1/2 Scale Cycle Kar(t)

irk miller

You've been mostly-dead all day.
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As some of you may know, I'm a teacher. For a while now, I've been pushing to diversify my courses with skills I've been holding on to, but never using for work. I was hired to teach Ceramics at my current school, which is something I've done at the college and high school level since 2006. Last year, I proposed a course or club to build a 1/2 scale cycle car. There are clubs around the US made up of enthusiasts who build and race cycle karts powered by a Honda GX200 engine. With our new Head of School, I finally got approval to start a club for this year and it will be offered as a class next year. And so begins Augusta Prep Motorsports and our first race car. It's my hope to begin this venture using the GX200 power plant, but eventually move up to something more roadworthy, like a CX500. If we stick to the rules of the regional clubs there will be a few specific restrictions:

A single seat ½ scale home built car, built to the following loose specifications:

Styling - 1920s and 1930s race cars, maximum pre WWII. Make it look good. Performance is secondary
Overall Maximum Length - 98", 2490mm
Overall Maximum Width - 40", 1020mm
Wheel Base - 66", 1675mm
Track - 38", 965mm
Chassis Frame Rails – 2 x 1"X3", 25mm x 75mm steel
Body Work – 1/4" (6mm) plywood and 3/4" (18mm) plywood Monocoque box, or metal work
Wheels and tyres – Honda 17"x 1 3/4", 177mm x 44.5mm
Minimum Weight – N/A
Maximum Weight - 250lbs, 113.6kg
Engine - 200cc, single cylinder 6.5 hp Honda OHV engine (GX200)
Engine Location – Rear
Drive - Comet TAV-30 (or similar) unit to one wheel only
Braking – Single rear wheel by mechanical disc. No front brakes allowed
Variation – Adjust all or any specifications above as required or desired

We're still in the voting stage of our design, but it's most likely going in the direction of this Richard Scaldwell Jap-powered GN Cycle Car:



I have the GX engine at school and ready to go. At this point, I'm collecting and preparing parts to begin the build. We've been waiting for the end of the Robotics season, which just had its state finals.

We'll run kart steering and drive components. I pressed out the kart axles so I can run adapted 16mm motorcycle axles, which are pretty common. It will require a bearing change.

steering.jpg


I collected a host of 17" wheels at Barber, with two being from a 185 Exciter and two unkown. The Exciter rear wheel is 16", but the hub matches one of the unknown hub diameters, so I'll swap the Exciter hub to one of the 17" rims.

wheels.jpg
 
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trek97

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This is so cool. Congrats on your success bringing the beginnings of this "club/class" project to working reality.

Since we briefly spoke about the legality of running un-tagged golf carts on the streets a while back. I was just sitting here thinking about this exact thing just yesterday. haha.
 

Rider52

Active Member
I started to build one a few years ago. I still have a new Subaru Greyhound 212hp 6.5 motor. The rules are pretty strict. I kept wanting to change them to fit my needs such as running 19" Comstar wheels, etc. At one time anything other than a 17" Trail 90 wheel was frowned on!
 

irk miller

You've been mostly-dead all day.
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I started to build one a few years ago. I still have a new Subaru Greyhound 212hp 6.5 motor. The rules are pretty strict. I kept wanting to change them to fit my needs such as running 19" Comstar wheels, etc. At one time anything other than a 17" Trail 90 wheel was frowned on!
Most, if not all, groups still specify Honda wheels. I scoured the swap at Barber only to find two that might be CT wheels. They look like CT90 wheels and match CT90 specs, but neither seller knew. I also found the Exciter wheels for cheap, and they don't look much different except for the spoke pattern. They are 17" and that should be good enough. If guys want to give me a hard time for using Exciter wheels, then they can suck it. They need to stick to size, not whether they are Honda or CT90, especially considering they were probably made by the same manufacturer. I'm okay with strict engine requirements, since that leaves the rest to engineering and chassis design. Lots of racing organizations require common engine packages. I have an association with an IMSA team (a student is on the pit crew and his dad is their engineer), which requires all teams to use the same uncorked Titan engine.
 

Rider52

Active Member
I'm still active on the CycleKart Club site. When I first joined (many years ago) they were still using wood frames. The first steel frame caused a stir. I do like the creativity of many of the builds. You should be fine with 17" but I bet you get some comments from some of the cork sniffers. My ideal would be very similar to the Scaldwell Jap-powered. I'd like to have a modern 4 cylinder, water cooled driveshaft motor and full suspension. I'l add street legal, but I have no problem running one outlaw.
 

Hurco550

Keep er' Between the ditches
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Im glad this is rolling. Don't hesitate to ask if anything can be done to help on my end. These projects are fun, but really can greatly change a student's life.
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
Im glad this is rolling. Don't hesitate to ask if anything can be done to help on my end. These projects are fun, but really can greatly change a student's life.
Thanks, buddy. I actually do need to talk to you and your dad about water jetting a couple radius rod axle brackets if I can't find any in a scaled size. I plan to run a single leaf spring suicide front end.
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
I was going to go with a live axle until I remembered the differential bolted to an old BGW Tri-Rod out back. Took a bit of work to make right.

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SONICJK

Reminds me of...me No, I'm sure of it. I hate him
This is awesome.
I would have been all over this if it were offered in highshool.
I went to a high end private school 2 miles down the road from me and have offered to teach both woodworking and metalworking classes but they all just look down their noses.
Sad state of affairs.
I'm surely glad to see you making headway in introducing kids to something fun and useful.
 

ridesolo

You only bear responsibility for your own actions
I'd have jumped on this club too if available when I was in school. So glad you are doing it.
Yeah, me too... of course when I was in school it probably would require steam power and the teacher would have been Henry Ford, Orville Wright, or Fred Flintstone.
 

The Jimbonaut

Well-Known Member
My life would probably have panned out very differently if I had an opportunity like this in school. The closest I got to formative mechanics was doing donuts on the school cricket pitch with soon-to-be-expelled Simon Vince.

Lucky kids. Nice one Irk.
 
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