Making more power from an 04' CR125

BroFoSho
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742
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9/26/2013
Location
Tucson, AZ US
4/29/2016 9:58am
I had an 02'. If you are an aggressive rider, go up a tooth in the front sprocket. It will kill what little bottom end the bike has, but it will pull soooooo much further up top.

All I did was fresh top ends (every 15 hours), PC pipe, v-force, up a tooth in the front.

Not a fast bike, but A LOT of fun to ride if ride it hard. Just hold the thing wide open everywhere. And if you blow it up, only $150 bucks to rebuild it.

4/29/2016 10:48am
I had an '01 CR125 brand new even when jetted good it wasn't as fast as my 02 YZ125 I traded it in on remember the first time I took the YZ to the track. This one small double jump I had to scream the CR to get over it without thinking I hit it the same way on the YZ and almost looped out it hit that much harder.

My 06 YZ 144 ported by Eric gorr ( I have had this bike since 05!!) vs my friends 06 CR125 that at the time (2006) gorr would only do 139 kits on it even with the pwk carb swap my YZ is still stronger everywhere. Sell the CR and the YZ and buy a newer aluminum framed YZ.
peelout
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Ogden, UT US
4/29/2016 10:56am Edited Date/Time 4/29/2016 11:02am
JM485 wrote:
Don't let these guys ruin that bike for you, I have an 04 and absolutely love it. Mine is stock with nothing but a V-force reed...
Don't let these guys ruin that bike for you, I have an 04 and absolutely love it. Mine is stock with nothing but a V-force reed cage + fmf pipe, and when I rode it back to back with a new yz at a demo day I didn't feel like the power gap was absolutely earth shattering like people claim. While the yz was a LOT easier to keep in the powerband, I didn't feel like my Honda was down a whole lot on peak power. Maybe it was just because I was more comfortable on my familiar bike, but I remember being surprised how well my Honda held its own. If anyone had dyno charts from a bike test or something I would love to see them, just to see if I'm crazy or if the Honda really isn't down all that much on peak power.

My plans for mine this summer include swapping to an 02 or older bottom end to mate with the 93 top end I bought off a member here. I'm going to keep my 04 motor completely stock as a back-up, and use the older motor to experiment with a little. Might go with the 6 speed trans if I can find one in decent condition, as well as the newer air boot and a general cleaning up of the ports. I still haven't found a bike that turns better than my cr125, not even the fabled rm250, so I say just ride it and enjoy it. If you want a way faster bike, jump up to a 250, but I'd keep the 125 just for fun.
i'm sorry to break your bubble Josh, but the '04 Honda is easily the worst 125 made in the 2000's.

i spent more money than God trying to get it to be competitive in the 125A class, suspension, motor work, porting, head work, i tried every exhaust known to man. that thing was a fucking turd. after all the money i spent it still had nothing for a stock YZ. i went from ripping 90% of the holeshots and winning a majority of my A-class moto's on the YZ to not even being in the same zip code in the first corner. it was a serious game changer in every negative way possible. i was over-riding the bike to the point that my '04 year was the worst season i ever had racing. every week we were messing with the suspension. ProAction, ProCircuit, RaceTech, i just couldn't get that thing to handle. the weed eater motor was only part of the problem.

now i'm not saying it won't be a fun bike to just dick around on, oh wait, yes i am. take and fill the gas tank, light one of your old Def Leppard t-shirts on fire and stick it in the tank and burn that turd to the ground.


to the OP, seriously, get rid of any sentimental memories you have of that red skidmark, put it up for sale and whatever extra change you get for it i would soak into that YZ. hands down a better machine in every way possible.

ps... wtf is up with those numbers? that just screams "Joey"
3
JM485
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Location
Davis, CA US
4/29/2016 1:21pm
JM485 wrote:
Don't let these guys ruin that bike for you, I have an 04 and absolutely love it. Mine is stock with nothing but a V-force reed...
Don't let these guys ruin that bike for you, I have an 04 and absolutely love it. Mine is stock with nothing but a V-force reed cage + fmf pipe, and when I rode it back to back with a new yz at a demo day I didn't feel like the power gap was absolutely earth shattering like people claim. While the yz was a LOT easier to keep in the powerband, I didn't feel like my Honda was down a whole lot on peak power. Maybe it was just because I was more comfortable on my familiar bike, but I remember being surprised how well my Honda held its own. If anyone had dyno charts from a bike test or something I would love to see them, just to see if I'm crazy or if the Honda really isn't down all that much on peak power.

My plans for mine this summer include swapping to an 02 or older bottom end to mate with the 93 top end I bought off a member here. I'm going to keep my 04 motor completely stock as a back-up, and use the older motor to experiment with a little. Might go with the 6 speed trans if I can find one in decent condition, as well as the newer air boot and a general cleaning up of the ports. I still haven't found a bike that turns better than my cr125, not even the fabled rm250, so I say just ride it and enjoy it. If you want a way faster bike, jump up to a 250, but I'd keep the 125 just for fun.
peelout wrote:
i'm sorry to break your bubble Josh, but the '04 Honda is easily the worst 125 made in the 2000's. i spent more money than God...
i'm sorry to break your bubble Josh, but the '04 Honda is easily the worst 125 made in the 2000's.

i spent more money than God trying to get it to be competitive in the 125A class, suspension, motor work, porting, head work, i tried every exhaust known to man. that thing was a fucking turd. after all the money i spent it still had nothing for a stock YZ. i went from ripping 90% of the holeshots and winning a majority of my A-class moto's on the YZ to not even being in the same zip code in the first corner. it was a serious game changer in every negative way possible. i was over-riding the bike to the point that my '04 year was the worst season i ever had racing. every week we were messing with the suspension. ProAction, ProCircuit, RaceTech, i just couldn't get that thing to handle. the weed eater motor was only part of the problem.

now i'm not saying it won't be a fun bike to just dick around on, oh wait, yes i am. take and fill the gas tank, light one of your old Def Leppard t-shirts on fire and stick it in the tank and burn that turd to the ground.


to the OP, seriously, get rid of any sentimental memories you have of that red skidmark, put it up for sale and whatever extra change you get for it i would soak into that YZ. hands down a better machine in every way possible.

ps... wtf is up with those numbers? that just screams "Joey"
Dammit Peelbro, don't mess with my bubble!!!Laughing

I can definitely agree on the motor part, but for me I thought the Honda handled better than the Yamaha, that's just me though and everyone is going to feel different about it. I don't know man, for whatever reason the Yam just felt a lot lower and longer, while the Hon felt lighter and better in the corners to me. Never know though, I may nor may not have skipped leg day that week when I rode them back to back. . .

For the OP, I think the best advise Peelbro and I can agree on giving is to make sure you lift. Like seriously, run to the gym (not at the gym, that's how you lose gains bro) and hit the free weights until nobody would dare suggest you're a Honda rider. When you go to the track, tell all the track snacks you rip a 450 bored out to a 700 on nitrous because regular 450s are for pussies (trust me, they won't know the difference). Finally, make sure to talk as much shit as possible in the pits, because the only way you're going to beat anyone on that thing is to steal their chick and kill the pathetic amount of confidence they have left to the point where they pack up and head home rather than face your rath on the track.

Did I miss anything Peel?

The Shop

PEPE001
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Location
NRW DE
4/29/2016 1:40pm Edited Date/Time 4/29/2016 7:55pm
You can get some more power in it but takes a lot of work.

1. The crankcase is a mess a lot of grinding and Epoxy here to get the air flowing.
2. Use a 2005 and up Airboot.
3. Changed the carburetor to a Keihin was way better jetting will be more consistent
3. Exhaust FMF or PC should work
4. Select a silencer based on where you want the power mid or high RPM
5. Use a VForce or Boyesen, if you want a Boyesen let me know have one here. Recomendation is Boyesen

But again to get significant more you have to do significant porting and fix the case.
Can add some pictures what needs to be done.

Did that on mine and it was ok not perfect but ok.

1
dcg141
Posts
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11/30/2009
Location
MS US
4/29/2016 2:57pm
JM485 wrote:
Don't let these guys ruin that bike for you, I have an 04 and absolutely love it. Mine is stock with nothing but a V-force reed...
Don't let these guys ruin that bike for you, I have an 04 and absolutely love it. Mine is stock with nothing but a V-force reed cage + fmf pipe, and when I rode it back to back with a new yz at a demo day I didn't feel like the power gap was absolutely earth shattering like people claim. While the yz was a LOT easier to keep in the powerband, I didn't feel like my Honda was down a whole lot on peak power. Maybe it was just because I was more comfortable on my familiar bike, but I remember being surprised how well my Honda held its own. If anyone had dyno charts from a bike test or something I would love to see them, just to see if I'm crazy or if the Honda really isn't down all that much on peak power.

My plans for mine this summer include swapping to an 02 or older bottom end to mate with the 93 top end I bought off a member here. I'm going to keep my 04 motor completely stock as a back-up, and use the older motor to experiment with a little. Might go with the 6 speed trans if I can find one in decent condition, as well as the newer air boot and a general cleaning up of the ports. I still haven't found a bike that turns better than my cr125, not even the fabled rm250, so I say just ride it and enjoy it. If you want a way faster bike, jump up to a 250, but I'd keep the 125 just for fun.
peelout wrote:
i'm sorry to break your bubble Josh, but the '04 Honda is easily the worst 125 made in the 2000's. i spent more money than God...
i'm sorry to break your bubble Josh, but the '04 Honda is easily the worst 125 made in the 2000's.

i spent more money than God trying to get it to be competitive in the 125A class, suspension, motor work, porting, head work, i tried every exhaust known to man. that thing was a fucking turd. after all the money i spent it still had nothing for a stock YZ. i went from ripping 90% of the holeshots and winning a majority of my A-class moto's on the YZ to not even being in the same zip code in the first corner. it was a serious game changer in every negative way possible. i was over-riding the bike to the point that my '04 year was the worst season i ever had racing. every week we were messing with the suspension. ProAction, ProCircuit, RaceTech, i just couldn't get that thing to handle. the weed eater motor was only part of the problem.

now i'm not saying it won't be a fun bike to just dick around on, oh wait, yes i am. take and fill the gas tank, light one of your old Def Leppard t-shirts on fire and stick it in the tank and burn that turd to the ground.


to the OP, seriously, get rid of any sentimental memories you have of that red skidmark, put it up for sale and whatever extra change you get for it i would soak into that YZ. hands down a better machine in every way possible.

ps... wtf is up with those numbers? that just screams "Joey"
Lmao...best post this year
5/15/2016 4:12pm
Thanks for the help guys haha sold the CR for $3000 and got a 2013 RMZ250 with 20 hours on it.
1
burn1986
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bossier city, LA US
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5/15/2016 4:59pm Edited Date/Time 5/15/2016 5:01pm
Camp332 wrote:
[b]I see that the most you can bore out a 125 cylinder is to 134cc... Is it worth the $500? Would [b]14cc[/b] really make much ?[/b]...

I see that the most you can bore out a 125 cylinder is to 134cc... Is it worth the $500? Would [b]14cc really make much ?[/b]

I dont want to be a math teacher Brodie. Is that 14, or 9 CC's?

Most people prefer the 134 big bore over the 144 (Eric Gorr or RPMs). These bikes need more airflow. Miedosoracing.com has some excellent advice on getting more air to these motors. You can do a search on here for some threads on it.
4/14/2021 10:00am
PEPE001 wrote:
You can get some more power in it but takes a lot of work. 1. The crankcase is a mess a lot of grinding and Epoxy...
You can get some more power in it but takes a lot of work.

1. The crankcase is a mess a lot of grinding and Epoxy here to get the air flowing.
2. Use a 2005 and up Airboot.
3. Changed the carburetor to a Keihin was way better jetting will be more consistent
3. Exhaust FMF or PC should work
4. Select a silencer based on where you want the power mid or high RPM
5. Use a VForce or Boyesen, if you want a Boyesen let me know have one here. Recomendation is Boyesen

But again to get significant more you have to do significant porting and fix the case.
Can add some pictures what needs to be done.

Did that on mine and it was ok not perfect but ok.

Did the Rad valve help the bike come on the pipe quicker, boost low to getting on the pipe ? I bought a 04 cr125 new, 1 st ride the bike has a nice mid hit, pulls a little then just revs with no pull. I was like oh shit. Installed a pc pipe and regular length silencer, icat- works on this bike, vforce made no difference, but didn’t hurt it. I put a Rad valve on my 06 125, improved low to mid a lot. A mod 04 deck the cylinder, porting is just reshape and widen exhaust port, bore carb. Still has trouble getting into the now much stronger and wide mid. 125 a and b riders that won motos recently said the same thing, they also said it’s a blast to ride and pulls strong, just wears you out. You have to ride it as hard as you can, to keep it ripping. Riders where 250f, 450f Guys.
peelout
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Ogden, UT US
4/14/2021 10:01am
only way to get any power out of an '04 CR125 is to drop a match in the gas tank.

9
1
4/14/2021 11:04am
peelout wrote:
only way to get any power out of an '04 CR125 is to drop a match in the gas tank.

Haha, I read your old post. Sounded like a rough season on the 04. But it made you a stronger man today. I would compare the stock 04 to a 91 yz125, slowest ever. With a stroker crank and 2mm ovr bore, 23 lbs of torque. You hv to keep momentum like no other bike ever, which is fun riding as hard as you can. The chassis sold me, goes threw deep huge square holes, like there not there and corners perfect every time. Confidence boosting chassis. With stiffer spring valving was good for cruising. I told FC set it up for 3 ft whoops, with the back down- like more sag. They killed it, whoops jump 4-5 in, and rip the tops. Best whoops bike in eastern brown county. Haha. Whoops are my specialty, best spot to make time up.
2
4/14/2021 12:09pm
Way to dig up a 5 year old thread 😂
Beats starting a new 1. One of the coolest bikes ever, released late because there making the 1st cr250f. Must use a different race plan, at Millville a great start is not happening , rail wide in 1st turn. Hv momentum for the straight away, get in 5th beat them to the corner. If not relax the whoops are coming up, and that’s PASS city. The rest of the track all inside lines, shorten the track up.
1
1
ZOBITO
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4/14/2021 12:29pm
That's the right setting.
Laughing





1
1
4/14/2021 12:45pm
ZOBITO wrote:
That's the right setting. :laugh: [img]https://p.vitalmx.com/photos/forums/2021/04/14/487745/s1200_Capture_d_e_cran_2021_04_14_a_21.19.21.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2021/04/14/487746/s1200_387d374c3ee58c1bd87b50ad86e6dec8.jpg[/img]
That's the right setting.
Laughing





Haha, yeah KTM rocket power. I don’t need that much, just enough to clear the jumps.
Bruce372
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4/14/2021 12:49pm
ZOBITO wrote:
That's the right setting. :laugh: [img]https://p.vitalmx.com/photos/forums/2021/04/14/487745/s1200_Capture_d_e_cran_2021_04_14_a_21.19.21.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2021/04/14/487746/s1200_387d374c3ee58c1bd87b50ad86e6dec8.jpg[/img]
That's the right setting.
Laughing





I take my hat off for rhe engineering and fabrication, but does anyone really think a great ktm125 engine stuffed into a big 450 chassis is gonna be better than a regular ktm125?

In many aspects in life, just because you can, doesn't mean you should.
3
ZOBITO
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4/14/2021 1:01pm
I just think it makes for a faster 125 CR.
Wink
1
1
Bruce372
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4/14/2021 1:54pm
ZOBITO wrote:
I just think it makes for a faster 125 CR.
Wink
Or a slower, heavier ktm 125? Depending on how you look at it....
1
4/14/2021 9:53pm
I driving to iL. And buying it tomorrow, 3,400 for a very clean all stock 04 cr125. Is a great deal, compared to what is out there. I hv a lot of parts for it, rg3 4 post triple clamp, pc and stock silencer, gp wiseco piston, carbon fiber stuff, a lot of gaskets, cables, brake pads, jets, needles, 5 air filters, stock pipe, icat, sprockets, etc I know how get it setup correctly- revalved. Porting and mods can get aprox 36.5 hp, that’s all Bubba had. I ran into a dude that rides at the ymca, got info on a track that I can ride teus- sun, 200 or 300 annual membership and it’s 20 minutes away. The track I was a member at 1990 to 2012 when it closed. Now it has more lanes up and down the hills, not ama legal race track now, jumps are calmed down. Kind of a off road park now. Cold, windy and snowing today, that’s bad. Just found out my Dad has dementia that’s bad. Reunited with a 04 cr125 not like my 04 mod bike that was stolen. But close enough, is awesome.
2
Chance1216
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Federal Way, WA US
4/14/2021 10:21pm
I driving to iL. And buying it tomorrow, 3,400 for a very clean all stock 04 cr125. Is a great deal, compared to what is out...
I driving to iL. And buying it tomorrow, 3,400 for a very clean all stock 04 cr125. Is a great deal, compared to what is out there. I hv a lot of parts for it, rg3 4 post triple clamp, pc and stock silencer, gp wiseco piston, carbon fiber stuff, a lot of gaskets, cables, brake pads, jets, needles, 5 air filters, stock pipe, icat, sprockets, etc I know how get it setup correctly- revalved. Porting and mods can get aprox 36.5 hp, that’s all Bubba had. I ran into a dude that rides at the ymca, got info on a track that I can ride teus- sun, 200 or 300 annual membership and it’s 20 minutes away. The track I was a member at 1990 to 2012 when it closed. Now it has more lanes up and down the hills, not ama legal race track now, jumps are calmed down. Kind of a off road park now. Cold, windy and snowing today, that’s bad. Just found out my Dad has dementia that’s bad. Reunited with a 04 cr125 not like my 04 mod bike that was stolen. But close enough, is awesome.
Sorry about your dad bud. Pm sent
2
ZOBITO
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574
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4/14/2021 11:02pm
ZOBITO wrote:
I just think it makes for a faster 125 CR.
Wink
Bruce372 wrote:
Or a slower, heavier ktm 125? Depending on how you look at it....
When you're used to a 125 CR, you don't give a crap 'bout that.
Laughing
1
4/15/2021 12:07am
I driving to iL. And buying it tomorrow, 3,400 for a very clean all stock 04 cr125. Is a great deal, compared to what is out...
I driving to iL. And buying it tomorrow, 3,400 for a very clean all stock 04 cr125. Is a great deal, compared to what is out there. I hv a lot of parts for it, rg3 4 post triple clamp, pc and stock silencer, gp wiseco piston, carbon fiber stuff, a lot of gaskets, cables, brake pads, jets, needles, 5 air filters, stock pipe, icat, sprockets, etc I know how get it setup correctly- revalved. Porting and mods can get aprox 36.5 hp, that’s all Bubba had. I ran into a dude that rides at the ymca, got info on a track that I can ride teus- sun, 200 or 300 annual membership and it’s 20 minutes away. The track I was a member at 1990 to 2012 when it closed. Now it has more lanes up and down the hills, not ama legal race track now, jumps are calmed down. Kind of a off road park now. Cold, windy and snowing today, that’s bad. Just found out my Dad has dementia that’s bad. Reunited with a 04 cr125 not like my 04 mod bike that was stolen. But close enough, is awesome.
Chance1216 wrote:
Sorry about your dad bud. Pm sent
Yeah Thx, it’s not the normal story most people have. He was in and out of mental institutions 1971-76. And extremely violent, compare it to world war 4. Every second of every minute of every hour of the year, you better be ready for it at any second. At 4-6 yrs old my Mom dragged me along to the clinics. I had to wait all day, while she is getting him help or something. I roamed around , stand in the hall and stare at a guys belted to a bed, yeah bizarre jiberish and all. I had to run most of a dairy farm at 9.5 yrs old. Divorce finally, Daddy day for a yr. then he writes me off, no card, call ,or apology even yrs later. I still helped him in 88, ran his produce farm. He stuck his hand into a belt conver and was hurt. Mainly because I never knew him. Again in 2018 on my 1 day off, his 2nd wife died. It was a back flash of the 70,s , I tried to help him. Gave him advice like stop talking bad about everyone and starting fights. Don’t do anything to devalue yourself, etc a couple of rules I made for myself. People hv no idea of the hell and exhaustion, mentally ill people bring and how screwup our system is. I never looked to him on that’s what a man should be like. I knew better. hey Chance how do I check the pm, sorry I’m tired.
1
Chance1216
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5166
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Location
Federal Way, WA US
4/15/2021 10:20am
Yeah Thx, it’s not the normal story most people have. He was in and out of mental institutions 1971-76. And extremely violent, compare it to world...
Yeah Thx, it’s not the normal story most people have. He was in and out of mental institutions 1971-76. And extremely violent, compare it to world war 4. Every second of every minute of every hour of the year, you better be ready for it at any second. At 4-6 yrs old my Mom dragged me along to the clinics. I had to wait all day, while she is getting him help or something. I roamed around , stand in the hall and stare at a guys belted to a bed, yeah bizarre jiberish and all. I had to run most of a dairy farm at 9.5 yrs old. Divorce finally, Daddy day for a yr. then he writes me off, no card, call ,or apology even yrs later. I still helped him in 88, ran his produce farm. He stuck his hand into a belt conver and was hurt. Mainly because I never knew him. Again in 2018 on my 1 day off, his 2nd wife died. It was a back flash of the 70,s , I tried to help him. Gave him advice like stop talking bad about everyone and starting fights. Don’t do anything to devalue yourself, etc a couple of rules I made for myself. People hv no idea of the hell and exhaustion, mentally ill people bring and how screwup our system is. I never looked to him on that’s what a man should be like. I knew better. hey Chance how do I check the pm, sorry I’m tired.
It should pop up in your email. Just open the email and you should be good.
1
4/17/2021 9:06am
Wed snowing, freezing rain, reg rain. I went to 2 ymca,s 1st 1 has a great whirlpool and pool, 2nd 1 open til 10, sauna lost 5 lbs . Leave get stuff from storage unit near the bay, for hauling the bike. Get food, etc, check vehicle over. Sleep 4 hrs thurs, travel to get the bike. I was a little tired, felt like a dream being there buying the bike. Same 1 that was stolen. It’s all original except the rear tire and grips. Yes the stock chain is on the bike. He just did a top end, starts 1st kick. Idles really high, turn the bars and it revs up. I adjusted free play, fixed. There is a couple bolts that don’t belong on it. Rear fender of course, from pals flipping it maybe who knows. It’s a builder bike, but I hv a lot of parts for it. Like the bumper stop on the shock, it’s crumbling apart, this is a 04. Others good, cases never been apart, stock crank. I think it’s a good idea, to split the cases and rebuild. What do you think ?
1
PL727
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FL US
4/17/2021 6:09pm
Send your engine to Varner and by the time you get it back it will feel like a rocketship compared to your hoveround
3
1
4/18/2021 9:04am
DL wrote:
Here’s a test on a 02 CR125 https://www.vitalmx.com/videos/features/Race-Shop-Build-2002-Honda-CR125,18652/Klinger,64408
Oh yeah, Leib,s cr125 is so Hot, Great rider too. No doubt Terry makes a cr125 rip. A Ernie tribute cr125, so awesome. I saw Ernie race at 97 gaterback on amateur day, on his Kodak yz125. My stolen 04 was a stroker crank, 2mm ovr bore, b4 that it was decked, ported, carb bore. All I need is porting and 36.5 hp, to have good days like this.
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1
4/20/2021 2:17pm
I got a ebay and PayPal account setup. Purchased a new icat, don’t laugh they work great on the 04. And I was the winning bidder on a new coil, snagged it for 15 bucks, yes. Where on our way, to the magic # 36.5 hp.
1
1
yota
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1427
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Location
Crystal River, FL US
4/30/2021 7:33pm
my 03 off-road bike. 134cc mod, porting, runs on 50% race fuel mix. lectron, V-force, 07 airbox boot with venting and sealing mods, TTX shock. It's now al most as fast as my YZ125 LOL.
1

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