Custom XR100R SuperMoto

Discussion in 'Mini Racing' started by apexspeed, Feb 4, 2014.

  1. apexspeed

    apexspeed Well-Known Member

    who wants this?


    I havnt rode it in over a year now! its one of Yates's old bikes, I got it from his buddy Jason.

    its actually a 2000 but I retro'd it with '85 plastics. running great and in top shape last time I rode it. I drained the fuel out of the carb at that time but I havnt started it since so it may need to be cleaned.

    it has a CBR900RR fully adjustable rear shock that utilizes the stock Pro-Linkage and slightly modified OEM XR80R front forks., the rims, chain, sprockets, swingarm, r.brake rod, cylinder head (smaller combustion chamber), camshaft (higher lift) are also from XR80R. I have a 100 swingarm and front rim but no rear rim.

    engine/trans is good and has +.050" piston, the good carb (from ATC250R I think it was) Iridium S.Plug but otherwise stock and stock trans. has Engines Only billet from mount.

    wasnt smoking or leaking anything last time I rode it and I always kept Everything in top condition. also added a grease fitting to the swingarm and only has mobile1 grease thoughout. make me a reasonable offer. more pics if needed (got some nice action shots too)
  2. backcountryme

    backcountryme Word to your mother.

    Ok, how do you get a CBR shock on this? I need something for my XR
  3. apexspeed

    apexspeed Well-Known Member

    I didnt do this one or the other one that had an RGV250 shock on it I sold a while back but its easy. remove the top shock mount and relocate to accept the desired shock. make sure to factor in ride height.

    the lower end can bind on the swingarm on some shocks depending on the lower mounting holes and their position related to the outer coil diameter so its nice to have a few swap candidates to chose from.

    other guys have chosen not to modify the frame and instead modify the swing-arm eliminating the pro-linkage which would be fine for flattrack or roadrace but thats not the way togo for supermoto duty with adult riders.


    this one has never bottomed out with me even when flatlanding it but I tend to land rear wheel first so the front has never been a problem there either.
  4. nitto182

    nitto182 Well-Known Member

    yes, how??
    but it wouldn't be spec legal anymore...
  5. backcountryme

    backcountryme Word to your mother.

    What those spec class Nazis don't know won't hurt them. Ha. Wait, I am an executive now. Damn
  6. apexspeed

    apexspeed Well-Known Member

    Location: E. Metro ATL Georgia, outside 285

    If you cant DIY I could probably be persuaded to do another shock mod.

    I have a stock bare frame I might turn loose of with some persuasion but it would be a shame to use this machine as a donor for a spec bike.

    alot of attention to detail on this one. no bad threads anywhere or strange cracks or anything like that. I utilized all the best parts from several others when I rebuilt it. Im sure its in better shape than most.

    it just looks "old" because I think the originals ('85 & 6) look better than all the ones that came after including the current CRFs but Im Old School..

    what are the "specs" for the spec class anyway? probably different for each org, right?
  7. backcountryme

    backcountryme Word to your mother.

    our rules are stock everything. a shock swap would be against the rules. I have an 86 by the way
  8. TurboBlew

    TurboBlew Registers Abusers

    Any paperwork with the bike?
  9. apexspeed

    apexspeed Well-Known Member

    glad you asked! I can only provide a bill of sale. we dont need anything here except a Bill of sale for dirt bikes and even older street bikes/cars/trucks so for anyone outside Georgia you might want to check for yourself.

    I guess thats the kinda paperwork you mean? otherwise.. got lotsa phone numbers ;-)

    edit: the EIN & VIN are stamped, legible and un altered FWIW
    Last edited: Feb 5, 2014
  10. dont621

    dont621 Well-Known Member


    Check PM
  11. vdub 2.0

    vdub 2.0 Well-Known Member

    Where are you located
  12. apexspeed

    apexspeed Well-Known Member

    see post #6

    rolled it out today, started but wouldnt idle (pilot jet) cleaned it and ran fine but idle still not perfect, it would idle but if you let it idle for several minutes it would slowly go down and quit so I pulled the ATC200R carb off and put the XR100 carb w/102 main back on and a new air filter and it runs and idles great.

    rode it a bit and decided to put the TW8 & 9 trailwings back on it (lighter and more useful and easier for novices to ride)

    I have several others to ride and dont do much mini supermoto (jumps) any longer so its still available and will include the take offs.
  13. sharky nrk

    sharky nrk Rubber Side Up

    I have bits of a xr80r (complete head), is there any real gain in swapping these guys over?
  14. backcountryme

    backcountryme Word to your mother.

    The XR80 head will bump compression (bolts right to the XR100), but the valves are a little smaller. I have heard of quite a few guys doing the swap with good results. I don't think the smaller intake is that big a deal, but the smaller exhaust is a bit restrictive. Although, unless you are running an aftermarket pipe it shouldn't be that bad. The stock XR100 pipe is a real weak link on these engines. An easy mod for the XR100 is to remove the base gasket completely. This will give you a free compression boost. I have done this and had no issues.
  15. apexspeed

    apexspeed Well-Known Member

    thats not correct, the valves are the same size but the ports are smaller. the ports can be opened up easy enough though but what I have noticed (by seat of the pants) is that the 80 head and cam move the power up slightly higher in the rev range and allow slightly higher revs.

    no dyno proof, just the way it feels to me but if you have ridden a stock 80 and then 100 back to back you will notice the 80 revs much higher than the 100 even though they both have the same stroke. by the same token the 100 has much more bottom end grunt.

    which head is better depends on alot of variables. rider preferences, track layouts, etc.

    its easy enough to swap them out and worth a try.
  16. backcountryme

    backcountryme Word to your mother.

    My bad, you are right it is the ports that are different. I got that mixed up. It has been a while since I looked at getting the 80 head.
  17. Kurlon

    Kurlon Well-Known Member

    From what I recall, the real poor man's hop up is to toss the OEM head and graft on a Lifan 'BVH' from a pitbike (or a comparable Chinese unit). Flows WAY better even before you break out the porting tools.
  18. backcountryme

    backcountryme Word to your mother.

    I thought it was quite a chore to make that work.
  19. Kurlon

    Kurlon Well-Known Member

    It's not a bolt on, but it's doable.
  20. backcountryme

    backcountryme Word to your mother.

    Care to share? That might be interesting for a Formula bike I am working on.

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