Easy Tachometer on 250 engines

Posts: 61

On the 10-wire TDCI units fitted to a lot of 250 engines, there's a unconnected wire coloured black with yellow tracer that provides an easy signal for a home-made tachometer. It is used on some scooters fitted with these engines, for example the Kymco and Daelim 250's.

The wire provides a positive output with respect to chasis (negative) that gives a linear one volt per 1000 rpm, so if you only want to connect a tacho for diagnostic or adjustment purposes, clip a multimeter switched to the 0-10 or 0-20 DC Volt range to read revs per minute directly.

If you can find a robust and reasonably well weather-proofed meter that reads, say, 0 to 10 Volts DC it can be fixed permanently somewhere on the buggy.

In the picture it's the wire on the extreme top left.

Note that I'm no genius, I found this whilst idly investigating what this lonely wire was for.

Posts: 1744

Nice info Ernie. Looks like you already contributed.

Posts: 61

Thanks for your reply. I have one or two other pieces of advice that could be useful, but I will post them later, as we Spaniards lost our credibility a long time ago with clusterf#cks such as the "Invincible" Armada and then the US-Spain Cuban wars Smile

Edit by Jabo. Please watch the foul words as there are alot of kids on this board.

Posts: 61

Sorry Jabo, won't happen again. I actually learned that word from Clint Eastwoods "Heartbreak ridge", watched by millions, so I thought it would be OK.

Posts: 6278

No problem Ernie, glad to have you aboard.

I wish we could get these buggies road legal here in the states. How fast does your buggy go?

Posts: 1744

Posts: 61

Yes, we are lucky, as these vehicles can then be used as daily transport as well as fun. It must have been an oversight by our political masters in Brussels, as they are normally all out to stop any kind of naughty fun activities...

The growth of Quad, ATV and buggy sales have taken off as a result. This is not always a good thing as 1000's of pampered teenagers take to the trails doing wheelies and generally clowning about. This will inevitably result in restrictions by local governments on outdoor trails, etc. It's already happening. This is of course helped by hospital wards filling up with accidents where a quad has overturned and maimed the driver.

The top speed of mine is 81 kmh or just over 50 mph. It appears to be limited by the gearing. It can be increased by playing with modified variators but I doubt it will do more than 90 kmh due to the sheer weight of some of these beasts. Mine weighs in at 300 kg !!.