Cr125r 2002 ultimate build(hopefully)

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11/6/2017 1:37 AM
Edited Date/Time: 11/6/2017 1:51 PM

So I just picked up this cr125 2002 for reasonably cheap(I think, need to wait for the tear down to really see if it was cheap lol) but anyway plan on doing a build that I like not what everyone else has. A build that I spend a reasonable amount of money on it to make it super, but then not be afraid to thrash it like a normal dirt bike. I will do as much as I can cosmetically to make it look super but also as much as I can to make it a reliable bike and do things to make it as powerful as possible.

The bike was covered in sand when I picked it up, with a typical answer of why it’s not clean is that he ‘forgot to wash it’. But anyway it has a 140cc kit with apparently only two hours but we will see about that on tear down. I will probably but a new cylinder to change it back to a 125 but then if I did want some extra power I could swap it. It also came with a fmf shorty and a near new rear tyre, and surprisingly straight radiators but that was about it for the pros. So from then on in it was basically all bad, with sand everywhere, front brake locked on, rusted to hell chain, leaking fork seals, no kill switch, bent bars!!, and general roughness. But not to worry it will all be replaced. Also aparently after the 140cc kit was installed it started fouling plugs quite often. This has happened on my other bikes before and it was just the carburetor needed some adjustments.

My plans for the bike so far are:
full engine rebuild
Upgraded suspension (want opinions on best to use)
2017 plastics conversion kit, also comes with new seat
Full pipe system( what’s the best brand for this bike?)
Boyseen or vforce reeds
New bars
New carb
All new tyres
New rim set
Lots of powder coating and anodizing
New chain and sprockets
And much more but that’s just a basic run down.

Basically I am trying to replace as much as I can on the bike, to get something awesome.

Any tips or thoughts on what to do with it are much appreciated.

This build is located in New Zealand

Here are some pics of the bike as is. (When bought) will start tear down over next couple days.Photo

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11/6/2017 2:36 AM

My brother had a 02 cr125 once, completely stock. It was painfully underpowered compared to my 03 rm125.

We put a pc pipe and shorty on it along with a vforce 3 reed cage and yetted it. Felt like it did 10+ hp more after that.

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11/6/2017 2:46 AM

TimR wrote:

My brother had a 02 cr125 once, completely stock. It was painfully underpowered compared to my 03 rm125.

We put a pc pipe and shorty on it along with a vforce 3 reed cage and yetted it. Felt like it did 10+ hp more after that.

Cheers for the advice Tim, that might just be what I do. Anything to add power?

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11/6/2017 6:02 AM

How much did you get it for?

Those bikes seem terribly underpowered compared to others. I'd recommend some mild porting and reeds, along with an FMF Fatty or PC pipe, whatever you prefer.

It might benefit from the 140 kit if that's your thing, but I liked mine in stock form.

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If you're not mixing gas, you're not haulin ass.

11/6/2017 8:17 AM

Please dont ruin it with tx-race plastics.ermm
Spend those money on an air striker carb instead.

Underpowered or not, i ran the same Times and (race)pace with my 06 125 as my 16 250f.. but with a awesome grin on my facew00t

Going wfo on big step ups and barely make it feels amazing on these scoots!devil

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11/6/2017 8:32 AM

The problem with the 2002 is the lack of air the engine receives. There isn't one simple fix, there's a million little items that combine to help it breath.
2007 air box and air boot. They slightly redesigned them to help air flow.
Boyesen Rad valve and reeds.
PWK airstriker carb conversion is a must. You can purchase the whole carb jetted and everything from JD or purchase the carb separately from Ebay then purchase the jetting kit from JD.
Cryca high-flow rear fender.
I have even seen people drill 1/2 sized holes directly into the air box, like husky did one year on their 250f
Boyesen exhaust flange.
Of course Pipe and silencer. I run FMF fatty pipe with shorty silencer. I have herd some suggest a pipe from a Stock Kawasaki 125, but have no experience myself.

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@wasummer46

11/6/2017 9:36 AM

Please dont ruin it with tx-race plastics.ermm
Spend those money on an air striker carb instead.

Underpowered or not, i ran the same Times and (race)pace with my 06 125 as my 16 250f.. but with a awesome grin on my facew00t

Going wfo on big step ups and barely make it feels amazing on these scoots!devil

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11/6/2017 11:41 AM

TrailDigger wrote:

How much did you get it for?

Those bikes seem terribly underpowered compared to others. I'd recommend some mild porting and reeds, along with an FMF Fatty or PC pipe, whatever you prefer.

It might benefit from the 140 kit if that's your thing, but I liked mine in stock form.

I got the bike for $1700 nzd

I will defiantly be getting an exhaust system, probably pc along with some vforce 3 reeds. And will consider some porting?

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11/6/2017 11:47 AM

wasummer46 wrote:

The problem with the 2002 is the lack of air the engine receives. There isn't one simple fix, there's a million little items that combine to help it breath.
2007 air box and air boot. They slightly redesigned them to help air flow.
Boyesen Rad valve and reeds.
PWK airstriker carb conversion is a must. You can purchase the whole carb jetted and everything from JD or purchase the carb separately from Ebay then purchase the jetting kit from JD.
Cryca high-flow rear fender.
I have even seen people drill 1/2 sized holes directly into the air box, like husky did one year on their 250f
Boyesen exhaust flange.
Of course Pipe and silencer. I run FMF fatty pipe with shorty silencer. I have herd some suggest a pipe from a Stock Kawasaki 125, but have no experience myself.

Cheers for that advice, as said before I will deifinatly be putting an exhaust on aswell as reeds and I have seen a lot of people swapping the carburetor so that might be another must. And also the air boot.

What’s the cycra high flow rear fender? Haven’t heard of it before

I will look into those other things u have stated and see if it’s worth the money?

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11/6/2017 11:49 AM

Kawasaki-rider wrote:

Please dont ruin it with tx-race plastics.ermm
Spend those money on an air striker carb instead.

Underpowered or not, i ran the same Times and (race)pace with my 06 125 as my 16 250f.. but with a awesome grin on my facew00t

Going wfo on big step ups and barely make it feels amazing on these scoots!devil

Hey, how come your not a fan of those plastics ? I will be getting the pwk carb aswell, if that would make it better lol?

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11/6/2017 11:53 AM
Edited Date/Time: 11/6/2017 1:53 PM

If anyone could help me determine how many hours this bike has had that would be great.

The reason I bought this bike was because I have always loved the frames on them and seen some wicked builds on here! It came up and for the right price so I went ahead. But now I have the bike there seems to be a few people on here basically saying the bike is powerless which kinda worries me?

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11/6/2017 1:37 PM

wasummer46 wrote:

The problem with the 2002 is the lack of air the engine receives. There isn't one simple fix, there's a million little items that combine to help it breath.
2007 air box and air boot. They slightly redesigned them to help air flow.
Boyesen Rad valve and reeds.
PWK airstriker carb conversion is a must. You can purchase the whole carb jetted and everything from JD or purchase the carb separately from Ebay then purchase the jetting kit from JD.
Cryca high-flow rear fender.
I have even seen people drill 1/2 sized holes directly into the air box, like husky did one year on their 250f
Boyesen exhaust flange.
Of course Pipe and silencer. I run FMF fatty pipe with shorty silencer. I have herd some suggest a pipe from a Stock Kawasaki 125, but have no experience myself.

Codey15 wrote:

Cheers for that advice, as said before I will deifinatly be putting an exhaust on aswell as reeds and I have seen a lot of people swapping the carburetor so that might be another must. And also the air boot.

What’s the cycra high flow rear fender? Haven’t heard of it before

I will look into those other things u have stated and see if it’s worth the money?

The cyrca high flow rear fender has grooves and extra minor air intakes incorporated into the rear fender that channel more air into the air box.
Will adding this piece alone result in drastic engine response? probably not. Again its a million little things added together that help it breathe more.
Also by looking at the pictures of your bike, it appears the previous owner has closed the intake ports on the side number plates, which doesn't help your case.
To your point asking whether or not some of the items are worth the money, do you consider titanium bolts worth the money? Some do, others don't, but I recall you saying " A build that I spend lots of money on it to make it super"
And to answer the question about the bike being "powerless". In a shootout comparison, yes the bike would probably rank pretty low on power output compared to similar 125s that year, or the current YZ or KTM 125.
But I have ridden my 2002 CR125 then switched to a similar build YZ125, and hands down the CR wins, in power and agility. And like one of the other guys said about having similar lap times on his 250f. Its how you ride it, fast guys go fast, slow guys go slow.

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@wasummer46

11/6/2017 1:49 PM
Edited Date/Time: 11/6/2017 1:54 PM

wasummer46 wrote:

The problem with the 2002 is the lack of air the engine receives. There isn't one simple fix, there's a million little items that combine to help it breath.
2007 air box and air boot. They slightly redesigned them to help air flow.
Boyesen Rad valve and reeds.
PWK airstriker carb conversion is a must. You can purchase the whole carb jetted and everything from JD or purchase the carb separately from Ebay then purchase the jetting kit from JD.
Cryca high-flow rear fender.
I have even seen people drill 1/2 sized holes directly into the air box, like husky did one year on their 250f
Boyesen exhaust flange.
Of course Pipe and silencer. I run FMF fatty pipe with shorty silencer. I have herd some suggest a pipe from a Stock Kawasaki 125, but have no experience myself.

Codey15 wrote:

Cheers for that advice, as said before I will deifinatly be putting an exhaust on aswell as reeds and I have seen a lot of people swapping the carburetor so that might be another must. And also the air boot.

What’s the cycra high flow rear fender? Haven’t heard of it before

I will look into those other things u have stated and see if it’s worth the money?

wasummer46 wrote:

The cyrca high flow rear fender has grooves and extra minor air intakes incorporated into the rear fender that channel more air into the air box.
Will adding this piece alone result in drastic engine response? probably not. Again its a million little things added together that help it breathe more.
Also by looking at the pictures of your bike, it appears the previous owner has closed the intake ports on the side number plates, which doesn't help your case.
To your point asking whether or not some of the items are worth the money, do you consider titanium bolts worth the money? Some do, others don't, but I recall you saying " A build that I spend lots of money on it to make it super"
And to answer the question about the bike being "powerless". In a shootout comparison, yes the bike would probably rank pretty low on power output compared to similar 125s that year, or the current YZ or KTM 125.
But I have ridden my 2002 CR125 then switched to a similar build YZ125, and hands down the CR wins, in power and agility. And like one of the other guys said about having similar lap times on his 250f. Its how you ride it, fast guys go fast, slow guys go slow.

Okay cheers for the response. I spose ur right about the money situation. I should probably edit that to say ‘reasonable amount of money’ but my bad. And in reply to the power, I totally get you there, at the end of the day it comes down to the rider not the bike.

And I’m not sure what u mean about the closed off intake ports as I have never owned a cr before just have always liked them. But I will google another bike and see if I can spot the difference. Thanks again for your reply.

Update! I now see what you were talking about closed off I take ports?

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11/6/2017 5:23 PM

Codey15 wrote:

Okay cheers for the response. I spose ur right about the money situation. I should probably edit that to say ‘reasonable amount of money’ but my bad. And in reply to the power, I totally get you there, at the end of the day it comes down to the rider not the bike.

And I’m not sure what u mean about the closed off intake ports as I have never owned a cr before just have always liked them. But I will google another bike and see if I can spot the difference. Thanks again for your reply.

Update! I now see what you were talking about closed off I take ports?

He's referring to your side number plates, if you look at the indentation it's solid, where as it should be open to allow for air flow, look at other CR's and you'll see the difference. You could open them by cutting or drilling holes or order a new set, I would look at the back of the plate and check the brand to avoid purchasing the same plates. The plastics actually look like the Flash Red color that Honda used in the 80's, anyway, good bike that just needs some attention and Go Faster Part's, you'll be happy with how well the bike handles once set up properly.

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There's something happening here, what it is ain't exactly clear.

11/6/2017 6:14 PM

ledger wrote:

He's referring to your side number plates, if you look at the indentation it's solid, where as it should be open to allow for air flow, look at other CR's and you'll see the difference. You could open them by cutting or drilling holes or order a new set, I would look at the back of the plate and check the brand to avoid purchasing the same plates. The plastics actually look like the Flash Red color that Honda used in the 80's, anyway, good bike that just needs some attention and Go Faster Part's, you'll be happy with how well the bike handles once set up properly.

Yes thank you ledger, I see now. I sure can’t wait till this thing is completed, it’s gonna be sooo sweet!

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11/6/2017 6:22 PM

I just sold my 06, poor thing couldn't get out of its own way. I had a PC platinum pipe on that really woke it up, holes drilled in air box, i preferred the stock reeds. Good luck on the build, I used my CR as a harescramble bike, Great turning bike but lacking some in motor. The stock suspension was pretty good too.

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Unleaded tastes a little tangy. Supreme is kinda sour, and diesel tastes pretty good.

11/6/2017 10:19 PM

Codey15 wrote:

Yes thank you ledger, I see now. I sure can’t wait till this thing is completed, it’s gonna be sooo sweet!

Welcome, just curious, you mention the 17 plastic kit....Are you referring to the TX kit ? I don't know if you are aware, but Polisport is releasing a...."Renew Kit" for the 02-07 CR's that match the 18 model, I know a few member's that aren't happy at all with the TX kit. Hmmm wink

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There's something happening here, what it is ain't exactly clear.

11/6/2017 10:25 PM
Edited Date/Time: 11/6/2017 10:27 PM

ledger wrote:

He's referring to your side number plates, if you look at the indentation it's solid, where as it should be open to allow for air flow, look at other CR's and you'll see the difference. You could open them by cutting or drilling holes or order a new set, I would look at the back of the plate and check the brand to avoid purchasing the same plates. The plastics actually look like the Flash Red color that Honda used in the 80's, anyway, good bike that just needs some attention and Go Faster Part's, you'll be happy with how well the bike handles once set up properly.

Codey15 wrote:

Yes thank you ledger, I see now. I sure can’t wait till this thing is completed, it’s gonna be sooo sweet!

ledger wrote:

Welcome, just curious, you mention the 17 plastic kit....Are you referring to the TX kit ? I don't know if you are aware, but Polisport is releasing a...."Renew Kit" for the 02-07 CR's that match the 18 model, I know a few member's that aren't happy at all with the TX kit. Hmmm wink

Yes I was referring to the tx kit and wasn’t aware of the pollisport 2018 version but, u have just changed my mind. Will defiantly be going with the pollisport version, thank you.

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11/6/2017 10:26 PM
Edited Date/Time: 11/6/2017 10:26 PM

Rickyisms wrote:

I just sold my 06, poor thing couldn't get out of its own way. I had a PC platinum pipe on that really woke it up, holes drilled in air box, i preferred the stock reeds. Good luck on the build, I used my CR as a harescramble bike, Great turning bike but lacking some in motor. The stock suspension was pretty good too.

Cheers for the reply, defiantly adding a bundle of power parts?

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11/7/2017 12:01 PM

Hey guys unfortunately I have been away so haven’t had time to tear into this thing which I have been dying to. And when we get back I’m going to have to study like crazy for upcoming exams.

Although I have made some progress, I have been contacting a few companies about parts. And have got together a bit of a price list for them.

Just need some advice from someone,
1: what year forks and what bike from, should I put into this bike? What year and bike will slide straight in?
2: will I need both air box or just the air boot from a 2007 CR125?
3: could someone post a link to a pwk carburetor they have bought from eBay without being scammed?
4: and what do u guys think about possibly powder coating the frame black? I haven’t seen many people do it to crs, so thought it might be a little different than a polished frame?
5: and what’s your guys best cleaning tips? For engine cases, frame, and basically everything on the bike since it’s completely covered with sand and corrosion. ( not looking for to seeing what’s underneath it’s skin)

Cheers codey

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11/7/2017 4:24 PM

1: Stock forks are pretty damn good on this bike
2. Just the boot
3. Look for a used one
4. I had my frame polished, Looked good from a far but started getting scratched and looked like shit, I've seen a few done in a works pipe like brushed aluminum finish and really like it
5. Sand blast, Scotchbrite, Simple green

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Unleaded tastes a little tangy. Supreme is kinda sour, and diesel tastes pretty good.

11/7/2017 4:57 PM

Rickyisms wrote:

1: Stock forks are pretty damn good on this bike
2. Just the boot
3. Look for a used one
4. I had my frame polished, Looked good from a far but started getting scratched and looked like shit, I've seen a few done in a works pipe like brushed aluminum finish and really like it
5. Sand blast, Scotchbrite, Simple green

Cheers for the response
I have found a guy parting a crf 250 who will sell the whole front end, forks (Showa), front wheel, axle, front brake assembly, clamps (ride engineering top clamp) and also the rear wheel. For pretty cheap so i think I’m gonna go with that.
Would there be any advantages using the 2007 air box aswell?
I’m not a fan of the polished look either so I will either get it back to the factory finish or powder coat it, I would like to powder coat but then it is another cost that can sometimes not look great if a bad job has been done. Also they can chip off quite easily. So not sure what to do there.

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11/7/2017 5:43 PM

Right now mine is 100% internally stock. Just threw on a PC Platinum pipe, R304 shorty, boysen rad block with rad valve petals, renthal 52 tooth rear, 13 tooth countershaft sprocket. New OEM top end. And the things a ripper. Still little to none on the bottom end, but if you can ride mid to top and keep it on the power band, the thing goes pretty quick. Iv'e heard the 07 air box actually makes a big difference. I have yet to find and purchase one. As for suspension im a fan of the stock stuff. I haven't had it sprung and re-valved for me yet even, and it still rides good. I love the cornering on the bike. Feels super smooth and pulls amazing. Overall I think the 02 was a great bike. Definitely under-powered compared to most other 125's, but with a little time and money you can get it to go plenty quick. And I'm extremely impressed with the durability on the 02. I've had mine hammered and abused more than a few times, and it always comes back for more. Also the PWK carb is a great idea. I've heard plenty of great things about them. I never was able to find one cheap enough, one of my few complaints about the bike is the carb. When I had it off to do a rebuild, it seemed kinda junky. Still pretty leaky with the new gaskets, just not a fan i guess. But one thing is for sure, you have great potential with this thing. Im stoked to see what ya get done! good luck smile

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Hope for the best, Prepare for the worst.

11/8/2017 2:25 AM

Also, get a thinner base-gasket when you're doing the engine, set the squish to around 1.0mm and you can use regular fuel.
That will wake the engine up a little

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11/8/2017 2:27 AM

Kawasaki-rider wrote:

Also, get a thinner base-gasket when you're doing the engine, set the squish to around 1.0mm and you can use regular fuel.
That will wake the engine up a little

Okay cheers, it’s the small things that matter.

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11/8/2017 2:29 AM

Squidward wrote:

Right now mine is 100% internally stock. Just threw on a PC Platinum pipe, R304 shorty, boysen rad block with rad valve petals, renthal 52 tooth rear, 13 tooth countershaft sprocket. New OEM top end. And the things a ripper. Still little to none on the bottom end, but if you can ride mid to top and keep it on the power band, the thing goes pretty quick. Iv'e heard the 07 air box actually makes a big difference. I have yet to find and purchase one. As for suspension im a fan of the stock stuff. I haven't had it sprung and re-valved for me yet even, and it still rides good. I love the cornering on the bike. Feels super smooth and pulls amazing. Overall I think the 02 was a great bike. Definitely under-powered compared to most other 125's, but with a little time and money you can get it to go plenty quick. And I'm extremely impressed with the durability on the 02. I've had mine hammered and abused more than a few times, and it always comes back for more. Also the PWK carb is a great idea. I've heard plenty of great things about them. I never was able to find one cheap enough, one of my few complaints about the bike is the carb. When I had it off to do a rebuild, it seemed kinda junky. Still pretty leaky with the new gaskets, just not a fan i guess. But one thing is for sure, you have great potential with this thing. Im stoked to see what ya get done! good luck smile

Cheers will keep all that in mind and thanks for the luck.

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11/8/2017 9:58 PM

I have to echo the other guys response. Rethink the plastic conversion. I won't get into all the reasons why I hate it. Fun project.

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11/9/2017 10:37 PM

Dan-The-Man wrote:

I have to echo the other guys response. Rethink the plastic conversion. I won't get into all the reasons why I hate it. Fun project.

Don’t worry guys, I have chosen a different route with plastics, I’m going to get the pollisport 2018 re new kit instead.

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11/10/2017 10:48 PM

Small update, I found a guy selling a complete crf250 2005 front end for $900 and was about to buy it till a complete crf250 2008 (seized, although it was really tidy) came up for 1500. Offered him 1200 and he took it! So for $300 more I got a complete bike so I can take the rear wheel and shock also. And then sell the rest of the bike as parts. So I was pretty happy last night I must admit. This is all nzd remember. Also got a little into tear down of the CR125. Below is a picture of the crf250.Photo

and here is where the CR125 sits nowPhoto

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11/10/2017 10:52 PM

Excuse the messy garage it’s only temporary

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