Pocket Bike Speedometer Part 2

Finally got the engine running well already. Was a seized piston the other time. And probably the fuel/oil mixture wasn’t good enough. Now we’re using 40:1 (40 parts of petrol and 1 part of 2t) but probably 32:1 will be a better mix. The power is there and there’s no lack of it. Ran alongside Marks’ bike and managed to record a top speed of 65KM/h. But couldn’t beat the acceleration of the 4-stroke 100cc bike.


All packed up in a small circuit to save space.


Rear insulated to prevent shorts.


Small display.


Bigger display and larger board for easier mounting.


Simplest way to mount it: using double sided tape.

Everything is installed already but I discovered a big mistake in the design. I forgot to take into consideration the interference generated by the magneto and the sparks on the spark plug. Since the plug wire is not the high resistance type, there’s nothing to stop the interference. Once the engine is started, the PIC freezes.

There is a way to rectify this. Build a metal enclosure around the circuit. I’m still thinking of how I can get a metal enclosure for my circuit. So stay tuned for part 3 and most probably the complete circuit and the source for the PIC. Till then, happy revving! Continue reading

Exhaust silencing

This is a failed attempt at silencing my bike’s 2 stroke exhaust in a bid to make it usable at night. To really silence the exhaust will make the exhaust so restrictive that it won’t be fun to ride anymore. Anyways, here’s how it’s done for those of you who are wondering.


Buy some exhaust fiber from bike shop. This cost RM1.


Take out your whole exhaust. Easier to work with.


Take out the muffler cover.


Holes for some of the exhaust gas to escape.


Take the fiber out and shred it. Your hands might get itchy because of the fiberglass. Then pack it like so.

Start your engine up and be amazed! There’s no difference! Unless you really restrict the pipe and make all the exhaust gas go through those fiber packings, there won’t be much difference. I think I can live with the sound for the time being. As long as I get to feel the 2-stroke powerband kicking in. Continue reading