Fortsätt till huvudinnehåll


Visar inlägg från juli, 2013

Ignition system: Progress!

I've gotten it to start! The electronic systems had probably been doing their parts correctly for a long time. Problems were in the mechanics department of the engine, where valve clearance was missing. 
That resulted in that the valves never closed correctly and compression was lost. After fixing that, the engine once again gave signs of life just after a few kicks.

 First it didn't want to rev up, so I thought that the carburetor was giving me troubles as it usually does. I tried to move the ignition trig point from around 17° to 30° before TDC (the same as opening the breaker-points on the original system).
The first of the aforementioned points is marked from factory with an “F”, 17° before TDC, and this is where the pre-ignition is supposed to begin when the motor is standing still. Point number two is the one 30° before TDC,  also factory marked, but without text. Maybe that one marks when the spark is supposed to come when the engine is spinning fast? 
When giving spark at…


To develop mechatronic and electronic system you need tools and materials, knowledge and loads of persistence.   While the development and design process can be quite time consuming it's probably the part when getting it to work in practice that steals most of the time and there I am right now. 
A new completely analog ignition circuit for debugging purposes

The bike started a few times during earlier attempts with my ignition system, so the bike hardware seem to do its part. However it didn’t run for more than a few seconds each time it started on that occasion.
During that time I timed the spark in relation to the zero crossings from the AC generator, so no external sensor was needed. However, phase shift from the generator was occurring especially during the critical start RPM’s which moved the zero crossing nonlinearly. That made it hard to actually know the position of the engine.
 When I got it to start I was just having luck with the values I choose on an ignition curve in t…

Creation of an ignition system: Introduction

Since I was a kid there has been a small Honda XR75 -1978 motorcycle around that never really have worked for more than around four hours straight.  One frequent reason of failure has been the mechanical ignition system that has a mechanical ignition advance mechanism. Though kind of neat that this somewhat complicated feature can be realized mechanically, this system hasn’t worked well in practice. 
The mission is to construct an electronic ignition system and then take a ride on a summery day.

Current progress
This project has been going on for a while, so I  skip ahead a little bit and publish material from the current progress. If or hopefully when I get it to work as desired I will probably post a full description of the whole project.

Recently I've mounted a hallswitch underneath the flywheel who's task will be to trigger another circuit I've designed. That circuit in its turn will do more or less the same thing as the mechanical contact-breakers on the original syste…