Installed 110 Jet in 125 and runs worse

We bought a used 09 125LE for my 11 year old. It ran pretty good but when I got on it, it would really miss out when I was hard into the throttle. We purchased a 17.5 and 110 jet based on input from many forums. We pulled the existing pilot out and it was already a 17.5. I then figured the previous owner already did the larger jets and that I would find a 110 in the main. I pulled the main out and it was a 100??? I left the 17.5 in and replaced the 100 with the 110. The bike now misses out with my son to the point where he is insisting I put the old jet back in. What is the problem? I know little to nothing about motors but wonder if I should replace the 17.5 with the new 17.5 (maybe old one is a bit clogged) and whether the carb needs more gas flowing to it. Should I adjust something else after putting in the 110?

Have you puuled out the rubber intake snorkel on top of the airbox, and the mesh screen in front of the air filter?

Removed snorkel and screen and have a uni high flow air filter kit on it.

another piece of the puzzle. The previous owner had an FMF powercore 4 on it. It did the missing out with me when that pipe was on it too. We removed the powercore and put the stock back on about 2 months ago because it was too loud for where we ride. We just did the 110 jet today.

When is it missing? Small or large thottle opening? If it is 1/4 to 3/4 open, check the position of the jet needle. It may need to be moved to a different position.

Did you remove and cleam the main jet holder?

3/4 to full throttle is where we have the issue. I did not clean the main jet holder. I have read about having to raise the flight a click. How do I do that?

Remove the main jet holder and make sure all the side holes are clear. The needle is in the slide that comes out with the throttle cable. Lower the clip makes it flow more while raising the clip flows less. If can get the bike warmed up and run as long as you can at the problem throttle position, then kill the engine and pull and inspect the spark plug to see if it is fouling or dry. Then you can tell if it is starving or drowning.

This link may help you.

http://www.justkdx.dirtrider.net/printcarbtuning.html

Excellent info. I will give this a try when we get a chance!

Is there a fuel mixture screw or Air/Fuel Screw on this carb? If so, where is it? Also, I shouldn't snug all of the jets up pretty tight right?

yes there is a mixture screw, heres a vid to help you... http://www.youtube.com/watch?v=ZnC9nXF0CWU

not real tight on the jets they are soft brass... just snug them up, I ran a 110 and a 17.5 on mine with the powercore 4 and it ran great!

The bike is running lean. If I am understanding all of this correctly, I can do the following:

1. Increase size of pilot jet to allow more gas flow

2. Lower the clip to allow more gas

3. Install a 98 main jet

Am I thinking correctly?

A 98 main jet is way leaner. I would run the bike down the street after it is warmed up, and while you're floored and accelerating towards high rpm's, pull the choke button up. Does it run better or worse? I can't believe that a 110 main is too lean. The next richer is a 112.5, though.

Raising the needle clip would solve a lean condition in the 1/4 to 3/4 throttle position, but above that, it's the main jet. I can't remember if there are needle clip positions on the stock needle, but you can put a little .020 washer under the needle and accomplish the same thing.

The pilot only affects starting, idling, and just off idle throttle response. A 17.5 has been proven to work over and over.

Are you at sea level? A 110 works well (usually), a 105 at 5,000 feet is a good high altitude starting point for an uncorked bike.

I pulled some of the jets, main nozzle, needle jet setter and needle vale set and soaked in carb cleaner with the o rings. Not sure if I should have removed the o rings before soaking or if they were messed up before soaking. When I went back to reinstall, the o rings were flaky. My local yamaha shop does not have them in stock so I need to order. Will provide updates later. I am tempted to just take it to a shop and get it fixed right...

I want to restate the history of this in hopes that one of you with experience that have already posted will have a better understanding of my shituation. The bike had a powercore 4 with a 100 main jet. The bike missed out when I had it 3/4 to full throttle and was too loud for our riding location. I removed the powercore and put a stock pipe back on. I didn't notice a difference in the WOT miss out. In an effort to get rid of the missing out, we put a 110 main in and it got noticeably worse. Today, the guy at the local yamaha shop told me that I should go backwards to a 98 (97.5) main jet. I then asked why are most people saying they get much better performance with a 110 or 112.5 main jet. He said cause they are running after market pipes and not the stock pipe.

I pulled some of the jets, main nozzle, needle jet setter and needle vale set and soaked in carb cleaner with the o rings. Not sure if I should have removed the o rings before soaking or if they were messed up before soaking. When I went back to reinstall, the o rings were flaky. My local yamaha shop does not have them in stock so I need to order. Will provide updates later. I am tempted to just take it to a shop and get it fixed right...

Soaking IS NOT cleaning. READ THAT AGAIN

Blow the jets out with a decent air blower, then look thru the jets to see if they're really clean.

Clean all the passages in the carb, and check that you're getting enough fuel to the carb. Even DR100s run a 105 main, 98 is crazy lean and more likely to blow a hole in the top of your piston than fix the problem.

Yes, I know soaking is not cleaning. They were soaking while I was taking other parts off of the carb and then we ate dinner. I came back out and the o rings were flaking. Is that from soaking or were they messed up before I soaked them? I didn't look closely at the o rings before I dropped the pieces in a small container with carb cleaner. Would carb cleaner eat o rings up. When I found the o rings were shot, I also jecked the jets and they were really clean but I am at a standstill until I get new o rings. I will blow them with an air compressor before I reassemble. You said to check that I am getting enough fuel to the carb. How would I increase the fuel to the carb? Back the pilot screw out?

So the dealer told me to do the wrong thing huh...that was nice of them.

Sounds silly, but did you put fresh gas in it?? Old fuel will makes this happen.

With a 17.5 pilot, 110 main, airbox mod and high flow filter, new plug, the TTR should be running like champ..:smirk:

Could be an electrical problem cutting out like that. CDI might be going bad. It's the little box on the left side of the frame under the triple clamps and in front of the tank.

Yes, fuel is good. Same fuel we are running in all our other bikes that we recently bought. Is there a way to test the CDI or do I just buy a new one?

Here are the things we did to the bike after we noticed it was missing out at full throttle in every gear.

1. Did the normal mod on the air box.

2. Uni high flow air filter

3. 17.5 pilot

4. 110 main

5. Fuel is clean. Should we use 87 or 93?

6. Cleaned the carb

7. new plug

8. New o ring for the main nozzle

9. New needle vale set

10. Raised the float a bit.

All of this and it still is not right. It is also leaking gas when it sits in the garage. I guess I raised the float too much? Is there a way to check the rev limiter or do I have to just buy a new one? If new, should I get stock or a BBR?

Yup, float level is too high, and you should turn the petcock off when it's not running.

If it's off and it's still leaking, you've got a bad petcock.

87 octane is fine.

My guess is it's still too rich, but first get your float height straightened out. If going to 110 from 100 (a big jump) made it worse, trying the 98 makes sense. (97.5?) But so does 102.5, and 105 and 107.5.

When you soaked it, did you take everything off the carb? If not, it's likely there's an o-ring or seal that needs to be replaced under something you didn't remove.

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