Eric 03 125 tuning times again:)

[marcusgunby]

So eric its already that time of year.Whats the scoop on the 03s?
Ive rode the KX and its a blast-great engine with a real good bottom and mid but lacking a tad of top.The 03KTM is meant to have the most torque of any 125 made.The CR ive read is better(how could it not be)we only have one in the UK so no real world tests.The RM sounds much the same but a tad better like every year.YZ again similar to the RM a bit better they say.Huskys?? not heards of a 03 model.Come on what do you know??? :worship:

 

[bclapham]

i am probably telling my grandmother to suck goose eggs here (how does that saying go), i read a report in a magazine stand they recon the CR125 motor is totally different from top to bottom with the biggest difference in the reed valve and a 38mm TMX carb, they also said it had a new 3rd generation frame..more power and responce everywhere compared to last year.

funny that MXA's test the KX engine didnt compare to the YZ!

 

[marcusgunby]

Had a good look at the 03Cr at a championship round-it had a strange change-the earth to the coil was bolted to a new lug on the head-couldnt see why?The reed area looked alot bigger but with the v force fitted before, i dont see the advantage ,as the reed area is the same on all the 125s as the v force shares the same reeds across all the 125s.The main advantage should be a closer pover valve flap to piston arrangement on the new cylinder.

Even a KX250 wouldnt compare to a YZ125 in MXAs mind :flame: funny thing is they are getting a bad reputation here as hard to get handling and suspended well.The 02 was a step backwards IMO in everything but engine. :whiner:

 

[EricGorr]

I haven't seen an 03CR125 yet. Does anybody know if they are delayed in shipment? Does anybody have one yet?

 

[flyinfinn]

my dealer said they are getting their bikes in december. 03 cr 125's that is.

 

[marcusgunby]

Due here next week.Apparently the have new cases/cylinder and powervalves.

 

[marcusgunby]

Right to move this thread on in a new direction-im going for a 03 KX now as steve125 has convinced me i need to bleed green-has anyone done any porting work on them or other mods we should know about?

 

[Eddy V]

marcusgunby,

we also changed for the next season from a KTM125sx to a kx125 because of the reason that the KTM was not a bike for short riders.I'm a Belgium motocrosser and i always tune my bikes myself.So i'm looking forward for some tips because this is an totally new bike for me after 6years RM125 and 1 year KTM.I think the first thing we must do ,is figure out how to broaden the powerband because i've heard some complaints about that.I expect my bike this week so we start immediatly with dismantling it an measuring all the values.we normally also do some dyno testings with pipes (Doma,Spes,HGS) but for the kx i'm also curious after the results of a Pro Circuit.So I should say,any tips are welcom.

 

[viking20]

This is not fair!How can you expect the rest of us CR guys to benefit from all your work on green bikes? ;)
Seriously,a few 03 KX 125 has showed up here,and people are impressed how much better they perform overall........

 

[steve125]

Eddie V ive tested the Pro Circuit pipe vs the stocker on a few different tracks. At this point i'm not so sure it's any better. The pc does fit the bike better and it seems to add some power up to peak, but it dosen't over rev as well as the stock pipe. I get the feeling this pipe will work much better with a cylinder that has had it's port time advanced a bit.

 

[marcusgunby]

Right the info i have so far.
The V force(pre production) didnt work-it lost at 6K and lost overrev.
The HGS pipe gave more power all the way to peak but like the PC it peaked early and died on overev.
The HGS rev pipe lost a tiny bit of roll on power but gained everywhere including overrev.
A VHM head can be used with a 02 KX125 piston to advance the port timing slightly.More rev and a free revving engine.
A 38mm TMX carb is said to produce cleaner running and easier jetting.
Local tuner has tried to lower and raise the cylinder with extra gaskets but std was best.
Even Tallon Vohlands bike is said to have std porting.
A wulf ignition adds overrev only.

 

[bclapham]

i am really suprized that all of the "usual" modifications on the 03kx havent given the bike more power, since its a new engine so you might think there is a lot of potential for much more performance increase with testing and mods that could be done! is it correct that the engine is very similar to the yamaha in design? have kawaski got it as far as it will go right now?

i cant wait to see james stewart on the full works bike at the san diego SX, but i suppose the real test is those big hills at glen helen, pastrana's rm looked to go very slow up them hills compared to the KTM of langston!

 

[steve125]

Yes in design and in performance! There's power to be made but Kawasaki did their homework on this one. I don't expect any big changes in tuning this bike. When a bike runs this good you have to be berry berry carefull. :) I look forward to my upcoming dyno time. :thumb:

 

[marcusgunby]

Im with steve 100% the 02Cr125 is easy to get big gains on as it is soo bad to start with.
If i can get 2-3hp more top end out the KX it will be a perfect engine
14-15hp at 7K
20hp at 8K
25hp at 9K
30HP at 10K
35ish hp at 11K
the only engine to come close is a 01 KTM 125sx with just a fmf fatty and shorty silencer(IMO the 01 engine was better than the 02)
Now i have dynos of a EG KTM133sx and that was even better and to be honest was the only 125 based engine that i found had too much pull-it could easily keep with a 98KX250, which most will remember to be very good even by 250 standards.

 

[steve125]

Yep thats what we hope to find, a bit more top power and over rev with no loss on the bottom. So stay tuned :thumb:

 

[bclapham]

i dont know when my next UK trip is planned marcus, so youve got plenty of time to sumon up enough big HP out of it so it will able to lug my weight around!:)

 

[bclapham]

i went back a read that MXA 125 dyno article, it seems like the yz, rm and kx ar very close in power (funny how the yz comes out on top in the reviews though!:)) however, the KTM's always come out on top, what do the austrians know that the japanese dont? pretty similar for the 250's also.

 

[marcusgunby]

I beleive its in the PV designs and they use Port 2000 software i wouldnt wonder.

There is no way a bike with such a dip in the powercurve could win any shoot out.The YZ looses power after 8K and takes 500rpm to get back to the same power level again.500 rpm missing in a 125 powerband is like asking me to lug around a extra 20lb round my waist :aj:

 

[steve125]

The KTM does have MOTOR!!!!! The yz has a dead spot at 8k, this more than likely is caused by a too LARGE of an exhaust port or the timing is too advanced in order to get a get a high rpm PULL!!. testing the new option in type here. :)

 

[Camstyn]

I always thought that KTM had the distinct advantage of the carb/intake coming into the engine at a straight angle, rather than in from one side, due to the position of the rear shock. Is there any proof of that?

 

[marcusgunby]

Yes Cam i do beleive it to be a benefit-however the Husky CR with a really angled carb still manages to make alot of power so its not conclusive.

 

[cr-man]

I'm with Cam I think the straight shot from airbox to the reed valve is a big factor in why the KTM's motors are so strong it's the only thing that really stands out from the Honda's, Kawasaki's, Yamaha's, and Suzuki's.

 

[marcusgunby]

Steve there ganging up on me;) also another interesting point is how KTM manage to get the 39.5mm carb to work on a 125- theory says a 40mm carb will be too big for a 125 and it will be all top end power-the KTM is anything but all top end?

 

[viking20]

Marcus,is the carb on the KTM oval shaped?I think someone mentioned one day,that besides the intake being "straighter", the exhaust port is different to the jap bikes?

 

[steve125]

I think there's alot more going on to the KTM's motor that just a straighter intake flow path. If that was the fix for all the other lame 125 motors then the RAD valve would be a big gain, but its not. The KTM is so fast because everything is right and works together. Port timing, exhaust valve design, cylinder head and squish clearance, crankcase volume, Ign mapping.....the list goes on and on..... All the instruments are working together, like in a orchestra, but in this case it's not beautiful music, just awesome horsepower from bottom to top :thumb: