these days, - I've really got behind here!

[Grumph]

Over the years, I have funded my addiction (hydroplane racing) by welding. A few hints for welding aluminum that may or may not help...

DC straight polarity and medical grade helium works. All the Top Fuel Dragster blocks are repaired with this set up. No pre heat and you can penetrate over 1/2" with no weld prep. The helium and regulator is not cheap, but it works.


Thanks Mike - I'll pass this one on to a friend here in NZ if I may. Every time I'm in to see him, he's got at least one drag or speedway block or head there for repair. He's always complaining about the preheat time too....

[Sketchy_Racer]

Hi all,

So I have made a start on the next phase of the NSR300 development which is to stroke the crank out to 59mm which will give me square bore and stroke and also a capacity of 322cc To do this I will be designing and manufacturing a custom crank.

Also part of this project is to maximise the potential of the NSR150 barrels that we use so I have got myself a seat of Engmod2T to entertain myself with.

I am in the very early stages of entering data at the moment and am working on modeling the exhaust port. I've taken a paper copy of the ports and brought this into solidworks to create a 3D barrel to use in my crank assembly.

319513


319515

But when modeling the ports in Engmod are they modeled as a flat pattern


319514

Or as viewed in the barrel as curved ports?
Either way using this method of measuring the ports in solidworks makes it very easy to get accurate geometry.

Below is the crank assembly in its very basic design stage.

319516

Below is the stock dimensions of the original NSR300 setup as raced last season

Stock Specs
Stock Stroke: 54.5mm
Stock Rod Length: 105mm
Piston Diameter: 59mm
Compression Height: 35mm
Deck Height: 0.00mm
Ex Duration: 194.7 Degrees
Trans Duration:123.1 Degrees
Capacity: 298.0cc

And this is the first pass at what we will be running in terms of rod length, capacity and Stroke for the coming season. (ignore port timing TBC with Engmod)

Upgrade Option Five
Stroke: 59mm
Rod Length: 118mm
Piston Diameter: 59mm
Compression Height: 32mm
Deck Height: +2.0
Ex Duration: 194.5 degrees
Trans Duration:129.4 degrees
Capacity: 322.6cc

[wobbly]

no,no,no,no,no,NO.
In Engmod all the port dimensions are normal to the flow direction, or simply chordal width.
Anything ( paper or Solidworks unroll feature ) is nothing like what is needed, as this is circumferential width.
In most all cases the A port is flow direction, the B and C are chordal as is the T port.
Dont forget to calculate the T port pocketing correctly as well.

[nasone32]

Basically you have two options for stroking the cylinder. (please note I am not calculating the longer conrod as it boils down to adding a spacer below)
with the longer stroke the piston will go 2.25mm more up and 2.25mm more down.

1) you leave the cylinder as it is, provided you have enough deck height for the piston ring to stay into the cylinder, and do the porting for the new stroke
this is not optimal because you will have the lower part of the transfer ports floating 2.25 mm above the piston at BDC.
You loose piston cooling and time area.
You could work the ports down but this is very difficult to do correctly, it is easy to break the inner radius of the ducts.

2)you take away 2.25mm from the bottom plane of the cylinder, AND add 4.5mm of deck height. If you have enough, great, otherwise you have to weld a slice on the deck and redo the plating.
Or does it have an iron bore?
In this case there's also a lot more porting job to do, but it would be the nicest way.

I did a couple as in case 2).
The cylinder i'm using currently is both bored from 47.6 to 52 and stroked from 39.3 to 46. totally worth it.

[Sketchy_Racer]

no,no,no,no,no,NO.


I'm guessing that's not the way to do it then :innocent:



In Engmod all the port dimensions are normal to the flow direction, or simply chordal width.
Anything ( paper or Solidworks unroll feature ) is nothing like what is needed, as this is circumferential width.
In most all cases the A port is flow direction, the B and C are chordal as is the T port.


This would still be possible to use the paper scratching in solidworks to measure for the chordial widths, No?




Dont forget to calculate the T port pocketing correctly as well.

Not sure I understand this part, care to elaborate? Thanks Wob.


-Sketchy

[Sketchy_Racer]

Basically you have two options for stroking the cylinder. (please note I am not calculating the longer conrod as it boils down to adding a spacer below)
with the longer stroke the piston will go 2.25mm more up and 2.25mm more down.

1) you leave the cylinder as it is, provided you have enough deck height for the piston ring to stay into the cylinder, and do the porting for the new stroke
this is not optimal because you will have the lower part of the transfer ports floating 2.25 mm above the piston at BDC.
You loose piston cooling and time area.
You could work the ports down but this is very difficult to do correctly, it is easy to break the inner radius of the ducts.

2)you take away 2.25mm from the bottom plane of the cylinder, AND add 4.5mm of deck height. If you have enough, great, otherwise you have to weld a slice on the deck and redo the plating.
Or does it have an iron bore?
In this case there's also a lot more porting job to do, but it would be the nicest way.

I did a couple as in case 2).
The cylinder i'm using currently is both bored from 47.6 to 52 and stroked from 39.3 to 46. totally worth it.


I'm going to have to do it as per case one. The cost involved of building up and re-plating cylinders is a great deal of work. I'm hoping that it will be possible to keep the duct radius in a good shape after porting.

I do have the luxury of having a couple of knackered cylinders that I can cut in half to get a better look at the existing geometry as well as have a practice on that first.

[TZ350]

Don't forget to calculate the T port pocketing correctly as well.
Not sure I understand this part, care to elaborate? Thanks Wob. -Sketchy

319525319526

Something like this maybe. The left is a T port, the right a Triple port, anyway it will be interesting to see what Wob says.

[wobbly]

In the diagram the A width is way smaller than measuring it like B.
If you take B and roll it out flat the circumferential length will be way wider again,and has no relevance at all to what we
need in EngMod.
You can measure B easily in the SolidWorks model by picking the two vertical port edges and using the measure function.
One of the width options will be the chordal distance.
But A must be measured using bent,ball ended dividers,in the direction of the duct flow actually in the cylinder,unless you have got clever and have modeled the
transfer ducts as well.

When you select T port in the Exhaust page, at the bottom it asks for the duct side exit angle C.
This is pocket exit angle, and done right it makes a huge difference to power in a T port.

[Sketchy_Racer]

Thanks heaps guys for the info, very helpful! I see that I am going to lose quite a few hours in this program!

[chrisc]

A KTM 65SX with a 50SX-cylinder (smaller bore, same stroke) is a good tool for 50 cc racing. One drawback: it has no balance shaft, so the way you mount the engine will influence the life span of the frame, the functioning of the carburettor and the amount of numbness in the rider's hands and feet.
The latter may sound futile, until you've experienced the difference between engines without and with a balance shaft. Vibration costs concentration.

Thanks for pointing that out Frits, I hadn't noticed that it didn't have a balance shaft! Rod and I rode his TZ125/AM6 bucket in the 2 hour in November to 3rd place. After that I couldn't feel my right foot and left hand from numbness and that does have a balance shaft. Rider comfort is high on my priority list after learning the hard way how much time there is in it on both my bucket and NX4 RS125.

I've test ridden 3 air cooled 125cc buckets with no balance shafts which although they went like rockets, vibrated like hell. If I had a choice, I'd get away from that as much as I could in a freetech bike where you have so much choice. Anyone care to suggest other alternatives to the KTM SX, AM6 and Derbi?

You've commented a few times about the appropriateness of using a RS125 chassis for a freetech 50 bike Frits, I'd love to continue that conversation but maybe without clogging the ESE thread. I'll ask the question on the race chassis thread :scooter:

[Frits Overmars]

A must be measured using bent, ball ended dividers, in the direction of the duct flow actually in the cylinder.I have a simple tool: a set of feeler gauges converted to an inner compass. Grind two of the feeler tips like in the drawing and you're done. You can even still use all of the feeler gauges.
I insert my compass in a port from the inside of the cylinder bore, push the legs against the duct sides, and then pull the compass back so that the legs are pushed towards one another. That way it is easy to find the minimum cross sectional width. Finally I measure that width with a caliper.
319554


When you select T port in the Exhaust page, at the bottom it asks for the duct side exit angle C.
This is pocket exit angle, and done right it makes a huge difference to power in a T port.Here are some sketches to go with that remark.
319566319561

[Frits Overmars]

Thanks for pointing that out Frits, I hadn't noticed that it didn't have a balance shaft! Rod and I rode his TZ125/AM6 bucket in the 2 hour in November to 3rd place. After that I couldn't feel my right foot and left hand from numbness and that does have a balance shaft. Rider comfort is high on my priority list after learning the hard way how much time there is in it on both my bucket and NX4 RS125.
I've test ridden 3 air cooled 125cc buckets with no balance shafts which although they went like rockets, vibrated like hell. If I had a choice, I'd get away from that as much as I could in a freetech bike where you have so much choice. Anyone care to suggest other alternatives to the KTM SX, AM6 and Derbi?There must have been something wrong with the timing of that AM6's balance shaft then. The AM6 can be quite civilized, vibration-wise.
I don't know all the engines that could be considered, but Derbi seems to be the most-chosen engine, preferably pimped with a KTM 50SX cylinder or an Emot cylinder.


You've commented a few times about the appropriateness of using a RS125 chassis for a freetech 50 bike Frits, I'd love to continue that conversation but maybe without clogging the ESE thread. I'll ask the question on the race chassis threadDid I? My intention has rather been to comment on the inappropriateness of an RS125 chassis, or any other 125 cc chassis for that matter.
They are simply too heavy for a decent 50 cc racer. Anyway, see you there: http://www.kiwibiker.co.nz/forums/showthread.php/145224-Race-chassis/page43

[41juergen]

Frits, I believe some longer time ago you mentioned how to define the size of the radius of the upper ExPort.... Was that something like approx. 4% of the bore?

[adegnes]

Anyone care to suggest other alternatives to the KTM SX, AM6 and Derbi?
:

Derbi flat reed maybe? With a powerful cylinder of course.

[nasone32]

YEAH i'm back to engines! today i enlarged the conrod window a fair amount. on the manual mill.

Also a little picture of the 52mm cylinder. Still have to round that edge inside and lot of porting to do. But i'm not planning to use this cylinder anyway. it's 100cc max and this would give 101,8cc.
So i'll stick with the 50mm bore and 95cc.
Unfortunately the regulations have changed to allow for 100cc, it was 95cc the year i designed the engine. otherwise I would have gone for a 50x50 instead of 50x48.
at that time most people was using 52x44 (94cc) because it was the most common "long stroke" for the stock crankcase. so they made the rules to suit that.
That's unlucky because i'm leaving behind a 5% of power.

and also a pic of the frame.
319562319563
http://imagizer.imageshack.us/v2/150x100q90/215/wp000237copy.jpg (https://imageshack.com/i/5zwp000237copyj)

[adegnes]

Lookin' good!

[TZ350]

I love these little sprint bikes.

[peewee]

YEAH i'm back to engines! today i enlarged the conrod window a fair amount. on the manual mill.

Also a little picture of the 52mm cylinder. Still have to round that edge inside and lot of porting to do. But i'm not planning to use this cylinder anyway. it's 100cc max and this would give 101,8cc.
So i'll stick with the 50mm bore and 95cc.
Unfortunately the regulations have changed to allow for 100cc, it was 95cc the year i designed the engine. otherwise I would have gone for a 50x50 instead of 50x48.
at that time most people was using 52x44 (94cc) because it was the most common "long stroke" for the stock crankcase. so they made the rules to suit that.
That's unlucky because i'm leaving behind a 5% of power.

and also a pic of the frame.
319562319563
http://imagizer.imageshack.us/v2/150x100q90/215/wp000237copy.jpg (https://imageshack.com/i/5zwp000237copyj)

nice job nasone. im working on a sprinter as well :niceone:

[TZ350]

Is this a snowmobile sprinter?

[AndreasL]

Here are some sketches to go with that remark.
319566

The radial approach apply to a single exhaust port as well, right?

If not, I have more adjustments to do.

[diesel pig]

Is this a snowmobile sprinter?

No I think it is a quad bike frame make for sprinting. I think the yanks call them sand dragsters.

[peewee]

Is this a snowmobile sprinter?

its a sand sprinter . i havent installed the swingarm and a-arms just yet

[peewee]

I think the yanks call them sand dragsters.

indeed that's what it is in yankee terms. I wanted to make some crankcases and use two ktm 250 or 300 cylinders but that's well beyond the budget. not to mention I wouldn't know where to start in designing them :lol:

[Frits Overmars]

The radial approach apply to a single exhaust port as well, right?Right. But you should concentrate on that second picture (repeated below). The 20° difference between direction angle and position angle means that the outflow is not 100% radial, but this approach should give the optimum between maximum outflow and minimum duct volume.
319588

[F5 Dave]

I've been out on my GG300 all day. A V twin of it would be a well useful engine.

[AndreasL]

Thanks Frits!

The "20* rule" was new to me and why I asked.
Will add it to the todo-list.

[dtenney]

Sent an email to your new email address. Did you get it?

[breezy]

looks like Ruaumoko is stamping his feet again... keep safe ..

[Niels Abildgaard]

I've been out on my GG300 all day. A V twin of it would be a well useful engine.

Jan and Frits has stated more than once that single cylinder two strokes are vibrating themselves to pieces.
The normal cure is a balance shaft that has some mass and eats some power.
As I read their sermons ultimate power from a twostroke is limited by blowdown time area.
If we make two halfsize cylinders the combined limitarea is 1.26 times as big.
The last 125 gave around 55 horsepower and one of the NSR500V 250 ccm cylinders around 80 horsepower and not 110 as one could suspect.
Two small give more than a single big.Surprice.
If the gg300 is nice a V twin with two 120 cylinders will drive just as nice ,be less mass,sound different and will not give driver chronic shaking.
A V2 90 degree twin with the two conrods side by side on a single crank throw have from birth a better balance as a fourcylinder fourstroke inline.
The argument that each cylinder must have sepparate crankchamber is maybe nonsense.When the pipes are doing their work it is surely not true.
This can be a very ligth and narrow engine if the two pipes can somehow be united to one system.Nobody has done it and gain is very beneficial for all mankind.One carb,one crank,two pistons and cylinders and one exhaust will also make unregulated aircraft engines better and safer.
Is there any law that says that buckets shall have one cylinder only?

[Flettner]

Jan and Frits has stated more than once that single cylinder two strokes are vibrating themselves to pieces.
The normal cure is a balance shaft that has some mass and eats some power.
As I read their sermons ultimate power from a twostroke is limited by blowdown time area.
If we make two halfsize cylinders the combined limitarea is 1.26 times as big.
The last 125 gave around 55 horsepower and one of the NSR500V 250 ccm cylinders around 80 horsepower and not 110 as one could suspect.
Two small give more than a single big.Surprice.
If the gg300 is nice a V twin with two 120 cylinders will drive just as nice ,be less mass,sound different and will not give driver chronic shaking.
A V2 90 degree twin with the two conrods side by side on a single crank throw have from birth a better balance as a fourcylinder fourstroke inline.
The argument that each cylinder must have sepparate crankchamber is maybe nonsense.When the pipes are doing their work it is surely not true.
This can be a very ligth and narrow engine if the two pipes can somehow be united to one system.Nobody has done it and gain is very beneficial for all mankind.One carb,one crank,two pistons and cylinders and one exhaust will also make unregulated aircraft engines better and safer.
Is there any law that says that buckets shall have one cylinder only?

No, just must be based on a road or trail engine. Not many 100cc twins around now, also will always be a parrallel twin at that. You may make a V twin but that would take some time and money, so far deemed not worth it. There have been twin cylinder buckets in the past (one had four pistons) and Suzuki twin engines used. I would like to see a tandem twin RV 100cc built, that might win a few dyno races:cool: I guess it boils down to time and money, no factory race teams here so the budget will ultimatly control the scope of develoment. Ideas are cheap
Dave, where were you riding the GG300? Aria?

[wobbly]

Got bored and decided to redesign the bypass thermostats I have used for years and just run out of.
They will fit all 2T bikes from 50 to 500cc and the bypass is set to start at 42*.
Up to this temp the water circulates from the pump,thru the cylinder and back to the pump,allowing the engine to get up to temp
on the warmup lap.
You can use the biggest rad you can fit and the temp stays at around 50*C with no tape in the coldest conditions., as the thermostat element cycles up and down
regulating the bypass flow.
I spent alot of time CAD designing the thing to make it real easy to CNC from stock bar, and it can be anodised any colour.
They still cost 200USD from RSC,and I reckon they are worth 1/2 that.
If interest is good enough I will get Flet to hoover up a bunch.

Also working on a speedshift sensor based on the Bazzaz unit as used on Superbike shift rods, with a proximity sensor that plugs straight into an Ignitech.
Those are 230E, and again I would say 1/2 that is reasonable.

[seattle smitty]

Shaking . . . heard a news item this morning, are you South Island guys all okay???

[F5 Dave]

The GG 3hundy will win no dyno day contests, it is pretty tardy in performance terms for a road racer. But a couple in a super light road bike with say 80hp with that lazy unstoppable spread.:drool:
Local moonshine ride. Roots tyres but close by.

[Bert]

No, just must be based on a road or trail engine. Not many 100cc twins around now, also will always be a parrallel twin at that. You may make a V twin but that would take some time and money, so far deemed not worth it. There have been twin cylinder buckets in the past (one had four pistons) and Suzuki twin engines used. I would like to see a tandem twin RV 100cc built, that might win a few dyno races:cool: I guess it boils down to time and money, no factory race teams here so the budget will ultimatly control the scope of develoment. Ideas are cheap
Dave, where were you riding the GG300? Aria?

Love to see a few more twin 100s they do sound great.
Here's Scotties twin (again) two MB50 barrels watercooled.


http://youtu.be/IIxcQr-eglE


Got bored and decided to redesign the bypass thermostats I have used for years and just run out of.
They will fit all 2T bikes from 50 to 500cc and the bypass is set to start at 42*.
Up to this temp the water circulates from the pump,thru the cylinder and back to the pump,allowing the engine to get up to temp on the warmup lap.
You can use the biggest rad you can fit and the temp stays at around 50*C with no tape in the coldest conditions., as the thermostat element cycles up and down
regulating the bypass flow.
I spent alot of time CAD designing the thing to make it real easy to CNC from stock bar, and it can be anodised any colour.
They still cost 200USD from RSC,and I reckon they are worth 1/2 that.
If interest is good enough I will get Flet to hoover up a bunch.

Also working on a speedshift sensor based on the Bazzaz unit as used on Superbike shift rods, with a proximity sensor that plugs straight into an Ignitech.
Those are 230E, and again I would say 1/2 that is reasonable.

I'd be interested in both? Love my current bypass I purchased from you and have two other twostrokes...

[husaberg]

Love to see a few more twin 100s they do sound great.
Here's Scotties twin (again) two MB50 barrels watercooled.


http://youtu.be/IIxcQr-eglE



I'd be interested in both? Love my current bypass I purchased from you and have two other twostrokes...

Plus Fletner needs money to purchase longer trousers.:whistle:

[peewee]

Got bored and decided to redesign the bypass thermostats I have used for years and just run out of.
They will fit all 2T bikes from 50 to 500cc and the bypass is set to start at 42*.
Up to this temp the water circulates from the pump,thru the cylinder and back to the pump,allowing the engine to get up to temp
on the warmup lap.
You can use the biggest rad you can fit and the temp stays at around 50*C with no tape in the coldest conditions., as the thermostat element cycles up and down
regulating the bypass flow.
I spent alot of time CAD designing the thing to make it real easy to CNC from stock bar, and it can be anodised any colour.
They still cost 200USD from RSC,and I reckon they are worth 1/2 that.
If interest is good enough I will get Flet to hoover up a bunch.

.

42* and less the valve only allows water through the lower hose , above 42* it closes off the lower hose and diverts everything to the rad top just as normal ? I would probly be interested in one

[Muciek]

http://www.crash.net/motogp/news/226619/1/500cc-suter-enters-isle-of-man-tt.html
What a great news :eek::eek:

[Sketchy_Racer]

This is my first pass at modeling a motor in Engmod.

319623

There are a lot of parameters that I am not familiar with so I have started with the Honda RS125 engine model Engmod supplied as a base point for things like the Delay, Duration, Vibe-A and Vibe-B in combustion settings along with the wall temperatures

The NSR300-2015 is as per the spec we ran our motors this season. The power output in Engmod is about 11% more than what we measured on the Dyno. The Curve is very close though and Engmod predicted Det (which we have battled all season)

The NSR330 v1.0 is What I am planning on running this season (Although the Capacity will actually be 317cc as i've had to reduce the stroke for deck height reasons) No Det predicted this time!

Interestingly, both simulations use the same flow widths and general port geometry as each other only the port heights and reed valve have changed significantly.

In NSR300-2015 sim changing to the Vforce reed made no difference however it makes a massive difference in the NSR330 sim though. I suspect this is to do with the increase of crankcase volume in the NSR330 sim. Perhaps this is because the Vforce is better with the weaker intake pressure differential?

I'm yet to play with the power valve settings to optimise it for the NSR330 file as it looks like it's opening too early.

I'm going to cut up my spare barrel tomorrow so I can verify my port measurements and hopefully get a more accurate model.

Very very addictive piece of software.

[ief]

Addictive ? Nahhhhhhhhhhhhhhhhhhhh

:banana:

[AndreasL]

Very interesting to see how others use EngMod and how you solve different issues.

I feel I'm way behind with my base model. :(

[wobbly]

EngMod is depicting crankshaft Hp, and I have found that a good sim will have around 12% more power over a Dynojet
showing rear wheel Hp.
This is entirely predictable with primary drive, gearbox gears/oil drag, chain and tyre losses to the drum.
You can also take your Dyno curve, add 12% in the software and display that with the sim result - dead cool.

The latest software has a new pipe heat release model incorporated, and for a racebike like the NSR you should use rpm driven pipe temp.
325*C at the start of the powerband and 425*C at peak power, say 8000 and 12,000.
If using a solenoid powerjet then this is modeled best by going to 450* in the overev.

Do you understand how to input the correct numbers for your actual combustion parameters, as this is very important to detecting, then eliminating deto.
If not I will do a show and tell as TeeZee likes.

Re the bypass thermostat, yes it starts to close at 42*C, and is fully closed by about 48*.
Thus as I said it will allow the engine to reach 42* in no time, then it cycles up and down, keeping the temp at around 50* ( due to hysteresis ) continuously no matter how cold
or hot the ambient temp is.
As long as your rad is capable of overcooling, it will hold it at 50* all day - every day.

[Perra.S]

A V2 90 degree twin with the two conrods side by side on a single crank throw have from birth a better balance as a fourcylinder fourstroke inline.
The argument that each cylinder must have sepparate crankchamber is maybe nonsense.When the pipes are doing their work it is surely not true.

Has a common crankcase ever been tried on a 90 degree? Someone with better knowledge than me (like 99% of the people in here) that has a good guess if it will work well or not?



I spent alot of time CAD designing the thing to make it real easy to CNC from stock bar, and it can be anodised any colour.
They still cost 200USD from RSC,and I reckon they are worth 1/2 that.
If interest is good enough I will get Flet to hoover up a bunch.


Would like to buy two as soon as you have them available.

[adegnes]

EngMod is depicting crankshaft Hp, and I have found that a good sim will have around 12% more power over a Dynojet
showing rear wheel Hp.
This is entirely predictable with primary drive, gearbox gears/oil drag, chain and tyre losses to the drum.

The latest software has a new pipe heat release model incorporated, and for a racebike like the NSR you should use rpm driven pipe temp.
325*C at the start of the powerband and 425*C at peak power, say 8000 and 12,000.
If using a solenoid powerjet then this is modeled best by going to 450* in the overev.

Do you understand how to input the correct numbers for your actual combustion parameters, as this is very important to detecting, then eliminating deto.
If not I will do a show and tell as TeeZee likes.

+1 for show and tell, and thanks for the info about the new heat release model! I'm booting up my computer as we speak to see how it'll affect my sims.

[AndreasL]

Show and tell please!

[TZ350]

This is my first pass at modeling a motor in Engmod.

319623


I'm yet to play with the power valve settings to optimise it for the NSR330 file as it looks like it's opening too early.

I'm going to cut up my spare barrel tomorrow so I can verify my port measurements and hopefully get a more accurate model.

Very very addictive piece of software.

Please keep us posted.

[TZ350]

Re the bypass thermostat

I now want two please .....

[ief]

Do you understand how to input the correct numbers for your actual combustion parameters, as this is very important to detecting, then eliminating deto.
If not I will do a show and tell as TeeZee likes.


I'm in as well :) And since I think this must be related, I have treid turbulent model as well and with more then a couple of models but it won't fly, error in the flamefront calculation (?) Didn't want to bother Neels again (yet)

[Peter1962]

Has a common crankcase ever been tried on a 90 degree? Someone with better knowledge than me (like 99% of the people in here) that has a good guess if it will work well or not?



Would like to buy two as soon as you have them available.

Yes, in 1981 Jean Bertrand Bruneau (JBB) made a V2 90 degrees two stroke GP engine, with common crankcase. It was a marvel.
He is a genius. http://www.pit-lane.biz/t5627p180-oldies-les-motos-jbb-toute-une-histoire

[Frits Overmars]

Yes, in 1981 Jean Bertrand Bruneau (JBB) made a V2 90 degrees two stroke GP engine, with common crankcase. It was a marvel. He is a genius. http://www.pit-lane.biz/t5627p180-oldies-les-motos-jbb-toute-une-histoireTrue about Jean Bertrand being a genius; not true about his V2-engine having a common crankcase. The separation between the left and right cases was taken care of by the center part of the crankshaft. It was grooved; the groove carried a 'piston ring' that expanded when fitted and then was stationary in the cases, forming a labyrinth seal.
319630319632319631319629

[marsheng]

I'm going to cut up my spare barrel tomorrow so I can verify my port measurements and hopefully get a more accurate model.


Use a 2 part silicon potting mix to copy the ports. Much better than cutting a barrel open. !!!

Cheers Wallace

[Sketchy_Racer]

Use a 2 part silicon potting mix to copy the ports. Much better than cutting a barrel open. !!!

Cheers Wallace

Normally I would agree, in this instance the barrel is beyond economic repair so it can be a offering to the gods of speed ;)

[Sketchy_Racer]

Do you understand how to input the correct numbers for your actual combustion parameters, as this is very important to detecting, then eliminating deto.
If not I will do a show and tell as TeeZee likes.



Please do, I'm eager to gain a better fundamental understanding of the software and how to most accurately use it. Much like FEA i'm sure with enough fudging you can get it to say whatever you would like it to.

[wobbly]

Dont mention the word "fudge" or Neels will cancel your software licence , he hates the word with a passion.
OK, so here we go with getting the correct combustion parameters into your sim.
Firstly be aware that the squish geometry is one of the inputs that the code uses to generate the parameters that govern the combustion numbers.
So this must be optimized or at the very least close to what the engine is/will be running.
Firstly enter the combustion page with the default entries - I have shown that page for the TZ400 engine, along with the actual ignition timing.
Then run the sim, and if you get any obvious area of deto at one rpm point, then that can usually be fixed by pulling some timing.
If on the other hand you get deto all over the shop, then something is very wrong with the compression for the fuel entered, or the stinger is way too small.
What I am saying is get the sim working reasonably happily initially, using the defaults and Burnrate Prescribed.
Then - change to Turbulent Model with the current setup and save that Combustion change - but you dont need to rename it.
Run the sim, and call that run say TurbMod,this will take forever, as its now actually calculating what is happening in the chamber.

Once its done open the Post Processor,and select Performance and Efficiency.
Open the engine files you are working on, and select the last sim run called TurbMod,now the page with the parameters you want to be looking at will open, and
on the RH side is a Write Combustion File radio button.
Click that and enter a new name for that file, like in my case TZ400 Reed TurbMod, and enter the other parameters needed.
This will then save to the 2Stroke folder with that new name.
Then when you reopen your EngMod Dat2T engine sim, you can select Existing Combustion Data, and select that newly named file.
This will now have all the correct Wiebe functions etc for your setup.

Very occasionally the new file will crash, due to one of the calculated numbers being out of range ( like duration at say 100+ on one line ) if so ask Neels to look at your packed up file.
You are not annoying him, as seeing the error helps him refine the code each time to prevent it occurring in similar circumstances.
Now you have the correct numbers, you can save the file with Burnrate Prescribed again, and it will now run as fast as before - just alot more accurately.

[crbbt]

I would also like a thermostat Wob

[Brett S]

The Italians make bypass thermostats for karts at 45deg cheap.
Dunno if pipe sizes are correct for your application.


Righetti Bypass thermostats (http://www.righettiridolfi.com/uk/cat/591_597_253/open-45)

[chrisc]

Would like to buy two as soon as you have them available.


I now want two please .....

I'm pretty keen to get one for my RS125 Wob and I think one or two other 125 riders I race with might be keen also.


The Italians make bypass thermostats for karts at 45deg cheap.
Dunno if pipe sizes are correct for your application.

Righetti Bypass thermostats (http://www.righettiridolfi.com/uk/cat/591_597_253/open-45)

Any idea on the price of those Brett?

[Brett S]

I just had a look and the americans are retailing them for $85US, with the NZ and AU dollar being worthless again not as cheap as i remembered.

So maybe best to give the work to Neil and fund his experiments :)

[Frits Overmars]

Any idea on the price of those Brett?You will find bypass thermostats here for €72,60: http://www.hvg-engineering.com/index.php?action=search&lang=en&srchval=thermostaat
319643

[ief]

Wob, tnx! (again!)

[Frits Overmars]

Use a 2 part silicon potting mix to copy the ports. Much better than cutting a barrel open.Use Vinamold. Much better than messing around with two-component stuff. Vinamold is meltable and reusable. The red version is ideal for duct copying.
319646 319647

[Tim Ey]

+1 Vinamold

Anyone got a source for CFK which is suitable for reed valves? The only source I got at the moment are the Polini plates - but they are quite expensive compared to other CFK plates on ebay...

Cheers
Tim

[nasone32]

I want to share this exhaust rescaler i made some time ago.
very useful for engmod.
You want to try an aprilia rsa exhaust on your engine? or the honda rs one?
easy!
you put in the data of the original engine the pipes come from, and the data of your engine, and it spits out the corrected geometry, as a good starting point.
Of course it works better for engines with similar state of tune.

It does not take into account the lenght and diameter of the exhaust duct in the cylinder, some manual tinkering required here.

the data already provided inside is aprilia tubo 102

I wrote it with an italian version of openoffice, please check it and report, as it uses RADQ() instead of SQRT() to make the square root function.
EDIT: now it uses elevation to 0.5 to make the square root. there is still the comma/point issue as decimal separator, please check if it works for you.

319650

[2005bully]

+1 Vinamold

Anyone got a source for CFK which is suitable for reed valves? The only source I got at the moment are the Polini plates - but they are quite expensive compared to other CFK plates on ebay...

Cheers
Tim

Seems that internet searching for carbon fiber sheet mainly brings up cosmetic products. Try searching for FRP, and or G-10 sheets, that should get you some business's that also work with industrial carbon fiber sheet. Here is a link to an aerospace based company that I have had excellent results from...
https://www.acpsales.com/Fiberglass-Sheets.html

Hope this helps.... Kermit Buller

[adegnes]

Various carbon fiber products here
http://www.easycomposites.co.uk/#!/cured-carbon-fibre-products/rigid-carbon-fibre-sheet/Prepreg-Carbon-Fibre-Flat-Sheet.html

Not the widest selection of sheet thicknesses.

[Niels Abildgaard]

True about Jean Bertrand being a genius; not true about his V2-engine having a common crankcase. The separation between the left and right cases was taken care of by the center part of the crankshaft. It was grooved; the groove carried a 'piston ring' that expanded when fitted and then was stationary in the cases, forming a labyrinth seal.
319630319632319631319629

V4 and V6 outboards have had crancases separated with discs for years.
The real solution for a V2 twostroke crank can be a Hirth coupling in the midle of the crankpin.
Jan Thiel has mentioned that someone wanted to put a 24 mm crankpin in the 125.
Will that destroy the needle cage in no time or 5 minutes?

http://www.ebay.com/itm/WSM-OUTBOARD-YAMAHA-150-HP-V6-90-DEGREE-SMALL-TAPER-CRANK-SHAFT-OE-6G5-11411-01-/201368656287?hash=item2ee281d99f:g:rcIAAOSwLVZV1a0 v&vxp=mtr

http://i.ebayimg.com/images/g/5owAAMXQlUNRLSeX/s-l1600.jpg

[Niels Abildgaard]

Has a common crankcase ever been tried on a 90 degree? Someone with better knowledge than me (like 99% of the people in here) that has a good guess if it will work well or not?



A 60 degree V2 common crankcase was tested and ran ,but no pipes and model diesel where there is next to no energy in blowdown.

http://www.homemodelenginemachinist.com/showthread.php?t=22760

[wobbly]

The SwissAuto/Pulse 500 90* V4 had a common case for cylinder pairs, but these were set on a flying web with pins sitting at 90*
apart as well.
Thus both pistons were rising and falling together.
Worked very well once a zillion Euros were spent on exotic materials for the crank.

Re the thermostats - both the Rigetti in usd and the one Frits linked to in Euro, work out at the same price in NZ dollars then freight on top.
What they dont tell you is the price for a replacement internal element,the Rigetti is 30 something Euro,if you needed one I will
replace it for the cost of the courier.
Opening at 45*C means the normal running temp is over 50*,not so flash in a racing 2T for best power.
So with the interest shown here and in PMs I will talk to Mr Knobbly Knees today and get a batch under way.

[Flettner]

The SwissAuto/Pulse 500 90* V4 had a common case for cylinder pairs, but these were set on a flying web with pins sitting at 90*
apart as well.
Thus both pistons were rising and falling together.
Worked very well once a zillion Euros were spent on exotic materials for the crank.

Re the thermostats - both the Rigetti in usd and the one Frits linked to in Euro, work out at the same price in NZ dollars then freight on top.
What they dont tell you is the price for a replacement internal element,the Rigetti is 30 something Euro,if you needed one I will
replace it for the cost of the courier.
Opening at 45*C means the normal running temp is over 50*,not so flash in a racing 2T for best power.
So with the interest shown here and in PMs I will talk to Mr Knobbly Knees today and get a batch under way.

No need, I read that, it's on the white board, thanks.

[Frits Overmars]

The SwissAuto/Pulse 500 90* V4 had a common case for cylinder pairs, but these were set on a flying web with pins sitting at 90* apart as well. Thus both pistons were rising and falling together.The Swissauto's V-angle was a bit more than 90° Wob. But how much more? According to their specs it was 108° but the picture tells a different story....
319653 319654

[husaberg]

The Swissauto's V-angle was a bit more than 90° Wob. But how much more? According to their specs it was 108° but the picture tells a different story....
319653 319654

I am not sure if it changed at all during its life but the early ones eyeball at around 108 degrees
http://www.kiwibiker.co.nz/forums/album.php?albumid=4833
plenty of pics and stuff I accumulated on the Swissauto
From Memory the Honda NSR500 was 112 for most of the time at least (87 on)

Yamaha altered their v angle a number of times both narrower and wider.


V4 and V6 outboards have had crancases separated with discs for years.
The real solution for a V2 twostroke crank can be a Hirth coupling in the midle of the crankpin.
Jan Thiel has mentioned that someone wanted to put a 24 mm crankpin in the 125.
Will that destroy the needle cage in no time or 5 minutes?

]

Honda for years ran both 24mm and 25mm pins in the 250's and 125's. But bigger will have a propensity to skid more and be heavier.

[lodgernz]

Anyone got a source for CFK which is suitable for reed valves? The only source I got at the moment are the Polini plates - but they are quite expensive compared to other CFK plates on ebay...
Cheers
Tim

Boyesen has CF reeds for many engines

[peewee]

wob few questions. the twins with single head use a bigger diam water hose than most engines. would it be to much trouble to not machine the nipples down so far on the one I was planning to buy, so the thermo would fit proper in the larger hose ? I cant recall the hose size and I don't have any spares laying around

what do you think of seperate two piece heads with orings instead of the single one piece with metal gasket ? or does the single offer some stabilization of the cylinders

[husaberg]

+1 Vinamold

Anyone got a source for CFK which is suitable for reed valves? The only source I got at the moment are the Polini plates - but they are quite expensive compared to other CFK plates on ebay...

Cheers
Tim

http://www.treatland.tv/SearchResults.asp?Search=reed+sheet
http://www.ebay.com/itm/CARBON-FIBRE-SHEET-FOR-REED-VALVES-10cm-x-11cm-25mm-thick-POLINI-RACE-QUALITY-/401038860729
http://www.spi-parts.com/feuille-fibre-doppler-pour-lamelleclapet-100x100mm.html
https://www.beedspeed.com/reed-petal-karbinit-fibre-sheet-malossi-100x100x035mm-p-9291.html?osCsid=1aq3rpcou0eca63ataqea40db6
http://www.ve-uk.com/general-and-universal-parts/malossi-reeds/0/malossi/
http://scootertuning.ca/en/11_doppler
http://www.mcmaster.com/#standard-carbon-fiber-sheets/=115p3lo


Fibreglass reeds according to the web are make from G10 sheet
http://www.matweb.com/search/datasheetText.aspx?bassnum=PGLAM04
http://www.professionalplastics.com/G10FR4SHEET

[Sketchy_Racer]

Dont mention the word "fudge" or Neels will cancel your software licence , he hates the word with a passion.
OK, so here we go with getting the correct combustion parameters into your sim.
Firstly be aware that the squish geometry is one of the inputs that the code uses to generate the parameters that govern the combustion numbers.
So this must be optimized or at the very least close to what the engine is/will be running.
Firstly enter the combustion page with the default entries - I have shown that page for the TZ400 engine, along with the actual ignition timing.
Then run the sim, and if you get any obvious area of deto at one rpm point, then that can usually be fixed by pulling some timing.
If on the other hand you get deto all over the shop, then something is very wrong with the compression for the fuel entered, or the stinger is way too small.
What I am saying is get the sim working reasonably happily initially, using the defaults and Burnrate Prescribed.
Then - change to Turbulent Model with the current setup and save that Combustion change - but you dont need to rename it.
Run the sim, and call that run say TurbMod,this will take forever, as its now actually calculating what is happening in the chamber.

Once its done open the Post Processor,and select Performance and Efficiency.
Open the engine files you are working on, and select the last sim run called TurbMod,now the page with the parameters you want to be looking at will open, and
on the RH side is a Write Combustion File radio button.
Click that and enter a new name for that file, like in my case TZ400 Reed TurbMod, and enter the other parameters needed.
This will then save to the 2Stroke folder with that new name.
Then when you reopen your EngMod Dat2T engine sim, you can select Existing Combustion Data, and select that newly named file.
This will now have all the correct Wiebe functions etc for your setup.

Very occasionally the new file will crash, due to one of the calculated numbers being out of range ( like duration at say 100+ on one line ) if so ask Neels to look at your packed up file.
You are not annoying him, as seeing the error helps him refine the code each time to prevent it occurring in similar circumstances.
Now you have the correct numbers, you can save the file with Burnrate Prescribed again, and it will now run as fast as before - just alot more accurately.

Thanks for the write up Wobbly, I'm running through the sim now will post results soon!

-Sketchy

[nick gill]

Sorry to digress from the discussion. Came across this on Fecesbook
As yet unexplained. Any ideas chaps?
CPS + hall sensor is obvious. Ambihelical confabulator?
http://i34.servimg.com/u/f34/16/23/10/69/rijeka49.jpg

[Yow Ling]

its the gear change mechinisim on a Gnani engine , same as Jan Thiel used on the Jamathis

[TZ350]

319669319670319668

Chambers has been preparing the 13+ hp number 2 bike for the next Mt Wellington round and the GP at Tokoroa. At least we are having more luck with this than the number 1 bike. Team GPR, C U at Tokoroa.

[mr bucketracer]

319669319670319668

Chambers has been preparing the 13+ hp number 2 bike for the next Mt Wellington round and the GP at Tokoroa. At least we are having more luck with this than the number 1 bike. Team GPR, C U at Tokoroa.who is chambers i must ask? heres mine (-;319672

[mr bucketracer]

319674the bike

[Flettner]

wob few questions. the twins with single head use a bigger diam water hose than most engines. would it be to much trouble to not machine the nipples down so far on the one I was planning to buy, so the thermo would fit proper in the larger hose ? I cant recall the hose size and I don't have any spares laying around

what do you think of seperate two piece heads with orings instead of the single one piece with metal gasket ? or does the single offer some stabilization of the cylinders

Just tell me what size and I'll make sure there is one in the heap that's your's.

[TZ350]

319674 the bike

Your bike looks great, our number 1 bikes graph is no where as good as number two's ... number two's :facepalm: did I just say that.

We have had varying luck with the GP50 engines some work much better than others. I guess small differences make a big difference with a 50.

[AndreasL]

TZ, are those advance numbers in the pic "the real ones" seen by the engine i.e. no adding/subtracting/fudging should be done to understand everything correct?

[TZ350]

TZ, are those advance numbers in the pic "the real ones" seen by the engine

Yes ......

[MotleyCrue]

Another simple and more clear looking way to show whats on a monitor screen is to press and hold the Ctrl button on the keyboard then press (just once) the Print Screen button on the keyboard (while still holding Ctrl), then open Paint click Edit Paste, voila there it is, click Save. Then its full size and crystal clear for all.

[Bert]

Another simple and more clear looking way to show whats on a monitor screen is to press and hold the Ctrl button on the keyboard then press (just once) the Print Screen button on the keyboard (while still holding Ctrl), then open Paint click Edit Paste, voila there it is, click Save. Then its full size and crystal clear for all.

You are assuming that the PC in question is:
1) connected to the net.
2) someone can be bothered
Else you are looking at not only generating a file: but also then moving it to a web enabled PC to post for your consumption...??
Many dyno PCs are running very old software on old OS (maybe even Windows 3.1 or DOS). Last thing you want is to connect it up and suffer windows updates etc. and hours of fixing registery errors to get the dyno to work again...
And it's Likely in the back of someone's workshop.
A quick Photo with a smartphone and a post via forum tool is a hell of a lot easier; while not crystal clear is enough for all of us to get an idea of what's being described&discussed.

[adegnes]

You are assuming that the PC in question is:
1) connected to the net.
2) someone can be bothered
Else you are looking at not only generating a file: but also then moving it to a web enabled PC to post for your consumption...??
Many dyno PCs are running very old software on old OS (maybe even Windows 3.1 or DOS). Last thing you want is to connect it up and suffer windows updates etc. and hours of fixing registery errors to get the dyno to work again...
And it's Likely in the back of someone's workshop.
A quick Photo with a smartphone and a post via forum tool is a hell of a lot easier; while not crystal clear is enough for all of us to get an idea of what's being described&discussed.

...but nonetheless a good tip for those who did not know how to.

[wobbly]

Re the thermo spigot sizes.
I have run essentially the same setup on a RZ485 with CPI Cheetah cylinder making 104RWHP on unleaded.
The head outlet size is 19mm OD /16mm ID,and this fits all the LC/RZ style twins.
As the thermo is on the high pressure side of the pump the return hose size makes very little difference as the biggest ( smallest area )
restriction is in the fully open valve plate in the thermostat element.
BUT here is a tip - going up in size on the suction hose from the rad into the pump,with a bigger spigot welded onto the pump inlet ( 25mm hose )
makes a big difference to the flow and cooling.
Having said all that its easy enough for me to change the 3D models for Leonardo Flettner to CNC up a bigger one off body.


TeeZee, something is very wrong when you have 0* advance at 13,000 peak power rpm in that 50 engine

[AndreasL]

Yes ......

Thanks TZ.

Asked since I'm in no way an expert but find the numbers very low from what Wob et al have told us.

Will be interesting to see why the bike runs best at such settings.

[adegnes]

And now for something completely different.

Can anyone enlighten my on the subject of fuel vapour pressure? I'm particularly interested in its effect on cold starting.
Having a hard time firing up my bike and I suspect the 70/30 pump gas/xylene homebrew "race fuel" is the culprit.

My shop is at around 2-3°C when I'm not there...
Preheating does help.

http://youtu.be/A3yURU_zRuw

http://youtu.be/5Pp6fDQQ51U

[TZ350]

I love Adegnes's engine pre heater.


TeeZee, something is very wrong when you have 0* advance at 13,000 peak power rpm in that 50 engine

Thanks for the heads up.


Thanks TZ. Asked since I'm in no way an expert but find the numbers very low from what Wob et al have told us. Will be interesting to see why the bike runs best at such settings.

Some time has been spent on optimizing the ignition curve for the best graph result.

But there can be errors in the static timing setup, and there may very well be shortcomings in the motor/pipe that are masked by over heating the pipe at 13k rpm. Still learning myself.

[wobbly]

RVP, is something of a hobby horse of mine at the moment.
Forever, so many people have had big issues with deto in KZ2 kart engines, and after reading several references in DynoTech magazine
about the effects I decided to do a test.
I ran our SKUSA Honda125 on the dyno one morning on fresh Avgas.
From a huge number of track tests where I have recorded the Altitude Density ( RAD ) and the egt, I have a straight line jetting chart that I know is
absolutely accurate.
RAD = 97% = 165 jet,I can simply go ahead with that and be tuned perfectly.
The baseline run gave the exact result as I would have expected,with the egt smack on 1340* and the deto first red light flickering at peak torque.
I left that fresh fuel in the dyno tank, with its normal breather to atmosphere sitting overnight.

Luckily the RAD was exactly the same the next morning, so I reran the test,and holy shit it was a complete surprise.
The egt had dropped nearly 100*F,with no changes whatsoever.
The power was down dramatically ,like 2 Hp in just over 40.So I leaned it down as you would - trying to regain the power and the egt number.
But as I leaned down, the power DROPPED, the deto lights started to warning flash,so I stopped right there.

The light front ends had all flashed off from the fuel, and as the DynoTech articles had said,the fuel simply wont vaporize entering the crankcase - it flows into the engine as big globs.
The globs dont burn efficiently,thus dropping the egt, and power simply goes away,badly.

I think I stated on here before that at the SKUSA World Finals this year we were allowed to use the 98VP racegas,or VP C12,a WAY better high octane race fuel.
For some reason we simply could not get the C12 to work on track,so I went to the VP race truck and asked them could they open a brand new drum of C12 for me.
They did, and completely the reverse to what one would expect, as the lid was unscrewed,NO vapour pressure went WHISHHHHH.
The fuel had No RVP ie it was "off" ie useless.
C12 has a published RVP of 9psi ie it should woooosh like hell.

The short of the story is that not only does fuel degrade VERY quickly, causing deto if left even overnight - hard starting in cold weather would be super likely if the light fractions wont vaporize and give
the engine something to actually burn, not drown on.

[MotleyCrue]

You are assuming that the PC in question is:
1) connected to the net.
2) someone can be bothered
Else you are looking at not only generating a file: but also then moving it to a web enabled PC to post for your consumption...??
Many dyno PCs are running very old software on old OS (maybe even Windows 3.1 or DOS). Last thing you want is to connect it up and suffer windows updates etc. and hours of fixing registery errors to get the dyno to work again...
And it's Likely in the back of someone's workshop.
A quick Photo with a smartphone and a post via forum tool is a hell of a lot easier; while not crystal clear is enough for all of us to get an idea of what's being described&discussed.

Hey, the tip I offered can be used for many things, not just as an alternate method to smartphone posting, most people dont know about it so I thought it might be of interest one way or the other, but I guess I'll just go FOAD now again.

[FastFred]

Hey, the tip I offered can be used for many things, not just as an alternate method to smartphone posting,

I think TZ uses it for posting EngMod screen shots from home but the works dyno computer is like Burt says, an antiquated piece of of gear best not connected to the net.

[FastFred]

319669319670319668

Chambers has been preparing the 13+ hp number 2 bike for the next Mt Wellington round and the GP at Tokoroa.


TeeZee, something is very wrong when you have 0* advance at 13,000 peak power rpm in that 50 engine

Actually TeeZee that is very encouraging making 13+hp with something seriously wrong. It could be 14-15 hp when you get it sorted.

[husaberg]

Another simple and more clear looking way to show whats on a monitor screen is to press and hold the Ctrl button on the keyboard then press (just once) the Print Screen button on the keyboard (while still holding Ctrl), then open Paint click Edit Paste, voila there it is, click Save. Then its full size and crystal clear for all.

You don't even need to push the ctrl button, just the print screen then right click and past into word or publisher or any other program.

All these were screen printed off a site that doesn't allow saving pictures

Yamaha 3 cylinder racers
I haven't even read them myself yet:scratch:
319683 319684 319685 319686 319687 319688

[2T Institute]

Re the thermo spigot sizes.


TeeZee, something is very wrong when you have 0* advance at 13,000 peak power rpm in that 50 engine

...........and 21* max advance

[peewee]

Re the thermo spigot sizes.
I have run essentially the same setup on a RZ485 with CPI Cheetah cylinder making 104RWHP on unleaded.
The head outlet size is 19mm OD /16mm ID,and this fits all the LC/RZ style twins.
As the thermo is on the high pressure side of the pump the return hose size makes very little difference as the biggest ( smallest area )
restriction is in the fully open valve plate in the thermostat element.
BUT here is a tip - going up in size on the suction hose from the rad into the pump,with a bigger spigot welded onto the pump inlet ( 25mm hose )
makes a big difference to the flow and cooling.
Having said all that its easy enough for me to change the 3D models for Leonardo Flettner to CNC up a bigger one off body.


TeeZee, something is very wrong when you have 0* advance at 13,000 peak power rpm in that 50 engine

the head I have measures 21mm OD at the spigot. 15mm ID but ill probly ream it out to 16mm. im guessing the hose ID is 19mm although I haven't got the exact hose to measure but I tried a 19mm ktm hose and it fit good and tight. I would prefer the thermo spigots OD to be more like 21mm or so and the ID 16 or so, atleast on mine, if its not to much trouble


spigot going into the pump is 25mm OD and 19mm ID on the one I have

[adegnes]

RVP, is something of a hobby horse of mine at the moment.
Forever, so many people have had big issues with deto in KZ2 kart engines, and after reading several references in DynoTech magazine
about the effects I decided to do a test.
I ran our SKUSA Honda125 on the dyno one morning on fresh Avgas.
From a huge number of track tests where I have recorded the Altitude Density ( RAD ) and the egt, I have a straight line jetting chart that I know is
absolutely accurate.
RAD = 97% = 165 jet,I can simply go ahead with that and be tuned perfectly.
The baseline run gave the exact result as I would have expected,with the egt smack on 1340* and the deto first red light flickering at peak torque.
I left that fresh fuel in the dyno tank, with its normal breather to atmosphere sitting overnight.

Luckily the RAD was exactly the same the next morning, so I reran the test,and holy shit it was a complete surprise.
The egt had dropped nearly 100*F,with no changes whatsoever.
The power was down dramatically ,like 2 Hp in just over 40.So I leaned it down as you would - trying to regain the power and the egt number.
But as I leaned down, the power DROPPED, the deto lights started to warning flash,so I stopped right there.

The light front ends had all flashed off from the fuel, and as the DynoTech articles had said,the fuel simply wont vaporize entering the crankcase - it flows into the engine as big globs.
The globs dont burn efficiently,thus dropping the egt, and power simply goes away,badly.

I think I stated on here before that at the SKUSA World Finals this year we were allowed to use the 98VP racegas,or VP C12,a WAY better high octane race fuel.
For some reason we simply could not get the C12 to work on track,so I went to the VP race truck and asked them could they open a brand new drum of C12 for me.
They did, and completely the reverse to what one would expect, as the lid was unscrewed,NO vapour pressure went WHISHHHHH.
The fuel had No RVP ie it was "off" ie useless.
C12 has a published RVP of 9psi ie it should woooosh like hell.

The short of the story is that not only does fuel degrade VERY quickly, causing deto if left even overnight - hard starting in cold weather would be super likely if the light fractions wont vaporize and give
the engine something to actually burn, not drown on.

Thanks!
When I think about it, this explains how it can act lean while at the same time be dripping fuel out the exhaust to...

[Lurifax]

This side of world it is ALT + PrintScreen that prints only the active window.

Ctrl + PrintScreen is the same as PrintScreen and prints the whole screen in my computer

[MotleyCrue]

You don't even need to push the ctrl button, just the print screen then right click and past into word or publisher or any other program.



Thanks that could be handy.

[TZ350]

Yes, I have been trying some of these tips, very handy, thanks.

[sitkuura]

http://www.pit-lane.biz/t6315p300-2stroke-ryger-engine#294442

[nasone32]

Although i respect Jan Thiel, I don't like comments based on a friend's telling.

[Haufen]

Although i respect Jan Thiel, I don't like comments based on a friend's telling.

Neither do I.
Unfortunately, that is all we have on the ryger, there is not a single fact, just tellings, and now both ways.

On the other hand, maybe if it looks like fish, smells like fish and tastes like fish then, you know, maybe it's just fish. After all, 30ish hp is what one would expect from a 125cc engine with reduced pumping capacity and a single exhaust port.

[MotleyCrue]

Neither do I.
Unfortunately, that is all we have on the ryger, there is not a single fact, just tellings, and now both ways.

On the other hand, maybe if it looks like fish, smells like fish and tastes like fish then, you know, maybe it's just fish. After all, 30ish hp is what one would expect from a 125cc engine with reduced pumping capacity and a single exhaust port.

I have wondered for sometime why Ryger didn't have both Frits and Jan onboard. Maybe it was for financial reasons or some other reasons but in hindsight I think it would have been best for all.

[SwePatrick]

Although i respect Jan Thiel, I don't like comments based on a friend's telling.

If it is some truth in that statement it all lines up with the bad design of transfers(in my eyes).
And makes me wonder how on earth Frits could have been sweettalking so much?

Let´s hope it´s just bullshit.

[MotleyCrue]

Yes, lets hope the 70 HP and Frits's fast ride in the kart was not done with some kind of spiked fuel, and that all that needs to be done is a bit of ironing out of bugs. But if the engine made 56 HP a few years ago before any of this 70 HP stuff came about it would seem like it could at least make 56 HP again.

[wobbly]

Here is a pic of the thermostat lid spigot.

[peewee]

sounds to me like jan is still king and rsa is still most powerful 125 on the planet :first:

[jasonu]

sounds to me like jan is still king and rsa is still most powerful 125 on the planet :first:

A shame there is no class for it anymore.

[Yow Ling]

A shame there is no class for it anymore.

They still run 125's with moto3 in BSB, the lease on a RSA125 might be a bit steep though

[Yow Ling]

So the Ryger makes as much power as TZ350's GP125 they could have saved a bit of money doing this, I would not doubt Jans opinion his friends may be well connected in the 2t world.

[Bert]

Rules....

Given the international presence on this page - im hoping someone maybe able to help.
(Sorry TZ for going left field - but it is two stroke related).

We are current writing some club rules for the inclusion of 250GP bikes (being twin cylinder two stokes GP not production) in our club series: given they are no longer part of our national manual of Motorsport - we are required to generate a set of supplementary rules for the 2016 season and permits.
Our fantastic national body can't seem to recover our documented national rules for consumption and reuse.
And I can't seem to find my older versions of NZ rules (was hunting it out for comparison around buckets) - in a box somewhere....
Would anyone internationally (or here in NZ) have access to technical rules for 250GP bikes and/or point me towards somewhere/someone whom might be able to help (rather quickly)...

Cheers
Brent

[d2t]

Rules....

http://www.usgpru.net
This is the premier organization for 125/250 racing in the USA. Go to the download section and there's a rulebook. More closely tied to club racing but follows the former Dorna-like professional experience. Hope that helps.

[sonic_v]

Rules....

Given the international presence on this page - im hoping someone maybe able to help.
(Sorry TZ for going left field - but it is two stroke related).

We are current writing some club rules for the inclusion of 250GP bikes (being twin cylinder two stokes GP not production) in our club series: given they are no longer part of our national manual of Motorsport - we are required to generate a set of supplementary rules for the 2016 season and permits.
Our fantastic national body can't seem to recover our documented national rules for consumption and reuse.
And I can't seem to find my older versions of NZ rules (was hunting it out for comparison around buckets) - in a box somewhere....
Would anyone internationally (or here in NZ) have access to technical rules for 250GP bikes and/or point me towards somewhere/someone whom might be able to help (rather quickly)...

Cheers
Brent

http://www.spelregels.eu/rules/motorracen/ROAD_RACING_GP_Eng.pdf

FIM technical rules for 2009 season.

[Bert]

Magics thanks Gents - a little more full on than I was expecting - but the key elements are there to hack into our wider rule set..

[marsheng]

Hi Chaps, I'm at a loose end here. Both KR150s exhibit the same wear patterns after an hour or less of racing.

Bike 1 new pistons (x2) in the original coated bore with a loose fit but within spec
Bike 2 new piston in a new cast iron bore with new tight (correct 0.05mm) fit.

Bottom of pistons shows no signs of overheating underneath the piston crown.

Bike 2 also had a really serious deep score mark where the rings ends meet.

Bike 1 uses TTS and bike 2 uses Spectro Platinum XS. Both bikes are using the standard auto lube system.

http://www.marshland.co.nz/ftp/KR150/ExhaustPort.JPG

http://www.marshland.co.nz/ftp/KR150/PistonExhaustSide.JPG

http://www.marshland.co.nz/ftp/KR150/PistonInletSide.JPG

http://www.marshland.co.nz/ftp/KR150/RingGroove.JPG

Open to suggestions.

[mr bucketracer]

Hi Chaps, I'm at a loose end here. Both KR150s exhibit the same wear patterns after an hour or less of racing.

Bike 1 new pistons (x2) in the original coated bore with a loose fit but within spec
Bike 2 new piston in a new cast iron bore with new tight (correct 0.05mm) fit.

Bottom of pistons shows no signs of overheating underneath the piston crown.

Bike 2 also had a really serious deep score mark where the rings ends meet.

Bike 1 uses TTS and bike 2 uses Spectro Platinum XS. Both bikes are using the standard auto lube system.

http://www.marshland.co.nz/ftp/KR150/ExhaustPort.JPG

http://www.marshland.co.nz/ftp/KR150/PistonExhaustSide.JPG

http://www.marshland.co.nz/ftp/KR150/PistonInletSide.JPG

http://www.marshland.co.nz/ftp/KR150/RingGroove.JPG

Open to suggestions.my 250 twin did that to my pistons more one of the 2 pistons , i got sick of it and sold it , turned out it was leaking seals and sucking in air making it run lean ?

[TZ350]

Or water .... water breaks down the oil film.

[speedpro]

Ring gap a bit tight causing score of bore and if it runs good with throttle then maybe the pilot jet is small, or an air leak, both making it lean on overrun and the piston trying to nip up causing the scuffs on the pistons. Do not re use the pistons once this happens. A careful measure will show they have changed shape, permanently

[Flettner]

Piston is not uncovering the eye ports at TDC are they?

[marsheng]

Ring gap a bit tight causing score of bore and if it runs good with throttle then maybe the pilot jet is small, or an air leak, both making it lean on overrun and the piston trying to nip up causing the scuffs on the pistons.

New bearings, conrod and crank seals in both motors.

The original bike had 40K on the clock and the piston and bore looked ok. As these are still running the standard ignition, ie no retard at max RPM, (I think) could it be that this is causing the overheating issue when used as a race bike and max RPM most of the time?

PS this is at Ruapuna full track so they are being given a good workout. .

Thanks Wallace.

[JanBros]

http://www.marshland.co.nz/ftp/KR150/PistonExhaustSide.JPG


don't know if the original KR150 piston has holes in it's skirt, but a KR1 piston has them to lube the bridge between main and aux exhaust ports (which gets realy hot). I'd drill some holes in the skirt :

http://i1277.photobucket.com/albums/y485/JamesP001/DSC01411a_zps4857238a.jpg

and if you use a piston with the ring pin in the C-port, you could also drill holes in the skirt between B and C ports.

[Muciek]

Exh main port looks high placed compared to transfers , is the bottom part of it in level with piston at TDC?

[Frits Overmars]

could it be that this is causing the overheating issue when used as a race bike and max RPM most of the time?Many if not most bikes run out of blowdown time.area before they run out of revs. Then exhaust gases enter the transfer ducts, rapidly heating the cylinder.
Maybe you can insert some distance pieces between the cylinders and the exhaust headers, or advance the ignition a bit in order to prevent the rider from revving too high all the time.


don't know if the original KR150 piston has holes in it's skirt, but a KR1 piston has them to lube the bridge between main and aux exhaust ports (which gets realy hot). I'd drill some holes in the skirt.I've never even seen a KR150 but I used to do some work on the KR1S. The sealing between the common head, the cylinders and around the KIPS bores could be problematic. And they did love the lube holes in the pistons that Jan mentioned. But do not make them bigger than 2 mm.

[JanBros]

The sealing between the common head, the cylinders and around the KIPS bores could be problematic.

indeed.
I made a CNC head for KR1's, and one of the problem's I faced was sealing the KIPS valves. Solved it by placing O-ringed inserts in the KIPS bores in the cylinders. you can read all about it here :

http://www.kr-1s.co.uk/forum/viewtopic.php?f=2&t=11307

[2005bully]

As Speedpro suggests a tight end gap can cause the scuffing of the cylinder at the ring end gap. Another less common cause is be the intimacy of contact between the ring locating pin and the clearance cutouts in the ring itself. Any contact between the pin and the ring should be on the 2 sides of the pin. When checking be sure to allow for clearance changes at operating temp..... Kermit Buller

[marsheng]

Thanks for all the replies - really some food for thought.

One thing I forgot to mention is the squish band is very narrow. 5-6 mm from memory. Could this be contributing to the extra heat being put into the piston crown edges ?

Cheers Wallace.

[Leed]

KR150
"Bike 1 uses TTS and bike 2 uses Spectro Platinum XS. Both bikes are using the standard auto lube system. "

1. why would you use autolube on a race bike? the pump meters out based on throttle cable opening, it doesn't know how much load the engine is under or how many RPM. Another setup variable that can be eliminated... New fuel = new oil, easy to remember NOT a reservoir to be forgotten (accelearation, banking left & right on a low reservoir). All the Formula 3 and Sports Productions kits blank off and remove the oil pump the road based bikes they were based. Spectro Platinum SX is premix only.

2. the bridge(s) between exhaust ports require piston lube holes - 2 each side of main

3. what brand is the pistons?
On the KR-1, pistons evolved into Recessed Ring Pegs due to 'reported' failures: growing or falling (peg then became fully encompassed by ring overlap)
"Generally, when measuring ring end gap, it is most always better to have too much than too little; a tight ring end gap can potentially cause the ring ends to touch during operation (length from thermal expansion), which may cause a failure"
For the skirt to have so many places its picked up, Youd think cyl/bore clearance or run hard not fully warmed.


REID VAPOUR PRESSURE - wobbly
I noted just the other week when installing a new petrol cap for my car, in a very warm garage, how easily vapour was trapped in the tank.
The tank was less than 1/4 full. Minutes later the cap could be removed again with similar pressure blow off.
I see the test procedure ASTM D323 has small cool volume of fuel expanding into a much larger receiver.

Having never opened full drums of race gas - is there much ullage space to pressurise in the first instance?

It seems significant consideration to be mindful of, the freshness of petrol left in your MX or racebike, might have a 5% performance/fuelling/det effect

Today's Factoid: ULLAGE MOTOR to maintain thrust and keep rocket propellant separated into liquid and gas states so that only the liquid is drawn into the motor (https://en.wikipedia.org/wiki/Ullage_motor)... kinda the opposite of combustion engines where atom/vapourisation is important?

[marsheng]

KR150

1. why would you use autolube on a race bike? the pump meters out based on throttle cable opening,

The KR has a very clever way of oiling the bigend. There are no slots in the bigend and going premix would reduce the lubrication. Could add some premix to the gas in addition to the autolube.


2. the bridge(s) between exhaust ports require piston lube holes - 2 each side of main

We can try this.


, pistons evolved into Recessed Ring Pegs

The pins are recessed.

[TZ350]

KR150
"Bike 1 uses TTS and bike 2 uses Spectro Platinum XS. Both bikes are using the standard auto lube system. "

Spectro Platinum SX is premix only.

Auto lube pumps don't like shifting premix treacle, you could have cavitation issues on the suction side and limited oil delivery.

[Leed]

what is thin and runny vs thick and slow?
water or ink has a kinematic viscosity ~1 cSt, your blood ~2.43, liquid honey ~950

Castrol TTS Viscosity Kinematic: 43 mm2/s (43 cSt) at 40°C (autolube or premix)
Spectro SX Viscosity: 37 cSt @ 40°C (premix only)

Castrol TTS vs Spectro SX both oils feature similar viscosity, and SX is actually lower = slightly more fluid
Spectro's injector oils range from 57-94 ! some where in the middle is engine oil 0W-30 (66)

viscosity then, isn't a good comparision of 2T oil any more than colour is
is fuel miscibility the separating factor between the two?
and if you have problems with both oils, it not the type or brand that's causing it.

[jonny quest]

What kind of pistons are they? Cam grind and taper may not be good for your application

[chrisc]

Quality racing over the weekend at the Auckland, New Zealand club round!

Here's one of Culley from Team ESE on a Honda NF4 RS125 chassis RG50 bucket. What a beaut!

Click the little blue arrows in the corner of this quote box to see more.


...AMCC Club Championship Round 4 - February 2016....

https://farm2.staticflickr.com/1583/25169416455_126c1a7b41_c.jpg (https://flic.kr/p/Em8QC8)

[peewee]

I thought autolube was mostly for scooters

[husaberg]

I thought autolube was mostly for scooters

Yamaha and Suzuki both used it.
Pretty sure both the TA125 and the TZ350 both originally had it as well. maybe it was the TR or TD?
But simple is best, less to bleed, less to check and less weight to boot.

[Yow Ling]

I think the autolube is unlikley to be the problem there are dozens of RG150's and many other KR150's that dont have this problem. All of Pete Jones's RGs ran TTS with no problems , I run it in my KR with the pump.
I think like others have said the problem might be the piston, its a cheap Thai piston? Probably sourced from china for about $3

With the genuine (ish) Kawasaki part they last for ages, I would go down that path first as the common thing in both these engines is the Piston manufacturer

[marsheng]

I think the autolube is unlikley to be the problem there are dozens of RG150's and many other KR150's that dont have this problem. All of Pete Jones's RGs ran TTS with no problems , I run it in my KR with the pump.
I think like others have said the problem might be the piston, its a cheap Thai piston? Probably sourced from china for about $3

With the genuine (ish) Kawasaki part they last for ages, I would go down that path first as the common thing in both these engines is the Piston manufacturer

Worth a try. I'll see if I can find one.

The holes in the piston seem like a good idea.

Cheers Wallace.

[Bert]

I think the autolube is unlikley to be the problem there are dozens of RG150's and many other KR150's that dont have this problem. All of Pete Jones's RGs ran TTS with no problems , I run it in my KR with the pump.
I think like others have said the problem might be the piston, its a cheap Thai piston? Probably sourced from china for about $3

With the genuine (ish) Kawasaki part they last for ages, I would go down that path first as the common thing in both these engines is the Piston manufacturer


Worth a try. I'll see if I can find one.

The holes in the piston seem like a good idea.

Cheers Wallace.

I recall Mike Chandler talking about cheap Pistons being a major source of issues with VMCC juniors (both KRs and RGs). Swapping back to OEM seemed to resolve a lot of issues. Higher expansion rate on the cheaper option, oil holes may resolve some of this??

[TZ350]

GPR, poster boys of Auckland buckets hahaha Check out the back drop of the bucket section of the AMCC website... two Welly region riders front and center. Probably saw those leathers and thought "shit that's definitely a bucket rider". http://amcc.org.nz/buckets/#bucket-news

319859

Welly riders, they come and take our trophy's, steel our women and get pictured pride of place on our club website ....... :crybaby:

[TZ350]

Page 1480 .......



Seems like "cht", "egt", or any other three letter word is not a valid search term on this forum, I get zero results. 4 is the magic number, "idle" works fine. Dumb
I use google custom search engine for looking up older items (items just posted don't show up directly)
https://cse.google.com/cse/publicurl?cx=009468122799118164990:5pd9xdluxce



As these are still running the standard ignition, ie no retard at max RPM, (I think) could it be that this is causing the overheating issue when used as a race bike and max RPM most of the time?

Many if not most bikes run out of blowdown time.area before they run out of revs. Then exhaust gases enter the transfer ducts, rapidly heating the cylinder.
Maybe you can insert some distance pieces between the cylinders and the exhaust headers, or advance the ignition a bit in order to prevent the rider from revving too high all the time.



There is no such thing as "good" Avgas at any place but an airport tank.
In those tanks it has to be checked constantly for volatility and water content.
At Ruapuna - Philip Island is even worse, the tanked fuel is absolute rubbish as it sits forever,flashing off all the good front ends in no time at all.
A small aircraft crashing due to fuel related engine failure simply isnt allowed,full stop.


I thought the avgas at Ruapuna was decent? I'm assuming you'll tell me it's just old stuff from the airport?


Yes, 909 will settle out in AvGas after only a few minutes of mixing it up - did exactly that to me on the dyno.
We tested for probably 20mins,stopped for a cup of tea,and it would not restart,I could see straight oil in the bowls of the Lectrons.
But add a cup of acetone in 5L and no issues after that.
Motul Kart GP does not do this in Avgas, I have had some mixed , sitting in the kart dyno plastic tank for weeks to test this.

Modern forged pistons made by Wossner run the same sort of initial clearances as cast ones.
In my TZ400 the 66mm Wossners run at 0.06mm,they get 2 - 5min heat cycles then thrashed.
After 1 race meeting they had shrunk by 0.02, and at 580Km I replaced them as they were now with 0.04 extra ie they were at 0.1mm in the bore.
This is with a 58 stroke spinning to 11200 in every gear, and topping out at 11800 in 6th.
They looked like brand new on the skirts, but I thought why take a chance.
As it stands I wouldnt use a Wiseco if they gave them away.


Re cooling the spigot in KZ2 engines - yes, this idea if done by milling slots thru the flange face on the cylinder allows water
to cool right around the duct to the face, then also the steel spigot face is cooler as well if you cut the slots thru the gasket material.
I can touch the tapered spigot on the engine after a hard dyno pull without being burnt.
As you say this keeps the trapped mixture in the cylinder duct much cooler,and the egt further out in the header dropped as well.
I can run at least 2 jets leaner to get the egt back , without getting into deto using that system.
The pic is an early testing one, now the slots go right thru to water,top and bottom.

The 100cc engines really wide power band is down to the pipe design, with its series of bleed holes in the rear cone.
This pulls down the peak power and adds plenty at the bottom, and in the overev area.
Take that pipe and remove the rear cone holes,and it becomes all but impossible to tune the pumper carb properly,and the power band is basically 1/2 as wide.
OK for a slipper clutch setup on direct drive, no good at all without the clutch set to peak torque rpm.
The 3 port system has plenty of STA for the power produced, and the scavenging regime has been slowly developed over time to enhance the band width as well.


It looks like burnt oil residue on top of more burnt oil residue.
My guess, you have had oil separation at some stage, and a period where the thing has been burning a mixture of mostly oil, with little fuel.
Many oils will separate under certain conditions - many semi synthetics do it all the time in AvGas without something like acetone in the mix.


It looks like a lot of bad oil in the mixture and a piston that didn't get hot enough to keep its nose clean. Maybe the engine has been slurping gearbox oil through a faulty oil seal.


Just stripped my Macio after a day's of testing and I have this strange carbon build up on the piston. It has had around 30 min running time.

It looks like the frying pan after cooking honey bacon. (Now I feel hungry)

It has these miniature hills and valleys. Any suggestions ?

Thanks Wallace.


I would like to believe that moving the rear Aprlia studs and then pulling back the rear wall would have a positive effect if that
operation reduced the backward lean of the B duct ie getting rid of the two dimensional bending of the flow around the corner into the port..
But as you say Frits this would upset the scavenging pattern by increasing the B port flow regime, but if the extra space gained was used then to increase the A port
flow area, this may then restore the balance - and gain an overall increase in transfer Cd.
That would then maybe allow slightly lower timings, to increase the all important ( and ultimately power limiting ) blowdown STA.
We started this discussion when it was suggested we look at ways of "improving " what Jan had achieved, but unless the same effort was put into restoring the leaning tower
geometry, then failure would be more than likely.
As we know well, several geniuses in R&D had a go at improving what Jan had done,as of course its obvious the crank needed cheek plates to reduce the case volume - only
to find the bikes thus delivered to the teams were somehow slower.
As it stands the only really optimistic direction of improvement would be to try my Ex duct length/area recommendations that work so well in the sim, and
maybe to improve the Ex duct cooling by having water all the way up to,and around the back of the spigot that I know works well in KZ2 engines.


Thanks!
Shure! I've posted some info here in this thread, just search for posts by me containing "spx"

I've also documented it pretty well on mopedarmy.com
Here's the thread where it all started:

http://www.mopedarmy.com/forums/read.php?7,3494948

This is the continuation and where I went custom cases and rotary valve:

http://www.mopedarmy.com/forums/read.php?7,3747121

These threads are basically documentation of my journey through the two stroke world. Lots of stupid ideas and failures, but I've kept at it, and still do!


Yes, Jans modification of the B-ducts front wall caused a reduction of the duct entrance area. But when I said that this area, and the duct volume, could easily be enlarged, I was not thinking of undoing this modification, but of removing material in the direction of the cylinder stud holes.

That seems like a logical thing to do if you look at the backward-leaning B-duct rear wall as it rises from the crankcase to the port, and if you notice the available amount of material between the duct entrances and the studs, both in the crankcase and the cylinder. It would certainly improve the inflow into the duct and enhance the kinetic energy of the flow exiting from the B-window. But that would be too much of a good thing. The B-windows are already higher and wider than the A-windows; increasing their flow even more would push the central scavenging column over to the exhaust side, causing scavenging deterioration and short-circuiting.
This peculiar set of circumstances came into being because Jan was obliged to develop new cylinders that should also do well on older engines.

Below you see an RSA cylinder with its small B-duct entry area and the extra area that seems so inviting to be added, but that would do the scavenging no good.

319932


Thanks Wob. I wasn't actually talking about duct entry, but volume. Older ports are of course less curved but also often skinnier. There must be an ideal volume to draw from and especially if you create a bigger engine which in effect Sketchy is doing stroking the already over bored 125 barrels the original design came from, say optimistically to 160cc


Just a couple of points about transfer duct geometry.
The main thing many dont " get " is that virtually all the bulk flow in a race engine occurs around BDC when the pipe
effects are at a maximum when the biggest depression is seen at the Ex port face.
When the transfers open there is more blowdown pressure above the dropping piston, than there is case pressure, thus for the port that
opens first there will always be backflow.
This is how stagger works, retarding the initial outflow from one particular pair of ports, and favouring the flow from the lower set (s).

Secondly is that All of the mixture that enters the cylinder, is stored in the duct volume - there is NO flow from the case,thru the duct and on out thru the ports.
Remember as I have shown before there is NO flow thru the reeds until the transfers are almost closed by the rising piston, and this flow is created " again " by
the depression in the case,caused earlier by the pipe ( and helped by intake tuning length if done right ) - Not a reduced pressure ratio due to the piston rising.

And as far as the measured dynamics as seen by EngMod, that is the wave action within the duct, moving from one end to the other,there is no difference
in power when going from a duct entry/exit ratio of 1:1 up to 1.4:1.
I tested this keeping the case volume the same in both cases.
But a change in case volume from 1.36 down to 1.32 had a huge effect.

And as always Frits hits the nail on the head,in that although the Aprilia has a very small B port entry area, most of the reduction came from Jan filling in the B duct front wall.
By making it perpendicular to the bore,the effect of this along with the large ( wide and high ) port area had a much more beneficial effect on scavenging ( thus power ) than any perceived ( real or not )
issue with duct volume or flow " ability ".


So with a bigger capacity presumably the transfer duct area should be larger to feed the cylinder if the mixture is firstly drawn from that general area.

On my MB I glued inserts to shape the flatish inner walls but I believe my mistake was removing area and not replacing it by removing from the outer wall.


Cutting away the duct outer entry will have more effect on the case compression ratio ( may not be what is needed ) than it will
affect the flow " ability " of the duct.
Adding a BIG radius to the inner entrance is far more a guarantee of a power increase, and I have sort of sketched what Frits was alluding to, change the radius such
that the duct CSA is constantly reducing, with a bigger radius that starts and finishes earlier and later.


Sure, removing that area will increase the volume. But it will considerably decrease the gasket area. And you really need that area. The cylinder is moving about on the cases more than you would believe.
A second consideration: Enlarging the entrance to the transfer ports is usually a good thing, but not always. In an Aprilia RSA cylinder you can easily improve the inflow from the crankcase into the B-ports. There's one snag: it will cost power; it will upset the scavenging balance that Jan Thiel established after years of testing.

By today's standards: yes. Initially there is a big radius that tightens up as the duct gets narrower. In theory it should be the other way around: as the duct narrows, the flow velocity increases and so will the tendency of the flow to detach from the inner curvature. Ideally the radius should increase as the duct narrows, but that would lead to very wide cylinders, so we content ourselves with constant-radius inner duct walls.


So i'm officially a addict with my computer desk looking more like the workbench!

A little question for the gods of two strokes (aka all of you lot ;)

In the photo that I have marked, is it beneficial to remove this area to increase the volume at the entrance to the transfer ports? Also to be the curvature of the inside wall looks wrong?

319881

319882

[seymour14]

319859

Welly riders, they come and take our trophy's, steel our women and get pictured pride of place on our club website ....... :crybaby:

Flamin hillbillies...:Punk:

[Bert]

319859

Welly riders, they come and take our trophy's, steel our women and get pictured pride of place on our club website ....... :crybaby:

Yea, not a great look. But thanks AMCC for recognising the out of towners that added such joy to your racing.:bye:

[ken seeber]

Only a few weeks and everything will be explained, so be patient for a little while.



OK Luc, two weeks have nearly passed, so time's up tomorrow We've been sitting on the edge of our seats, twiddling our thumbs, waiting for the big moment. Is it only 30 hp? Does it break? Was it just a plan to sell VM engines? How does it really work?

You seem to be pretty close to the action. The whole of the southern hemisphere is waiting on you. Put us out of our misery. We're all looking forward to it. :niceone:

Thanks

[Sketchy_Racer]

So i'm officially a addict with my computer desk looking more like the workbench!

A little question for the gods of two strokes (aka all of you lot ;)

In the photo that I have marked, is it beneficial to remove this area to increase the volume at the entrance to the transfer ports? Also to be the curvature of the inside wall looks wrong?

319881

319882

[Frits Overmars]

In the photo that I have marked, is it beneficial to remove this area to increase the volume at the entrance to the transfer ports?Sure, removing that area will increase the volume. But it will considerably decrease the gasket area. And you really need that area. The cylinder is moving about on the cases more than you would believe.
A second consideration: Enlarging the entrance to the transfer ports is usually a good thing, but not always. In an Aprilia RSA cylinder you can easily improve the inflow from the crankcase into the B-ports. There's one snag: it will cost power; it will upset the scavenging balance that Jan Thiel established after years of testing.


the curvature of the inside wall looks wrong?By today's standards: yes. Initially there is a big radius that tightens up as the duct gets narrower. In theory it should be the other way around: as the duct narrows, the flow velocity increases and so will the tendency of the flow to detach from the inner curvature. Ideally the radius should increase as the duct narrows, but that would lead to very wide cylinders, so we content ourselves with constant-radius inner duct walls.

[RGVforme]

So i'm officially a addict with my computer desk looking more like the workbench!

A little question for the gods of two strokes (aka all of you lot ;)

In the photo that I have marked, is it beneficial to remove this area to increase the volume at the entrance to the transfer ports? Also to be the curvature of the inside wall looks wrong?

319881

319882

Sure but remember that any increase in volume in the entrance must be matched to the flow restrictions coming out or a mod like this a waste of time esp if you upset the back pressure too much.

[TZ350]

But thanks AMCC for recognising the out of towners that added such joy to your racing.:bye:

It was a great day, really enjoyed it and catching up with the PN and Welly crew. .... :)

[wobbly]

Cutting away the duct outer entry will have more effect on the case compression ratio ( may not be what is needed ) than it will
affect the flow " ability " of the duct.
Adding a BIG radius to the inner entrance is far more a guarantee of a power increase, and I have sort of sketched what Frits was alluding to, change the radius such
that the duct CSA is constantly reducing, with a bigger radius that starts and finishes earlier and later.

[F5 Dave]

So with a bigger capacity presumably the transfer duct area should be larger to feed the cylinder if the mixture is firstly drawn from that general area.

On my MB I glued inserts to shape the flatish inner walls but I believe my mistake was removing area and not replacing it by removing from the outer wall.

[wobbly]

Just a couple of points about transfer duct geometry.
The main thing many dont " get " is that virtually all the bulk flow in a race engine occurs around BDC when the pipe
effects are at a maximum when the biggest depression is seen at the Ex port face.
When the transfers open there is more blowdown pressure above the dropping piston, than there is case pressure, thus for the port that
opens first there will always be backflow.
This is how stagger works, retarding the initial outflow from one particular pair of ports, and favouring the flow from the lower set (s).

Secondly is that All of the mixture that enters the cylinder, is stored in the duct volume - there is NO flow from the case,thru the duct and on out thru the ports.
Remember as I have shown before there is NO flow thru the reeds until the transfers are almost closed by the rising piston, and this flow is created " again " by
the depression in the case,caused earlier by the pipe ( and helped by intake tuning length if done right ) - Not a reduced pressure ratio due to the piston rising.

And as far as the measured dynamics as seen by EngMod, that is the wave action within the duct, moving from one end to the other,there is no difference
in power when going from a duct entry/exit ratio of 1:1 up to 1.4:1.
I tested this keeping the case volume the same in both cases.
But a change in case volume from 1.36 down to 1.32 had a huge effect.

And as always Frits hits the nail on the head,in that although the Aprilia has a very small B port entry area, most of the reduction came from Jan filling in the B duct front wall.
By making it perpendicular to the bore,the effect of this along with the large ( wide and high ) port area had a much more beneficial effect on scavenging ( thus power ) than any perceived ( real or not )
issue with duct volume or flow " ability ".

[husaberg]

From Brian Dmarge
Air cooled tech ignore the extra valves and oiling.
url]https://www.dropbox.com/s/g83k5qveoa533v8/_cylinder%20review%20.pdf?dl=0[/url]
https://www.dropbox.com/s/qumzhe8k27wffh6/_fins.pdf?dl=0

[F5 Dave]

Thanks Wob. I wasn't actually talking about duct entry, but volume. Older ports are of course less curved but also often skinnier. There must be an ideal volume to draw from and especially if you create a bigger engine which in effect Sketchy is doing stroking the already over bored 125 barrels the original design came from, say optimistically to 160cc

[husaberg]

Thanks Wob. I wasn't actually talking about duct entry, but volume. Older ports are of course less curved but also often skinnier. There must be an ideal volume to draw from and especially if you create a bigger engine which in effect Sketchy is doing stroking the already over bored 125 barrels the original design came from, say optimistically to 160cc

From memory the NSR150 rods are about 6mm longer than the NSR125, which means they are likely about 6mm longer than the NSR250's
I have the measurements somewhere
NSR150 110mm
NSR125 104mm
NSR250 104mm

Pretty sure most of the NSR300 conversions involve making the NSR150 cylinders shorter. But Food for thought.
I am not sure how the piston deck heights work re the 150 and the 125/250
(it looks like 32mm vs 30mm)

[Frits Overmars]

Enlarging the entrance to the transfer ports is usually a good thing, but not always. In an Aprilia RSA cylinder you can easily improve the inflow from the crankcase into the B-ports. There's one snag: it will cost power; it will upset the scavenging balance that Jan Thiel established after years of testing.
as always Frits hits the nail on the head,in that although the Aprilia has a very small B port entry area, most of the reduction came from Jan filling in the B duct front wall. By making it perpendicular to the bore,the effect of this along with the large ( wide and high ) port area had a much more beneficial effect on scavenging ( thus power ) than any perceived (real or not) issue with duct volume or flow " ability ".Yes, Jans modification of the B-ducts front wall caused a reduction of the duct entrance area. But when I said that this area, and the duct volume, could easily be enlarged, I was not thinking of undoing this modification, but of removing material in the direction of the cylinder stud holes.

That seems like a logical thing to do if you look at the backward-leaning B-duct rear wall as it rises from the crankcase to the port, and if you notice the available amount of material between the duct entrances and the studs, both in the crankcase and the cylinder. It would certainly improve the inflow into the duct and enhance the kinetic energy of the flow exiting from the B-window. But that would be too much of a good thing. The B-windows are already higher and wider than the A-windows; increasing their flow even more would push the central scavenging column over to the exhaust side, causing scavenging deterioration and short-circuiting.
This peculiar set of circumstances came into being because Jan was obliged to develop new cylinders that should also do well on older engines.

Below you see an RSA cylinder with its small B-duct entry area and the extra area that seems so inviting to be added, but that would do the scavenging no good.

319932

[adegnes]

First time on the roller for my spx/m50 creation.
There's power!
Alot of stuff needs sorting;
More belt tension for obvious reasons and the carb is hopelessly out of tune. A clutch, variator tuning, higher octane fuel etc.
It's fierce on the pipe, and dead below it.
I'm excited!


http://youtu.be/QTjppmtH3-o

[nasone32]

Adegnes, great to see your work, can you provide more details?

[adegnes]

Adegnes, great to see your work, can you provide more details?

Thanks!
Shure! I've posted some info here in this thread, just search for posts by me containing "spx"

I've also documented it pretty well on mopedarmy.com
Here's the thread where it all started:

http://www.mopedarmy.com/forums/read.php?7,3494948

This is the continuation and where I went custom cases and rotary valve:

http://www.mopedarmy.com/forums/read.php?7,3747121

These threads are basically documentation of my journey through the two stroke world. Lots of stupid ideas and failures, but I've kept at it, and still do!

[breezy]

Thanks!
Shure! I've posted some info here in this thread, just search for posts by me containing "spx"

I've also documented it pretty well on mopedarmy.com
Here's the thread where it all started:

http://www.mopedarmy.com/forums/read.php?7,3494948

This is the continuation and where I went custom cases and rotary valve:

http://www.mopedarmy.com/forums/read.php?7,3747121

These threads are basically documentation of my journey through the two stroke world. Lots of stupid ideas and failures, but I've kept at it, and still do!



looking good ... good work:2thumbsup

[wobbly]

I would like to believe that moving the rear Aprlia studs and then pulling back the rear wall would have a positive effect if that
operation reduced the backward lean of the B duct ie getting rid of the two dimensional bending of the flow around the corner into the port..
But as you say Frits this would upset the scavenging pattern by increasing the B port flow regime, but if the extra space gained was used then to increase the A port
flow area, this may then restore the balance - and gain an overall increase in transfer Cd.
That would then maybe allow slightly lower timings, to increase the all important ( and ultimately power limiting ) blowdown STA.
We started this discussion when it was suggested we look at ways of "improving " what Jan had achieved, but unless the same effort was put into restoring the leaning tower
geometry, then failure would be more than likely.
As we know well, several geniuses in R&D had a go at improving what Jan had done,as of course its obvious the crank needed cheek plates to reduce the case volume - only
to find the bikes thus delivered to the teams were somehow slower.
As it stands the only really optimistic direction of improvement would be to try my Ex duct length/area recommendations that work so well in the sim, and
maybe to improve the Ex duct cooling by having water all the way up to,and around the back of the spigot that I know works well in KZ2 engines.

[AndreasL]

Well done adegenes!

The moped army forums format is criminal at best though. Grrr

[adegnes]

Well done adegenes!

The moped army forums format is at least criminal at best though. Grrr

Thanks!
I think you will have a much better experience with it if you switch to "Flat view". You'll find it near the top of the page when you're inside a thread. "Threaded view" is just hopeless! Can't believe it's the default setting! :facepalm:

[marsheng]

Just stripped my Macio after a day's of testing and I have this strange carbon build up on the piston. It has had around 30 min running time.

It looks like the frying pan after cooking honey bacon. (Now I feel hungry)

It has these miniature hills and valleys. Any suggestions ?

Thanks Wallace.

[Frits Overmars]

Just stripped my Macio after a day's of testing and I have this strange carbon build up on the piston. It has had around 30 min running time. It looks like the frying pan after cooking honey bacon.It looks like a lot of bad oil in the mixture and a piston that didn't get hot enough to keep its nose clean. Maybe the engine has been slurping gearbox oil through a faulty oil seal.

[Grumph]

It looks like a lot of bad oil in the mixture and a piston that didn't get hot enough to keep its nose clean. Maybe the engine has been slurping gearbox oil through a faulty oil seal.

I looked in at the track briefly. LACK of heat wouldn't have been an option - 30 deg plus air temps with a dry wind blowing and an air cooled 250....
Oil would be my guess - either gearbox or the mix has gone off.

[F5 Dave]

Never seen such goop. But I do feel like some bacon. Its a superfood don't you know?

Hey 10 more posts and we'll be at #22222.

[wobbly]

It looks like burnt oil residue on top of more burnt oil residue.
My guess, you have had oil separation at some stage, and a period where the thing has been burning a mixture of mostly oil, with little fuel.
Many oils will separate under certain conditions - many semi synthetics do it all the time in AvGas without something like acetone in the mix.

[Grumph]

It looks like burnt oil residue on top of more burnt oil residue.
My guess, you have had oil separation at some stage, and a period where the thing has been burning a mixture of mostly oil, with little fuel.
Many oils will separate under certain conditions - many semi synthetics do it all the time in AvGas without something like acetone in the mix.

Bet he's using the avgas available at Ruapuna....

[adegnes]

My comuter-scooter had similar stuff on it's piston after running 5% r40 for a short period of time. Also ran a very tight squish. The goo/tight squish combination quickly destroyed my piston, small end bearing and wrist pin. The wrist pin was missing 1mm from the bearing surface. Never heard it detonate.
Yep, I use my daily driver as a test bench.

Must add; it was not running particularly hot

[bjorn.clauw.1]

I would like to believe that moving the rear Aprlia studs and then pulling back the rear wall would have a positive effect if that
operation reduced the backward lean of the B duct ie getting rid of the two dimensional bending of the flow around the corner into the port..
But as you say Frits this would upset the scavenging pattern by increasing the B port flow regime, but if the extra space gained was used then to increase the A port
flow area, this may then restore the balance - and gain an overall increase in transfer Cd.
That would then maybe allow slightly lower timings, to increase the all important ( and ultimately power limiting ) blowdown STA.
We started this discussion when it was suggested we look at ways of "improving " what Jan had achieved, but unless the same effort was put into restoring the leaning tower
geometry, then failure would be more than likely.
As we know well, several geniuses in R&D had a go at improving what Jan had done,as of course its obvious the crank needed cheek plates to reduce the case volume - only
to find the bikes thus delivered to the teams were somehow slower.
As it stands the only really optimistic direction of improvement would be to try my Ex duct length/area recommendations that work so well in the sim, and
maybe to improve the Ex duct cooling by having water all the way up to,and around the back of the spigot that I know works well in KZ2 engines.

Hi Wobbly, by cooling the spigot in kz2's, does it help by cooling (/not heating as much) the fresh mixture that's in the spigot before it gets pushed back by the pipe?
About port geometry, I have been looking for an answer about 100cc kart engine port layout to no avail.
Namely what gives these engines their long powerband (and what has to be compromised to do so) and why most have only 3 transfer ports.

[TZ350]

First time on the roller for my spx/m50 creation. It's fierce on the pipe, and dead below it. I'm excited!


http://youtu.be/QTjppmtH3-o

I love it, please keep us posted as your project progresses.

[wobbly]

Re cooling the spigot in KZ2 engines - yes, this idea if done by milling slots thru the flange face on the cylinder allows water
to cool right around the duct to the face, then also the steel spigot face is cooler as well if you cut the slots thru the gasket material.
I can touch the tapered spigot on the engine after a hard dyno pull without being burnt.
As you say this keeps the trapped mixture in the cylinder duct much cooler,and the egt further out in the header dropped as well.
I can run at least 2 jets leaner to get the egt back , without getting into deto using that system.
The pic is an early testing one, now the slots go right thru to water,top and bottom.

The 100cc engines really wide power band is down to the pipe design, with its series of bleed holes in the rear cone.
This pulls down the peak power and adds plenty at the bottom, and in the overev area.
Take that pipe and remove the rear cone holes,and it becomes all but impossible to tune the pumper carb properly,and the power band is basically 1/2 as wide.
OK for a slipper clutch setup on direct drive, no good at all without the clutch set to peak torque rpm.
The 3 port system has plenty of STA for the power produced, and the scavenging regime has been slowly developed over time to enhance the band width as well.

[marsheng]

Bet he's using the avgas available at Ruapuna....

I'm not sure if this could be the reason but, when on the dyno after a fresh rebuild, it wouldn't run without the choke. On stripping the carb the ElF HTX 909 had turned to gum. We washed it out, drained the tank and used fresh 100+ octane from the Challenge station. Probably only ran for 10-15 seconds on the old stuff.

[marsheng]

I'm stumped again on this one. As you may be aware I have had a few issues with KR150 cold seizing.

My guidelines are Top End Rebuild by Gordon Jennings.

66x64 mm 2 stroke engines made 33 bhp with pistons with .002- inch piston/bore clearance. The same engine made 30 with .004 and 27 with .006 and then seized,.

So in doing rebores, I have tried to stick to the minimum recommended clearance.

On the Macio (67mm bore) the recommended clearance is 0.07 mm (.0027mm) for my first build I used this clearance. After 20 min of running, the barrel flange broke. On measuring the piston, it was now 0.06 mm smaller than original but still had the teflon coating and the bore was good.

On the second rebuild, I used a new piston and same clearance and raced it for almost a year. This piston also "shrunk" by 0.06 mm but looked perfect did so did the bore. So this running piston/bore clearance was 0.12 mm or .0047.

This last rebuild I decided to use the original piston of 20 minutes and bore to its new size plus clearance. I bored to + 0.08 mm. I did a few good heat cycles and took it very gently on the track for 2 x 5 laps.

Still being gentle but with a bit more power, I felt it start to slow down on the main straight and then 2 corners later it nipped up. On cooling it freed up.

So the question is, was Gordon using a cast piston ?

On the track, should forged pistons be given bigger clearance. ?

Or do I have something else wrong ??


Thanks Wallace

[wobbly]

Yes, 909 will settle out in AvGas after only a few minutes of mixing it up - did exactly that to me on the dyno.
We tested for probably 20mins,stopped for a cup of tea,and it would not restart,I could see straight oil in the bowls of the Lectrons.
But add a cup of acetone in 5L and no issues after that.
Motul Kart GP does not do this in Avgas, I have had some mixed , sitting in the kart dyno plastic tank for weeks to test this.

Modern forged pistons made by Wossner run the same sort of initial clearances as cast ones.
In my TZ400 the 66mm Wossners run at 0.06mm,they get 2 - 5min heat cycles then thrashed.
After 1 race meeting they had shrunk by 0.02, and at 580Km I replaced them as they were now with 0.04 extra ie they were at 0.1mm in the bore.
This is with a 58 stroke spinning to 11200 in every gear, and topping out at 11800 in 6th.
They looked like brand new on the skirts, but I thought why take a chance.
As it stands I wouldnt use a Wiseco if they gave them away.

[chrisc]

Bet he's using the avgas available at Ruapuna....

I thought the avgas at Ruapuna was decent? I'm assuming you'll tell me it's just old stuff from the airport?

[wobbly]

There is no such thing as "good" Avgas at any place but an airport tank.
In those tanks it has to be checked constantly for volatility and water content.
At Ruapuna - Philip Island is even worse, the tanked fuel is absolute rubbish as it sits forever,flashing off all the good front ends in no time at all.
A small aircraft crashing due to fuel related engine failure simply isnt allowed,full stop.

[peewee]

Just stripped my Macio after a day's of testing and I have this strange carbon build up on the piston. It has had around 30 min running time.

It looks like the frying pan after cooking honey bacon. (Now I feel hungry)

It has these miniature hills and valleys. Any suggestions ?

Thanks Wallace.

not sure if I have the photo anymore but I had a piston with weird stuff like that on the top. was heavy black gum or carbon with divets like golf ball. castor at 6% with Sunoco is what I was using. my thought was it must of been partially separated in the tank and continued through the engine that way

[Grumph]

There is no such thing as "good" Avgas at any place but an airport tank.
In those tanks it has to be checked constantly for volatility and water content.
At Ruapuna - Philip Island is even worse, the tanked fuel is absolute rubbish as it sits forever,flashing off all the good front ends in no time at all.
A small aircraft crashing due to fuel related engine failure simply isnt allowed,full stop.

Agree 100%. particularly given we've had 30 plus degree days for what seems like weeks now. I'd be surprised if there were any good front ends left at all by now. Your avgas ex challenge, Wallace, is probably just as bad.
I've been using the BP 98 pump gas - bought from a station with a high turnover. It isn't avgas but likes a lot of advance - and it's consistent.

[Grumph]

I thought the avgas at Ruapuna was decent? I'm assuming you'll tell me it's just old stuff from the airport?

When they put the tank in, they swore, up, down and sideways that it was going to be topped up every time the tanker went to the airport. On the way to the airport they said - so fresh...
BUT as it turns out, the fresh stuff costs more - so it's back to overage delivered on the way back FROM the airport....

What pees me off is that they were going to carry E85....but don't.

[JustHarry]

I've been using the BP 98 pump gas - bought from a station with a high turnover. It isn't avgas but likes a lot of advance - and it's consistent.

what about putting an octane booster into the 98 to bring it up to more av gas levels. so a consistent fuel with a high octane.
the kr150 got a bit noisy on 98. av gas seemed to fix it

[marsheng]

Modern forged pistons made by Wossner run the same sort of initial clearances as cast ones. In my TZ400 the 66mm Wossners run at 0.06mm,they get 2 - 5min heat cycles then thrashed..

Does it make a difference being a water compared to air cooled with piston/cylinder clearance ?

Could the cold seizing be not enough retard at the higher RPMs? Ie more heat in the combustion chamber heats the piston very quickly and it expands too fast for the liner ?
My thoughts are, more heat in the combustion chamber could heat the piston by XX degrees or so over its working temperature etc but the plug and carbon temperature may still be at a low enough to not show any signs of overheating.

Thanks Wallace.

[TZ350]

Bacon. It is a superfood don't you know?

Hey 10 more posts and we'll be at #22222.

320030

Looks like CrispyBacon took line honours for post 22222

[MotleyCrue]

As it stands I wouldnt use a Wiseco if they gave them away.

I've heard this a million times from different sources but I haven't heard a good explanation. What is the reason they suck ? They have been in business a long time and still sell lots of pistons, is it just certain applications they aren't good for ?

[Flettner]

I've heard this a million times from different sources but I haven't heard a good explanation. What is the reason they suck ? They have been in business a long time and still sell lots of pistons, is it just certain applications they aren't good for ?


I used to buy a Wisco piston for my 350 Kawasaki, it was a prolite type, cost a bit too but it did the job. After a few pistons used (ordered on the same part number), a standard pistons turned up, not prolite, same price. Wisco said "get stuffed" thats all we will supply now and you will have to pay the same price, to bad. So I turned them into prolite myself with the milling machine. Then I find Wossner, only make prolite type, cheaper, available without waiting and seem to work well. I can order them from the factory in lots of ten, even cheaper still! Won't catch me dealing with Wisco again until they change their attitude, and make a decient product again.

[wobbly]

The Wiseco Prolite range was a big step forward for the company, where they finally changed the forging material.
But the bottom line still is that they will 4 corner seize instantly if run at the minimum clearance recommended, and if run even slightly loose
they rock badly in the bore ( alot of taper,top to bottom ) then shrink insanely.
This then of course doesnt help the ring stay true in the bore and you quickly get blowby darkening the area under the groove.
Recently ( last 18 months ) the company has been groomed for corporate takeover.
The cash its worth comes down to the bottom line profit margin on sales, so they have deleted nearly all CNC ops on the basic forging.
The pistons are now way heavyer,more expensive and still have the issues explained above.
They used to do small run specials,but are now not interested.
Not even close to a Wossner in any respect.

Wallace, I suspect the complete opposite to what you said - when buggering about at low rpm trying to run it in,it has way too much advance for that part throttle
operation.
When we set up a race bike on the dyno the lower midrange always responds way better to winding in the throttle, with plenty of advance.
And this level of advance is only safe if you are accelerating hard into it - ask TeeZee,he has seen this and its serious effects on the engine when just chugging about for no good reason.

[TZ350]

Wallace, I suspect the complete opposite to what you said - when buggering about at low rpm trying to run it in,it has way too much advance for that part throttle
operation.

When we set up a race bike on the dyno the lower midrange always responds way better to winding in the throttle, with plenty of advance.

And this level of advance is only safe if you are accelerating hard into it - ask TeeZee,he has seen this and its serious effects on the engine when just chugging about for no good reason.

................... :yes:

[Grumph]

Whilst I respect Wob's experience with Wiseco pistons, and agree broadly with what he's saying, I suspect the target market for Wiseco now is mainly 4T pistons. I've used a lot of their 4T forged pistons over the years and will continue to use them as long as the price stays reasonable.

I'd also suspect that Wossner and others have seen a vulnerability in the 2T market where Wiseco is concerned and jumped in with a more up to date product.
Fair enough, that's the American way of business. As consumers we should be aware of it and take advantage.

[JanBros]

Once I bought Woessner's for my KR1S because they were the only ones that had an oversize.
200km's later I cut off my engine because suddenly it made a slightly different sound. restarted it and it would only run on 1 cylinder.

after getting my bike home on a trailer and dismantling my engine, I found that the bridge between C-port and the (useless ?) port underneath it (running KR1 cylinders, and that port disappeard in the later KR1S cylinders). didn't know why, thought it must have been bad campfering so I ordered a knew one.
it was only when reassembling that engine that I figured out the problem.

apparently Woessner put's the ring pins "somewhere in the region where they are supposed to be" , between B and C ports. And you have to take that "somewhere" lteraly ! I had 3 woessner's at that moment and no pins was exactly where they were supposed to be ! the damaged one was the worst of the 3 : the pins where 0.5cm!!! closer to each other than on an original. the pins from the other piston in the engine were a bit better but the ring was also already damaged, from 1 side the ring end was already gone, the other side bent.
I ran tuned cylinders (done by Heiden tuning at that time, a dutch company) and checked if in an original cylinder, the ring ends would also snap into the C-port and they did, si I took all 3 woessner's, an original piston and an original cylinder to the Belgian importer and explained him the problem. He agreed with me Woessner was 100% at fault and I agreed that he would ship everything to them so they could make piston's with the pins in the correct position.

Only many month's later they responded that it wasn't a problem, that they never had problem's with them and that they could do nothing for me !!!!! while it was so obvious what the problem was, and that their 3 piston's proved that they putted the pin's "at random somewhere where they should be".

The Belgian importer also wasn't happy with that response, so they took back the new uninstalled Woessner and offered me any 2 piston's of my choice in return for the 2 bad/damged ones. As they also import the Wiseco's, I finaly went for YZ125 '89 piston's (had to adjust my engine because of the 2mm lower deck height) because many manufacturers make them and are available in oversizes. And up to date they are still working wonderfully and show only normal wear.

Never again do I put Woessner's in any engine (not even if someone would pay me to do it, just out of principle) and my advice to anyone who would want to use them, is to check the pin positions and refuse the piston's if they are not exactly where they need to be !
btw : I never got back the original (used, but that doesn't matter) piston . to me they are :tugger:

http://i41.tinypic.com/ynjuf.jpg

http://i43.tinypic.com/rkatj4.jpg

[TZ350]

320041

I have been wiring up the bike, there is one shed load of wire on this thing.

320040

EFI pressure gauge, RH switch is for the fuel pump, it is pretty handy to be able to turn the EFI fuel pump off so as to be able to clear a flooded engine. RH gauge is the det counter, LH ignition switch and LH gauge is a Volt/10A Ammeter. I have 8A available from the generator to play with so it's pretty handy to be able to see the electrical load at any time while testing the bike on the dyno.

Now that I have begun to get somewhere with installing the Ignetech digital ignition and Ecotrons EFI systems. I have started to think about what we could do like power valve servo and rpm controled auto gear change quick shifter.

320042

Some time ago Frits posted an idea on how to reduce over run deto and cylinder overheating by lowering the pipes internal operating pressure in the over rev zone.

320043

I made my own version of a pipe pressure blead from a model aero engine carburettor body and gave it a try.

Unfortunately it was only hand controlled and I could not get an overrun picture but it did show some interesting pre peak power results.

320044

Blue is with it closed and the pipe at its normal internal pressure and red is with it open and some of the pressure bleed off. A surprisingly useful extra 500 rpm at the lower end and another surprise was that it was not that noisy.

I am sure that once it can be automatically controlled by the IgniTech, say closing at 10,500 rpm and opening again at 12,500 it would add some usefull spread and reduce over run deto and maybe even extend the over rev a bit.

500rpm at the bottom plus another 500 at the top and a reduction in cylinder overheating would be very handy in anyone's books.

So a pipe pressure bleeder looks like a useful option if you are looking for ways to extend the power spread and avoid (reduce) over heating from hot exhaust gases back flowing down the transfer ducts during over rev when blowdown is time limited and the internal pipe pressure is high.

320045

If the EFI thing does not work out then I have this 36mm smooth bore EI Blue Magnum carb with home made adjustable power jet and modified to be 24mm compliant if its measured according to MNZ's latest misguided carb clarification.

Previous tests have shown this carb to work quite well and whether its on a air cooled 125 or my new soon to be released water cooled 110 there is every reason to think 30+ is possible with it. The limitations will be port and blowdown STA not the 24mm restriction imposed by the old 24mm equivalent rule.

[Martin1981]

to me they are :tugger:
:lol:

A German RGV250 Tuner i once talked to also was not very impressed by the wössner pistons. he complained about too much shrinking after only a short time of use and uses only wiseco after that. but who knows if it really was wössners fault.

[adegnes]

500rpm at the bottom plus another 500 at the top and a reduction in cylinder overheating would be very handy in anyone's books.

So a pipe pressure bleeder looks like a useful option if you are looking for ways to extend the power spread and avoid (reduce) over heating from hot exhaust gases back flowing down the transfer ducts during over rev when blowdown is time limited and the internal pipe pressure is high.


I know atac type systems have been discussed before, but anyway here's "jbot"s experience with it, "The Boner".
http://www.mopedarmy.com/forums/read.php?7,3661232,page=1
(remember to choose "flat view")

Great guy! His got his own robot band too, "capturedbyrobots".

https://flotationdevice.files.wordpress.com/2011/03/capturedbyrobots.jpg

[adegnes]

Something weird/interesting:

I had another go with my bike on the roller yesterday. Now with the gas/xylene mix. It started and seemed to run fine, but didn't want to rev much higher than 12k under load. Max temps where low, CHT 280°F, EGT 1035°F. It did not sound/act rich.
Could this be the fuel once more? Maybe most of the xylene is just passing through without contributing much to the combustion? I'm basically running lean, but not hot cause the unburnt fuel cools the chamber/piston?

I'm ditching the homebrew fuel.

[peewee]

wob ,frits im still kicking around the idea of a electric fan on the back side of the rad. theyre 652g according to the spec sheet so I was just planning to use one to keep weight at a minimum. would it be best mounted at the top where the hot water enters or down at the bottom to make cool water even colder ?

[TZ350]

wob ,frits im still kicking around the idea of a electric fan on the back side of the rad. theyre 652g according to the spec sheet so I was just planning to use one to keep weight at a minimum. would it be best mounted at the top where the hot water enters or down at the bottom to make cool water even colder ?

My pick is the top where the water is hottest as more thermal energy is lost the greater the thermal difference is, ie bulk energy is lost more rapidly from a hotter surface than a cooler one.

[TZ350]

I know atac type systems have been discussed before, but anyway here's "jbot"s experience with it, "The Boner". http://www.mopedarmy.com/forums/read.php?7,3661232,page=1 (remember to choose "flat view")

Hi Adegnes I am going to check out his band. I tried to join mopedarmy but all my create account attempts failed. They kept telling me I had not entered a password, how many passwords do they want? Anyway probably get it sorted when they are back at work.

My pipe pressure bleed is a little different to an ATAC valve/chamber. My aim is to lower the actual working pressure inside the chamber about 1000 rpm both sides of maximum torque.

Below peak torque it has an effect like an ATAC chamber, by reducing the disruptive effect of the pipe and above peak torque the lower pressure allows blowdown to be more effective and reduces the amount of residual hot exhaust gas being pushed back down the transfers. Any way that is what I am hoping for.

Hope to get registered on the mopedarmy site so I can get a good look at "the boner".

[TZ350]

Something weird/interesting:

I had another go with my bike on the roller yesterday. Now with the gas/xylene mix. It started and seemed to run fine, but didn't want to rev much higher than 12k under load. Max temps where low, CHT 280°F, EGT 1035°F. It did not sound/act rich.

Could this be the fuel once more? Maybe most of the xylene is just passing through without contributing much to the combustion? I'm basically running lean, but not hot cause the unburnt fuel cools the chamber/piston?

I had a similar problem, motor lean and cold when I was running Methanol. The cure was to blend the fuel with Acetone to reduce the fuels cooling effect. I had to get the motor to run warmer so the fuel actually evaporated. Maybe you will need to blend your fuel too, but you would think 280F - 138C would be warm enough .... :scratch:

[husaberg]

Hope to get registered on the mopedarmy site so I can get a good look at "the boner".

Oh dear................ :lol:

[marsheng]

I seem to have lost a post


Recently ( last 18 months ) the company has been groomed for corporate takeover.
The cash its worth comes down to the bottom line profit margin on sales, so they have deleted nearly all CNC ops on the basic forging.


I presume you are talking about Wisco here.


Wallace, I suspect the complete opposite to what you said - when buggering about at low rpm trying to run it in,it has way too much advance for that part throttle
operation.


I was running between 5-8k, basically 3/4 power all the time during the beak in period. The power seems to have come in a bit earlier than the last cylinder by 750 RPM . Maybe I should have changed the retard point. My mistake, not enough dyno time before getting to the track.

I do have an new old stock Wisco piston here with a Dykes ring. Maybe worth a try.

Thanks to everyone. This forum just eggs me on to do more. Hopefully I'm not too annoying.

Cheers Wallace

[adegnes]

I had a similar problem, motor lean and cold when I was running Methanol. The cure was to blend the fuel with Acetone to reduce the fuels cooling effect. I had to get the motor to run warmer so the fuel actually evaporated. Maybe you will need to blend your fuel too, but you would think 280F - 138C would be warm enough .... :scratch:
One would think so...
Thanks, I'll try blending with acetone.
I hope this is fuel related not some other issue.
Engmod says peak power @ 15500rpm. In the simulations I used the default temperature numbers + wobblys recently posted guidelines on rpm dependent exhaust temp. My real numbers could be vastly different I suppose...

[adegnes]

Seems like "cht", "egt", or any other three letter word is not a valid search term on this forum, I get zero results. 4 is the magic number, "idle" works fine. Dumb

[bjorn.clauw.1]

Seems like "cht", "egt", or any other three letter word is not a valid search term on this forum, I get zero results. 4 is the magic number, "idle" works fine. Dumb

I use google custom search engine for looking up older items (items just posted don't show up directly)
https://cse.google.com/cse/publicurl?cx=009468122799118164990:5pd9xdluxce

[adegnes]

I use google custom search engine for looking up older items (items just posted don't show up directly)
https://cse.google.com/cse/publicurl?cx=009468122799118164990:5pd9xdluxce

Great tip, thanks!

[bjorn.clauw.1]

Re cooling the spigot in KZ2 engines - yes, this idea if done by milling slots thru the flange face on the cylinder allows water
to cool right around the duct to the face, then also the steel spigot face is cooler as well if you cut the slots thru the gasket material.
I can touch the tapered spigot on the engine after a hard dyno pull without being burnt.
As you say this keeps the trapped mixture in the cylinder duct much cooler,and the egt further out in the header dropped as well.
I can run at least 2 jets leaner to get the egt back , without getting into deto using that system.
The pic is an early testing one, now the slots go right thru to water,top and bottom.

The 100cc engines really wide power band is down to the pipe design, with its series of bleed holes in the rear cone.
This pulls down the peak power and adds plenty at the bottom, and in the overev area.
Take that pipe and remove the rear cone holes,and it becomes all but impossible to tune the pumper carb properly,and the power band is basically 1/2 as wide.
OK for a slipper clutch setup on direct drive, no good at all without the clutch set to peak torque rpm.
The 3 port system has plenty of STA for the power produced, and the scavenging regime has been slowly developed over time to enhance the band width as well.

Excellent info, thanks for sharing! Regarding the 100cc pipe; can we say that a properly controlled sliding exhaust could mimic the wider powerband and maybe even give a little more peak power than the 100cc pipe?

I'm currently trying to apply all the things I have learned here onto a rs125 aprillia engine. (Also finishing the engine testbench) I believe Frits once said that Jan Thiel modified a reed intake engine to give 48hp. I was wondering if anybody had any info on this. Also not sure what to do with the large boyesen intake ports on the aprilia.
I always thought that big boyesens delivering the fresh charge directly into the transfers could be an advantage, but finding any information on this is proving to be hard.