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TTR 125 Carb question

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Hi all,

 

I just purchased a 2008 TTR 125 for my kids. Ive read some of the posts concerning the poor response off idle couldn't find an answer. My question is. Whats the screw for that's located on the throttle cable housing. Its got a spring on it. right side of carb

 

Thank you,

 

Mark

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That's the idle adjustment, buy a 17.5 pilot jet and a 110 main jet these bikes are jetted lean out of the box, also read up on airbox mods and do that aswell the bike will have much better response

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Anything else just ask, I recently bought a ttr125 myself for my girlfriend, I've already asked these questions myself and learned along the way, her bikes pretty hopped up now but I've learned every step of the way.

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+1 on those jetting specs and opening the airbox. I only removed the snorkel but u can drill holes as well if u don't ride in too extreme of conditions. I also found out that you want your idle (flathead screw on left side of carb) to be adjusted to fairly low (so that it idles comfortably) - this will give u the best throttle response

I HIGHLY advise you to pull your choke assembly right away and oil it with a lightweight oil like gun oil or such because it will get stuck or corrode after a short time, then you are stuck buying a $30 cable and/or a $50 choke plunger assembly, which is what I had to do. While u have carb off to do this just remove large hex run (can be brass colored or silver) and oil the plunger and make sure it operates smoothly.

Once you do this you'll have a bulletproof bike that's much better than stock and it barely costs a thing!

Good luck!

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+1 on those jetting specs and opening the airbox. I only removed the snorkel but u can drill holes as well if u don't ride in too extreme of conditions. I also found out that you want your idle (flathead screw on left side of carb) to be adjusted to fairly low (so that it idles comfortably) - this will give u the best throttle response

I HIGHLY advise you to pull your choke assembly right away and oil it with a lightweight oil like gun oil or such because it will get stuck or corrode after a short time, then you are stuck buying a $30 cable and/or a $50 choke plunger assembly, which is what I had to do. While u have carb off to do this just remove large hex run (can be brass colored or silver) and oil the plunger and make sure it operates smoothly.

Once you do this you'll have a bulletproof bike that's much better than stock and it barely costs a thing!

Good luck!

May I ask what year your referring too where the idle screws on the left?

I know 2008 and newer uses a dual cable version of the carb and the idle is a thumb screw on the right hand side, this carb may differ from the older style single cable with the twist off top, and I also agree with lubing the choke cable good advice.

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Its the 2008 and as you stated the idle screw is on the throttle cable housing.

 

Thanks for all the replies

Edited by jaws134

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Mine is a 2005. ImageUploadedByThumper Talk1447777590.514130.jpg

The flathead screw in the middle is my idle adjustment screw. I'm sure u can find where it is online somewhere if u can't find it yourself

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If I decide to put on the Mikuni VM24 will the stock throttle assembly work with the single cable. I would assume it would and then just cap off the other hole.

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I opted to use a crf150f carb, i got mine off of eBay from a 2006 with the cable and throttle tube for 75 bucks, I bought the bbr billet adapter and trimmed about 1/4" off the boot on the airbox.

It made a decent difference honestly, it should compliment my big bore kit and cam when I get them installed too.

ImageUploadedByThumper Talk1447825095.888556.jpg

ImageUploadedByThumper Talk1447825131.036534.jpg

ImageUploadedByThumper Talk1447825165.571403.jpg

Edited by yzdude250f

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The 17.5 Pilot and 110 Main worked. Bike runs 100% better than it did with the stock 15 and 100.

 

Thanks all!

 

Mark

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New guy here so please be kind, I own a 2015 ttr 125 and have been reading as much as I can but never owning a bike before its kind of confusing. I am just trying to get a little more out of the bike and am looking at doing the air box mod and jets, do the 17.5 pilot and 110 main apply to my bike also. And would any dealer carry these, I mean what info do I need to give them to be sure I am getting what I need, I am sure if I read some more threads it should be a pretty easy project. Thanks for any help.

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New guy here so please be kind, I own a 2015 ttr 125 and have been reading as much as I can but never owning a bike before its kind of confusing. I am just trying to get a little more out of the bike and am looking at doing the air box mod and jets, do the 17.5 pilot and 110 main apply to my bike also. And would any dealer carry these, I mean what info do I need to give them to be sure I am getting what I need, I am sure if I read some more threads it should be a pretty easy project. Thanks for any help.

Most dealers should have them in stock. Tell them your bike and what size jets you want. Or you can go on a website like Rocky Mountain atv mc, put in your bike and search for the jets there and they will give you the right ones. It's $7 shipping so it won't be worth it unless you are buying other things with it but they shop fast and have great customer service if anything goes wrong

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Thanks, might actually buy an exhaust to. So swapping out the jets shouldn't be a big deal then, I mean I have mechanical aptitude just not on bikes, i tried looking for a video or how to but haven't had any luck yet.

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http://youtu.be/ZnC9nXF0CWU

This is what I used. Once you open carb once you'll know how to do it every other time.

Key points when opening carb:

Be VERY careful not to strip any screws

Don't lose the small parts

Do NOT overtighten jets. Snug is all you need

The throttle cable is connected to a slide with 2 different kinds of slots - make sure the short and fat one faces the rear wheel when installing.

Take pictures of carb before you take it apart and you'll know where all the different tubes good

Good luck :)

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ok, installed new jets, being a 2015 I believe I need to adjust the idle air screw, silver thumb screw with a spring under it, but do I go 1 turn in or out to start, thanks

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Sorry, I think I meant , Do I need to adjust the fuel screw, and where is it located, I read somewhere on her I do, and it might be in the carb under a cap, is this right? thanks

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ok, installed new jets, being a 2015 I believe I need to adjust the idle air screw, silver thumb screw with a spring under it, but do I go 1 turn in or out to start, thanks

 

For my TTR230, I did 2 full turns out starting from the fully seated position (screw turned all the way in until it won't turn anymore, then 2 full turns out from there).

 

You could start with 1 or 2 full turns and see how the bike runs, and adjust from there. The good thing is that you don't need to take the carb off to access the screw since you have now done the rejetting already.

 

EDIT: If the carb is the same one as the TTR230 (which I assume it's going to be similar), then you will need to drill out this cap in order to access the screw, but once the cap is removed, you can make adjustments without needing to remove the carb from the bike. 

 

fuel%20screw.jpg

 

Go very slow while drilling the cap out so that you don't punch through and damage the screw that is underneath.

Edited by Irishman301

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ok, its 11:35 pm and I just decided I couldn't wait any longer to try this so I went out to the garage where its freezing right now, 25 degrees, and drilled it out, I then counted the turns to where it  bottoms, which was a surprising 2 1/2 turns to stop, I find this weird because everyone states they are only half a turn out from the factory, I then backed it back out the 2 1/2 turns and will put the exhaust on tomorrow to see how its running. not going any further than the 2 1/2 because the bike starts with just the push of the button and no choke right now. Scary as heck trying to drill that little cap out, didn't expect it to be so long of a plug, plus I was going slow so it seemed forever.

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ok, its 11:35 pm and I just decided I couldn't wait any longer to try this so I went out to the garage where its freezing right now, 25 degrees, and drilled it out, I then counted the turns to where it  bottoms, which was a surprising 2 1/2 turns to stop, I find this weird because everyone states they are only half a turn out from the factory, I then backed it back out the 2 1/2 turns and will put the exhaust on tomorrow to see how its running. not going any further than the 2 1/2 because the bike starts with just the push of the button and no choke right now. Scary as heck trying to drill that little cap out, didn't expect it to be so long of a plug, plus I was going slow so it seemed forever.

Glad to hear you got it drilled out! Now you can make adjustments without having to take the carb off the bike.

It kinda sounds like you may need to go in a bit with the screw, because a completely cold engine should need the choke on for at least 15 to 30 seconds or so...Maybe I me wrong about that, but every carbureted vehicle and machine that I've ever owned needed some sort of choke on when first starting cold. The fact that it doesn't require any choke from a dead cold start suggests that your mixture may be running a bit rich. A half turn in will probably get it right to where it needs to be.

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