Hi, there is a big bore kit available that turns it into a 53cc, dont expect much added speed but there will be more torque definetely. This engine is commonly used in goped's, midi moto's, petrol scooters, mini choppers, mini harleys, some older pocket bikes, petrol skateboards etc.
You can get expansion chamber pipes for it, air filter and velocity stack sets, boost bottle, even nitrous!
Mine has an exhaust manifold spacer and a velocity stack . The boost was not huge but improved the low end which is great. And gave it a deeper sound. The manifold spacer also makes the motor run a bit cooler. A good thing if one plans to stress the engine with other add on's.
I got an adjustable carb which is hopefully bigger than the stock one for $26. That alone (given it is bigger) should provide more giddyup. I am still waiting for my boost bootle to go with the new carb. I put out a post hoping to get some inside info on the boost bottle but so far no replies.
..hehe , you and me brother. I've been patiently tapping my foot waiting for the B B kit to arrive. But as far as boosting performance, it's not all in the engine I've come to notice. Having tough strong rims will boost pull and top end.
After I bound my spoke crossings with copper split bolts, I can feel how the torque pulls on the snap ring side of the wheel while accelerating thus straining the spokes on one side more and making the tracking of the rear sublety wheel wobbly.
I only noticed that becuase the new split bolts reduced so much slap, sway and flap in the overall performance of the rear rim typical at the speeds of a motorized bike. From what I've been reading about the spoke ring / rim strenght issue I'm surprised that the GEBE spoke rings hang on for so long with weak stock rims before they lose grip.
And tires. I plan on doing more motorized bike builds in the future. I cannot see myself using any other tire than the Geax Evolution. For the street running motorized bike rider, it's the best tire out there.
I run a friction drive, so I don't have the spoke issue. Since I have got my tension down PERFECT I have at least a hundred miles on my current tire, an Oddyssey Frequency G 20x1.75... We're talking apples and oranges! All of these kits/systems require some tinkering. I like the idea of the GEBE, and I rode a HT Boygofast today, vibrates like **** but it's got some power. Friction's OK at best but I have mine dialed in and I'm pretty happy. I'll either keep my Mitsu and put it on something else, or I'll do something completely different with a chain drive like Staton's... Anyone in the Seattle area have a GEBE I can test ride to help me make up my mind?