
I was browsing the aisles of
Harbor Freight a few months ago and noticed
6.5 horsepower engines for a little over $100. I had no idea what I would do with it, but I went ahead and purchased one anyway. I got the motor to the house and it sat on my desk for a week before I decided I
needed a mini bike. Why a mini bike? Well, because I never had one as a kid and I had a motor on my desk.

I did some research on the net and found several sources for mini bike kits, but the prices were a little too high. I browsed over to craigslist and found a "Lil' Indian" rolling frame advertised by a local seller for $100 bucks. I responded to the ad and the frame was in my garage in no time. The frame was nice and straight with no bends, but needed a good cleaning and another coat of paint. I completely stripped the frame of all parts and re-painted it in an afternoon.
I can never keep anything in "stock" configuration. My new engine was no different. I completely dismantled and "hotrodded" it before I even put oil and gas in it. I obtained most of the modification tricks from a few karting websites that use the same engines for kart racing. I won't go into how the mods were done, but here is a list of what I did to my engine.
- Governer/limiter removed
- 1.2:1 rocker arms
- ARC billet aluminum flywheel
- flat-top piston

- GX160 ported 14cc cylinder head
- Mikuni 22mm carbuerator (jetted 130main/12.5 pilot)
- Briggs and Stratton "Animal" intake manifold
- Mikuni pulse-type fuel pump
- 8 degree timing advance
- Exhaust header
- 18 lb. valve springs

The listed mods are pretty standard for the GX200 style engines running in the karting world. The compression ratio is raised from the factory 7.9:1 to around 11.3:1 with the smaller combustion chamber of the GX160 head and the flat-top piston thus making premium fuel a must. I was lucky and experienced no detonation problems with 93 octane fuel. I highly recommend the following websites as they greatly assisted me in this project.
Affordable Go Karts
karting.4cycle.com
oldminibikes.com
GFRT
Click here for photos of the build-up
Update 8-4-2008
I decided the paint job was not holding up as expected. I completely stripped the paint down to the bare metal and re-shot it in bright yellow. Also, the seat was upgraded.