TZR125 4DL (track bike)

Calum

The 3MB00P is not 30 bhp either. That's what I run at the moment. The only difference between the 3MB and the 3MBP is a 1mm height difference on the exhaust port. THE SP barrel as you said was far superior.

louis

Some pictures regarding this project

For testing some off my ideas I can use my street 4DL
alt text

For CDI ypvs testing I'm working on adapting my (testing machine)
So I can measure/test the 4DL CDI and YPVS motor
alt text

The project it self
alt text

Most can be seen on my site.

Slowly getting the feeling that nobody have measured the 4FL servo motor or any other one??

Cheers

louis

''The 3MB00P is not 30 bhp either''
Regarding the 30HP
Here you go: http://www.tzr3ma.com/dyno-readings.html

Interesting, What is your setup?
What CDI do you use? (stock advange or more)
What Carb (mm)
What cylinder head

30HP is measured with correction (factor 5) with factor 25 (is a lot) you end up with a 27HP

Factor 25 is relative much around 15 you will be good.
So a 29HP should be possible

Calum

@louis A ported 3MB00P barrel with the Compression increased and squishband altered using the VHSA 32mm Carb and Zeeltronic ignition system. I also run an underslung pipe.

alt
alt text

The ported Belgarda barrel on the right

P stamped head.

alt text

louis

"Compression increased and squishband altered"

Ah there you something.

You have probably used modern value's regarding the head

Higher compression tightened the squish (perhaps a smaller head volume)

Have done that to but with bad results
Changed the headvolume tightened the squish (0,8mm) changed the squish wideness. (to race specification)
It does not work on a older engine.

Most tuning stuff are copied from latest designs (RSA/RSW engine with the 50HP by Jan tiel) etc etc

Have had discussions on forums about this.
The material used on these real GP engines is different.
Have you thought about the stretching off your conrod at 10.000rpm or crank
The squish set on 0,9mm will not be a 0.9mm at 10.000rpm closer will be 0,6 or 0,7mm (or less)
Specially with the old designed crank and conrod in the 3MB or 4DL engines.

The higher compression will work agents you in the higher revs
It Will give you more power in the mid section.

You have changed so much in one time what did what?
The power you have now will be higher than a stock engine that's for sure, (but what did what?)

The ported cylinder from abbey gave you? (compared with stock)
The changed head gave you?
The zeel?
The exhaust?

Do you know what I mean?
Don't get me wrong, I'm not criticizing you but just have a different point a few regarding tuning

Step by step

For example: if you take your engine as it is now, but use a stock "p" head how does it perform then? do you lose 3HP or will it be the same?

Mention HP outcome is always difficult
Let just say my street 4DL has 27HP
That is with 4degrees more advange, a RR exhaust and a open airbox and well setup
will that be OK?

Calum

@louis Yeah the porting was the only thing I let a professional do.

Uhm no, I don't have that deep pockets.

Each component was done separetly. The final piece of the puzzle has been the underslung exhaust in an attempt to maximise the ponies out of the engine.

I ran the barrel stock on stock ignition for around a year.

However, the DTRE ignition, combined with the higher exhaust port actually had adverse effects.

So the engine in theory would have higher peak BHP, but because the CDI retarded ignition I was unable to utilise the gains.

So I then decided what I needed was an ignition system that would allow me to utilise the higher RPMs.

I didn't perform the porting work, but a professional did.

This is why I said, compression increased and squish altered so that the CC's are remained. Otherwise as you correctly said, you reduce the volume of combustable gases and thus reduce power.

You definitely sound like you know your stuff and you sound like a valuable asset to this forum!

The work on this engine has been an iterative development for around five years.

After everything I have done, it's still no better than a stock Rotax 122 engine. As such I have decided to end the tuning on the DTR engine and begin looking at building a Rotax weapon.

louis

After everything I have done, it's still no better than a stock Rotax 122 engine. As such I have decided to end the tuning on the DTR engine and begin looking at building a Rotax weapon.

Don't have experience with the Rotax 122 engine.
But I understand from you that a stock Rotax122 engine has more power then your tuned 4DL engine?
Unbelievable, how much has a stock rotax engine?
Can understand the frustration, how much did you end up with?

Wilt measuredyno all changes I make and report back.
This wont be a fast topick, but hopefully one with nice info for the 3MB/4DL riders out here.

Calum

@louis A bone stock rotax 122 is 26 bhp.

But they still use these engines in the super teen 125 series. Very good engine.

I am saying the bone stock rotax engine is better than a 3MBP 4DL. It's about on par with the SP engine.

louis

Don't know where your enthusiasm comes from regarding the HP outcome

Don't judge to soon regarding a 4DL engine.

Let i put it this way,
A TZR125 4DL has 26-27HP as completely stock.
A TZR125 SP should outperform a stock 4DL so they are close to 30HP

The 26-27HP is produced with the combination off all components. (carb, ignition, CDI, YPVS, Exhaust, TOP END, etc)

So if you only take the 4DL TOP END and CARB you wont see the 26-27HP back on a DT125R

Putting a 4DL top end on a 3MB bottom using stock ignition and exhaust wont do anything.
A TZR 4DL peeks stock around 10.300rpm.
By the looks off the ignition curve from a DT125R it peeks around 9250rpm?
alt text
So when the 4DL top end wants to give power, the ignition is already to low
Even if you use a performance exhaust the ignition is dropping to soon

Its not the top end only what makes the HP
We clearly have a different point a few about this. But that's OK.

Calum

@louis I ran the full engine bud, the casting on the engine wad appalling compared to the DTRE engine.

I think we will have to agree to disagree about the engine output of the Belgarda 4DL engine. I was under the impression that the 4DL engine was going to be a monster. But it was poor.

I have examined both engines in great detail, there. Is nothing to suggest that the 4DL engine was 10 horsepower more than the DTX engine.

Again I don't dispute that the SP made some magical numbers due to its limited production, but the basic 4DL 3MB00P engine is nothing fancy.

As said it's just a basic engine is all.

louis

''think we will have to agree to disagree about the engine output of the Belgarda 4DL engine''
No problem, remember I don't mean you any harm just have a different point a few.

''I was under the impression that the 4DL engine was going to be a monster. But it was poor''
No its not a monster at all that is for sure, your yz125 will kick its ass any time.

''I have examined both engines in great detail, there. Is nothing to suggest that the 4DL engine was 10 horsepower more than the DTX engine''
That I belief, apart from a slightly different timing from cylinder perhaps a tiny difference in head design.
Think the main difference is electronically, carb and exhaust compared with the 3MB engine
(Are there no restrictions in the exhaust on a DT125R (just a thought))

Have quickly draw a 4DL curve inside a DT125R curve.
alt text
As you can see after the 9300rpm the 4DL curve is different. (its designed to peek higher)
This is a big difference at about 10.300rpm the 4DL has 10degrees and the DT125R has 4degrees

That is a 6 degrees differences

For example if you see how much the 4 degrees pickup move does on the TZR it gained about 2,5HP
http://www.tzr3ma.com/tzr125-dyno-runs-two.html

So calculating it back lets say 26HP -6 degrees (roughly 3HP) will be 23HP this in combination with a stock exhaust (witch will peek less then a TZR one)
You end up with around 22HP??

Know its all guessing, its just a other point a few

Calum

@louis You definitely sound very knowledgeable that's for sure!

Darty

@louis Welcome to the forum,

Really enjoyed your website.

I have a TZR125R/4DL Y-1 3MB-P-00 top end , 134cc, with slightly larger port volume and appropriate port timing with 0.6mm, squish' cylinder head I'm testing.

The compression ratio slightly reduced.

alt text

The tuning will be for pump 97 Octane.

I need to tune the ignition and Powervalve timing. I have started with a basic map similar to that of a 4DL and can support there being a potential 2hp increase.

I'm moving on to fitting a TM34ss with WR200 inlet manifold (slightly longer inlet tract) and VFORCE3 Reed block, However I can't isolate better running over a 4DL reed cage.

There is not much information about modified 4DL's and I have always believed that the 4DL Y-1/Y-3 was only good for 22-23bhp in stock configuration?

I have yet to sort out my Dyno run, but I still don't believe it will be making an extra 6hp around 11,000 or so. But I would hope that is possible?

What are your experiences with altering squish height with a 4DL? very interested to gain some insight.

The design for the RR' Airbox is interesting, I am struggling to modify and work out a good increase in Air volume for this engine.

louis

''Really enjoyed your website''
Thanks,

''I have a TZR125R/4DL Y-1 3MB-P-00 top end , 134cc, with slightly larger port volume and appropriate port timing with 0.6mm, squish' cylinder head I'm testing.
The compression ratio slightly reduced.''
That is a interesting setup.
0,6mm squish that is pretty tight, going to race specifications.

''I need to tune the ignition and Powervalve timing. I have started with a basic map similar to that of a 4DL and can support there being a potential 2hp increase''
Ok that is positive, small step towards more

''I'm moving on to fitting a TM34ss with WR200 inlet manifold (slightly longer inlet tract) and VFORCE3 Reed block, However I can't isolate better running over a 4DL reed cage''
Have good results by enlarging the crank case volume a bid so don't thing the longer manifold will be a problem.
34mm carb, that would be the max I think regarding the inlet volume from the reedblock?

I have always believed that the 4DL Y-1/Y-3 was only good for 22-23bhp in stock configuration?
Don't know way you guys are all so low on the HP outcome.
In Germany they had to bring back the power to 15HP if a younster (16) want to drive it on the road (drosselt)
They did this by letting the exhaust valve closed, or mound it in restricted mode or by gearing or black box.

''I have yet to sort out my Dyno run, but I still don't believe it will be making an extra 6hp around 11,000 or so. But I would hope that is possible''
It will be strange if it won't!!!.
How much do you have right now?
What exhaust do you use, and where does that exhaust peek.10500rpm?

''What are your experiences with altering squish height with a 4DL? very interested to gain some insight''
Currently non, I want to change it in the future.
But for now like to see ho far I can go with a relative stock setting

''The design for the RR' Airbox is interesting, I am struggling to modify and work out a good increase in Air volume for this engine''
Yes the RR airbox is relative larger than the R airbox.
I'm running the rr airbox without airfilter and snorkels currently.
Mus say until now it works fine like this

louis

It took me a while to read through the older forum posts (because English is not my home leagues)

Now I know why my positive HP outcome is not taken that well.
I see that a DT125R has already having trouble to reach a 20+

I have explained that my 30HP can be reduced to a 27BHP (regarding the settings of the filter's)
This 27HP is with 4 degrees more advange (that gained me about 2HP) so the 'relative stock'' setting would be around 25BHP
And a small note regarding ''relative stock'' is a well setup carb (absolutely not stock)

So perhaps with a stock jetting the bike prudes a around 24BHP? (Don't know haven't dyno'd it then)

Hope this takes a way the trouble I have corse.

Not meaning that a nice discussion can bring new ideas.
Example, just measured the 4DL and 3MB servo's
http://www.tzr3ma.com/tzr125-servo-openings-curve.html
Having a 3MB servo on a DT125R would not be perfect if that bike has its peek power at 9000rpm or lower.

Just pointing it out

Cheers

Calum

@louis I mean I got a 4DL engine with Zeeltronic ignition, underslung exhaust, ported barrel, altered head, VHSA 32mm carb all jetted and mapped accordingly, it's probably around 20bhp at the wheel.

https://www.youtube.com/watch?v=n8NCG4xdbqY&list=PL66C1264C7D6205BB

https://www.youtube.com/watch?v=SQuHkq-22Xo&t=58s

That's my experience with the engine you're describing and it is not 30 bhp.

louis

''@louis I mean I got a 4DL engine with Zeeltronic ignition, underslung exhaust, ported barrel, altered head, VHSA 32mm carb all jetted and mapped accordingly, it's probably around 20bhp at the wheel.''

All those mod's you did gained you roughly 5 till 7HP (going from a stock 15HP DT125R to a+/-24HP)

Having trouble to believe that.
Did you dyno your DT125R?
What ignition curve do you use and what ypvs opening curve?
What is your exhaust length?

A 200cc NSU superlux from 1956 has stock 12HP and a tuned DT125R has a 20+
Is it just me that I'm thinking that's a bid low

For example her is a TDR125 (roughly the same)
4 degrees more advange and some changes
alt text
http://www.yam2stroke.fr/viewtopic.php?f=18&t=21900

How did they dyno your bike?

-fifth gear or six gear
-Lights on or off
-Tire pressure

There must be a reason way it is (from my point a few) a bid low

Calum

@louis No Dyno mate.

You can show me graphs all you like.

The true test is how does it go out on the road.

You can see from that video that this bike is FAR FAR behind that YZ. What's a YZ roughly?

It may very well be different in your country, fuel octane will make a huge difference.

I'm just telling you how it is, these bikes don't make anything near 30 HP.

Darty

@Calum I'll dyno mine and we can square this up...

I thought 25hp max,

Calum

@Darty What you running?

There is a bike dyno near me, it's just never bothered me. Figures don't mean jack, it's how it goes on the roads/track that counts.

DT125R FORUM

TZR125 4DL (track bike)