TTR125 Thread

Discussion in 'Thumpers' started by mikesova, May 10, 2012.

  1. mikesova

    mikesova Michigander

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    I think this cool little bike deserves it's own thread.

    I just bought a 2001 TTR 125L (kickstart) for my wife to learn on. I thought I got it for a good deal, but maybe not, now.

    The bike doesn't want to idle without the choke on, based on my research, clogged pilot jet. Not a big deal.

    However I noticed a clunking or clicking in first gear that I didn't notice on the test drive. From my research, it sounds like there is a broken tooth on the first gear.

    I put the bike on a stand, started it, and engaged 1st gear, I couldn't hear the sound then, but would that be just because there was almost no load on it?

    Anyway, here's the happy lady and bike:

    [​IMG]
    #1
  2. mikesova

    mikesova Michigander

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    update, without the bike started and rolling it on the floor in the garage I can feel a clunk in 1st gear, but not the other gears....
    #2
  3. JWhitmore44

    JWhitmore44 pistolero

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    These little bikes came jetted pretty lean from the factory. You will need to bump the idle jet up quite a bit and probably wouldn't hurt to bump the main jet. This will also make the bike start easier when cold.

    Make sure your chain and sprockets are good before condemning first gear. I had an old Yamaha XT250 that had a tooth off of 2nd gear. You defiantly knew it was a tooth as it had a pretty rhythmic clunk when in gear and under power. It wasn't anywhere near a click :) A stiff link on a chain may be causing your noise.

    There's a few things you can do to squeeze a little more performance out of the little motor. Remove the air box snorkel, some remove the back fire screen, and take a long drill bit or drill bit extension and drill 3 more 1/2 inch holes down in the baffle in the exhaust. If you do that you will need to redo your jets again. My son had the small wheel version and the gearing was really low, once he got past learning, 1st gear wasn't real useful. I put a 1 tooth larger counter shaft sprocket which helped make it feel like you weren't wringing the little motor out as much.
    #3
  4. mikesova

    mikesova Michigander

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    The previous owner has already rejetted it. It starts really easily and runs fine, it just won't idle for very long before it quits.

    Unfortunately, I would say that the sound is closer to a clunk than a click and it only shows up in 1st gear. The chain/sprockets are almost brand new, as well.

    So, I think the reason I didn't notice the clunk, was that when I test rode it, I was probably in 1st gear for about 2 seconds. How big of a deal would it be to just leave it as is? I've got 600$ into the bike and I don't think that I'm at the skill level to replace the trans gears myself. I can just imagine that the shop bill would be around what I have into it or more. Is it doing any damage when the bike is not in 1st gear?
    #4
  5. Krazyjohnny

    Krazyjohnny Been here awhile

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    Take the carb off and clean the jets and all of the passages. You will be amazed at how much better it will run/idle. The biggest thing to remember is how many turns out the fuel screw is right now. This in hand you can reset it right back to that setting when you put the carb back on the bike.
    #5
  6. mikesova

    mikesova Michigander

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    the carb is the least of my worries...:D
    #6
  7. mikesova

    mikesova Michigander

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    I changed the oil and didn't see any metal. I even ran a magnet around in the oil and nothing picked up. That leads me to believe that the oil has been changed since the damage was done.
    #7
  8. JWhitmore44

    JWhitmore44 pistolero

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    I ran my old XT for a couple years bypassing 2nd gear :D as long as the tooth isn't bouncing around in there someplace so that it jams into another gear and causes more damage. Not sure how you would find out with out taking it apart. Maybe try a magnet on a flex head to see if it can be fished out.

    Wonder if it's too rich now? What does your plug look like after idling? I wonder if it's "loading up" and drowning the plug out.

    One other thought, is your idle set too low? might try raising your idle speed up a little.
    #8
  9. STFU

    STFU Found

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    We have a 2001 L also, good little bike. I have upgraded ours (the kids bike really, but I try to ride it when I can) with some USD forks from a YZ85 and relocated shock mount (to level it back out again). Made a HUGE difference in ride quality and and hadles great in the woods now.

    As for your carb problem, before taking it all apart just check the clamp around the boot between it and the head. Ours didnt idle for crap, unitl I figured out it was loose and the engine was sucking air. Quick fix.
    #9
  10. mikesova

    mikesova Michigander

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    Does she need to bypass 1st gear, or can she just start out in it and upshift soon, without causing any damage? She is going to be learning, so 1st gear will be important.
    #10
  11. mikesova

    mikesova Michigander

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    here's the 1st gear noise:

    <iframe src="http://player.vimeo.com/video/42038855" width="500" height="889" frameborder="0" webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe>
    #11
  12. mikesova

    mikesova Michigander

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    idles fine now after adjusting the idle screw. :clap Draining and replacing the gas and checking the jets was good idea, too. :rofl
    #12
  13. JWhitmore44

    JWhitmore44 pistolero

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    I would avoid 1st gear, and it does sound like my old XT did in 2nd. While she's learning you could go with a tooth smaller front sprocket and start in 2nd. But like I say, if that tooth is still hanging out in the motor that would concern me.
    #13
  14. mikesova

    mikesova Michigander

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    If I was to replace the broken gear, would it be easier to remove the specific gears that need replacement, or buy the whole gearset used and replace the whole set? It looks like I can get the whole gearset for about $100 on ebay.
    #14
  15. JWhitmore44

    JWhitmore44 pistolero

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    I really don't have any idea. Assuming it was only 2nd gear with the damage it may be cheaper to just get the gear. If you have more than one gear you may exceed the $100 fairly quick. I haven't heard of any issues with the gears on those bikes, my guess is that the chain came off at some time and took out the tooth on 2nd with a sudden stop. With either a new gear or a used gear set you will need a gasket set.
    #15
  16. ballistic_ken

    ballistic_ken Helmet hair victim.

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    I have a '05 TTR 125 and the clutch engagement is way out, no engagement at all until the clutch is almost fully released.

    I am assuming the clutch pack is due for replacement, but am open to other ideas.

    :ear
    #16
  17. JWhitmore44

    JWhitmore44 pistolero

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    I know the lever on the clutch actuator is a bit short, but that usually causes a stiff clutch pull. I have heard (think it was thumper talk) of folks extending the that little lever. It may make the throw a littler longer but it sound more like you have a worn clutch. I assume you are getting close the the end of adjustment? it's not a stretched cable is it?
    #17
  18. truck6driver

    truck6driver The Fireman

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    Hey folks,

    I bought an 08' for my son a week ago. It had what I thought was rocker arm noise that ended up being piston slap. So I pulled the top end and found a galded piston, well crap. The kicker is I accidently dropped the cam gear washer behind the flywheel. I pulled the side cover but could not see the washer. Using a puller I attemped to pulle the flywheel off. the puller ended up bending the threads of the crankshaft. Now I have an engine that needs a piston and a crankshaft.

    Is the crankshaft really that soft? Has this happened to anyone else.

    No aftermarket crankshafts and a new OEM one is $300 :eek1


    Any help would be appriceated.

    Ray
    #18
  19. Cpt. Ron

    Cpt. Ron Advrider #128

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    Sounds familiar.....

    Yes, the crank is that soft. When I did it to my son's bike, I ground down the end of the crank shaft so the flywheel would slide back on easily without screwing up the tapered finish of the flywheel. I then machined down the left side of the inner hub of the flywheel so that the thread of the bolt would engage again. I believe I ended up removing something like 1/4" of steel. Bolted it back up and off we went.
    #19
  20. Baconologist

    Baconologist Been here awhile

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    bump and old dead thread. But I don't know where else to ask this.

    Has anyone done SUMO wheels on a TTR 125 small wheel?
    #20