Dedicated Race Bike For The Young Wrenchers

msrfan

Well-Known Member
Sep 17, 2010
1,799
95
48
Southern California
I've been mentoring these kids I met at Donut Derelicts for a while. Max, the leader of the pack has been putting motorbikes together for the gang and teaching them how to build and maintain them on their own. I'm trying to get them to install front brakes and put the loose wires in looms and shorten and clamp all the cables. Basically making them safer and better looking. I tried to get them to the October race and Neil sent me a bunch of Waivers because they range from 13 to 17 years old. I told them I would take them as long as one of the parents who knows all of them comes also and they have read the rules and gathered up all the safety equipment. Well, a few days before the race, Max was being pulled on a skateboard by his friend on a motorbike, on the way to buy a used 2 stroke engine, when he lost control and crashed, breaking his collarbone. So some of the other guys called me and wanted to go race anyway, no waivers, no parents on board and very little preparation. Needless to say, it didn't happen.
The kids thrash their bikes all week, or until they break, and fix them as needed. John at Banzai Machine and I help them to make repairs that need more than they're capable of doing.
So I'm making them a race only bike so when it comes time, it won't be broken. I'll take them to the track sometime to dial in the bike and see who cuts the fastest lap time. That will determine who races first. And if any of the other bikes are running, they can also race them.
Anyway the bike will be a stock Chinese motor on an old Hawthorne 24'' frame. No chain tensioner, heavy spokes, drum front and rear brakes with no suspension. Still needs a little work, but we have plenty of time.

 

JankeyKevin

Member
Aug 10, 2016
32
1
8
MotorCity
MSRFAN, thanks for making a difference in young men's lives! Youth require exciting activities which can occupy their minds and keep them away from mischief. Motor bicycling is a perfect fit. Keep up the good work!

On the other hand, that is a really nice looking ride! I certainly dig it!
 

msrfan

Well-Known Member
Sep 17, 2010
1,799
95
48
Southern California
Made some progress on the bike today. Installed axle adjusters. Then drilled and tapped the fork and frame where the brake stay buttons will go. Used 1/4-20 allen bolts threaded from the inside out, then need to weld the outside.
















I used double straps for the fuel tank so the studs won't tend to pull out when tightening. It seems to be more secure also.







After that, I made a heavy duty front brake cable and front motor mount. Installed the module and exhaust end cap. I'll try to get more done tomorrow.
 

msrfan

Well-Known Member
Sep 17, 2010
1,799
95
48
Southern California
Thanks baird, I may need you between now and race day. I have some time to test ride and get the bugs out. I finished the wiring, cables and clamps. May still install an exhaust brace. I had to trim the rubber flange on the air cleaner to clear the frame.

















 

msrfan

Well-Known Member
Sep 17, 2010
1,799
95
48
Southern California
Been having some trouble dialing in the power. Max took it home and cleaned up the ports for a big improvement, then rode it to my house (just 6 miles) for some finish work. I changed back to a stock carb and it runs better but still tops out too quickly. Baird dropped off a jet to try and I have a set coming from Amazon. We'll have to test it when we get to Grange in the higher altitude. I made number plate brackets from a chunk of plastic I had lying around and mounted one of my aluminum plates on it. Painted it aluminum so the numbers will show up. Got the cables squared away and secured, adjusted the brakes and added return springs at the backing plate lever, trued up the wheels and greased the gears.

Nothing special about this bike, just a bunch of stock parts. First race for these kids so I'm going for dependability. I want it to hold up and finish. I may have as many as 5 racers in my group or as few as 2 and they want to race their own bikes, so mine might just set this one out. A couple of the racers are supposed to come over this afternoon and get some things worked on, like front brakes, chains, cables, etc. We'll see how it goes. Hope they can get their parents on board.















 

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,549
238
63
living the dream in southern california
If it's winding out too quick, it's the gearing. Those kids (like me) are lightweights, and I'm running a 41t with my 24".

I've gone as low as a 35t and still have low end power, but the Grange has that uphill/downhill massive straight-away, plus all the corners, so it's a trade-off between getting outta the turns fast or bombing the straight.

With that 50+ tooth you have on there, you probably won't get over 30mph.
 
Last edited:

msrfan

Well-Known Member
Sep 17, 2010
1,799
95
48
Southern California
Thanks Baird, unfortunately with the moped drum I'm stuck with that gearing unless I make time to graft a smaller one onto it. The boys need to learn quick cornering, so I will probably leave it. I went dirt bike riding in the desert Saturday and I'm healing up from an endo trying to catch Greg, so I don't feel like working too hard on it right now. But, like I said, they can always make their bikes pass tech and race them. If you get a chance, stop by and ride this thing and tell me what you think.
 

MotorBicycleRacing

Well-Known Member
Jul 28, 2010
5,845
107
63
SoCal Baby!!!
www.facebook.com
If it's winding out too quick, it's the gearing. Those kids (like me) are lightweights, and I'm running a 41t with my 24".

I've gone as low as a 35t and still have low end power, but the Grange has that uphill/downhill massive straight-away, plus all the corners, so it's a trade-off between getting outta the turns fast or bombing the straight.

With that 50+ tooth you have on there, you probably won't get over 30mph.
Beginner China girl race on the half track using the cut out so no long straights.

Very cool that Dale is mentoring his local kids.

We had some school kids before but the teacher left so no more.

Perfect weather, 69* on Friday practice and 75* on Sat raceday.
See you there!

 

msrfan

Well-Known Member
Sep 17, 2010
1,799
95
48
Southern California
Thanks Jeff. 3 of them came over last evening trying to get last minute stuff done for the race, What a nightmare. They won't quit riding them long enough to make repairs or adjustments. They all have worn out tires and chains. Their cables are too long, the coaster brakes are all junk, loose headsets, broken motor mounts, etc. We worked 2 hours and barely made a dent in the problems. They don't understand this is crunch time and there's rules and tech inspection and safety equipment to round up. They'll just have to go to the race and see for themselves, and maybe be a little more ready for the next one. Anyway, I'll try to get as many as I can to go. We'll leave early Saturday and get there in time for some practice.
 

MotorBicycleRacing

Well-Known Member
Jul 28, 2010
5,845
107
63
SoCal Baby!!!
www.facebook.com
Thanks Neil. Does beginner China girl include 4 strokes?
If by 4 strokes you mean 49cc Huasheng motors then that would be a yes.
Are any of your kid wrecking crew racing one?

Also other small 4 stroke motors like small friction drives, etc.

First heat:
10:25 - 10:35 (4) BEGINNER (48cc - 69 cc aka "80" China Girl) + 50 cc 4 Strokes, Friction drive.