Focus Applied Technologies Sdn Bhd: GXI Road Trip: Madden Voyage of WF 3235

Gaseous Fuel Transfer Port Injection System for 2-Stroke Motorcycles

- Horizon Gitano

As part of our ongoing testing of our Gaseous Transferport Fuel Injection System we recently acquired a road legal Yamaha RS100 in Kuala Lumpur, Malaysia. It was our goal to convert it on site, and ride it back to our design center in Penang Malaysia that same day, a distance of 350km. While the fuel injection system is relatively mature, we wanted to demonstrate that a vehicle could be converted and immediately placed in service, including a fairly long initial voyage.

The fuel injection kit consists of a modifies 2-stroke cylinder bore, fuel injector and fuel pressure regulator, ECU, Throttle body, wiring harness and various sensors and other parts. Kit cost, excluding the LPG tank should be under 200$, and will be available for purchase via our partner CEI in the Metro Manila area starting in September 2012.

In preparation for the trip we had a shop put together a custom cooking gas cylinder holder and saddle bag for counter balance. LPG is not sold as a vehicular fuel in Malaysia so we use commercial cooking gas which is mostly butane, and comes in 15kg cylinders. Here the tank holder is under going final touches on one of our Pilipino test bikes before the trip.

I had to go down to KL to explain the latest E-Vehicle standards to the road transportation department, so that morning Syaz and Hairy got the “new bike” (1976 Yamaha RS100), and converted it to fuel injection in the parking lot of the flat of the former owner, who amusedly watched. There were a few problems associated with the fact that this bike is actually a US spec bike, and out parts are designed for the Pilipino version. The CDI wiring had to be changed out, and it turns out that we had to use back the US spec head, which resulted in a very high compression ratio.

After finishing the meeting and the conversion we got back together in the afternoon and started the bike up. It fired up straight away (converted bikes usually start on the 1^st or 2^nd kick after a new install). Test riding the bike we noticed it wasn’t tuned quite right, and found out that the Throttle Position Sensor had been miss wired, indicating ½ of the actual throttle position and resulting in under fueling. This was quickly remedied and we were on our way.

On the road the bike was running unusually hot, so during a rain brake we looked into the engine and noticed that the US spec head combined with the Pilipino piston was giving us very high compression. In a flash of inspiration and good planning, we decided to put 4 head gaskets on to help space the head out, reducing the compression to a more manageable level. It was a quick fix, and worked brilliantly. We ran a little extra fuel (5%) and 2-stroke oil just to keep the temperatures down a little and provide extra lubrication. Even with the extra oiling the bike only used about ½ liter of 2 stroke oil for 350km.

Any time we stopped a crowd would gather around to gawk, and ask questions about the bike and GXI fueling system. Many were interested in how much power it makes (about 5% less than the original carbureted bikes), what about fuel economy (35% reduction in fuel consumption) and cleanliness of the engine parts (they’re MUCH cleaner running LPG than gasoline) and range (about 1000km on one 15kg tank of LPG). Notable no one asked about smoke (they don’t smoke, where as the gasoline engine smoke like crazy). Mostly folks were just curious, and very interested in the whole project and trip.

The ride back went well, and we only had to stop for rain the one time. We road mostly at night to avoid traffic and because I like riding at night in the cool breeze. Indeed it was cold enough to put on a jacket before arriving back in Penang. Despite the extra, slightly unbalanced weight of the tank the bike handled surprisingly well in part because we chose to mount it as low as possible… maybe a bit too low as I occasionally scrape the bottom of the tank holder on the road in left handed turns! You can see a “bevel” in the lower edge of the tank holder for “enhanced road clearance”. The bike had ample power taking most hills in 4^th gear even with all the weight and tools in the saddle bag.

In the end it was a very successful trip. Even with the non-standard parts we were able to convert the bike in the morning and ride it back 350km that afternoon, hardly making a dent in our supply of cooking gas.

Many thanks go out to those making this EFI Conversion Adventure possible, including our own Ahmad Syazli, Suhari Mamat, as well as the folks of CEI Philippians: Marte and Luicito, and CEI US: David, Greg and Bill. We’ll be doing a “Malaysian tour” on our 2-stroke and 4-stroke LPG kits some time in the next few months to really see how far 1 tank can go.