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..
Uses:
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.
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.
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...
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..
b3nhacker@yahoo.com
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.
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

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.