Help from Italy!

[akronos]

Hello everyone, I recently bought a Yamaha TDR 125 Belgarda for 100 €, I thought it was fitting the 3mb00 tbarrel, but I noticed (as you can see in the picture) that the 3mb00P series was installed in my country. The head has also marked "P". Reading on various forums the 3mb00P cylinder is mounted on the TZR 125 4DL models with matching the CDI 4DL. On my TDR (which is totally original) a 3mb CDI is mounted. Can you give me some indication? Should I find a CDI 4DL or leave its original?

[akronos]

This us my CDI

[Chris_]

sorry

[Louis]

Hello Akronos,

Im not a expert on 125 TDR's but I think what you have seems to be correct.

A TZR Belgarda engine and pipe peeks around 10500rpm (as its designed to be sport/race etc like)
A DTR Belgarda engine and pipe would peek around 9500rpm (as its designed to be more offroad/city etc like)

The 3MB cdi hase a better ignitioncurve to mach a +/-9500rpm peek as the 4DL cdi matches more with a 10500rpm peek

In fact I would be more intended to try a TDR 4BL CDI if your bike peeks around 9500rpm
So if your bike is stock, keep the 3MB cdi.

But on a other note.
If I look at your second picture from your bike, its wiser to spend your money on other parts than a cdi
Like a seat, paint, cleaning stuf etc etc

[akronos]

Of course, I already bought a good part of the pieces. My doubt about the CDI was the fact that the cylinder reports the code 3mb00  "P ", and from what I understand this cylinder is modified by Minarelli in the factory to obtain high revolutions. I do not understand why the TDR has it as standard with the 3MB00 control unit that instead cuts power at high speeds.

I bought a very little money even a 3mb00 cylinder, taken from a DT125R. At this point since the standard TDR mounts the CDI 3mb00 is not advisable to install the cylinder of the DT125R or leave the 3mb00p?

[Louis]

My doubt about the CDI was the fact that the cylinder reports the code 3mb00  "P ", and from what I understand this cylinder is modified by Minarelli in the factory to obtain high revolutions.

That is correct, the "P" are reworked cylinders and heads but there is no real info how much HP that reworking gave
Its not that the 3MB00 has 15HP and the 3MB00 "P" 25HP
Perhaps the difference is around 1 or 2HP? Nobody knows it exacly

The biggest difference should be in the pipe length I think, most likely the DTR pipe is longer then a TZR pipe therefore its peek is a bid lower.
Carb size is also a factor.

I bought a very little money even a 3mb00 cylinder, taken from a DT125R. At this point since the standard TDR mounts the CDI 3mb00 is not advisable to install the cylinder of the DT125R or leave the 3mb00p?

I would hold it original and use the "P" cylinder, all bids help (on paper it should be better)

If you already thinking off tuning/performing try to do it step by step.
You can see/feel what the changing's do, like bigger carb, or different exhaust pipe, different cylinder or head etc etc.
If you change thinks step by step you will enjoy it longer and understand what did what

[akronos]

all right, you're right! However, despite having the CDI 3mb-00 I still recommend the cylinder "p". Obviously I also have the head marked with the letter "p"

[2stroke]

Welcome Akronos.

I have two TDRs Belgarda, and one of them is tuned for track-only use.

The TDR 125 Belgarda and the TDR 125 R (the bike in the picture you posted) share the same cylinder of TZR 125 R 4DL and the code is 3MB-00 "P". The "P" stands for "ported" version, that is a 3MB cylinder with hand-revised factory porting by Belgarda to have more performance. The power outlet at wheel was about between 25,5hp and 26,5hp, if you have a "lucky" cylinder. Why lucky? Because the porting was revised by hand and some cylinders are more performing than others. Some difference is also due also to piston/cylinder tolerances.

The head should be "P" version. If you have the stock pipe, the CDI has to be marked with 3MB-00. The original pipe is meant to give more boost at midrange, and so are ignition and YPVS curves.

The 4DL CDI version is electrically compatible : also if ignition and powervalve curves are different. But for best performances, you should change the pipe with one that pikes after, as the TZR 125 R 4DL does. And of course also carburetion. This TZR has also the sportier Dell'Orto 32 VHSA carburetor, that makes the difference.

Only the TZR 125 R Sport Production shipped with a 4DL coded cylinder, but this bike was factory deeply tuned and has a dedicated CDI, among an infinity of fine tuned details.

The 3MB-00 (not "P") version has less power due to less aggressive porting, and to the head design.

Keep care of your bike, before you ride, be sure all the components are in perfect conditions.

[akronos]

Ok thanks! What exhaust can i search to install to my tdr?

[roby267]

Hello everyone, another help from Italy and always for a TDR 125. I took this bike a few days ago, I was given, and goes to support a TZR 125 and a RD 350.
Even the TDR mounts a 3MB00 cylinder, but I miss the P :-). In addition to the "P" nn I found the wires / cables that control the YPVS valve and also the YPVS valve motor, so it went without. The bike worked until a few months ago, then the previous owner told me that he suddenly did so much smoke and the bike stopped. In fact I found the rear wheel full of grease and oil, a lot of effort to remove everything.
I tried to see if current comes, but not from signs of sparkle on the candle. now I will have to buy a new engine for the YPVS, can I also buy that of the TZR or do I have to take the TDR one?
I read that you were talking about the different control units and cylinders, on my TZR I mount a doffered cylinder from the TDR, it is marked 4DL00, while the TDR 3BM00, I do not know what the differences are between the two.
Even the control units have different codes, I read that the TZR, 4DL00, runs the highest revolutions engine making it reach 10,500 revolutions while the control unit of the TDR 125, 3BM00, reaches up to 9500; maybe this is right and it is also due to the different characteristics of the two bikes, the TZR is road therefore more track character while the TDR will be more ready at low revs, perhaps it will have more torque. My TDR, in the booklet, declares 21 KW, so about 28 horses compared to 32 of the TZR that has a bigger carburetor, from 32, TDR 125.
I'll have to open the engine so I accept all your suggestions for some improvement.
For Akronos, if you want you can contact me directly, I leave my email
roby267@yahoo.it

[2stroke]

Welcome roby267

Which year was manufatured your TDR?

For the "oil smoke cloud" and oil on the rear wheel : you may have a problem with the right crankshaft seal, "clutch side" to be more clear. Your cylinder "drinks" gearbox oil through the broken crankshaft seal and send it to combustion chamber, resulting in an altered carburetion. An exaggerated quantity of oil that the engine is not able to burn, sending it to the exhaust. Be careful because you could remain very quickly without gearbox oil. Check for the level on right carter's cover.

You can fix the problem without taking away the engine from the bike, but it requires the right tools, experience and...time!

Feel free to ask, if you need help : I have two of these bikes, as you may read through the posts.

[roby267]

Hi, yes, in fact I think it's the deteriorated clutch side seal; I removed the engine to work better and also because I have to do other work, the bike has 45,000 km and has never been done any work, so I have to overhaul the YPVS valve, water pump etc. etc.
With the manual everything would be easier, if I can remove the oil seal without opening the engine would be better, the bearings do not make noise so they should be ok, but I would like to open it and redo everything, even the flywheel side seal, and bearings.
I will change the piston, it is worn from the side of the exhaust, if you see it from above, the elastic band is out of its seat!
Is the head gasket commercial, valid? on the RD 350 they recommended me to put it original.
An important advice, can I remove the airbox and put a conical filter? not to have more performance but for the convenience of putting the carburetor and to be able to put, if convenient, the manifold of the TZR and the carburetor of 32.
bye thank you

[2stroke]

45000km are really a lot for the bearings, crankshaft and piston rod. Cylinder sleeve, if never rectified, could be slightly oval.

To be safe, I suggest to open the engine and completely rebuild it. 

For the head gasket : the original from Yamaha is the best, but also Athena ones are really very good, in my experience.

For the conical filter: I don't know if there is enough space to place it between engine and rear shock absorber. For this reason the two original manifolds to and from the carburetor are bent to the left of the bike. So, the straight TZR inlet manifold could be not the best choice, in this regard.

[roby267]

Redoing the engine would certainly be the best choice, with the manual it would be much better having this engine the counter balancing shaft.
The cylinder I redo, I rectify it, and I put the new piston probably I put a Mitaka or if it does not cost much I put the Namura that usually sell it complete with gaskets and roller cage (Big End Bearing)
I put a link where I found some spare parts, olte at Yambits
http://www.pjme.co.uk/cgi-bin/sh000002.pl?WD=125%20tzr&SHOP=%20&PN=Yamaha_TZR125_Engine_Parts_Bottom_End_%2ehtml#SID=297

[2stroke]

Redoing the engine would certainly be the best choice, with the manual it would be much better having this engine the counter balancing shaft.
The cylinder I redo, I rectify it, and I put the new piston probably I put a Mitaka or if it does not cost much I put the Namura that usually sell it complete with gaskets and roller cage (Big End Bearing)
I put a link where I found some spare parts, olte at Yambits
http://www.pjme.co.uk/cgi-bin/sh000002.pl?WD=125%20tzr&SHOP=%20&PN=Yamaha_TZR125_Engine_Parts_Bottom_End_%2ehtml#SID=297

Countershaft's timing setting is not diffficult :  you have a mark ( round shaped ) on the primary and countershaft gears. You have to match them, nothing else.

You've choosen a very good shop. They're very professional. 

I tried Mitaka pistons and they're a really good alternative to the originals. The main difference versus the original is that Mitaka's piston for TDR/TZR doesn't have the hole at the inlet side. The best would be Wossner forged piston. Pay attention to clearance.

Be careful when you choose small end bearing ( roller cage) because it depends from the piston inside shape :  there are two kinds of roller cages, and they differ in width.