Well, after some messing about I can now run an MC21 complete wire system up to full noise on the bench, without having to run an engine. This has given me the chance to get a little deeper into what's going on.
So let's start with the Or/Bu wire.
As standard this wire is earthed. What happens is as the rpm increases the RC valve starts to open. It then reaches it's fully open position at Xrpm. All sounds good so far eh? Then as the rpm increases further the bloody thing starts to close again!! Say bye bye to the ponies.
The splice sees this wire fixed to +ve. What happens now?
RPM increases and again the RC valve starts to open up to it's maximum at Xrpm, but this time it stays at max all the way to red line. Ahh, that's better
Anything else? Oh yes, the ignition timing is also different between the standard setup and the spliced setup. The splice advances the timing.
I'm not giving numbers at the mo 'cos I can't measure it accurately enough just yet, but from what I've seen this far I'd say that the RC valve is in need of some retiming, which could net some better power on the way up to peak. It's totally different to RS250 RC valve timing.
There's lots of other things going on, but I'll start with the splice before going anywhere else.
So what's it all about?
I built the test bed so that I can quickly test PGMIII's and also build some other systems to ride on the back of the PGM. My mate sussed his RC valve controller and it proved to be quite reliable, but he was wired into the rev counter itself and it was a bit of a task for the untrained to rig up. I wanted to see it simply plug inline somewhere but he couldn't get that bit of the circuit working properly. I've since got my version working so we're gonna try a new idea. The new version should give us adjustable opening and fully open timing. We should be able to set it up pretty accurately on my test bed.
I've got my shifter light working, so I'm pretty pleased with myself. I'm no electronic expert, infact I struggled to wire up a lightbulb this time last year
I'm messing with some carbs for Andy which I can now (hopefully) rig up my solenoid controlled power jet to which will give us adjustable switch on/off timing just like the A kit RS250/125. Probably shouldn't have said that 'cos he'll be hassling me now.
I'm also ready to have a go at a water injection system (into the pipe) on my CR500 Super Retard. This is a total waste of time as it's got plenty of mojo as it is, but if there's more to come then I want it.
I'll modify the test bed for MC28 and 18 as soon as I can be bothered.