2004 CR125

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12/11/2017 11:11 PM
Edited Date/Time: 12/17/2017 12:40 PM

Picked up this 04 CR125 about 2 weeks ago for $600. Not too bad, but cylinder and piston are trashed. Picked it up just how it sits in the picture. Top end off, along with the radiator and pipe.

As of now, this is going to be a pretty much all out build. I will not be doing anything special, like one of parts or anything like that. But I do have a few things in mind to make it a nice looking bike and motor.

This will be a slow build over the next couple months as I am having ACL/meniscus surgery on Dec 20th. So I will have plenty of time to make this bike exactly how I want it.

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Now the bike is in pieces, and I am starting the cleaning process. Starting with cleaning up the linkage and removing the casting marks.

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12/12/2017 12:35 PM

Man good luck with surgery, I will be going through same surgery about 10 days after you. I even got a 125 in case i was bored this winter but I've done finished the engine already

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12/12/2017 12:53 PM

What a great price and a great base to start with!! I’m also building an 04 good luck and have fun!

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12/12/2017 4:32 PM

jbrass715 wrote:

Man good luck with surgery, I will be going through same surgery about 10 days after you. I even got a 125 in case i was bored this winter but I've done finished the engine already

Haha, great minds think alike!! Thanks and good luck with your recovery!

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12/12/2017 4:40 PM

I also picked up an 04 for 600 bucks. Same deal, trashed cylinder. I went with the Eric Gorr 134 kit running on VP c12. Thing is a blast. Photo

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12/12/2017 6:18 PM

joshredy wrote:

I also picked up an 04 for 600 bucks. Same deal, trashed cylinder. I went with the Eric Gorr 134 kit running on VP c12. Thing is a blast. Photo

I was thinking about doing his 144 kit.. Why did you go with the 134 instead? And was he able to just use the cylinder that was already trashed? Or did you have to buy a new one and have him use the new one?

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12/12/2017 6:31 PM

Awesome, I have an 04 as well and it's a great bike! I've slowly been collecting parts for a few years to make it one of a kind, hoping to swap an 01 bottom end with a six speed trans in, and mate it to a 93 HPP top end. Can't wait to see how yours come out, it's a shame how bad of a reputation they have because the bikes can be incredible to ride.

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Make Hillclimb Great Again

Ratbeach Racing

Instagram / YouTube: @485Josh

3dpmoto.com



12/12/2017 7:21 PM

He used the cylinder I had. I believe 134 is as big as you can go on the 04. 05-07 you can go larger.

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12/12/2017 7:35 PM

joshredy wrote:

He used the cylinder I had. I believe 134 is as big as you can go on the 04. 05-07 you can go larger.

Interesting, either way a 134 or a 144 would be a blast to ride!!

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12/13/2017 8:51 AM

JM485 wrote:

Awesome, I have an 04 as well and it's a great bike! I've slowly been collecting parts for a few years to make it one of a kind, hoping to swap an 01 bottom end with a six speed trans in, and mate it to a 93 HPP top end. Can't wait to see how yours come out, it's a shame how bad of a reputation they have because the bikes can be incredible to ride.

98' was the first year of 5-speed trans; you'll have to go 1997 and older bottom-end for the 6-speed. Or, you can throw a 6-speed setup right into your 04' cases: https://thumpertalk.com/forums/topic/1086470-cr125-six-speed-tranny-swap/

Another clean Gen3 CR125 here: http://www.vitalmx.com/forums/Moto-Related,20/2003-CR-125-build-finshed,1283462


Agree 100% on the unnecessary bad-rap these bikes got. With a little fine tuning, they're a blast!

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12/13/2017 7:11 PM

One of the best mods for the dollars on the 2004 is send the head to Eric Gorr and have him mill it to match the RM125 piston. The mod is around $200 and comes with the top end kit. Piston and milling change the port timing and broaden the power band. I was going to do this to my 04 but found a 97 CR125 Motor to swap into it.

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12/13/2017 7:40 PM

Started cleaning up some of the axle and pivot bolts this evening! Got all the black markings and lines off of the axles. Just need to get that polish finish..

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12/13/2017 7:41 PM

cclay47 wrote:

One of the best mods for the dollars on the 2004 is send the head to Eric Gorr and have him mill it to match the RM125 piston. The mod is around $200 and comes with the top end kit. Piston and milling change the port timing and broaden the power band. I was going to do this to my 04 but found a 97 CR125 Motor to swap into it.

I will have to keep that in mind! Thanks.

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12/17/2017 12:48 PM

Little update; been sanding all of the casting marks off to the linkage pieces and triple clamps. Everything is apart and I am going to town on cleaning and getting it to look how I want it.

I will cut the spokes out of the rims since they are all stuck together. Once apart, I will remove casting marks from the stock hubs.

Then I will sand blast the linkage pieces and triple clamps and polish the linkage. Then I will send out the triple clamps and hubs to get coated!

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Also need to clean this nasty swing arm and bring it back to life!

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12/17/2017 12:53 PM

Love how you labelled the needles for each bearing, pretty sweet! Looking forward to the build.

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12/17/2017 1:16 PM

yjgfikl wrote:

Love how you labelled the needles for each bearing, pretty sweet! Looking forward to the build.

I try to keep everything as organized as possible, makes it easy when I go to reassemble it!

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12/17/2017 6:53 PM

What kind of coating are you going to do on the hubs and clamps?

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12/18/2017 4:42 PM

zac_k3 wrote:

What kind of coating are you going to do on the hubs and clamps?

Pry powder coat the triple clamps, since it’s a thick material won’t get dinged up with rocks and what not. On the hubs I’ll pry go with a ceramic coat on them in black.

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12/18/2017 4:51 PM

Got some more time today to get a few hours in on the bike.

Finished the linkage pieces today and got them back together so there are not bearings just laying around waiting to disappear lol. After thinking on the linkage pieces, I didn’t polish them. Instead left the dull look from the sand blasting. Just took a scrotch bright and wd40 to finish them off.

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Got started on cleaning the frame and subframe. Still have a ways to go on the inside of the frame with all the little holes. But got the subframe back to life. Just need to finish off the frame cleaning and polish her up!

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12/18/2017 5:33 PM

dylanv21 wrote:

Pry powder coat the triple clamps, since it’s a thick material won’t get dinged up with rocks and what not. On the hubs I’ll pry go with a ceramic coat on them in black.

Nice. I’ve been trying to decide if I wanna do the cerakote on some stuff, can’t wait to see some finished pics!

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12/18/2017 7:30 PM

dylanv21 wrote:

Little update; been sanding all of the casting marks off to the linkage pieces and triple clamps. Everything is apart and I am going to town on cleaning and getting it to look how I want it.

I will cut the spokes out of the rims since they are all stuck together. Once apart, I will remove casting marks from the stock hubs.

Then I will sand blast the linkage pieces and triple clamps and polish the linkage. Then I will send out the triple clamps and hubs to get coated!

Photo

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Also need to clean this nasty swing arm and bring it back to life!

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AE shock oil .... spotted .... hahaha

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12/18/2017 10:54 PM

jaredtebo17 wrote:

AE shock oil .... spotted .... hahaha

Haha! Got into some rc racing since I’ve been out. Cheap and still pretty fun! Lol.

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12/19/2017 2:04 PM

dylanv21 wrote:

Haha! Got into some rc racing since I’ve been out. Cheap and still pretty fun! Lol.

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Sweet man, that’s actually what I do for a living. Started RC after a bunch of injuries racing 80’s as a kid. Turned professional at 13 years old, 17 years later, I’m still at it!

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12/19/2017 4:33 PM

jaredtebo17 wrote:

Sweet man, that’s actually what I do for a living. Started RC after a bunch of injuries racing 80’s as a kid. Turned professional at 13 years old, 17 years later, I’m still at it!

Haha, that's sweet! Yeah its pretty fun.. I usually only race the spec slash class since I am still learning everything about it and SCT is a down hill class in my area!

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12/19/2017 6:13 PM

JM485 wrote:

Awesome, I have an 04 as well and it's a great bike! I've slowly been collecting parts for a few years to make it one of a kind, hoping to swap an 01 bottom end with a six speed trans in, and mate it to a 93 HPP top end. Can't wait to see how yours come out, it's a shame how bad of a reputation they have because the bikes can be incredible to ride.

crc245 wrote:

98' was the first year of 5-speed trans; you'll have to go 1997 and older bottom-end for the 6-speed. Or, you can throw a 6-speed setup right into your 04' cases: https://thumpertalk.com/forums/topic/1086470-cr125-six-speed-tranny-swap/

Another clean Gen3 CR125 here: http://www.vitalmx.com/forums/Moto-Related,20/2003-CR-125-build-finshed,1283462


Agree 100% on the unnecessary bad-rap these bikes got. With a little fine tuning, they're a blast!

Sorry, I should have been more clear. I bought a bottom end, but included in the sale was a six speed trans. I can't remember the exact year of both, but I believe you're probably right about the cutoff year.

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Make Hillclimb Great Again

Ratbeach Racing

Instagram / YouTube: @485Josh

3dpmoto.com



12/21/2017 7:47 AM

So ended up having my knee surgery yesterday. Might not be able to work on the bike for a week or so. But I’ll pry take my suspension to get rebuilt and have the fork tubes and lower fork lugs coated. And take the triple clamps to have them coated as well here soon that way they are done for when I can get back out in the garage to work on this thing.

Surgery went good as far as what the doc said. But he did say it was worse then what they thought. Surgery was only supposed to be an hour or hour and a half. It was over 3 hours.

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12/21/2017 10:39 AM

Best of luck with the recovery. Your pretty much doing what I did 3 years ago with my 02 CR125. 30 hrs after 3 years I pulled it apart to look it over and do a top end. Everything looked great except ended up finding the exhaust bridge cracked. After some google searching it seems common with the Honda RC valve cylinders both 250 and 125 alike. I have a 95 cyl I bought few years ago. So I was at a cross roads. Fix the 02 cyl, buy a new 02 cyl (275$) or use the 95 cyl. After looking into things. It seems the 00-04 CR125 cyl crack on the bridge more then any other years. The power valve design is the problem. It pushes the water jacket far away and makes the material around the bridge and valves very thin. This same design limits a big bore to 134cc/2mm over bore and looks like doing so would make the power valve/bridge area even thinner and more prone to cracking. Again just my opinion. I ended up going with a 144 kit from millennium using the 95 cyl. Unfortunately your stuck using a 04cyl.

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2010 crf450
2002 cr125
1993 Yamaha waveblaster
1993 Kawasaki 750sx

12/21/2017 1:01 PM

mx621 wrote:

Best of luck with the recovery. Your pretty much doing what I did 3 years ago with my 02 CR125. 30 hrs after 3 years I pulled it apart to look it over and do a top end. Everything looked great except ended up finding the exhaust bridge cracked. After some google searching it seems common with the Honda RC valve cylinders both 250 and 125 alike. I have a 95 cyl I bought few years ago. So I was at a cross roads. Fix the 02 cyl, buy a new 02 cyl (275$) or use the 95 cyl. After looking into things. It seems the 00-04 CR125 cyl crack on the bridge more then any other years. The power valve design is the problem. It pushes the water jacket far away and makes the material around the bridge and valves very thin. This same design limits a big bore to 134cc/2mm over bore and looks like doing so would make the power valve/bridge area even thinner and more prone to cracking. Again just my opinion. I ended up going with a 144 kit from millennium using the 95 cyl. Unfortunately your stuck using a 04cyl.

Did the 95 cylinder bolt right on?

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12/21/2017 1:58 PM

mx621 wrote:

Best of luck with the recovery. Your pretty much doing what I did 3 years ago with my 02 CR125. 30 hrs after 3 years I pulled it apart to look it over and do a top end. Everything looked great except ended up finding the exhaust bridge cracked. After some google searching it seems common with the Honda RC valve cylinders both 250 and 125 alike. I have a 95 cyl I bought few years ago. So I was at a cross roads. Fix the 02 cyl, buy a new 02 cyl (275$) or use the 95 cyl. After looking into things. It seems the 00-04 CR125 cyl crack on the bridge more then any other years. The power valve design is the problem. It pushes the water jacket far away and makes the material around the bridge and valves very thin. This same design limits a big bore to 134cc/2mm over bore and looks like doing so would make the power valve/bridge area even thinner and more prone to cracking. Again just my opinion. I ended up going with a 144 kit from millennium using the 95 cyl. Unfortunately your stuck using a 04cyl.

dylanv21 wrote:

Did the 95 cylinder bolt right on?

For my 02 yes. It bolts on. Requires the older PV governer and linkage, pipe modification and port matching the transfer ports to case. But this cyl swap only works up to 2002. In 2003 + the cases are diff and it will not work.
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2010 crf450
2002 cr125
1993 Yamaha waveblaster
1993 Kawasaki 750sx

12/21/2017 3:30 PM

mx621 wrote:

For my 02 yes. It bolts on. Requires the older PV governer and linkage, pipe modification and port matching the transfer ports to case. But this cyl swap only works up to 2002. In 2003 + the cases are diff and it will not work.
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I getcha. Thanks for the info..

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