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Cr 500 supermoto/roadrace

Discussion in '2-Stroke Machines' started by XRACER510, Aug 13, 2009.

  1. Tdub

    Tdub Say what???

    I have built a few...:up:
     
  2. yam rookie

    yam rookie Member

    @ 60:1 im sorry to say, you were very lucky not smart. You got a gift, not to melt that motor. I persopnally have done some shifter kart racing, and nobody runs a 60:1 ratio. or for that matter a 32:1 ratio. Most if not all run 20:1, although some run 24:1
     
  3. funfetti

    funfetti Banned

    60:1 was for MX only if you read through the other posts...for supermoto it says 20:1 like the kart motors.
     
  4. L.W.

    L.W. Well-Known Member

    CR 500

    GREETINGs, For -WFO- riding, your mix needs to be 16:1 to keep from SEIZINGs :tut: L.W.
     
  5. goldman812

    goldman812 Well-Known Member

    the one i built and roaraced never had any issues with the motor.. i only had vibrating issues. i did have a wide ratio tranny and i had to custom make the sprockets to get enough top speed. it was plenty fast, just vibrated to much to ride hard for more than 3 laps.
     
  6. L.W.

    L.W. Well-Known Member

    cr500

    GREETINGs, Did you have the CRANK -BALANCE-:confused:
     
  7. ducati366

    ducati366 Member

    very interesting thread! i keep coming back to read further input.
    Also i'm impressed about the fact that it has NOT HEATED UP !... it is a 2stroke Motocross Vr Roadracing related conversation..lol.
     
  8. Matt399

    Matt399 Well-Known Member

    I want sooo bad to build a CR500 or KX500 in a TZ chassis, but everyone who's done it says it is definitely NOT worth the trouble. I don't wanna race a bike in supermoto trim and don't wanna super single-style a 20 year old steel frame; however, a super single CR500AF or KX500AF (aluminum frame conversion) would definitely be a SV killer in the right hands if it won't vibrate itself to pieces. Anyone have any experience with one of these on a road race track? How bad are the vibes? With the aluminum frame I mean.
     
  9. KrooklynSV

    KrooklynSV Usual Suspect

    There's a guy that did a CR in an NSR250 frame. Ah, HERE IT IS.

     
  10. goldman812

    goldman812 Well-Known Member

    no, i sent the crank to falicon and they said they could not balance it as it was a lead filled crank.
     
  11. goldman812

    goldman812 Well-Known Member

    Matt, read my reply on the first page of this thread. i built a cr500 in a roadrace ns400 frame. it vibrated alot.
     
  12. L.W.

    L.W. Well-Known Member

    cr500

    GREETINGs,Well I'am building one now,Been RESEARCHING it for two years. The KX500 is the way to Go. Need to use an STEEL frame,and BALANCE the crank...,cr500-rod,..custom made piston with smaller cut outs,.and two 1/4" snake eyes, cut in the back,of the piston...16:1 oil mix...well there is more but this the BASIC.....to get it started,,,,KXRiders.com will answer alot of your questons?? SEE you all in the SPRING,,, GO GREEN K5.........L.W.
     
  13. Matt399

    Matt399 Well-Known Member

    Yeah I saw that I was asking if anyone has tried road racing one in a newer CR250 or CRF450 aluminum frame and if it's any worse than the stock frame as far as cracking stuff. Stories of welding pipes and motor mounts is what scares me!

    I assumed the problem was with trying to road race one, regardless of the chassis it's mounted in, but it seems like the guys road racing them in stock frames aren't having the same issues. That's what got me thinking CR500 aluminum frame super single.:rock:
     
  14. Matt399

    Matt399 Well-Known Member

    Good info, keep us updated on the build! Have you looked into the aluminum frame conversion for a road race application?
     
  15. beechkingd

    beechkingd Well-Known Member

    What would the advantage of having an aluminum frame? I would think with all the vibration issues mentioned that you would want to have a steel frame bike.
     
  16. Matt399

    Matt399 Well-Known Member

    I was thinking weight, stiffness, and geometry would be better. However, I was just browsing kxriders.com and it seems the steel KX frame is actually lighter than the aluminum ones (according to a guy that weighed both) and the geometry can be changed anyway so I think you're right. I just like the super single 450 idea but they're slower than my SV and I think a 500 2 stroke engine would fix that!:beer:
     
  17. goldman812

    goldman812 Well-Known Member

    to know the potential of a cr500 roadracer, look at rob tulies bike called the tulda. he made that bike and he says it has no vibration issues and is reliable and fast. he has won many championships on it.
     
  18. 418

    418 Expert #59

    You sure about that?


    A single cylinder motorcycle is going to vibrate. The way Tuluie has delt with the vibration was to put it where he wouldn't use it--at idle. The Eccentric vibrates a lot at idle and smoothes out at 5,000 rpm. Through the power band (from 6,500 to 9,000 rpm) the bike is "supersmooth" according to Rob. "TZ250s shake more." A TZ250 is a twin. The Tul-da redlines at 9,500 rpm.

    I assume he had the crank balanced to work with in a rpm range, so he didn't get rid of the vibration, he just moved it around to RPM where he used the bike least at.

    http://www.motorbyte.com/mmm/pages/bikebuilders/tulda12_96.htm

    Though at one time I thought it was, I personally think the 500 idea isn't worth the hassle.
     
  19. VFR#52

    VFR#52 Well-Known Member

    Maybe you should have tried to balance the crank! I have a 98 Cr250 framed 500 that i built! It was a paint shaker!!LOL,So i balanced the crank and man what a difference!i love mine! Never at a loss for power and with a big nasty flywheel weight it so easy to ride fast or slow! I did all the motor work and its way faster than all those 450s out there!Later!

    Steven Isenhower VFR #52 2001 V-6
    2nd Sucks Racing
     
  20. goldman812

    goldman812 Well-Known Member

    well he says no vibration at rpm where he is riding it. of course a single 500 will vibrate somewhere.i do agree with you about a single 500 roadracer not being worth the hassle.i have a 1996 rs125 and its way faster (unless your rob tulie and a rocket scientist like he is.)
     

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