TZR125 4DL (track bike)



  • Well what about this. I'm the first topic starter here.

    As I mentioned I'm building a TZR125 Track bike
    alt text
    http://www.tzr3ma.com/tzr125-track-bike.html

    Now i'm investigating the Tuning aspect for my project
    I like to see what is possible with combining stock components to gain max performance from a stock engine.

    What I mean by leafing it stock is no porting, no head changing, no programmable ignition.

    My setup for the moment is this.
    -Stock engine (Real condition unknown, by the look of the engine/piston relative low mileage) http://www.tzr3ma.com/engine-2.html
    -Shortened exhaust by 10mm
    http://www.tzr3ma.com/shortened-exhaust-en-tacho-change.html
    -Pickupmove of 4 till 5 degrees
    http://www.tzr3ma.com/tzr125-stock-performance.html
    -Changed carb rubber
    http://www.tzr3ma.com/changed-carb-rubber.html
    -Stock CDI
    http://www.tzr3ma.com/tzr125-4dl-cdi.html
    -Stock YPVS

    Now like to know if there are people who have experimented with different servo motors. (openings curve is set in the servo it self)
    The 3MB servo is opening a bid to quick for a higher rev engine.

    But what does a servo do from a?

    • TZR 4FL
    • GPR 125
    • Sachs XTC
    • etc

    Anybody experimented/measured these?

    Cheers



  • Gorgeous bike by the way.

    What is the engine. Is it just a vanilla 3MB or is it the Belgarda SP barrel.

    I had a Belgarda engine and it was pathetic.

    If you want a solid stock track bike then you need the SP which is incredibly rare to find.

    If you are looking for performance and want it stock then it kinda looks like you have done all you can. Removing the weight is essentially your best friend in that respect.

    The best bang for buck you can get is the Zeeltronic ignition system. It's jusf going to make the bike come alive.

    Also the YPVS is controlled by rhe CDI on the later DTR's. So changing the motor is going to achieve nothing. The Zeeltronic will allow you to control the Powervalve curve which will give you a huge bonus.

    Even then for a trackbike YPVS is unnecessary, the bike should never be dipped below 6000 RPM and that's what the powervalve helps with. So in a sense all of that can be removed to save weight and the powervalve simply pinned open.

    Replace every nut and bolt with aluminium to save more weight. Really tighten up the aerodynamics as well to reduce drag.

    As said if you want it bone stock then that's about all you can do.



  • @louis Sweet looking bike bud - nice work!!! 👍



  • Hello Calum,

    ''What is the engine. Is it just a vanilla 3MB or is it the Belgarda SP barrel''
    No, its for now a bone stock 3MB engine. (''vanilla'' 😆 )

    ''If you want a solid stock track bike then you need the SP which is incredibly rare to find''
    Yes the SP engine does have the best papers, but the question will be how much better.
    Its not that a SP engine starts wit 40HP at the back wheel.

    May I say that a good 3MB (belgarda) has about 28HP at the rear wheel and a SP engine (around) 32-33HP
    That about 5HP differences,
    With some relative small changes you can get the 3MB (begarda) to 30HP as the SP engine is more difficult to change do to the nicalsil setup.
    Also have my doubt regarding the inlet, the reedblock is bigger, but not enormously bigger. If you look to a TZ125 reedblock or 3MA reedblock they are bigger than a SP one

    ''If you are looking for performance and want it stock then it kinda looks like you have done all you can. Removing the weight is essentially your best friend in that respect''
    Don't want to keep it stock, but my starting point will be a stock engine.
    And measure the changes on my dyno when i have changed something.

    The problem that I read on forums is that the tune the whole engine and measure it on the dyno.
    Going (example) from a 25HP to a 30+HP but what does what.

    I like to do it step by step and measure it

    ''The best bang for buck you can get is the Zeeltronic ignition system. It's jusf going to make the bike come alive.''
    Yes fully agree with you, have two of them lying in my workshop.
    But first like to see how far you can get with using the stock components (changing them a littlebit of course example by changing the pickup location)

    ''Also the YPVS is controlled by rhe CDI on the later DTR's. So changing the motor is going to achieve nothing''
    Ok, but the first models do have the three wire setup?? all 3MB servo's
    The example 4FL also have a three wire servo (if i'm not mistaken) it has a different part number so perhaps it has a different opening curve (could be)
    Same idea for the servo's used on other models, like to know if the opening curve is different on them.

    ''Even then for a trackbike YPVS is unnecessary, the bike should never be dipped below 6000 RPM and that's what the powervalve helps with''
    Fully agree with you, but sadly I'm not a GP driver. Just a hobbyist.
    There will be a point that i may have picked the wrong gear, or something happened etc etc then it will be nice to have the ypvs kicking in.

    ''Replace every nut and bolt with aluminium to save more weight. Really tighten up the aerodynamics as well to reduce drag''
    As I say I'm just a enthusiast. I'm 1.98m and about 100kg not even suppose to ride on a 125.

    Just like to ride my rounds, and feel the differences I made.
    Keeping it a hobby is important
    Let the young guys race, let me ride it and having fun.

    ''As said if you want it bone stock then that's about all you can do''
    Have a feeling I can do more 😉
    Will post it here

    But nobody have tried or measured the ypvs openings curve from a 4FL or sachs, GPR, ect ????



  • @louis The 3MB engine is not 28BHP lol. They were marketed at 11KW power and around 15 BHP but I doubt they made that sort of power.

    You will never be able to port the 3MB barrel to the levels of the SP, the differences are a lot more than Nikasil plating. The port windows and timings are massively uprated. The compression ratio is dramtically different and they also contain two auxillary exhaust ports.

    The 3MB engines are not really designed for racing, they were great for reliability and commuting. But they do lack that oompf for performance.

    The older three wire Servos ran a separate unit to control the Powervalve I believe..

    The whole setup of that bike looks great, it's only pitful is that the engine isn't highly strung.

    A Rotax engine would suit that bike tenfold and in stock trim would be far superior to anything the 3MB engines could be made to do



  • Hello Callum,

    I feel some passion in your reactions, that's good like that.

    Kept me thinking for a while why you mentioned so low HP outcome.
    But found it.
    Have made a mistake in my info regarding this project, was to focused on my question about the 3MB servo that I named my engine also 3MB but of course this is not the case.

    I use a complete 4DL engine with the ''P'' cylinder, "P"head, 32mm carb, en 4DL CDI (so a complete TZR125 4DL belgarda setup)

    Have read that indeed the 3MB engine have a much lower in HP outcome than a 4DL do to a lower cilindertiming restricted head (ring) and a CDI (with a lower ignition curve), smaller carb (28?) perhaps also exhaust, etc ect

    So my excuse for the mismatch in engine coding
    Got my street 4DL at a 30HP currently (filtering factor 5) dynojet filtering would be 27-28HP
    alt text
    http://www.tzr3ma.com/tzr125-dyno-runs-two.html

    You will never be able to port the 3MB barrel to the levels of the SP, the differences are a lot more than Nikasil plating. The port windows and timings are massively uprated. The compression ratio is dramtically different and they also contain two auxillary exhaust ports.

    Never say never😉
    I'm quit familiar with cylinder timing and the triple exhaust ports myself.
    Also porting, making exhausts, and working on the CDI processor it self is not unknown to me.

    I have a imitation SP 4DL cylinder lying in my workshop using that one will be quit easy.
    http://www.tzr3ma.com/imitation-sp-cylinder.html
    But then I'll be ignoring my own hobby and just go the easy way.

    Like to do it step by step

    The 3MB engines are not really designed for racing, they were great for reliability and commuting. But they do lack that oompf for performance.
    That is correct the 3MB engine is not ideally for racing (also the gearbox is not good for race purposes) The 4DL engine is better but far from perfect its just better. 🙂

    The older three wire Servos ran a separate unit to control the Powervalve I believe..
    Yes the CDI runs the servo motor with a separated ypvs rpm signal
    http://www.tzr3ma.com/tzr125-4dl-ypvs-measuring.html

    A Rotax engine would suit that bike tenfold and in stock trim would be far superior to anything the 3MB engines could be made to do

    If we keep it yamaha related and i could fit a TZ125 engine in it (and start with 40HP)

    But no, will use the 4DL engine and go from there.
    You will like the ideas what I'm planning for it😋



  • 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.



  • 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



  • ''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



  • @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

    alt text



  • "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?



  • @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.



  • 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.



  • @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.



  • 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.



  • @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.



  • ''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



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



  • @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

    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.



  • ''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