2000 RS125 intro and questions

Discussion in '2-Stroke Machines' started by vance, Sep 25, 2017.

  1. vance

    vance *

    Just picked up Scott's 2000 RS125 and plan to have it out next weekend for a track day. I'm sure I'll have lots of questions and will be looking for lots of parts, as I'm a "planner".
    USPGRU
    RS Cycles
    TSO (just ordered my starter tool)

    Any other sources appreciated. The long term plan is to learn the mechanics of the motor, mesh with the bike and start looking for a 250. I had a tz125 7 years ago, made the mistake of selling it and have spent the last 7 years trying to turn turd street bikes into proper race bikes. Will keep and ride said turds, but if the idea is to go fast around a corner, an EX500 ain't the way to do that. :D
     
  2. zrx12man

    zrx12man Captain Amazing

    We thrashed about with our first RS125 trying to "make it faster" for about a year until a friend told me the secret is to get it as close to stock factory spec as possible and follow the factory service manual meticulously. We won a lot of races and set lap records with very conservative jetting and timing and no porting work. Actually, I only jetted "to the limit" using a det counter for 1 weekend out of 4 years running 125's. They are amazing machines right from the factory.
     
  3. dave3593

    dave3593 What I know about opera I learned from Bugs Bunny

    Most of my parts for my TZ250 come from Accu-Products in Ohio and Fondseca in the UK. Both have been very good. Also TZ250.com is an excellent help for technical assistance that includes Honda GP bikes.

    I recommend a 250 Yamaha instead of Honda because of parts availability. Also buy a 250 soon because they continue to go up in value.
     
  4. vance

    vance *

    Thanks for the reply, Captain. :beer:
    The bike has had some things done to it, but one major reason for the purchase was to learn to be a mechanic, so I'll leave well enough alone until the next service interval or I break something. I'll then start to move it back toward factory spec while learning to work on it. At 5'10" 170lbs, I don't plan to set any lap records, so the bike will be set up very conservatively.
     
  5. vance

    vance *

    Thanks Dave for the links, want to use this thread as a catch-all for sources. I'll need to clear out a few more bikes in the garage and convince the wife that an early purchase is a better "investment" :D
     
  6. NOLAracer

    NOLAracer Well-Known Member

    I'm 6'1" 180lbs on tz125 so I'll be right there with you.
     
  7. vance

    vance *

    giraffe on a unicycle :D. Man, this is gonna be fun and TZ250.com is a dangerous site. I foresee vast amounts of money leaving my possession :beer:
     
  8. NOLAracer

    NOLAracer Well-Known Member

    TZ hoarders are just as bad if not worse than the the Fzr400 guys.
     
    britx303 likes this.
  9. vance

    vance *

    I like to think of myself as a planner, not a hoarder :D I'll dig into the spares box this weekend, but I think I'm good for a few seasons with the 125, assuming I don't blow anything up.
     
  10. britx303

    britx303 I H8 HIPPIES.com

    Heeeeeyyyyy..........ok you gotta point:p
     
  11. expat

    expat Member

    Don't wait for it to blow up. Stick the the maintenance intervals. I push a top end an extra 50 miles or so and the bottom end an extra 250ish but check every time out for crank play etc. (feel for play on the generator side nut)
    As others have said, stock is best for reliability and take meticulous care with the rebuilds.
    Have fun, oh yeah and join a yoga class!! You will see why after your first session on it!
     
  12. vance

    vance *

    Yoga may not be a bad idea :beer: Holy cow that's a lot of moving on the bike, and I think I shifted more at one track day than I do over several weekends, no joke. Will take some time and the loss of 10lbs or so to help get comfortable on it.

    Had a blast this weekend and the seller met me to go over the bike. Spent the whole day showing me his typical day at the track.

    What should I be "feeling" when checking for crank play?
     
  13. expat

    expat Member

    Any slight movement. The LH bearing usually wears the most. If you feel anything at all, tear it down. The play will ovalize the bearing pocket quickly if left unattended.
    Shifting is a serious work out. Don't be frightened to slip (read abuse) the clutch to keep it in the power band.
     
  14. vance

    vance *

    Interesting weekend. I'm at the track with a long time friend who is a motorcycle mechanic from back home and the previous owner of the bike. You 2T guys are meticulous. :beer:. I'm scared to ride the thing. :D Regarding "abusing the clutch", at the end of the day, we are loaded up and getting on the road, my buddy turns to me and says, "Dad's put their 10 year old kids on these bikes, and there're certainly not checking the temp gauge. Wring the sh*t out of that thing, it's a real race bike for crying out loud." :crackup:
     
  15. nantahala

    nantahala Well-Known Member

    x2 on everything here. Stick to the manual, keep the setup simple, have fun, learn to ride it, flog the clutch, take ibuprofen. :)

    Matt
     
  16. nigel smith

    nigel smith Well-Known Member

    My ten year old kid failed to check the temp gauge once. The ensuing cold seize made him much more conscientious going forward.
     
  17. vance

    vance *

    Touché. It will definitely take some effort to get the timing right to roll out for the warm-up lap at around 40°. Doing it at a track day was easy, I just rolled up to pit out and sat there for a minute.
    My friend's broader point was that I could very easily put this in the garage and admire it, but it will likely take what a 42-year-old novice racer can dish out.
     
  18. nigel smith

    nigel smith Well-Known Member

    You will soon develop a feel for how much tape to put on the radiator. Apply it vertically right in the centre and it does double duty protecting the radiator from road debris. The little RS is pretty dependable if you follow the maintenance schedule. I loved ours, even more so after running an abomination of a Moriwaki.
     
  19. expat

    expat Member

    Another tip, put a heat cycle into the motor first thing in the morning. The heat takes time to dissipate even on cold days so usually, restarts can be done without the choke even on cold days and the motor gets up to temp quicker. I will roll out for a warm up lap at nothing below 38 degrees, prefer above 40. Create a tab at the top of the piece of tape on the radiator about 2" long. It makes removal with gloves on possible if necessary. On the grid or at a pit in if at a track day.
     
  20. vance

    vance *

    Scott, the previous owner briefly went over the tape on the radiator. Temp below 40, don't go out. Temp above 60 shut it off. Being in Florida the majority of the year will help with the low temp. Once choked and started in the AM I should be good the rest of the day. It was a pretty hot day Sunday and it ran at 56-57 all day.
    I still can't bump start the thing. Had to walk it to my pits after a red flag because I couldn't bump start it. It's an art, I'm sure. Operator error on my end.

    Tape on the center is a good idea for debris.
     

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