Questions on 04 125sx

What's up guys, I got a 125SX earlier this year and it's about time to get a top end redone. I been spraying ether to get it started the last couple rides because it has low compression and it's hard to start. Did a compression test and results is 90 first test and 100 second test. It's ready for a top end I can tell you that. I have to many projects on my hands right now. Got one of my cars motors tore apart and parts all over the garage so I don't want to tear into another project at the same time. There's no telling how long it'll be before my cars done but I'd let to just get the top end done by a local shop. Than maybe next rebuild i'll have space to tear it apart and do it myself. Can anyone tell me what a shop should charge for a 2 stroke top end rebuild in labor? I know a top end rebuild kit with wiesco piston etc is going to be $155. So what should a shop charge in labor? I called 1 shop so far and they said $210+tax in labor which seems high for a top end rebuild on a 2 stroke to me. Just want others opinions on what the going price is.

 

Next question is where can one find a graphics kit for a 04 125sx? I got new plastics and it's just plain orange. Can't find any graphics kits besides newer ktm's so if anyone could guide on where to find some it'd be great.

 

Last question, Stock rear tire size is 100/90/19. What's everyones opinion on 110/90/19? I've been told that it'd be alittle bit heavier and the stock tire size would be better. I got a new dunlop mx51 for the front and needing to get a rear tire soon now.

What's up guys, I got a 125SX earlier this year and it's about time to get a top end redone. I been spraying ether to get it started the last couple rides because it has low compression and it's hard to start. Did a compression test and results is 90 first test and 100 second test. It's ready for a top end I can tell you that. I have to many projects on my hands right now. Got one of my cars motors tore apart and parts all over the garage so I don't want to tear into another project at the same time. There's no telling how long it'll be before my cars done but I'd let to just get the top end done by a local shop. Than maybe next rebuild i'll have space to tear it apart and do it myself. Can anyone tell me what a shop should charge for a 2 stroke top end rebuild in labor? I know a top end rebuild kit with wiesco piston etc is going to be $155. So what should a shop charge in labor? I called 1 shop so far and they said $210+tax in labor which seems high for a top end rebuild on a 2 stroke to me. Just want others opinions on what the going price is.

 

Next question is where can one find a graphics kit for a 04 125sx? I got new plastics and it's just plain orange. Can't find any graphics kits besides newer ktm's so if anyone could guide on where to find some it'd be great.

 

Last question, Stock rear tire size is 100/90/19. What's everyones opinion on 110/90/19? I've been told that it'd be alittle bit heavier and the stock tire size would be better. I got a new dunlop mx51 for the front and needing to get a rear tire soon now.

Ok...you don't want to take apart the dirt bike cause you have other projects.. You can rebuild the engine on one of these in under 2 hours..drain the coolant, remove tank, pipe, and carb. disconnect the powervalve and pull the jug. I don't even think you need to remove the head.  It so easy you would be stupid to pay someone to do the work for you. its not a car engine. And if you attempted to start a bike with ether...really..why? I pretty sure if you had to go that far..that you shouldn't be riding it. do you just ride a dirtbike up and down the street?

Yea, I can do mine in 45 min after you've removed the tank, which takes less then 10 minutes.

I'd just do it, piece of cake!

Even if you haven't done a top end before it shouldn't take you more than a couple hours.

Ok...you don't want to take apart the dirt bike cause you have other projects.. You can rebuild the engine on one of these in under 2 hours..drain the coolant, remove tank, pipe, and carb. disconnect the powervalve and pull the jug. I don't even think you need to remove the head.  It so easy you would be stupid to pay someone to do the work for you. its not a car engine. And if you attempted to start a bike with ether...really..why? I pretty sure if you had to go that far..that you shouldn't be riding it. do you just ride a dirtbike up and down the street?

 

Everyone's been telling me it's easy and just do it but I can't find a single manual to tell me how. I've never worked on a dirtbike before and just don't want to tear it apart and be stuck with no guidance at all. All I've done with the dirtbike is keep the gear oil changed, coolant, spark plugs, basic things. I put new wheel bearings in the rear and random stuff. And no I've ridden it down the street once when I got the bike but the only place i've ridden the bike is on a track. My yard is so small you can't do anything.

 

 

Yea, I can do mine in 45 min after you've removed the tank, which takes less then 10 minutes.

I'd just do it, piece of cake!

 

 

Even if you haven't done a top end before it shouldn't take you more than a couple hours.

 

 

Those 2 say the same as everyone else! Makes me want to go tear it apart but just as I've previously said I have 0 guidance, torque specs, etc

Anyways since so many people said it'd be stupid to pay someone I went out and started the project. Took 2 hours and got the piston off etc.. Pics. Piston/cylinder measure to be about 53.8mm with the gauge I was using. Here's a link to the kit I was looking at.  http://www.amazon.com/dp/B001TXFLN8 Is it the proper kit, Is it what I need? Here's pics..

 

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Edited by KGAP1

looks good...besides the dirty engine dropping sand everywhere...you should be alright..next time remember to give the bike a good bath before tearing apart..haha... I'm not a wiseco fan..but others are..piston expands faster then the cylinder walls so when you do use them make sure you get the bike warm before giving it...

Yes next time it's get a good wash before I tear it down! Looks like i'll order the piston kit and give it a try, I've read alot of good stuff on wiesco, If it turns out I don't like them I can always try another brand next time. I'll remember that on lettin it warm up before getting on it. Have to do the same with my car. Especially if you have aluminum rods. Let that oil get warm before anything! I've read a break in routine for a 2 stroke, Let it idle 10 minutes. Cool down 2 hours, Ride it 10-15 minutes nothing over 50% throttle. Let it cool down 2 hours, Than have at it.

Buy the Vertex double ring piston. Vertex is the OEM supplier for KTM and has all the updates to the rings which make them seal better. The single ring pistons don't seal well and are designed foe people who are replacing their piston every few hours.

Call Andrew Cooksey @ Cooksey cranks. He has a deal on the 2 ring Vertex piston and gasket kit for that bike. ;)

You might as well rebuild the crank while you have it apart. It is 10 years old after all. As far as the break in, f that. I usually ride it a lap and check it a bit to make sure there are no leaks or anything, then have at it. You want to make sure the rings are seated.

Well the wiesco top end kit I was talking about on amazon actually has the wrong image for some reason, The wiesco piston actually has 2 rings, According to wiesco's website and this is the image of the kit. !Bs+7jSQBmk~$(KGrHqIH-E!EvPKy9uNmBL6GqQS

Well the wiesco top end kit I was talking about on amazon actually has the wrong image for some reason, The wiesco piston actually has 2 rings, According to wiesco's website and this is the image of the kit. !Bs+7jSQBmk~$(KGrHqIH-E!EvPKy9uNmBL6GqQS

I don't think that is a ktm piston either...by looking at the head gasket. The stock ones are o rings right? They normally just post a generic pic of the product. Vertex is a great piston. I really think if you stay away from cheap pistons you will be good. I let my bikes warm up pretty good anyway. But I still never had great luck before with wiseco. But that was my fault at the time.

Well, I had ordered the wiesco piston kit, I've heard from multiple people get quite a bit of hours out of those, If it doesn't last that long than I can always use a vertex one next time. Live and learn right? If you search wiesco pro lite piston  on motosport for my bike it's also showing 2 rings. I guess there's no way to know for sure until the parts get here. Amazon is the only one I've seen that shows 1 ring.

 

I'll never personally know whether I like wiesco or vertex until I use both of them. I've read tons of good reviews on wiesco even if there is the occasional bad review, Same way as vertex you can find lots of good reviews and occasional bad reviews. So I'd say overall both pistons will be good in the end. Which one lasts longer will depend on the way you ride and maintain the bike etc. Same way for building cars, Alot of people like arias, wiesco, JE pistons, But I prefer CP Pistons and that's what I use in my car.

Edited by KGAP1

 And if you attempted to start a bike with ether...really..why? I pretty sure if you had to go that far..that you shouldn't be riding it. do you just ride a dirtbike up and down the street?

 

Alright, give the guy a break.  There's no telling why the bike was difficult to start, aside from the compression being low from the piston/rings being worn.  This bike is a decade old..

 

But I agree with you, the piston is a quick and easy job to do yourself, no need to pay someone else to do it. 

Buy the Vertex double ring piston. Vertex is the OEM supplier for KTM and has all the updates to the rings which make them seal better. The single ring pistons don't seal well and are designed foe people who are replacing their piston every few hours.

Call Andrew Cooksey @ Cooksey cranks. He has a deal on the 2 ring Vertex piston and gasket kit for that bike. ;)

 

And I would argue to use a better quality synthetic oil, the piston crown looks filthy dirty.  My 300 piston was clean as a whistle after 125 hours of riding, using Amsoil Dominator at 50:1.. you can't go 125 hours with your 125 but your piston will be cleaner with a better oil.

Alright, give the guy a break.  There's no telling why the bike was difficult to start, aside from the compression being low from the piston/rings being worn.  This bike is a decade old..

 

But I agree with you, the piston is a quick and easy job to do yourself, no need to pay someone else to do it. 

 

Havn't had the bike too long. Got it earlier this year. The compression test came out at 90 before I tore it apart. Which from what i've seen is really low.

 

And I would argue to use a better quality synthetic oil, the piston crown looks filthy dirty.  My 300 piston was clean as a whistle after 125 hours of riding, using Amsoil Dominator at 50:1.. you can't go 125 hours with your 125 but your piston will be cleaner with a better oil.

 

Yep, Previously mentioned havn't had the bike too long so there's no telling what oil the previous owner had through this thing. I've used Motul 800 since I got it and I got a case of amsoil dominator in my garage that will be going through it next time around

 

 

But aside from all the top end talk. The 2 other questions in first post. Do you all prefer 100/90/19 or 110/90/19 on a 125 and why? Also as far as graphics. From what i've seen I can get 05-06 radiator shroud's and there's tons of graphic kits for 05-06 but none for 01-04  or so.

Do you all prefer 100/90/19 or 110/90/19 on a 125 and why?

I had YZ 144 that I put a 2.15 rim and a 110/80/19 on and loved it. Most 125 guys will say don't do it as it will rob a lot of power, they're mostly right. I found with the 144 engine it would stick better and not break traction as much, but it definitely robbed some of the power. I think the 125sx comes with a 2.15 rear rim already, I liked the velcro-ish type traction it got.

I'm on the stock MX51 on my 150sx still, I'm pretty sure it's a 100/90/19, I'll put that size on next time too. If you trail ride, or won't miss the power go for the bigger tire, you'll love the grip. If you ride track I would stick with the 100/90/19.

Edited by poldies4

Havn't had the bike too long. Got it earlier this year. The compression test came out at 90 before I tore it apart. Which from what i've seen is really low.

Yep, Previously mentioned havn't had the bike too long so there's no telling what oil the previous owner had through this thing. I've used Motul 800 since I got it and I got a case of amsoil dominator in my garage that will be going through it next time around

But aside from all the top end talk. The 2 other questions in first post. Do you all prefer 100/90/19 or 110/90/19 on a 125 and why? Also as far as graphics. From what i've seen I can get 05-06 radiator shroud's and there's tons of graphic kits for 05-06 but none for 01-04 or so.

I would run a 100/90 even offroad bc the motor has to work so hard to turn anything else, but that's conjecture I've never owned 125 cc bike

I too run a 110 rear and vastly prefer it to the 100. The weight difference is nominal.

About the graphics, you can use 04-06 SX and 04-07 exc/mxc/xc/xc-w. Check e-bay.

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