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Finally worked on the wife’s TTR125, jetting some tweaks and maintenance

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Well I finally got around to giving my wife’s 02 TTR125 a little attention. I haven’t done anything except routine maintenance since we bought it. What prompted the work was it was leaving a puddle of oil when setting. It turned out to be a shifter leak so I had to change the seal. To keep from damaging the seal, I wrapped Teflon tape around the splines to cover the sharp edges. Once I decided to start, I just went all the way. One thing that I have noticed about dirt bikes, is that most owners never seem to grease the linkages, swing arm etc. So the swing arm shock and brake all got a good cleaning and lubing.

As I was working on the bike I started to look at this post for suspension setup. I have a manual, but it doesn’t say squat. But I did notice a lot posts about jetting. My wife’s bike came with the air box mod (ugly) and a Pro Circuit pipe and T4 muffler. It also took for ever to warm up so I decided to see what the jetting was. The PO had changed the main jet to a 110, but everything else was stock. I dropped the needle clip one notch, but I still had to replace the pilot. Couldn’t find a 17.5 locally, so I dug out my jet drill set. The 15 pilot measured at 0.0125” so I drilled it out to 0.015”. I don’t know how close that is to the 17.5 pilot, but it sure woke the bike up. No more waiting to turn of the choke. You can almost turn it off as soon as the engine fires. The throttle response is almost instantaneous, no bog or hesitation and it feels like a whole new bike.

The last tweak I did was to the shift linkage. My wife always complained that she had a hard time going from first to second. I took a look at the linkage (piece of :banana: ). There seemed to be a lot of play in the pedal (side to side). I took off the pedal and lubed it with moly then measured the shims on either side. I left the inner shim in place and started looking through my hardware assortment to see if I could find a washer that was a little thicker then the outer shim. The outer shim measured 0.040” and I found a washer that was 0.062”. It seemed to work fine until I tightened the Allen fully, then it bound up a little. So I mounted the washer on a magnetic holder and using a flap disc on my grinder I slowly thinned the washer down. When I finally hit the magic thickness of 0.058”, it bolted right up. No side play at all and the pedal moved freely. This improved the shifting immensely.

I then set the sag on the rear shock to fit her weight, I used myself because we are pretty close in weight. I then tightened up the steering a little for a little more stability. For most of the mods she was off running around, so she didn’t really know what I was doing to her bike. When she got home I told her to fire it up and give it a little ride. About a 1/2 hour later she stopped with a big smile on her face. She said that it felt like a whole new bike to her.

One last word, for those of you that do a lot of changing or modifying your bikes, invest in a large assortment of metric nuts, bolts and washers. Not the pre-made up kits, but from the motorcycle salvage companies. They will box up a bunch of hardware and sell it on eBay. Off of eBay I bought a couple of boxes of these (about 20 lbs. each) and I almost always have something that will fit what ever I am building and the cost is usually dirt cheap.

Edited by toomanytoys2
forgot a word

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Nice job! I'm gettin around to workin on my TTR as well. The shift lever solution...Didn't even cross my mind haha. Amazing what a washer er two can do. I can't wait to Re-Jet this beast. Amazing little bikes tho. Good to know the airbox mods (as ugly as they are), and the new jets give it suck I boost, I was beginning to think there wasn't much hope :banana:

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I have three or four TTR's worth of bolts from buying and selling a bunch of TTR's on ebay. I just never got around to selling the bolts. I find them hard to part with. You never know when you need that exact one. Good job on getting all that stuff done. :banana:

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