Yamaha TTR250

Discussion in 'Thumpers' started by Tex_Aus, Jan 23, 2011.

  1. LC Garage

    LC Garage On Any Sunday

    Joined:
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    793
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    Just bought a used Scotts dampener off ebay, it appears to be from a road bike as it seems to dampen in both directions, but I did get a great deal ($91) and have heard varying opinons on using one way or two way dampening. The main thing I was looking for was to prevent crashes similar to last year where I hit a rock and the bars were jerked out of my hands. Here it is;

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    I'm planning to mount it "sub" style or under the bars and will be ordering a kit from Scotts. :D
    #21
  2. LC Garage

    LC Garage On Any Sunday

    Joined:
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    A few weeks ago, I called Scott's and explained what I was working on and that I had bought a used dampener off of ebay. They started asking questions like "what do the knobs look like?" and "what is the serial number?" and after further discussion and research they concluded I had a 1996 dampener that had not been serviced in at least 8 years. They could tell the age from the serial number and the time since serviced by the old style knobs that should have been replaced when last serviced. :eek1

    They said they could help me, but the first thing was to get it serviced. They also did some research on mounting and after having me take measurements concluded that they were only going to be able to help with mounting it in the upper position, not the sub mount as hoped. Oh well, no big deal. By the way, the Scott's guys were extremely helpful and encouraging thru the whole process. They were great! :D

    So off goes the old dampener in the mail and a few weeks late comes back looking very pristine, with all new brackets and hardware for TTR 250. Cool! :clap

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    Stock look;

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    Removing stock upper clamps;

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    New components loosely in place, cross bar not wanting to roll over dampener;

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    Cross bar loose on one end;

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    With cross bar loosened, bars rolled right into place, and cross bar was re-installed. Snug fit but just enough clearance to work. Those guys at Scott's know what they are doing.

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    Weld on style post, slightly too long, will shorten and weld onto upper frame backbone (Phase 2)

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    Steering stops will need to be modified, as they are now, too much rotation for the dampener, and as Luke said "you don't want your dampener working as a steering stop". Any creative ideas to reduce rotation? If nothing creative pops up, will probably just weld some material onto the lower frame stops.

    [​IMG]

    Cant wait to get this completed, as soon as this is done and the new gel battery installed, she'll be ready tear up the trails! :D
    #22
  3. tdvt

    tdvt Been here awhile

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    Thanks for taking the time to post the pics, let us know how it functions.

    Probably a number of folks watching this as I found it through the TTR forum even though I've got it subscribed to here.

    I don't think I could find it, but in researching WR/YZ to TTR fork swaps I saw a nice photo of some steering stops that were modified by drilling into each stop (on the side towards the middle) tapping the hole & adding a small socket head bolt.

    That way they were somewhat adjustable too.

    I recently picked up a WR exhaust to try (there are a few posts of another installation on the TTR forum) Nice & light, hopefully not too loud.

    I'll post results when I get to it.
    #23
  4. LC Garage

    LC Garage On Any Sunday

    Joined:
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    In the first phase, I was able to fit up the dampener and get a rough idea how it all fits together. Phase 2 is the location and mounting of the weld on post. Start by removing fuel tank, seat and anything directly in the way.

    Before;

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    After;

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    Careful measuring showed I would need to remove .50 inch from the post;

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    Post length before;

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    Post length after;

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    Cut accomplished with Luke's cut off saw;

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    High tech locating system for spot weld consisted of black tape, wood screw and gravity;

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    Spot welded in place, needed to be fairly vertical (side to side and front to back) and the tip of the guide post centered in dampener arm. Not perfect but serviceable;

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    Next step is to disassemble for finish welding. Tacking is ok assembled & neccessary for locating parts, but the full weld process would burn up bearings, seals and possibly the wiring.

    Before disassembly;

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    After disassembly;

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    I still need to remove the ignition switch before welding, but did not have the correct torx bit for that. Phase 3 will be finish weld, touching up the paint, and reassembly. Not sure if these handlebars are going to work, the center bar clears the dampener but does not allow the slow speed adjustment to fully rotate. Also am considering going through the fork legs while they are off. Pondering installing "gold valves", anyone have experience with installation and performance improvement with them?
    #24
  5. LC Garage

    LC Garage On Any Sunday

    Joined:
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    After this weekend, the dampener project is nearly completed. I'd thought about doing the finish welds myself, but as Luke is getting lots of Tig practice on his MK1 project, it seemed like a better idea to have him do the finish welds. Got home Saturday afternoon and had a pleasant surprise:

    Luke & TwinDuro after finish welding the post and welding on steering stop tabs;

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    They had made the steering stop tabs plenty big, to allow material to be removed slowly and check clearances as the tabs got smaller and smaller. Earlier it had been determined that the post itself was almost in the right position as a stop to protect the dampener, but of course you would not want the upper triple hitting the post instead of the stops as you would bend and/or eventually break it. Almost 5/8" between post and upper triple to start. Ideally this clearance will be closer to 3/16" when completed. Note tab is marked for first cuts based on measurements. Each round of cuts and grinding required the triple clamp, fork stem and one fork leg to be rough assembled for checking clearance.

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    After first rough cut;

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    Still too much tab;

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    This after the third round of cuts and grinding, clearance appeared ideal;

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    Note: not much tab left!

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    Front end rough assembled with dampener, confirmed two things; first, that the upper triple has adequate clearance both directions and two, that the steering stops will prevent the dampener from bottoming out. Mission accomplished!

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    Last step of dampener project will be to disassemble, clean everyhting up, touch up the paint and final reassembly. :D
    #25
  6. TimCC

    TimCC Been here awhile

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    Looks great. I'm happy that you're doing this. I've been dreaming of adding one to my TTR. Make sure to give us feedback on how she rides with the new addition.
    #26
  7. Krazyjohnny

    Krazyjohnny Been here awhile

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    My wife I went out to ride today at Lake Murray. Her TTR 250 just up and quit running. We found out the gas cap breather valve locked shut. I just unscrewed that mechanism and removed the one in the breather tube and all was good to go unitl the rain soaked us.

    It is all good.
    #27
  8. LC Garage

    LC Garage On Any Sunday

    Joined:
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    All taped up and ready for paint;

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    Painted with an automotive metallic blue;

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    Yikes, the color on the paint can was a much closer match than this! :puke1

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    I realize that it's just a dirt bike and most of this will be covered, but I just had to get the paint a little closer to stock. Here was my last attempt;

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    This is after the 4th different can of paint, ended up using a very ordinary navy blue. Best match found and this time I felt was acceptable. Stem is in foreground, starting to get serious about cleaning everthing up in prep for final assembly. This is when things went awry. :huh

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    While cleaning the paint and gook off of the bearings and races, I took the first good look at the lower race after the weld process and it wasn't good. I'd mistakenly thought that the heat of the TIG would be low enough to not harm the race. Definitely damaged and needs replaced. Kicking myself for not knocking the race out before welding! :cry

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    Will pick up new a new lower bearing and race this week (& probably a set of handlebars), would really like to have this rideable by next weekend. Already have the new gel battery, and other than possible suspension upgrades, am nearly ready for the first XC in March.
    #28
  9. LC Garage

    LC Garage On Any Sunday

    Joined:
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    Today's mission; get the bike together and running!

    Started with this;
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    And this;
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    Bearing kit from All Balls;
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    Started with cut off wheel and removed cage and rollers;
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    Then used the cut off wheel to groove the inner race;
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    After additional cuts and grooves, a chisel was used to crack the race, then it just fell off;
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    After removing all traces of grease (and before my wife could stop me) into the freezer for a cool down;
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    And the new bearing goes onto the wood stove to be warmed up:
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    After setting the lower seal in place, used the old inner race (upside down & with an assortment of washers stacked on top) to drive the warmed up bearing onto the cold steering stem (with a length of pipe);
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    All cleaned up & greased;
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    Steering stem back in place, not shown was driving the new bearing cup into the lower steering head;
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    Fork legs and wheel;
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    Front brake and speedo cable;
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    Cables & wiring, should have paid more attention when disassembling, had to take the headlight and speedo off a couple of times before all the wires and cables were properly in place;
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    Getting there, took my time getting everything just right, so far it looks like I may be able to get by with these handlebars, I did rotate the cross bar back so that the low speed adjuster can be rotated a full 360 degrees;
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    Out with the old battery that lasted barely a year, in with a new gel battery;
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    Ready to button up;
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    Fired up almost instantly;
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    After all the work it felt great to ride her again! :clap
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    Now that it's rideable again, I can tweak, tune and practice, our first cross country event is on 3-17 and on 4-6 we have the Stump Jumpers D100. Can't wait! :D
    #29
  10. AfricaWim

    AfricaWim Been here awhile

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    Bought one of these earlier this morning for my son to use on outrides.

    Needs some work but we will sort it out in time. She's a heavy old girl and I struggled somewhat to get it loaded....but surprisingly quite lot more performance than I expected TBH.
    #30
  11. LC Garage

    LC Garage On Any Sunday

    Joined:
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    #31
  12. tdvt

    tdvt Been here awhile

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    Sounds like you held your own & the TTR made it out alive. I am on a suspension kick at the moment trying to figure out where to start, so feel free to share any insights or impressions.

    Looked like fun!
    #32
  13. LC Garage

    LC Garage On Any Sunday

    Joined:
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    I am definitely struggling with the question of how far to take the little TTR, where is the line when you look for a purpose built machine and stop putting money in? As a trail or even true enduro bike (this race was just a giant hi speed mx track, not really an enduro) the TTR really shines. As I rode the other day, was trying to objectively sort out the pros and cons and here are the pros; excellent transmission and brakes, love the electric start, very comfortable. The cons; suspension, weight and horsepower. I would have to give the steering dampener a big thumbs up, just because my arms were not fatigued nearly as much as I suspected they would be and also the sense of confidence when riding through the rocks.

    Suspension can be fixed, whether you go with a set of YZ forks or maybe just the gold valves & springs and have rear shock built and sprung, horsepower can be massaged a little, not much to be done about weight. We are going to practice this Sunday and I will be trying out my buddies KTM 300 and may end up riding that a the St Patty's day event.

    Haven't given up on the TTR yet, just trying to be realistic about its intended use will it be up to the task. It is also part of the equation to figure out if I am just getting slower and more cautious, but riding the KTM 300 should give a bit of a measuring stick for that concern as well. :wink:
    #33
  14. sanjoh

    sanjoh Purveyor of Light

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    Better get the checkbook ready:D You will want er need a KTM 300 after the first 5 minutes on it:deal
    #34
  15. tdvt

    tdvt Been here awhile

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    That about sums it up for me as well.

    But I'm not there yet as I can't really justify the expense of another bike & I'm too stupid to stop tinkering.
    #35
  16. tdvt

    tdvt Been here awhile

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    LC, You might enjoy this video if you haven't seen it & check out the front end of the bike.

    VIDEO

    Turns out Geoff Ballard (Big time Aussie racer, ISDE medalist, etc.) runs TTR forks on his WR & it seems others on his race team use them from time to time as well. Found it during all my Google-ing TTR suspension, also posted it on TTR site.

    Love to know what the mods are.
    #36
  17. LC Garage

    LC Garage On Any Sunday

    Joined:
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    great video, he hauls A$$ on that bike! :clap

    never thought I'd see a world class competitor (nowadays) with old school forks, but there they are!

    thanks for sharing this info, definitely food for thought...:thumb
    #37
  18. LC Garage

    LC Garage On Any Sunday

    Joined:
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    Recently joined the OMRA and received my number, it is the same as before but with different colors and letter designation (old T98, new is 98Y). Have been working like mad on the motor home, helping with Luke's MK1 bike and assorted other stuff, so needed a break to do something fun. Putting on new numbers would be fun and still be forward progress. BTW; TTR vs. something new, enjoyed riding the KTM 300MX as well as the CR450X, but the TTR is my bike and I'm not wanting to buy or borrow right now, so am going to forge ahead and ride and race this bike until I can make up my mind on the ideal bike(s):lol3.

    Before, with old numbers and the add ons from the cross country team race;
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    After using heat gun to peel off all the old stuff, (the heat gun worked really well!);
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    Bought a kit with yellow backgrounds you cut to shape, installed those and then mocked up the numbers/letters;
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    Completed;
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    Now she's up on the stand waiting for fork oil change and reinstall of old handguards. The old brushbusters were on the handlebars when I crashed last year and dont fit the new bars and I'm just too lazy to modify them right now. Only 9 days until the Desert 100. :D
    #38
  19. LC Garage

    LC Garage On Any Sunday

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    After reading quite a few interweb posts on TTR250 handling and what fork oil, what height, what method, blah blah blah, decided to get the fork oil changed and see for myself what kind of effect it might have on the handling.

    First, removed the front wheel and dropped the left fork leg. Dropped it down where I could reach the upper cap and loosen before removing leg;
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    First leg was critical as this was going to be my learning curve and no manual. Luckily Luke was nearby to offer a few tips and pointers. Put the leg in the vise (with wood blocks to protect) and dismantled upper cap from dampner rod, spacers and spring;
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    Then I carefully tipped it into a clean coffee can, so I could capture all the old fork oil and measure;
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    Approximately 425 cc's of fluid;
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    The plan was to put approx same amount of fluid in as came out and measure oil height, then go from there. Various accounts on the always reliable internet stated oil heights, depending on application and desired results, should be from 130 mm to 150 mm.

    Highly technical measuring device ready for action, made marks at 130, 140, 150 and 160 mm;
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    Decided to start with 450 cc of Honda 10 wt fork oil;
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    After carefully pouring in the oil and then moving the dampner through multiple cycles to clear air bubbles, measured the height. It came in at 165 mm. Added 50 cc's and remeasured, this time it was at 135mm. This was pretty close to what I'd read as the maximum oil height and decided to stop there. It was also a nice even number to remember for future use, 500 cc = 135 mm oil height. This may differ from bike to bike and also how much of the old oil you are able remove.

    For reassembly, you will need to attach a piece of bailing wire just under the top nut on the dampner rod. Trust me, you need the wire!
    [​IMG]

    Now assemble the spring and spacers, then the top cap;
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    Screw it all together, slip the fork gator back on (not shown, after draining the leg I found the gator was in the way and should have been removed from the start, makes it easier to handle and also to wipe down and check fork seal) and slide part way into the triple calmp, tighten the top cap and then reassemble. Repeat on right hand side. Note: I cheated on the right side, saw no reason to go through the whole measuring process and skipped the top cap and spring removal steps, just took the cap loose, allowed leg to collapse, put a stop in the spring to keep the leg from collapsing downward and stood upside down in the coffee can and let it drain for a good long while. Stood it back upright, deflected the spring to one side and very carefully poured in 500 cc of oil. Reassembled. Done.

    [​IMG]

    Ride report in about two weeks. :D
    #39
  20. tdvt

    tdvt Been here awhile

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    Again, thanks for taking the time to document the process. This is something that I have thought about but have been putting off.

    We still have a few weeks of thawing out left to go here but it is finally getting warm enough to do some work in the garage without being miserable.

    I have not finished my WR exhaust install, the one I got was from a much newer bike & was shaped differently the the swap I'd seen. I also just received a few OEM jets to try as I've never been completely happy with the carb since I got the bike running. Is yours running the stock US sizes?

    So, I've got a good list & hope to get to all this maintenance stuff before there's bare ground to ride on.

    Look forward to your ride report regarding the front-end.

    TD
    #40