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HELP. TTR125 carb help. What the heck????

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I would like to work on my carb but I tried locating the pilot screw on my bike. I poked around TT a little and found where it should be. Well when I looked there was only what looked like a plug with no slot for a screwdriver tip, at all. I also notice another thing that I didn't see on any other photos or the schematic for the carb. It looks like a hole in the side of the carb that does not go anywhere. It's near the vent tube on the slide stop screw side of the carb. What is this carb?

History. I bought this bike a couple weeks ago and am going through fixing a few things here and there. It ran OK but I could not figure out how to get the idle down. It was a little high so I looked for the idle screw and did not see one, at least not one that looked like I have seen on other carbs before. Well I figured out the choke was stuck open so I thought that explained the high idle. I freed up a stuck choke plunger, with the help found on TT. I also identified the idle screw. So thinking I was closer to getting it all corrected, I put the choke on yesterday and started her up and got it warmed up. Then I pushed the choke back in and it died. I messed with it a little but could not get it to idle with the choke off without using the throttle a bit. I messed with the idle screw but that didn't cut it even with it screwed all the way in. I gave up for the night and poked around TT again. Looks like I might have to adjust the pilot screw and possibly change the pilot jet to a 17.5 and up the main to a 107.5. I do not know this for fact but it looks like others have done this with success, at least with the 17.5 pilot jet. I also read one of the Moderators threads on how to determine if a pilot jet change is needed. I forgot where the thread was at but it said I needed to adjust the pilot screw. I could not find that screw so I dug deeper and found out it is located on the bottom of the carb. I looked at mine this morning and saw that it did not have any slot for a screwdriver tip. What the heck does that mean. I also notice that the side of the carb had a hole in it that I didn't see in any other photos or on the schematic. Is this a non-stock carb? Everything else seems ok like the choke plunger, vents, screw locations, etc.

I also noticed that the vent tube on the left side of my carb was routed up instead of down. Could this make a difference? I just noticed while making a photo bucket that the vent line going up was also kinked. Any thought on this?

http://i1099.photobucket.com/albums/g388/MarkF1967/DSC02827.jpg

http://i1099.photobucket.com/albums/g388/MarkF1967/DSC02829.jpg

http://i1099.photobucket.com/albums/g388/MarkF1967/DSC02836.jpg

http://i1099.photobucket.com/albums/g388/MarkF1967/DSC02838.jpg

http://i1099.photobucket.com/albums/g388/MarkF1967/DSC02839.jpg

http://i1099.photobucket.com/albums/g388/MarkF1967/DSC02841.jpg

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Edited by Mark6299

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That's where the idle mixture screw is.

Drill a small hole with a 1/8" or smaller drill. You want to drill through to the point where it "pops" through. Drill slowly.

After it's popped through, use a drywall, sheet metal or wood screw to make a handle. Pull the cap out.

Make sure you clean the carb. You'll want to soak the pilot and main jet as well as any other metal parts you can remove. I'm going to advise you not to soak the carb body because, IIRC, there are some plastic/rubber components that are not easily removed by the novice. Do not soak any plastic or rubber parts, they will never be the same.

Kinked vent hoses usually will starve the motor, you don't want kinks under most circumstances.

I use GUNK brand carb/parts cleaner. Comes in a 1 gallon can with parts tray for about $25. I'm still on the same solvent I purchased several years ago although a different can (long story). I'd imagine it would last the average person half a life time.

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Thanks, I will try cleaning some parts up and see what happens. I will take the cap off as well so I could make some adjustments.

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Well I got the brass plug out of the pilot screw opening. I guess that was placed there from the factory so you don’t mess with it. I turned the pilot screw in and it stopped at about 1 turn. I unscrewed it and took it out along with the spring and sprayed it down with carb cleaner. Then I seated it and unscrewed it 2 turns. I also took off the bowl and pulled the pilot and main jets. I cleaned those up too. The o-ring between the carb and the body that the main jet screws into was not in great shape so I replaced it with a new one. I put it all together and choked it and warmed it up good. I turned off the choke and it idled for a bit but a little rough. I unscrewed the pilot till it idled ok but not great. This was just over 3 turns out and with the idle screw in all the way. I think I will change the pilot jet to a 17.5 and see how that works out. The pilot that was in there was a stock 15 with the stock 105 main jet. I will not mess with the main until later on if I need to. I think I am on the right track, especially since it would not idle at all with the choke in the off position. I can't help but wonder though how it must have ran before with the 15 pilot and the pilot screw out 1 turn. What could have changed, could it be a bad O-Ring I replaced? Anything else???

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Please show a pic of your carb without the bowl on it, I think I know exactly what your problem is. Its that plastic white washer that sits above the main jet me thinks

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We have had two of the ttr 125s. Both were nearly the same. Very difficult idling and long warm ups on the choke. Both responded excellently to opening the idle fuel jet just as you did. I had to turn out the idle mixture screw a bunch. Both start and run great. Playing with the mixture screw was needed to give the best drivability rather than the perfect idle. The main jet has seemed fine. Initally I had raised the needle but after the idle fuel screw adjustment I ended up putting the needle back down.

I don't understand why but the 4 stroke slide throttle carbs have an idle fuel jet and the two strokes use a idle adjustable air jet.

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