TZR125 4DL (track bike)

[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

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.

[Darty]

@Calum To be fair, it is something you need to do.

How will you tune the PV or Ignition timing without a couple of Dyno runs??

Can't just bolt this stuff on and expect the best results.

The data will tell me how to tune it all together the best I can.

Still, a stock (de restricted) Aprilia RS125 and Kawasaki KDX125SR will probably have similar numbers to a tuned DTR.

So waving HP numbers will be kind of pointless anyway.

But mine is lovely on the road so far, considerably more torque!

[Calum]

@Darty It's an all day event if you are on a rolling road lol. You could spend an indefinite amount of time sorting the maps out.

You can get "good" enough results just going up and down the road.

[Darty]

@Calum Nah, you can be happy getting good enough results after a few power runs. A day would be enough for that.

It's just I can't measure or test progression with a tune that accurately just going up and down the road. Feel isn't enough.

Too many variables.

I've spent far to much just to make do.

Incremental tuning, true could spend weeks on a race tune.

Go balls out, what's left after that? Job done for the summer.

[louis]

@Calum
''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?''

You got a 5UN00 cylinder that's a 2002/2003 engine.
You can not compare that with your DT125R, not at all.
Those engine's start with 32/33HP and most off the time they have performance pars on them as well. Bringing it to mid 30's (pipes, CDI's, reedblocks, etc)
Also gearing is plays up with comparing

Keep in mind I'm thinking with you not against you.

You need to know at least the peek power from your bike.
This helps you to set the ignition curve.

You aim on a 14 degrees at peek power there it is where it happens.
After peek power you drop it to a +/-5 degrees

[louis]

@Darty
''I'll dyno mine and we can square this up...
I thought 25hp max''

The 25HP is this with your latest setup?

[scrimsmustang]

@louis

Interesting, most powerful stock from the factory DTR,s are the first 4 years of production. The 1988 models, code 3BN1 is the european full power model sold in France and Italy, code 3FW1 is the Japanese full power model these are all rated at 21.4 hp. The restricted 1988 code 3BP was also sold in France, 3DB1 in the UK.

First of the full power flatslide carb 1989 models are codes 3PY2 for Italy and 3RM1 for France rated 22.9 hp. Restricted 1989 model code for France 3NC1, 3RN1 in the UK. Pretty much stay the same for a few years after.

[Minia]

I sort of understand what calum is saying. But personally, I'd run it by the numbers. I have no experience with rolling roads, Dynos and rebuilding engines etc... But I have plenty of experience with getting the maximum of performance out of computers. Now you can build yourself a nice rig and all and it can run your programs, engines, games or whatever absolutely fine. But if you don't tune your rig and set it up properly, then you're just losing some of the extra kick. And in which case, I then have to go and run the numbers

If you're happy enough with a smooth ride, that's fine. If you want to push it to the limit then you'll need the numbers.

https://www.youtube.com/watch?v=9D-QD_HIfjA

[louis]

Sometimes thinks do not go as planed.
When you belief in something that hard, and your are convinced that others have it wrong it will take you some time to conceder that they are right.

It turns out that my own dyno was not set correct, re calculated my drum an that gave a massive drop in the measurements.
Of course not very nice for me to know, as I thought I was going the right way.
Thankfully don't have a company/ or a tuners name to keep high so a note on my site regarding the wrong setting should be enough.
http://www.tzr3ma.com/dyno-correction.html

But specially here I post a personal reaction, because they told me here over and over it is not making a +30HP and I did not belief it.

So my apologies for that.

The trough now is as followed.
After the new settings the HP's where dropping faster than I could think off.
But fair is fair, if this is what it should be, so be it.

The results so far

Stock the TZR125 (trackbike) has a 22,3HP at the rear wheel
And with all the mod's i did so far (shortened exhaust, 6 degree more advance, changed carb rubber, open carb) it produced 24,8HP rear wheel.

Currently have changed the head to a O-ring conversion, but need to dyno it first.
http://www.tzr3ma.com/head-to-o-ring-conversion.html
It drops the squish from a 1,3 to a 1mm and combustion volume to a 11,2cc

Hope this will bring me a 1,5 a 2 HP and it end up around 27HP
(not saying it will, but hope it does)

After this like to do some other steps but that would probably bring more in the mid section than on peek power

Will let you guys know

Cheers
Louis

[Calum]

That is sounding much more realistic! I'd rather underestimate the power and demolish others in that class, than overestimate and lag behind!

Good for you for pushing on!

[Nottsbiker]

Will probably feel like a massive improvement in the real world compared to the small increases shown by the dyno

[louis]

That is sounding much more realistic! I'd rather underestimate the power and demolish others in that class, than overestimate and lag behind!

You have a good point there.

[louis]

Will probably feel like a massive improvement in the real world compared to the small increases shown by the dyno

Well standing on two feeds again that's for sure.
The shown dyno curve, are a couple off same runs they always have a small tolerance

Perhaps this is a better shown between stock and with the mod's

Orange curve is with ignition filter, that's way its so smooth.
You can see the progress

[louis]

I see its almost a year back sins my last post.

Not much has changed, currently at 27,7Hp back wheel.

Hope to gain some more with the use off a more suitable exhaust (currently waiting on a test exhaust so I have a indication witch dimensions I need to make it)

Engine changed a lot this can be read here.
www.tzr3ma.com at section Tzr125 trackbike

Currently mounting a zeel on my roadgoing bike, but have some problems with the setup.
Hope to do some runs with here ones it is setup correct

Cheers
Louis

[Calum]

@louis A little archive you've got going on there. And you're seeing good returns on your modifications. More than I would expect.

But I'm correct in thinking you're now running the SP barrel.

[louis]

No its a 3MB cylinder only modified lifted port timing and two huge sub ports for the exhaust (bigger then the SP)

Problem now lies in the stock exhaust, this will need a update.
Still want to beet the 30HP. But it turns out to be much tougher then I thought