Best Mini Bike for Big Bike Training

Discussion in 'Mini Racing' started by NoMad7700, Dec 2, 2016.

  1. NoMad7700

    NoMad7700 Member

    I recently got into the mini moto scene by buying an xr100. I have raced it in a 24 hr race and done a bunch of track days with it, and now am at a decent pace relative to other xr100 riders.

    The goal of getting into mini moto riding is to progress my big bike riding skills. While the xr100 has definitely helped, there are a few things I think it falls short on helping with. The primary areas I feel the XR100 falls short in are trail braking (xr100 has drum brakes), out of corner acceleration (bike has like 5 hp), tire slide feel (the bridgestones either crash right away without warning, or warn by "hopping" instead of a slide like the big bikes), and learning suspension adjustments (eg. what does adding more rebound do to the feel of the bike; this cannot be done with a stock XR100).

    I am thinking of either switching from an XR100 to another bike, or doing upgrades to the XR so it can help with some of these things.

    The main upgrades I would make to the bike are disc front brakes and a big bore kit, and possibly a front end change to allow for adjustable suspension.

    The other bike I am considering is an CRF150, which basically has all of the above upgrades.

    I'm open to other suggestions as well. I will be looking to race the bike as well, to get more racer experience.
  2. RFairbairn

    RFairbairn Well-Known Member

    Where do you ride your 100?
  3. TurboBlew

    TurboBlew Registers Abusers

    which bridgestones are you running?? The 59V tires are the most predictable out there in the 16" variety... Even if you are just being stupid with a ton of lean angle and the throttle on the stop. You can lace up some 17s if you want a wider variety of rubber.

    As for suspension... well its a kids mini bike. It will most certainly teach you about chatter and feel. It can definitely be "trail braked" deep into a corner. You can put stiffer springs on XR for under $150. Changes the soft stock progressive suspension to something much more responsive.
    Which org do you run with? Are you handily winning stock class races??

    Sounds like you want a TTR. Makes the same power as an XR/CRF but has a better chassis to start. You may win a braking duel against an XR... but the XR will ride right back around you on the gas out of a corner. You can also run the 59v tires on a TTR if you get the big wheel model. 16"s front & rear just like the 100. The TTR is painfully slow in stock form.

    The 150r will head & shoulders above either of the above bikes... but you are looking at way more money to turn laps or race on. Plus you have to run warmers, then a generator, etc.
  4. jpence

    jpence Well-Known Member

    I have a kx65 that is set up for road, fun and cheap to set up. Cheap to buy the bike too easy to find them for 500$

    Sent from my SAMSUNG-SM-G935A using Tapatalk
  5. rk97

    rk97 Well-Known Member

    150R is a legit race bike and good for big bike practice.

    ...but it's not cheap. Other than the entry fees, the maintenance and tire costs (combined) aren't that far off an SV.

    you probably want a built NSF100
  6. AshdontcrAsh

    AshdontcrAsh Member

    Keep in mind if you go with a front disc conversion on your xr you will also want to upgrade to 12" or 17" wheels which would make up the bulk of the cost if that's a concern. I personally went went 12's on my xr because my org races only small kart tracks. The '86 Cr80 front end is a direct swap but you need to swap head bearings.

    I also went with a 115cc big bore kit plus a few other engine mods to get a little more from my xr.
  7. NoMad7700

    NoMad7700 Member

    To answer the questions, in order...

    RFairbairn - Southern California.

    TurboBlew - I ride the 16" bridgestone bt45s with the V front. Its gotten to the point that I lose the front and/or rear almost every lap for some reason. Most of the time I catch it, but sometimes I go down. The loss is not a transitional slip like the big bike Pirelli tires I'm used to. It's more of a violent chatter that you don't want (I like sliding the pirellis, hate sliding these bridgestones). I've done the rear and front stiffer springs mod, as well as added some thicker oil to the front, but it doesn't give me any adjustability, which is something I'm trying to learn on a bike. I don't want to waste a big bike track day and/or tires testing something like "what would adding more front rebound do?". I'd rather spend $35 or so and adjust my suspension all day on a mini bike and get a feel for how it changes the bike's handling/grip.

    I don't mind running warmers and a genny. I already do that for the bike bike, so why not do it for the mini bike? The biggest expenses on the big bike I'm trying to avoid are track day fees and tires.

    jpence - why 65 and not an 85? I'm a big guy (6'0" 200 lbs). Wouldn't the 85 fit me better? Do bigger guys ride 65s and are still competitive?

    rk97 - I've looked into the NSR50, but it's a very small bike, and I will be so uncomfortable riding it. I imagine the NSF100 is the same thing, although I have never seen them in person. Do tires really cost that much on an CRF150? I was thinking the major expense would be the top end rebuild every 20 or so hours that's required.

    AshdontcrAsh - That's another thing I should have added to the mod list. I'd probably go with 17s to get those tires choices and not lose the clearance. But if making all these changes, maybe just buy a crf150 and sell the xr100?
  8. Will9465

    Will9465 Well-Known Member

    I have a 150r and a 100.
    The 150 is a mini track bike. Hard brakes and hard acceration. The 100 is slow and has no front brakes. Both are good practice.
    On the 150 it has 17's and the 100 has a 17" front and 16" rear. It works fine with my tires : BT45's. I run the BT45's at 19PSI and they have good grip, I wouldn't complain.
  9. jpence

    jpence Well-Known Member

    I've ridden xr100s groms other small bikes the 65 was the most fun. A 150r would be awesome but a 65 can be had for nothing.

    Our classes support the 65, also our cart tracks are fairly small.

    Rider size makes a difference but fast riders are fast. So not a huge difference. Id think you could be competitive.

    Sent from my SAMSUNG-SM-G935A using Tapatalk
    TurboBlew likes this.
  10. Will9465

    Will9465 Well-Known Member

    Both are extremely fun and will help with the big bike. I think they teach me about sliding the rear more than anything.
  11. TurboBlew

    TurboBlew Registers Abusers

    If you have the stiffer springs both ends ... the bike should be easy to ride fast. Springs & oil helped me from using all the fork travel to maybe a 4" section. Also have the fork legs up through the triples about 20mm. The rear BBR spring on a fresh stock shock works pretty good. I think Robby Bobby put a stock R6 shock on one of his bikes if you wanted to fiddle with rebound & compression.
    Are you riding in the center of the bike? Do you still have the stock handle bars? What you say you are feeling sounds like you arent far enough forward on the bike.
    At the end of a day I get fatigued and sloppy... first thing I notice is I'm way back on the bike and the front is not hooking up. Thats probably the biggest disadvantage over the TTR... the XR is kinda cramped with a stock seat.

    The hassle of dealing with a generator, plus warmers, etc is not my idea of fun. The BTs heat up in a couple laps and work pretty good for what they are. On my old TTR I had 17" slicks... you couldnt even bump start the bike on a cooler day, even in 5th gear it would still be dragging the
  12. jpence

    jpence Well-Known Member

    For the mini forks (kx65) I also jb welded 1 of the compession and rebound holes in the dampening rod. Then put some pvc on the bottom of the dampening rod which lowers the fork height and puts more preload on the sprint. Heavier springs are much better but shortened forks helped a lot with how it sat. Not sure how the xr forks works though

    Sent from my SAMSUNG-SM-G935A using Tapatalk
  13. TurboBlew

    TurboBlew Registers Abusers

    I think a couple guys had mentioned welding up some of the rebound orafices. I kept it simple.
    Funny when you get on a stock bike and try to push it... so much drama if youre heavy! :D
  14. JTRC51

    JTRC51 El Speedy Gonzalez

    What about those Kayo 125cc bikes? Would they be allowed to run with the Groms, XT, etc.?
  15. AshdontcrAsh

    AshdontcrAsh Member

    The cost of the upgrades to the xr would be less than the price of the crf150r alone AND you would still have the added expense of the wheel conversion on the 150r.
    I would suggest you figure out if you want 12's or 17's then decide which bike to go with. 12's for the xr 17's for the 150r. There are a few different options in 12" tires if you concerned about selection.. My xr100 with cr80 front end with 12's

    Attached Files:

  16. sharky nrk

    sharky nrk Rubber Side Up

    ^^ like to know more about that XR
  17. AshdontcrAsh

    AshdontcrAsh Member

  18. sharky nrk

    sharky nrk Rubber Side Up

    ^^ like what you have going on with the foot peg mounts. Looks like you have moved them up with some custom brackets. Are those 70 plastics? Just looks a bit "off" and trying to sort out why lol.
  19. AshdontcrAsh

    AshdontcrAsh Member

    Ah gotcha. So yes, I custom made some brackets and levers for it with some 3/4" and 1/2" aluminum to have more clearance when I was using the stock fork springs. They weren't too hard to fab although I can't use the kickstarter anymore. And the plastics are the original shrouds and tail fender, the seat is a tall seat from ebay and the front fender is a supermoto fender, Acerbis I think..
  20. RFairbairn

    RFairbairn Well-Known Member

    Sounds like you've got your 100 right as far as tires and suspension, what pressures are you running? We run 16-17 psi front/rear. If you're running oem pads with a clean brake drums and newer oem front brake cable, the brakes are ok, and if you're using engine braking, rear brake/front brake together it stops pretty good and lets you trail brake pretty predictably. I would keep the 100 stock and just ride the wheels off it instead of spending a bunch or $$$ on it.
    It sounds like for your weight and what you're looking to do, considering you can ride the 100 near it's potential, the 150r would be the best bet. Find a well set up used one and save some $$$.
    Have you considered a dirt school like Rich Olivers, Cornerspin, Edwards boot Camp Etc……? I think riding the 100's on the dirt will teach you as much or more than riding kart tracks, plus it's an absolute blast..

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