ESE's works engine tuner

[TZ350]

Maybe not, well not an orphan anyway as I hear Chambers might be making a RS/RG50 combo for Av.

Attachment 287196

Originally posted by Cotswald, Av riding in Italy top right corner, her bike (A1 ???) has the white faring.

Av's race number is usualy 21. attached is an email received this morning. And it looks like Av's RS/GP125 bucket will be getting a dust off in preparation for the 2-hour.

Hey guys,
Hope everything has been trucking along well at ESE.

I just realised you haven't been receiving my race reports from over here in Europe so a couple are attached. How rude. Sorry! Presume facebook has been keeping you in the loop at least a bit..

Would love to hear how buckets is getting on? And the rg50, Cully?
I will be home in time for the two hour this year!! Should we give it a crack on the two smoker?

Catch ya soon
Av

[marsheng]

This is some interesting reading on detonation.

http://www.avweb.com/news/pelican/182132-1.html

[RomeuPT]

I have a question about plug to piston top distance.

I had measured the 125 head and domes I got for domed pistons, two hemi head's with 0.7 squish would have about 8.7 distance from plug to piston dome top. But the domes I got have more volume and they would make 10.3 mm of distance, toroidal head's have a lower distance and I have one stock toroidal Honda RS 125 head but my bike does'nt seem to like it with the domed piston.

Aprilia RSA head drawing show a 7,6mm distance.

Is there an optimun for this distance? I understand that the volume and squish width needed would play with the distance, or even it can be corrected with proper ignition.

fast 125 engines running unleaded run low compressions, how much is the distance in them?

Is there any good baseline for this?

Thanks

I would like this a bit of discussion around this. I guess is important for everyone here.

[Drew]

I would like some video updates on the injected GP125.

GET TO WORK FUCK YA! It's the most interesting mod to date!

[husaberg]

This has been posted before...... but there is another similar version.. maybe Indian or Chinese but i can't remember what it was......
http://www.crp-racing.com/portal/en/...o-rotante.html

[Bert]

I would like some video updates on the injected GP125.
GET TO WORK FUCK YA! It's the most interesting mod to date!

I want some video updates of the sidecar.... been waiting long enough.
GET TO WORK FUCK YA! the most interesting thread in the racing section..

[Drew]

I want some video updates of the sidecar.... been waiting long enough.
GET TO WORK FUCK YA! the most interesting thread in the racing section..

I shall oblige you today then sir. Have to take a break from the hospital visiting with the missus, the chairs are fucken terrible even in a private hospital!

[TZ350]

I would like some video updates on the injected GP125. GET TO WORK FUCK YA! It's the most interesting mod to date!

Yep keen as mustard ... the next move is to try and get it started on the dyno, but there is a bit of a backlog of dyno work to be done on the 50's before next weekends racing, so some time, soon as, after next weekend.

[TZ350]

I have a question about plug to piston top distance.

I had measured the 125 head and domes I got for domed pistons, two hemi head's with 0.7 squish would have about 8.7 distance from plug to piston dome top. But the domes I got have more volume and they would make 10.3 mm of distance, toroidal head's have a lower distance and I have one stock toroidal Honda RS 125 head but my bike does'nt seem to like it with the domed piston.

Is there any good baseline for this? Thanks

I would like a bit of discussion around this. I guess is important for everyone here.

Here you go .....

And if you left click on a posters name then click "View Forum Posts" you can search back and find all the interesting stuff they have posted.

To do a toroid properly you need to drop the plug tip approx 6mm from the piston crown.

Means welding the chamber and counterboring the plug seat face.
Very difficult to do repeatable and accurately unless done on CNC.
I model the piston dome and the head shape in SolidWorks to generate a solid then I have an accurate curve the toolpath follows and a calculated volume.

You dont really need the Ex timing to establish the head geometry, and yes the 6mm number seems to work with most " usual " combustion chamber geometries.
Avgas works with anything from around 192 to 202 Ex duration at around 15.8 full stroke.
Smaller bores or lower bmep setups can go 16.2, big bore oversquare or very high bmep like slightly less at 15.5, air cooled of course needs alot less.
As long as you hit the lower mechanical squish depth limit, then adjust the width to hit 38M/Sec MSV you will have good squish turbulence that helps the flame speed - reducing any tendency to deto
the end gasses.
That MSV number is meaningless in the context of all but hitting the head when within the normal rev limits, but as a guide it works every time.
The sharp bowl edge increases the flame speed, and a very deep angle away from that edge into the bowl is synergistic by pulling the turbulence further into the combustion space, again increasing the flame propagation speed,
over a wider band.
Pushing the combustion parameters this hard means a digital ignition is mandatory to balance the timing against the high peak cylinder pressure now being generated.

No free lunch today except that its all been done before and in most cases a guide is available.
It depends upon the stroke length, the piston weight and the crank integrity.
Suffice to say that a 125 single will usually go down to 0.65mm when spinning to 14000
A 250 twin like the RGV with a single middle bearing will go 0.75 spinning to 12,000
A 250MX type with 72mm stroke is OK at 1mm spinning to 11,000.
But I stress again, as I dont want the Honda faggots off their forum abusing me that the NSR wont rev if taken below 0.8mm - the ignition has to be optimised
to work with a combustion chamber that is designed correctly, and does actually do what its supposed to.
A stock PGM simply wont cut it - but then we wont be using HRC parts, so they just cant be any good at all, as everyone should realise.

Yep, looks fine.
The flat squish area should have 0.1mm taper upwards from the bore edge.
As I found the piston will clip the inner edge first when the vertical gap is at the mechanical limit for the rpm.
This is the sort of shape you are after.

There is only one rule grasshopper,NO radius from the squish into the bowl.
The other rule is to pull the squish down to the mechanical limit - ie probably around 0.7mm on an RGV then adjust the width to get around 38M/Sec MSV, usually 45 to 50%.
This generates good response and " torque" as you put it - but for sure will need a digital to retard the top end advance to get the overev back.

[2T Institute]

This has been posted before...... but there is another similar version.. maybe Indian or Chinese but i can't remember what it was......
http://www.crp-racing.com/portal/en/...o-rotante.html

There was the Mahindra engine made by Engines Engineering, was for all intents and engine designed by looking at pics of the RSA without actualy getting hold of a RSA to copy. There is still a few Euros outstanding apparently

[husaberg]

There was the Mahindra engine made by Engines Engineering, was for all intents and engine designed by looking at pics of the RSA without actually getting hold of a RSA to copy. There is still a few Euros outstanding apparently

Yes it was likely the Mahindra but i can't find the pics other than these. From the pic i seen some where it looked like a simpler set up re the drive to the disk than the RSA.

think it became the lochin/lambretta?

On further investigation the drive i am thinking of may be actually on the RUMI rear disk? Anyone got any pics of the disk drive set up?


For Rob the Most sucessful arrow.


I have often seen this but never the story behind it.

[Myron]

The statement also seems at odds with what I have been working with in KZ2 kart engines.
These 125 engines have a U bend stinger dumping into a large muffler.
Two mufflers are available, one with the muffler perf a couple of mm bigger than the stinger ID, the other around 50mm ID.
The larger muffler would in effect create the conditions at the stinger end replicating dumping into atmosphere.
It also happens to add around 6 Hp at 14000 - so if the wave action within the stinger due to its length is having no effect, then what is causing this.
It certainly isnt the small muffler simply affecting the pressure in the pipe due to a flow restriction.
The length appears critical, so i am going to try adding length to the stinger inside the big muffler to see what happens ( this isnt a tech item by the way, and yes I put a venturi inside the stock stinger as well ).

Hello, first time poster. I'm not into buckets, but Two Stroke race engines in general. Wobbly is an acquaintance from another site. I agree with Wob. Two different approaches can be taken, to try to lessen stinger influences, or embrace them. Simply put, when pipe effects are phased correctly, the low pressure pulse emanating from the stinger can be phased with the tail end of the next suction pulse, creating what Wob may be experiencing.
Myron

[RomeuPT]

Here you go .....

And if you left click on a posters name then click "View Forum Posts" you can search back and find all the interesting stuff they have posted.

Ok TZ350, I kind a remember those post's, but those 6 mm are for a toroid. I wonder if the hemi is the same, thinking if the toroid brings to the flat piston the same height of the a 2mm dome piston.

Thanks for your research...

[Haufen]

Here you go .....

And if you left click on a posters name then click "View Forum Posts" you can search back and find all the interesting stuff they have posted.

Thanks TZ. I am curious to know the difference in those numbers when running pump fuel (ROZ 98) instead of Avgas. Do you happen to know if this has been covered here, already, too?

What I found was:

The issue that your test doesn't address is that with pump gas you may be able to get away with 13:1 com.
With AvGas its just starting to work properly at 15:1 and this attribute will always far outweigh any advantage flame speed or whatever may be contributing from the pump gas scenario.

The other issue is that unleaded fuel works best with plenty of advance, no com, and rich as hell.
AvGas loves com, loves running lean and hates advance, so you need to spend days on the dyno just optimising for the fuel.
Much better things to be doing in making a fast reliable race engine I believe.

Unleaded fuel to make best power likes to be rich and have plenty of advance with low com.
Thus in general a shorter pipe would be needed, as you say due to the lower egt.
But as usuall there is a fly in the ointment in that the FIM race fuel that needs gloves and a respirator, acts differently,and ends up with the same tuned length as was used with ELF124.
But the bulk pipe temp isnt what the egt probe reads in the header, its the average temp and is alot lower overall.

Unfortunately, I did not stumble upon any numbers for low com (well, maybe that is the 13 as mentioned in the post?) and plenty of andvance (35° at max torque? 25°? 20°?).

[TZ350]

Ok TZ350, I kind a remember those post's, but those 6 mm are for a toroid. I wonder if the hemi is the same, thinking if the toroid brings to the flat piston the same height of the a 2mm dome piston.

RomeuPT I dont realy know but Emess posted a possibly easier way of finding the good stuff posted by those who do.

... some may find this useful. Rather than use the site search which usually fails, use Google so to search this site use an ordinary search phrase and after it add

site:www.kiwibiker.co.nz

for example

Frits priceless site:www.kiwibiker.co.nz
or
Frits pisa site:www.kiwibiker.co.nz

the same will work for other sites with the appropriate site address

Mick