ESE's works engine tuner

[crazy man]

Sounds about right. I think my bog standard engine was 17.5 with carb and exhaust change. What Kit? Is there a kit?. 20 seams easy to get on an FXR its the other 6 or 7 that come hard.


Doing a nice job of hijacking the 2 stroke thread here well the boys are at the track. Sorry Lads. Hope you all had a good day racing.

yip there is a factory race kit. cams ,piston, exhaust , rear sets , stearing damper lol .l have the hole kit but not the exhaust . my engine in stock was 14.3 hp what was your one stock? it may tell the dyno diffence? sorry 2 smokers you lot will be to busy fixing your bikes up to look in here for a week or so lmao

[richban]

yip there is a factory race kit. cams ,piston, exhaust , rear sets , stearing damper lol .l have the hole kit but not the exhaust . my engine in stock was 14.3 hp what was your one stock? it may tell the dyno diffence? sorry 2 smokers you lot will be to busy fixing your bikes up to look in here for a week or so lmao

Never had it on a dyno bog stock. Had a 28mm flat slide and a shorter exhaust only. Have run a PWK30 and they work well for a 2 stroke carb. Nice and easy to tune. I would be interested in seeing that piston. Has it got really big valve pockets. Like 4mm deep if so I want one.

[husaberg]

yip there is a factory race kit. cams ,piston, exhaust , rear sets , stearing damper lol .l have the hole kit but not the exhaust . sorry 2 smokers you lot will be to busy fixing your bikes up to look in here for a week or so lmao

If he (Crazy man) is allowed a factory race kit.
well then it is only fair if i have one as well.
OK HRC do do one they call it an....er..... RS125.




Should be a easy fit into a RS125 frame



On a more serious note i seen these today Yummy A rear disk valve Honda RS125 The japanese are still copying the Italians.
The other is a billet cased std configuration.

it is here
http://www.ekartingnews.com/viewtopic.php?t=97465

[husaberg]

These are on the same page as above.
http://www.ekartingnews.com/viewtopic.php?t=97465

[TZ350]

Whow look at that rotary valve conversion, thanks Husaburg

[TZ350]

EngMod2T

There have been a few very informative postes lately that have got me thinking.

As we were on the subject of scavenging angles, now would be a good time to write something about the radial angles of the A-transfers.......

Like Frits explination of the leaning tower of Pisa and scavenging angles and how the front transfer ports are used to support the rear ports.

And the vital percentages in pipe design, Frits mentioned that things had to be held within certain % limits and Wobbly gave more detail of this % aspect of pipe design and something of its importance.



EngMod2T displays these vital % values in the pipe picture.

If I were to explain pipe design I would need to write a book, but in general things are pretty straightforward in relation to the % values.

End of header is always 31 to 33%

And end of diffuser is always 62 to 68%.

To see the effect of a silly long header, you can watch the pressure ratio at the Ex port, and thus the effect this has on the depression in the cylinder.

We are looking for the lowest and widest negative ratio we can get around bdc when the transfers are fully open.

A long header delays the beginning of the depression too late in the cycle, when in the power band.

In a race 2T we are always fighting power range Vs peak power.
Shorter diffusers create steeper angles, thus greater wave amplitude, but this narrows the effective band width.

So - in general the best compromise is around 66%

The % I quoted for header means that portion of the length from piston to rear cone end.
It’s from the piston to the beginning of the diffuser, what happens in between isn’t relevant.

Unless of course you use a small Ex duct and a bigger header, that makes more power.
And of course same for the diffuser end, that is simply 66% of the length from the piston to the end of the rear cone.

These little teco insights are very much appreciated......

This whole thing has got me thinking about making a new triple exhaust port cylinder liner, not so much for more power but to do away with the 75% exhast port and gain some extra mechanical reliability by reducing the width of the main exhaust port window.

And also by getting the transfers low and wide I might be able to reduced the exhaust duration from 203 deg to something closer to 196 which if I remember correctly, is the ideal as it stays in resanance with the pipe for longer giving a wider spread of power.

And at the same time re-arrange the transfer port layout so the bulk flow comes from the rear ports and the smaller front ports are used to support the scavinging column.

[2T Institute]

On a more serious note i seen these today Yummy A rear disk valve Honda RS125 The japanese are still copying the Italians.
The other is a billet cased std configuration.

it is here
http://www.ekartingnews.com/viewtopic.php?t=97465

That is a kit from the Italian company CRP

[husaberg]

That is a kit from the Italian company CRP

is it Who said Irony is wasted on the Aussies



http://www.crp-racing.com/portal/en/...o-rotante.html

[Yow Ling]

is it Who said Irony is wasted on the Aussies



http://www.crp-racing.com/portal/en/...o-rotante.html

From the CRP website "Use of innovative technologies like Reverse Engineering" isnt reverse engineering a flash way of saying copying?

[TZ350]

From the CRP website "Use of innovative technologies like Reverse Engineering" isnt reverse engineering a flash way of saying copying?

Yep the inovative Italians copying the Japanese ......

...... "world domination of bucket racing with a fleet of MB powered buckets" - Gary got a 3rd and 1st today on his and I don't think he was trying too hard. Only a playday though. Tokoroa should be fun next weekend with both Gaz and Dave M riding, and Rick though he has some pussy Suzuki motor.

The 4-Stroke boys might have to get their skates on.

[SS90]

Well in saying that T ports use the bulge because of the bridge interfering with flow is the obvious answer, and I agree.
But these are bloody 2 strokes we are talking about and very little seems to work in the way you might think at first glance.
I would put the question, and it may be one hell of a discovery if it works.
Take a maxed out single Ex port like the one on TeeZees 31 Hp 125 engine - that is blowdown limited by design - though the small carb may mask the effect somewhat I would say.
Grind the bulges on the top 1/2 of the port, outside the cylinder wall, above the transfers to see if this increases blowdown flow.
.

I think I may have posted some old images of the first bridged exhaust ports I made quite some time back. In there somewhere I there are one with these bulges, for the same reasons you have outlined.

Many guys running unbridged ports use this method over here.

I found when you grind the "bulges" in an existing port, you definatley get measurable gains, (up until a point). Much like alot of aspects of 2 strokes, such things only make gains when it is restricting something. After this point, I have seen no gain.

I have never put this on any sort of flow bench, but the numbers on the dyno rolled the right way.
When I increased blowdown time area by increasing duration (as I was fearful of cylinder studs after a misadventure), these bulges, while useful on one time/area combo (lower duration) proved absolutely no gain what so ever on one that I would have thought superior.

I have found that with limited gear ratios and air cooling, 191 degrees of exhaust duration has been the best compromise for me......(get your time area through width) as if it won't "pull the top gears"..... it doesn't matter a toss what the max HP is, as an engine putting out 20% less power will whip ya ass, just by virtue of the fact that it can actually drive out if the corner. Overrev or not.

[rgvbaz]

Anyway, I've asked my dad to have go at translating Frits's article. It's been 44 years since he moved back from the Netherlands where he lived for 8 years. Not sure how he will get on with the technical bits as he grew plants out there, he did say he used to think in Dutch in his mind, when he first came back home he had to translate the English word to Dutch for a while so his Dutch was good but 44 years is a long time.

Anyway, I will email it to him and he will see what he can do.

Cheers

Dave

I spoke to my Dad tonight, 44 years is a little to long for him plus most of the technical words he wasn't familiar with. He could read the intro which talked about how Frits got into tuning bikes but then it got all technical. He said the hardest part for him is that he never translated what he read and spoke in Dutch to english as he understood in Dutch, which has made it even harder for him to translate back 44 years later.

I hope one of the other guys having a look at a translation has got a little further.

Sorry.

Dave

[gamma500]

What kind of porting tools do you guys use for 2t cylinder porting? Do you prefer electrical tools or air tools? I'm asking because I've been planning of buying better porting tools, at the moment I dont have proper tools for transfer port modifications...

[TZ350]

What kind of porting tools do you guys use for 2t cylinder porting? Do you prefer electrical tools or air tools? ...

Team ESE have managed very good results using basic hand tools. Persionaly I have produced 31 rwhp with about a 4k power spread from a 125cc air cooled rotary valve single exhaust port 2-stroke running a 24mm carb. Even on the world scene this is probably not a bad effort considering its been achieved using the engines original 1970's cylinder.



With these basic tools I have even managed to cut in aux, side exhaust ports, but we have not yet tried this cylinder properly.



With my earlier engine I had a very flat torqe curve about 3k wide



At 31 rwhp (est 34 crank) not so flat a power spread, but I expect that I will improve it with a bit of development.

We posted our results a while ago and no one has suggested that there have been better in the past, and there are still plenty of old hands around who would know.

31rwhp and 4k power spread was achived with a single exhaust port and is pretty much the best ever for a Bucket engine in the history of miniture road racing here in NZ, although there are a few more high hp 2-stroke engines in the pipe line around the country which should hit the tracks soon.

I still have the tripple port to try but according to simulations done with EngMod2T, to get the best from it I need to improve the inlets STA.

I owe my success to reading widely on the net and everything I can get my hands on, making good use of simulation software and listening to "real" industry people and friends who know what they are talking about.

So there is a lot you can do with just basic workshop hand tools, a bit of reading, net searches and if your budget streches to it, some simulation software.

[F5 Dave]

Think someone posted this place for RA tools earlier & I'd bookmarked it but not stumped up the readies.

http://www.ccspecialtytool.com/182a-...dpiece-adapter