13th Feb 2008, 10:07

I have a 125ZR. My 125 can reach 230km/H. I only use original parts because the original parts are better than racing parts.

1st Mar 2008, 08:43

I also have a 125z (open). It can beat an Aprilia RS250 (std) even top and beat it by a lot.. my bike is 1km bike..


Enduro piston

38mm carb..

YZ125 magnet

YY pang open exhaust (modified)

YY pang racing parts

Sprocket 15 34

Motul oil

RXZ; no need to fight.. quite satisfied with this bike.

12th Jun 2008, 07:10

Hi.. anyone know where I can get the Yamaha 125z racing magnet and the 38mm carburator.. URGENT PLS thanks... can email me at amylia07@hotmail.com if you know any shop in Malaysia selling it or anyone.

30th Aug 2008, 06:07

My bike can only goes 130k/m hr.

1st Nov 2008, 14:35

Please tech me, my motor can't go faster, only 120, and the fuel use is very much. How can I solve it?

2nd Nov 2008, 09:32

I want to know what is the standard modification for a 125zr to reach a top speed around 200 km/h?

9th Jan 2009, 04:43

It's easy to modify a 125ZR. My new 125ZR (2008) after modifications can reach 260km/h, but only for short distances (overheating).

14th Jan 2009, 11:00

For owners of the 125ZR, don't worry if your motorcycle is stuck with a 140KM/H limit. I'll give you a good hint, and this is based on my experiences. Don't modify the engine. Just follow my advice and you'll get something different.

What you need to do is first change your sprocket (just follow as previous post). Second change your clutch plate (racing clutch plate - to get more pick up). Third, remove your air filter sponge (but I'm not suggesting this if you ride on dusty roads, and you've got to take care to clean the air filter box every month or week).

After you do this you can gain speed over 180KM/H. Yeah, as the previous user said, that is true, you can get speed at 260KM/H if you do more modifications, but the main problem is the temperature of the engine will rise up, and you'll end up with your engine blowing up.

21st Jan 2009, 23:43

Can I know where to get the racing parts for my RXZ??? I tried at the local shops, but could not find it, especially the carburetter... and rims... when I use the original it is expensive..

18th Feb 2009, 18:37

Hi, I'm new here. May I know what is the suggested speed limit for new bike (125ZR)? I just took a new bike (125ZR). Not really sure on what speed I'm supposed to ride since it is still a new baby. Can I ride him less than 80KM/H? Please advise. TQ.

9th Mar 2009, 20:54

Hi... I'm new here and I would like ask that what is the suitable size of back sprocket so that I can finish my meter? I'm using size 15 39 now... if use small sprocket there will be no power when I shift to 6th gear...

29th Mar 2009, 12:30

125z can only reach 220kmh.

1st Apr 2009, 11:29

Man - There are so many people that say the 125z hits 170km/hr or over the speedmeter limit... Please do some homework, check the gear ratio, primary and secondary reduction ratio and tyre size, then you'll get an idea that under stock condition the 8000rpm@6th gear just can give you 100.13km/hr real speed.

I also own one, but 5000rpm@6th gear already hit 120km/hr on the meter...

If anyone finds a chance riding some big bike, trying the feeling at 100/120/150 km/hr, then you'll know how funny the 125z meter is...

28th May 2009, 22:18

I have 125z 2004 model... it can reach about 165km/h only... I only changed coil racing and mag saver (for reduced oil). Now I want to know which CDI is more better... CDI first model 125z or cdi racing... because I really want my bike to reach 180km/H...

8th Jul 2009, 01:26

My 125Z only can run 170km/h. How to make it more powerful? I already change the spocket 13-35, carburator TZM, ekzos BM Power, but still cannot reach full meter.

27th Oct 2009, 06:03

For those who want 2 try to modify their 125z...

my 125z's top speed is still unknown, but I did reach 180kmh before I freed my throttle.. in 400m I can reach 165kmh-170kmh.

Here is my settin:

Sprocket ratio 14/36

I'm using 1 layer yy pang ekzos chamber..

standard stock carburator but I set my pilot 35 and my mainjet 245.

I'm still using sport rim.. with big tires.

Original block I used 1.75 piston size and I port the air and fuel hole make it bigger and smoother...

Other than that, everything is standard stock..

For those who really want to race... try not to use cable keys.. unplug it for direct firing sys.. from the coil ignition cable, don't use the head plug, just direct connect it to the spark plug from the bold cable..

That's all my own setting that I did myself to my lovely 125zr... correct me if my method is wrong.. because all start from trial and error...

Welcoming any PM in my YM about 125z modification..


8th Dec 2009, 22:27

My 125z can go to 180kmh at gear 6. Ported my standard block, rebore piston to size 0.50, skimmed headblock, ported rxz carb, stock pipe and using 15-38 sprockets. But it could clear meter only at 1km. What other mod can I do to increase the speed? It seemed slow for me.

14th Dec 2009, 06:46

Izzit yy pang exhaust is better or AHM (pro racing exhaust)??

14th Dec 2009, 06:51

My 125z also can reach 180km. But still not satisfied with the speed...

26th Dec 2009, 09:39

Hello there, I'm from Phil. I'm a 125z fan. In our country it's very hard to have one of these 125zs. We can have it here by illegally transporting from Malaysia :( I want to have one someday; I really love this bike.

9th Jun 2010, 16:45

Hi I'm from SG.

I'm a mechanic, I ride a 125z. Still not satisfied with my carburator setting... I'd like to share my modifications.

Racing block 58mm using YZ125 piston

rxz carburator = mainjet 270, pilot jet stock

racing springs, five clutch plates, sprocket 15/38

& customised illegal exhaust.

Well, I've smoked CB400 vtec3 & DRZ & other 2 stroke bikes.

15th Jun 2010, 04:45

Hello somebody please answer me...

I have a used Yamaha RXZ carb, but my 125z only can go at 170km/h..

I heard if I used an RXZ carb, this bike can reach full speed...

Why not???

15th Jun 2010, 22:29

Hi, I'm from Malaysia. I've owned this bike for more than 2 years. Here you can buy a brand new 125z, but unfortunately the production is limited due to our government's policy to encourage people to buy 4 stroke motorcycles.

29th Jun 2010, 03:19

I want to ask something; my 125Z got a problem after I changed the original carburetor to an RXZ carburetor. My ride is hard to start every morning; to me it's okay as long my ride wants to start, but now I just leave it for a few hours after I use it. My ride is hard to start just like early in the morning.. every time I start the engine, I have to use the choke. e-mail me at axxis72@hotmail.com

18th Aug 2010, 21:38

Original or chamber exhaust.. which is better?

20th Aug 2010, 08:05

Try to use original parts.. although it's expensive, but it's better..

If you're still not satisfied, try some modification on the block, sprocket and carb.. but still on original parts..

Then, you'll find satisfaction while riding your 125z!