2004 CR125 broken carb slide

motofab36
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motofab36
Edited Date/Time 5/25/2021 4:13pm
I
I had a kid bring me this cr125 to work on that was idling high and running irratic. I checked for air leaks, adjusted the air screw, all tge regular stuff. Then i pulled the slide out and found the rear side is broken off, kinda looks like it has been eatin away. Have any of you seen this before?
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motofab36
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motofab36 3/11/2020 6:34am
3/11/2020 6:34am
DynoDan22
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DynoDan22 3/11/2020 6:44am
3/11/2020 6:44am
Wow. Never seen that before. I'd be very curious to see where the missing pieces went (through the engine I'm sure). The only way I could see that happening is the bike was run with no idle setting and the slide bottomed out on the carb body and basically kept smashing the slide. Weird...
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digger
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digger 3/11/2020 6:48am
3/11/2020 6:48am Edited Date/Time 3/11/2020 6:50am
motofab36 wrote:
I[img]https://p.vitalmx.com/photos/forums/2020/03/11/409858/s1200_20200310_173823.jpg[/img] I had a kid bring me this cr125 to work on that was idling high and running irratic. I checked for air leaks, adjusted the...
I
I had a kid bring me this cr125 to work on that was idling high and running irratic. I checked for air leaks, adjusted the air screw, all tge regular stuff. Then i pulled the slide out and found the rear side is broken off, kinda looks like it has been eatin away. Have any of you seen this before?
That is actually more common than you think in those Mikuni TMX-x slides. Especially the slides with the hole semi filled for the throttle position indicator. I believe it is caused by the harmonic vibrations from the engine. I've seen it on both 125 and 250cc engines. The newer TMX-x slides, without the hole filled, I see the chroming flaked off quite a bit.
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motofab36
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motofab36 3/11/2020 7:27am
3/11/2020 7:27am
The oem slide and also a complete carb is discontinued. Looks like a Lectron may be in order. Unless any of youns know where I can get a slide or carb. I didnt see much on ebay
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digger
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digger 3/11/2020 7:51am
3/11/2020 7:51am Edited Date/Time 3/11/2020 7:52am
What slide # was used in 04' ? It should be marked on the pad at the top of the slide ?
motofab36
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motofab36 3/11/2020 8:07am
3/11/2020 8:07am
digger wrote:
What slide # was used in 04' ? It should be marked on the pad at the top of the slide ?
4.5
YZed250
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YZed250 3/11/2020 2:07pm
3/11/2020 2:07pm
motofab36 wrote:
The oem slide and also a complete carb is discontinued. Looks like a Lectron may be in order. Unless any of youns know where I can...
The oem slide and also a complete carb is discontinued. Looks like a Lectron may be in order. Unless any of youns know where I can get a slide or carb. I didnt see much on ebay
I have a whole one of these carbs with a #4 slide, pretty low hour carb that I have for sale. just DM me if you are interested.
digger
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digger 3/11/2020 4:53pm
3/11/2020 4:53pm
How did you like the way the bike ran before the slide broke ? You have a few options for a new slide. Yamaha still offers a 4.25 slide that is a direct drop in. It will be ever so slightly richer than the 4.5 that you have now, but it’s a little pricey. https://www.partzilla.com/product/yamaha/1C3-14112-42-00?ref=1f5a4d0c5d…

Honda offer a 4.0 slide that is a little still than the Yamaha 4.25, but again is a direct drop in. With either of the 4.25 and 4.0 slides you also have the ability to cut them leaner into a 4.5 or leaner.
https://www.partzilla.com/product/honda/16022-KSR-734?ref=a2dd5c8e0915e…

JD jetting offers a 5.0 slide that will be leaner than the 4.5 slide, but will need the port fill to work with the TPS. I fill the port with paper and finish the top 1/2 inch or so off with JB Weld.
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savvy
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savvy 5/12/2021 5:41am
5/12/2021 5:41am
digger wrote:
How did you like the way the bike ran before the slide broke ? You have a few options for a new slide. Yamaha still offers...
How did you like the way the bike ran before the slide broke ? You have a few options for a new slide. Yamaha still offers a 4.25 slide that is a direct drop in. It will be ever so slightly richer than the 4.5 that you have now, but it’s a little pricey. https://www.partzilla.com/product/yamaha/1C3-14112-42-00?ref=1f5a4d0c5d…

Honda offer a 4.0 slide that is a little still than the Yamaha 4.25, but again is a direct drop in. With either of the 4.25 and 4.0 slides you also have the ability to cut them leaner into a 4.5 or leaner.
https://www.partzilla.com/product/honda/16022-KSR-734?ref=a2dd5c8e0915e…

JD jetting offers a 5.0 slide that will be leaner than the 4.5 slide, but will need the port fill to work with the TPS. I fill the port with paper and finish the top 1/2 inch or so off with JB Weld.
Nice info mate, which out of them would you go for? Which is better leaner or richer?
digger
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digger 5/12/2021 11:11am
5/12/2021 11:11am
savvy wrote:
Nice info mate, which out of them would you go for? Which is better leaner or richer?
What bike will you be using it in ?

From rich to lean, it would be ---4.0, 4.25, 4.5, 5.0, 5.5, 5.75.....
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JMCR250
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JMCR250 5/12/2021 7:45pm
5/12/2021 7:45pm
Had the same thing happen on my 05 CR250. Just noticed it when I had the bike apart this past winter for a top end rebuild. The bike had started running a little crappy, but nothing terrible, towards the end of last season. I was shocked when I pulled the slide and saw the exact same damage as the OP's pics. Like many, I'm wondering where the broken bits went. No damage to the cylinder/head, and nothing in the lower end. For all I know, this may have happened a year or two ago. I don't really recall the last time I had the slide out before this.
profeshenal125 5/16/2021 9:57am
5/16/2021 9:57am
digger wrote:
How did you like the way the bike ran before the slide broke ? You have a few options for a new slide. Yamaha still offers...
How did you like the way the bike ran before the slide broke ? You have a few options for a new slide. Yamaha still offers a 4.25 slide that is a direct drop in. It will be ever so slightly richer than the 4.5 that you have now, but it’s a little pricey. https://www.partzilla.com/product/yamaha/1C3-14112-42-00?ref=1f5a4d0c5d…

Honda offer a 4.0 slide that is a little still than the Yamaha 4.25, but again is a direct drop in. With either of the 4.25 and 4.0 slides you also have the ability to cut them leaner into a 4.5 or leaner.
https://www.partzilla.com/product/honda/16022-KSR-734?ref=a2dd5c8e0915e…

JD jetting offers a 5.0 slide that will be leaner than the 4.5 slide, but will need the port fill to work with the TPS. I fill the port with paper and finish the top 1/2 inch or so off with JB Weld.
Ha found the thread. Thx for the jetting info. The 04 cr125 I just bought, has a worn slide. If I get the 4.25 slide, I would need a leaner needle correct ? And maybe a leaner pilot. I never cut a slide, how much do I file off. To make it a stock 4.5, Thanks. All my spare needles are richer. My leaner needles, are in my stolen cr125,s.

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JMCR250
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JMCR250 5/17/2021 12:09pm
5/17/2021 12:09pm
Yeah, yours is on the way to what happened to mine. Wish I had I caught it when it still looked like yours, but I don't think it caused any internal motor problems. Will a slide from a 250 not work in the 125 carb? For the 05-07 models, at least, I think they were the same part number.
1
savvy
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savvy 5/18/2021 3:02am
5/18/2021 3:02am
savvy wrote:
Nice info mate, which out of them would you go for? Which is better leaner or richer?
digger wrote:
What bike will you be using it in ?

From rich to lean, it would be ---4.0, 4.25, 4.5, 5.0, 5.5, 5.75.....
Hi, it's for a Cr125 04. Which slide would be best you think?
1
profeshenal125 5/19/2021 8:23am
5/19/2021 8:23am
savvy wrote:
Nice info mate, which out of them would you go for? Which is better leaner or richer?
digger wrote:
What bike will you be using it in ?

From rich to lean, it would be ---4.0, 4.25, 4.5, 5.0, 5.5, 5.75.....
savvy wrote:
Hi, it's for a Cr125 04. Which slide would be best you think?
According to Diggers post, a 4.25 would be the closest. A 4.75 would be ideal, since the bike runs rich, but no one makes it. A 5.0 would be a great choice also, but the epoxy fill in, is a no go. I hv 3 richer needles, now I need leaner needles with a richer slide, I believe. Not saying this is perfect, I changed to a 37.5 pilot, air screw 2 turns out, new stock needle in the middle, 380 main. Pump Gas is from seller yet, could be mixed wrong. I polished the carb, checked reeds, there boyseen pro series. Install a new coil and iKat, very quick throttle response, couldn’t ride it. Buisness owners get pissed. A 380 main is for a decked, ported engine, like my 1st 04 . This engine could be ported also, no time to break it down, pipe side on cylinder it has hrc or hro, faded . My other 04 didn’t hv that. Runs stronger that my other 04, when it was stock.
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savvy
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savvy 5/19/2021 9:19am
5/19/2021 9:19am Edited Date/Time 5/19/2021 9:36am
digger wrote:
What bike will you be using it in ?

From rich to lean, it would be ---4.0, 4.25, 4.5, 5.0, 5.5, 5.75.....
savvy wrote:
Hi, it's for a Cr125 04. Which slide would be best you think?
profeshenal125 wrote:
According to Diggers post, a 4.25 would be the closest. A 4.75 would be ideal, since the bike runs rich, but no one makes it. A...
According to Diggers post, a 4.25 would be the closest. A 4.75 would be ideal, since the bike runs rich, but no one makes it. A 5.0 would be a great choice also, but the epoxy fill in, is a no go. I hv 3 richer needles, now I need leaner needles with a richer slide, I believe. Not saying this is perfect, I changed to a 37.5 pilot, air screw 2 turns out, new stock needle in the middle, 380 main. Pump Gas is from seller yet, could be mixed wrong. I polished the carb, checked reeds, there boyseen pro series. Install a new coil and iKat, very quick throttle response, couldn’t ride it. Buisness owners get pissed. A 380 main is for a decked, ported engine, like my 1st 04 . This engine could be ported also, no time to break it down, pipe side on cylinder it has hrc or hro, faded . My other 04 didn’t hv that. Runs stronger that my other 04, when it was stock.
Thanks for reply mate, I'm having trouble with my 125. Engine has no leaks, sealed crank half's and put seals in with new bushing. Holds leak test all day long. It really smokes and oil is in pipe, got to be fuel related but can't work it out, its never done this before.
1
profeshenal125 5/20/2021 7:57am
5/20/2021 7:57am
Sat I worked on the bike, installed a new coil and iKat. Started 1st kick, it blurbured bad, sounded like a 10cc bike. I was in a hurry with wind and rain , I never put the pilot jet back in. The engine would not rev up, I look at the parts tray and there’s the pilot jet. Engine was flooded bad. Sunday put 3 new plugs in, still wouldn’t start. Took the iKat off, started 1st kick. Then installed the iKat again, runs super crisp, real zippy. My float keeps getting stuck, gas running out the lines. Mxa said not to pull the plug and try to clean the flooded engine out, bump starting it could take the cdi out. Just kick it over with the plug out, I did that a few times. I didn’t think it would ever start. 37.5 pilot with air screw 2 out, should fix the overly rich foul plug jetting.
1
profeshenal125 5/25/2021 4:13pm
5/25/2021 4:13pm
savvy wrote:
Hi, it's for a Cr125 04. Which slide would be best you think?
profeshenal125 wrote:
According to Diggers post, a 4.25 would be the closest. A 4.75 would be ideal, since the bike runs rich, but no one makes it. A...
According to Diggers post, a 4.25 would be the closest. A 4.75 would be ideal, since the bike runs rich, but no one makes it. A 5.0 would be a great choice also, but the epoxy fill in, is a no go. I hv 3 richer needles, now I need leaner needles with a richer slide, I believe. Not saying this is perfect, I changed to a 37.5 pilot, air screw 2 turns out, new stock needle in the middle, 380 main. Pump Gas is from seller yet, could be mixed wrong. I polished the carb, checked reeds, there boyseen pro series. Install a new coil and iKat, very quick throttle response, couldn’t ride it. Buisness owners get pissed. A 380 main is for a decked, ported engine, like my 1st 04 . This engine could be ported also, no time to break it down, pipe side on cylinder it has hrc or hro, faded . My other 04 didn’t hv that. Runs stronger that my other 04, when it was stock.
savvy wrote:
Thanks for reply mate, I'm having trouble with my 125. Engine has no leaks, sealed crank half's and put seals in with new bushing. Holds leak...
Thanks for reply mate, I'm having trouble with my 125. Engine has no leaks, sealed crank half's and put seals in with new bushing. Holds leak test all day long. It really smokes and oil is in pipe, got to be fuel related but can't work it out, its never done this before.
Reeds not sealing ? That will cause a rich condition. I bought a 2020 yz125 4.25 slide today, slightly richer slide. 136.79 from service Honda web ordering. Ordered a 26-70 leaner needle, 1/2 leaner needle not available . 04-07 carb is the same. Full carb rebuild kit came in today, float is sticking.
1
profeshenal125 10/21/2024 8:09pm
10/21/2024 8:09pm
JMCR250 wrote:
Yeah, yours is on the way to what happened to mine. Wish I had I caught it when it still looked like yours, but I don't...
Yeah, yours is on the way to what happened to mine. Wish I had I caught it when it still looked like yours, but I don't think it caused any internal motor problems. Will a slide from a 250 not work in the 125 carb? For the 05-07 models, at least, I think they were the same part number.

Yup I found a piece of the slide stuck in the head.  I think I can just peal it off.  I stopped using that slide last yr.  I,m using the slide from the 5 hr bike. I didn’t try the yz slide yet. I found out you hv to fill that hole on the left on top with jb weld . Because the wheel sits down into the yz slide. Start the bike and it’s screaming. 

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