On my Cr the only thing I've done is remove the reed spacer. I'm looking to increase it's overall power, to pull longer and harder maybe a little more over-rev. I really like the power band and don't want to change its characteristics too durasticly. From what I've been reading the V-force reed assembly and SST pipe combo will do wonders. For now I'd like to keep the cost down by not sending the motor away, but I'm open to that later in the summer. Any help is greatly appreciated.
2002 cr 125 mods
- Thread starter xtreme73
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NO HAND
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(Taken from: Link)
The intake manifold is too small and doesn't work in sync with the agressive porting stock. You would gain over-rev if you would switch over to a 00 CR125 intake manifold. See it's part #9 on the diagram.(Click Diagram) The Honda part #16221-KZ4-A90 and it's around 30$. To get your money's worth, you would be better getting the v-force before the pipe.
marcusgunby
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If you use the 00 manifold you will need to match the cylinder to it using a grinding stone in a drill.
NO HAND
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Marcus. I think you are refferring to the exhaust manifold. It sure would be a good idea to go for the exhaust manifold also but think the 01 is better than 00 and 02 for over-rev. I was first talking him about the intake manifold. There is no mod needed for the intake one, right? Marcus, I guess also the ignition would be a much better mod than the pipe. What do you think?
marcusgunby
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Sorry
Complete brain fade-i was talking about the exhaust side.The same applies to the exhaust side however.The Cr would be a great little engine for bottom to mid power with a vertex/wiseco piston and lowered cylinder(0.75mm) but it would then peak at 11000rpm no matter what other mods are done.For top end the intake and exhaust need to be opened up to match the cylinder configuration.For top end no cylinder mods are needed.A v force is a good choice for all CR125s.For the 02 i would choose a 99 inlet manifold as the 02 carb is slightly bigger OD then the 01 carb.On the exhaust side i have just opened up the std manifold to 01 spec(3mm higher at the top)but i havnt rode it yet to see if it improves top end.The SST pipe i tried was a 01 model (on my 02)and it was terrible without the Wulf ignition.The 02 SST may be better -i cant say but a local rider bought one and took it off the same day.Also the SST has a major effect on detonation-i had a 440 main jet and head mods and still had bad detonation.The ignition is definatly good but the ones from FMF for $99 wont work on the 02 and the others are very expensive.
In conclusion my mods would be
v force 2002 model
99 reed manifold or open up the std one
open up the exhaust manifold to 01 spec
shorty silencer
vertex piston.
Head mods are the most important mod if you arnt running race gas.
Complete brain fade-i was talking about the exhaust side.The same applies to the exhaust side however.The Cr would be a great little engine for bottom to mid power with a vertex/wiseco piston and lowered cylinder(0.75mm) but it would then peak at 11000rpm no matter what other mods are done.For top end the intake and exhaust need to be opened up to match the cylinder configuration.For top end no cylinder mods are needed.A v force is a good choice for all CR125s.For the 02 i would choose a 99 inlet manifold as the 02 carb is slightly bigger OD then the 01 carb.On the exhaust side i have just opened up the std manifold to 01 spec(3mm higher at the top)but i havnt rode it yet to see if it improves top end.The SST pipe i tried was a 01 model (on my 02)and it was terrible without the Wulf ignition.The 02 SST may be better -i cant say but a local rider bought one and took it off the same day.Also the SST has a major effect on detonation-i had a 440 main jet and head mods and still had bad detonation.The ignition is definatly good but the ones from FMF for $99 wont work on the 02 and the others are very expensive.
In conclusion my mods would be
v force 2002 model
99 reed manifold or open up the std one
open up the exhaust manifold to 01 spec
shorty silencer
vertex piston.
Head mods are the most important mod if you arnt running race gas.
- Thread starter
- #8
Ok, for now I should get a 99 intake manifold and bolt it on with the V-force system. Instead of a SST would another pipe work better or is the stock one best?
At the first rebuild then get a vertex piston and match the exhaust manifold to 01 spec (What's the difference anyways). I'm capable enough to grind away but what would I need to get started and know how much to take out, I'd hate to screw this up. What head mods are you suggesting. I don't want to get where I'm running race gas because I went through that crap with my 98 KX 125.
Is your powerband a top end, narrow power screamer with a hard hitting powerband or one that is more forgiving. What power characteristic changes have you noticed with your engine?
At the first rebuild then get a vertex piston and match the exhaust manifold to 01 spec (What's the difference anyways). I'm capable enough to grind away but what would I need to get started and know how much to take out, I'd hate to screw this up. What head mods are you suggesting. I don't want to get where I'm running race gas because I went through that crap with my 98 KX 125.
Is your powerband a top end, narrow power screamer with a hard hitting powerband or one that is more forgiving. What power characteristic changes have you noticed with your engine?
marcusgunby
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To be honest the stock exhaust is a good one that can be improved on but its not worth the money.A silencer is the best thing to buy-i like the doma tailpipe-very nice sounding and not too loud.
The difference between the 01 and 02 exhuast manifold is the 02 is longer by 15mm and is necked down(if you remove it you would notice it has a flat towards the top,instead of being full round).The 01 top comes down only 4mm into the round section, the 02 comes 7mm into the round section.Just mark 3mm from the top and grind away in a nice arc shape.Refit the manifold and grind the cylinder to match,It really is so much easier to do than describe.My bike has many mods but all my mods go for overall power gain.I have a few dyno charts up in the members gallery-take a look,my bike has the same bottom and mid as std then takes off to make approx 4.5hp more :)
Head mods-the easiest thing to do is to use 2 head gaskets-a better mod is to recut the head to a spec listed by eric(cant remember exactly-a search would find it)
The difference between the 01 and 02 exhuast manifold is the 02 is longer by 15mm and is necked down(if you remove it you would notice it has a flat towards the top,instead of being full round).The 01 top comes down only 4mm into the round section, the 02 comes 7mm into the round section.Just mark 3mm from the top and grind away in a nice arc shape.Refit the manifold and grind the cylinder to match,It really is so much easier to do than describe.My bike has many mods but all my mods go for overall power gain.I have a few dyno charts up in the members gallery-take a look,my bike has the same bottom and mid as std then takes off to make approx 4.5hp more :)
Head mods-the easiest thing to do is to use 2 head gaskets-a better mod is to recut the head to a spec listed by eric(cant remember exactly-a search would find it)
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Hey marcus. I have the reeds and hogged out my 02 manifold, have a stock shorty silencer, and thats about it. What should i do next. The exhaust mod seems cool but i dont think my dad would like the idea of grinding the cylender. Do you have to do that in order for it to improve anything? Or can i just get the 01 manifold and match it up? Also how much roughly is that ignition in canadian $ and do you think it is worth it.
marcusgunby
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Honda you can buy the 01 manifold and it could work better than my hogged out 02 manifold-the only reason i have done it this way is because my SST wont like the shorter 01 manifold-im sure a std front pipe would fit ok.You still need to open up the cylinder side to match the 01 manifold though.Without the exhaust side opened up you will not get the Cr to pull hard on the top end.
I have no idea what the ignition is in canadian $(do a search on the web)but a ignition is only as good as the programmer-they all work similar but need to be mapped for your application.On mine i was very happy with a 1hp gain from 8K upwards-the only other mod i have seen as good is the v force.One inetersting point was when the bike got hot after 5 runs the power was terrible with the std ignition but with the wulf it hardly altered.
I just looked back and noticed no mention of what piston you are running?
I have no idea what the ignition is in canadian $(do a search on the web)but a ignition is only as good as the programmer-they all work similar but need to be mapped for your application.On mine i was very happy with a 1hp gain from 8K upwards-the only other mod i have seen as good is the v force.One inetersting point was when the bike got hot after 5 runs the power was terrible with the std ignition but with the wulf it hardly altered.
I just looked back and noticed no mention of what piston you are running?
- Thread starter
- #12
I went searching for Wulf and found nothing, do you have a helpful link???
From what you say this is what I need to make a kick ass bike
-99 cr 125 intake part #16221-KZ4-A10
-01 cr 125 exhaust manifold part #18352-KZ4-L10
-vertex piston part #626-116
-V-Force Delta 2 Reeds
-and Eric's head mod, if I want to run race gas
I found the two-stage AOF Power Ignition from FMF, retail is $300. Would this ignition perform like the Wulf? The only reason I ask is I get my parts at cost as long as they're in the catalogs.
From what you say this is what I need to make a kick ass bike
-99 cr 125 intake part #16221-KZ4-A10
-01 cr 125 exhaust manifold part #18352-KZ4-L10
-vertex piston part #626-116
-V-Force Delta 2 Reeds
-and Eric's head mod, if I want to run race gas
I found the two-stage AOF Power Ignition from FMF, retail is $300. Would this ignition perform like the Wulf? The only reason I ask is I get my parts at cost as long as they're in the catalogs.
Hmm i dont feel too comfortable still doing that but if i did or took it to someone can a leave the engine in and head on? Or do i have to take it apart because i realize all of the metal shavings that will go flying but could you just cork the exhaust port close to the cylender wall?
I beleive your not finding the ignition in your search because it is a Wolf (not Wulf)ignition. If this is the one you're talking about it is distributed in the USA by Tom Morgan Racing(928)453-3188. I have one that was used once. It worked good, I thought, but the person I bought it for has tried all of the brands of ignitions and is not happy with any. So I am stuck with another one to try to sell to get some of my money back.
If you would like to run the 2001 CR unit on your 2002, I can arrange to tell you which wire needs to be modified so you can buy your friends unit and then go riding.
I am the manufacturer of Wolf CDI in Australia and will be happy to assist in any way.
To contact me please email at steve@wolfcdi.com and I will tell you what to do.
Good Luck and if you have any problems please contact me.
I am the manufacturer of Wolf CDI in Australia and will be happy to assist in any way.
To contact me please email at steve@wolfcdi.com and I will tell you what to do.
Good Luck and if you have any problems please contact me.
marcusgunby
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xtreme 73 you have the mods correct apart from you need head mods to run pump fuel but i think thats what you meant.You will need a shorter silencer.The AOF ignition is a reboxed wolf as far as i know.
Honda the Husky vertex doesnt seem to loose power anywhere.And it should give better pick up.You will need to clean out all the shavings after altering the exhaust manifold etc but thats the easy part.Just use nice hot soapy water a few times then lube up with a bit of premix.
Honda the Husky vertex doesnt seem to loose power anywhere.And it should give better pick up.You will need to clean out all the shavings after altering the exhaust manifold etc but thats the easy part.Just use nice hot soapy water a few times then lube up with a bit of premix.
- Thread starter
- #25
From what I understand the flat part on top will become more round. Is this correct?
For pump gas 2 gaskets or this mod by Eric
When I cut the base (1mm from the base and sleeve of the cylinder) I cut the recess in the head 1.25mm at 2 degrees and a 5.5mm wide squishband.
02 Head Mods Thread
Thanks a lot Marcus (and everyone else) for all of your help, it's greatly appreciated!
