03 KX125 Exhaust on an 03 CR125

KICKERMAN360
Edited Date/Time 10/31/2015 3:29am
So after some recommendations from the internet (where everything is 100% true and factual) I fitted an 03 KX125 to my 03 CR125. According to many posts online, this is the best exhaust. It's mated to the Pro Circuit silencer that came with the bike. I made up two brackets and used the original rubber flex bracket for the pipe. It lined up pretty well although at a very slight angle on the flange. I had a spare 98 CR125 flange that fitted pretty well. Although it needs a gasket. Then I just dented it slightly with an engineers hammer (ball head) to clear the radiator and presto, all done.

Anyone else done a similar mod? i was thinking of cutting the head part of the expansion chamber to bend it out a little but might see how it goes. I have ordered a bunch more OEM parts to get it ride-able although the rear shock is woeful and is basically just a spring as the damper does nothing.









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Tracktor
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Tracktor 9/14/2015 9:18am
9/14/2015 9:18am
Done it and it works really well for us. 02 CR125 with a '96 HPP top end...........
mx621
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mx621 9/14/2015 9:53am
9/14/2015 9:53am
I have a 95 hpp top end im sending out soon for my 02 cr125.. wonder how a fmf or pc kx125 pipe works on the Hondas..
MxKing809
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MxKing809 9/22/2015 6:25pm
9/22/2015 6:25pm
I had a 05-07 Cr125 PC works pipe on my 02/HPP bike and really liked it. I had to bend the throat down and reweld it but it was easy. I want to try the kx pipe as well..... I just need to find one
MxKing809
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MxKing809 9/23/2015 4:05pm
9/23/2015 4:05pm Edited Date/Time 9/23/2015 4:10pm
So the CR silencer will slip right onto the KX pipe?

And it looks like the Kickstarter hits the pipe..... what's up with that?

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dadofagun
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dadofagun 9/23/2015 4:55pm
9/23/2015 4:55pm
MxKing809 wrote:
So the CR silencer will slip right onto the KX pipe?

And it looks like the Kickstarter hits the pipe..... what's up with that?
Not to sound like a total smartass..... The problem with the kick starter may have something to do with the pipe made for a KAWASAKI is now installed on a HONDA....
Now, on a side note.....curious if my sons 5.0 Mustang engine will fit my girlfiriends Nissan Sentra? Wondering if anything may be out of place?
DirtJumper936 9/23/2015 5:16pm
9/23/2015 5:16pm
I have a 03 kx125 fmf sst pipe i would sell. It has one small dent an inch long. I was told the sst pipe is what's causing me to burn huge holes in the front of the piston.
MxKing809
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MxKing809 9/23/2015 5:19pm
9/23/2015 5:19pm
MxKing809 wrote:
So the CR silencer will slip right onto the KX pipe?

And it looks like the Kickstarter hits the pipe..... what's up with that?
dadofagun wrote:
Not to sound like a total smartass..... The problem with the kick starter may have something to do with the pipe made for a KAWASAKI is...
Not to sound like a total smartass..... The problem with the kick starter may have something to do with the pipe made for a KAWASAKI is now installed on a HONDA....
Now, on a side note.....curious if my sons 5.0 Mustang engine will fit my girlfiriends Nissan Sentra? Wondering if anything may be out of place?
Little different bro..... lol.

Half the fun is building cool shit.... and tinkering with combos..... don't kill our vibe
BobPA
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BobPA 9/23/2015 5:59pm
9/23/2015 5:59pm
DirtJumper936 wrote:
I have a 03 kx125 fmf sst pipe i would sell. It has one small dent an inch long. I was told the sst pipe is...
I have a 03 kx125 fmf sst pipe i would sell. It has one small dent an inch long. I was told the sst pipe is what's causing me to burn huge holes in the front of the piston.
That is called detonation. Not at all caused by the pipe. Jetting and/or fuel quality is your issue.
DirtJumper936 9/23/2015 6:13pm
9/23/2015 6:13pm
DirtJumper936 wrote:
I have a 03 kx125 fmf sst pipe i would sell. It has one small dent an inch long. I was told the sst pipe is...
I have a 03 kx125 fmf sst pipe i would sell. It has one small dent an inch long. I was told the sst pipe is what's causing me to burn huge holes in the front of the piston.
BobPA wrote:
That is called detonation. Not at all caused by the pipe. Jetting and/or fuel quality is your issue.
I thought the same thing. 3 pistons and 2 cylinders later I sent it to Eric gore/millinium. the first thing they asked after seeing it was are you running an fmf sst pipe. They said it builds up to much heat.
cwtoyota
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cwtoyota 9/23/2015 6:35pm
9/23/2015 6:35pm
DirtJumper936 wrote:
I have a 03 kx125 fmf sst pipe i would sell. It has one small dent an inch long. I was told the sst pipe is...
I have a 03 kx125 fmf sst pipe i would sell. It has one small dent an inch long. I was told the sst pipe is what's causing me to burn huge holes in the front of the piston.
BobPA wrote:
That is called detonation. Not at all caused by the pipe. Jetting and/or fuel quality is your issue.
DirtJumper936 wrote:
I thought the same thing. 3 pistons and 2 cylinders later I sent it to Eric gore/millinium. the first thing they asked after seeing it was...
I thought the same thing. 3 pistons and 2 cylinders later I sent it to Eric gore/millinium. the first thing they asked after seeing it was are you running an fmf sst pipe. They said it builds up to much heat.
The SST does the same thing on the YZ250 engine.

The "secret" to the SST is a reduced outlet at the back of the pipe. It does build up more heat inside the pipe and inside the exhaust port.

On the YZ250 you can run a larger main-jet, but then the bike feels fat most of the time. Race fuel and head mods help, but ultimately I threw my SST out back behind the shed and run PC and DEP pipes. The SST is still sitting there rusting away... Fact.
KICKERMAN360 9/23/2015 6:59pm
9/23/2015 6:59pm
MxKing809 wrote:
So the CR silencer will slip right onto the KX pipe?

And it looks like the Kickstarter hits the pipe..... what's up with that?
The CR silencer fitted perfectly onto the end. The rubber Honda thing was difficult to get onto the Kawasaki pipe though, but a little oil or lube made it work.

The kickstarter knuckle is worn so right now it does hit the pipe but once I get a new one it should clear it. At this point I'm just seeing how it runs. If it feels good I'll keep it on.
KICKERMAN360 9/23/2015 7:01pm
9/23/2015 7:01pm
MxKing809 wrote:
So the CR silencer will slip right onto the KX pipe?

And it looks like the Kickstarter hits the pipe..... what's up with that?
dadofagun wrote:
Not to sound like a total smartass..... The problem with the kick starter may have something to do with the pipe made for a KAWASAKI is...
Not to sound like a total smartass..... The problem with the kick starter may have something to do with the pipe made for a KAWASAKI is now installed on a HONDA....
Now, on a side note.....curious if my sons 5.0 Mustang engine will fit my girlfiriends Nissan Sentra? Wondering if anything may be out of place?
2 stroke pipes are typically quite universal. Plus, this one was $80 for the complete system and a PC pipe was over $300 (AUD). So worth it right now. Plus, apparently it's the best pipe.
Cancerman
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Cancerman 9/23/2015 11:31pm
9/23/2015 11:31pm
A friend has an 05 CR125. Ports were cleaned and matched. Stock compression. I suggested a PC pipe. He finally got one and we are shocked at the difference it made. Extended the power considerably. Those years CR125's are known to be rather slow.

II had an 03 RM250, with an FMF SST pipe. It had no hit what so ever. I was always chasing the jetting, and the only way to jet it to not ping and rattle, was to run it fat. I installed a PC factory on it, and wow, it was a different big altogether. I think the other FMF pipes are fine, but the SST is pretty touchy. I think it would work well on a real slick track. No hit at all. Just my experience.
KICKERMAN360 10/31/2015 3:29am
10/31/2015 3:29am
So I finally got around to fixing the bike up. I found out the water pump shaft was worn so I replaced that and did a top end because I was in the area.

So I fired it up and it runs fine at idle, but feels like the RPM isn't rising too high enough. It doesn't sound the same as my 98 CR125 which revs much higher. The jetting probably needs work is my thinking (but I'm gonna do a leakdown test also). Just wondering what jets people might reccomend for this pipe combo? Judging by the smoke I might think it's too rich in fuel. The ratio is 32:1.

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