mini bike building with the kids!

[724wd]

Anybody dig mini bikes?!  I got two mini bikes this summer from a friend who had a stroke.  There's a thread somewhere here in AOG, but let's get to the meat of the discussion.

Winter is deep here in the inland northwest so I thought I'd get to work! My daughter and I removed the little Briggs from the Muskin frame and pulled the wheels to check bearing and tubes and such. Also yanked the throttle as it's cracked. Yesterday I bought a HF Predator 212 for it. I've got a pile of Briggs 5 horse motors in the garage now, but I want this one to progress a little faster than if I needed to rebuild an engine, too.

Someone welded a bike sprocket next to the original, so we'll grind that off and get it out of the way. Also thinking of going to a larger front wheel/tire (has a 4.10-3.5-4 now). I see there's not bushings in the fork head tube, so I'll pull the fork and grease it up good. Adding bushings would mean either welding on a larger head tube to keep the fork bolt the same size, or reducing the bolt size, something I'm not sure would be a good idea.

Been looking a lot at what parts to get and haven't figured out what kind of gearing to go for. The original sprocket is nearly the size of the rear wheel, which surprises me! seems it might not be built for speed. I'm planning more of an offroad, gravel road rig for the kids. Also looking at tires... WHOA! Too many choices! 4.10-3.5-6 Carlisle knobbies seem to be a favorite, but then I happened upon snow blower tires! Maybe too aggressive? And not speed rated, of course.  I see Snow Hogs are also well thought of. 

Quite interested in a brake kit, as well. I'm thinking a scrub brake might not be ideal for the kids.  Disc over drum? Sprocket caliper over dedicated disc? again, many choices!

The Plan, so far...
Muskin Cat 250 or 300
Harbor Freight Predator 6.5 horse
OMB predator throttle kit
OMB Throttle for 7/8” bars or possibly BMI Thumb throttle/brake handle   
OMB clutch 5/8” bore
Tires   Carlisle stud 4.10x3.5x6
   Kenda Scorpion
   Snow Hog
Tubes
Extreme Gold chain #35
chain master link #35
bearings
Yamaha seat foam
seat shocks
clutch cover
Brake Kit

[7mmstalker]

Those little scooters are a blast!
My strongest memory of riding them is the many times going over the bars due to lack of suspension for the speed !

[Boss .300 winmag]

Nice project, some fun times to be had soon. Those little bikes leed to these. My son started out on a Mini KTM 50, now he's in college in Arizona, the pic was from today's ride.

[Wanttohuntmore]

Many great memories from my childhood!  Mine had only a 2 1/2 hp Briggs.  To get more power my dad ran an extra two sprockets to reduce the drive output.  It would pull wheelies even with adults, but top speed was 15mph, fast enough on gravel and trails, but slow on pavement.  I miss that bike!

[724wd]

ordered up a new front wheel and bearing (going from a harbor freight 4" wheel to better quality 6") and some Kenda Snow Hog snowblower tires.  These tires are popular with offroad mini bikers for their aggressive tread and cornering ability!     Kids should be ready to ride come spring!

[Boss .300 winmag]

Got any progression pics? 

[jrebel]

I've got a little 50cc bike I would sell for $100 bucks if you want to use the parts or get it running.  Needs a little carb work (leaks fuel) and rear brakes.....otherwise ran as of last year.  Might find some good usable parts for you kids scooters if you wanted to part it. 

[724wd]

PM sent

[724wd]

HOLY CRAP!!!!  I got the Creamsickle buttoned up last night.  White vinyl seat, white powder coated wheels... she's a looker!  Took it out front after breakfast and fired it up.  At idle it wanted to take off!  So I did the sensible thing and hopped on.     at idle it runs around 15mph.  The clutch-brake works REALLY good and I stopped in the middle of the street.  Then I cracked the throttle a bit.... and the bike jumped out from under me, front tire looking for the clouds and got thrown to the ground!  I never let go of the handlebars, so the throttle pegged and the bike spun me in a circle, using my right leg as the pivot.  Got it whoa'd up after 360 degrees of rotation  and picked it and myself up off the street.  Knee is twisted, but not terrible, in my expert medical opinion.  This is supposed to be Anya's (she'll be 10 in June) but I don't know.  The clutch is so tight it wants to run off by itself, and the gearing will allow it to climb a tree!     after the maiden voyage/maiden wreck, I ran it back up the street at idle; a bit scared to crack the throttle.   

[Timberstalker]

 

[Fl0und3rz]

Glad you're OK.  Sad nobody was videoing.

[KFhunter]

I need one to scout Elk spots with 

I suppose you can't run these off private property huh, sucks.  Guy (kid) can't have fun anymore.   I used to run all over the country with about anything I could burn gas with.

[BDildine]

sounds like quite the test drive. next time i would recommend some safety gear (ie: helmet with the mandatory gopro attached )

[Woodchuck]

 

[724wd]

you can see the G*&$%#M left grip where my F*&*$%G dog chewed it yesterday 

[rasbo]

awesome topic here,this orange mini bike brought tears to my eyes,my dad bought me one many yrs ago,mine was red..funny it didn't go fast enough for my dad so he put more power to it,the problem was the spark plug ended up being above the frame,first time I slid off the little black seat my world was awakened to the power of a spark plug :chuckle:so he built a seat that covered it..what a blast,we had..great job on the lil bikes

[724wd]

second ride went MUCH better!    as i thought, once the bike is moving, I can open the throttle without going @55 over teakettle.  but it's still spooky.  It's such a small frame and small wheels...    Not sure what I'm going to do.  keep it and wait for the clutch to wear in?  sell it and get something more stable?  time will tell.