Tacho Fast and Serious Lack of Power

[F5 Dave]

Golly 15.3 seems pretty high, I guess if it is kept no higher than that with the light off then the regulator must still be working. What about with light off? No higher I would hope.

It used to be they were reigned in at about 13.7 & if they went higher then they were kafunk. I was surprised my RF sits at 14.5, so maybe they have bumped them to 15.3 but I’d expect the battery to get a hard time at that voltage & the occasional bulb to blow. Incidentally the high wattage bulb in a bike with a relatively puny alternator is a bit tasking on the system. On an 80s Suzuki that would prove certain doom to the alternator which would take the battery & rectifier with it, with the rectifier gone the voltage would spike up high enough to kill the ignition. Oh joy.

[Motu]

That charge voltage sounds way too high,turn the lights out and see what it's putting in - 14.75v is the max you want to see.I'd say your rec/reg has failed,the excess voltage may have killed one or two CDI units.The rev counter will be triggered by one cyls ign pulse...sounds like it's firing erraticaly,which makes the rev counter leap up and down.

[edit] oops,too slow on the typing again..still,two similar diagnosis may be confirmation?

[louisb]

The manual say 14.5 - 15.5 volts at 3000rpm. Which does sound pretty high...

[thepilot]

I had a similar problem with my ZXR250C last week, it had the same power loss when you gave it any revs and the tacho was going bezerk. Funnily enough when the brakes were engaged it fixed the problem, as it was generating a new earth to the chassis. Hence i rewired the earth lead from the batt to the engine block and had the battery load tested and charged and it runs like new. So i suggest at least testing to make sure you have a good earth to the frame, and get the battery tested. Not running, the battery should read above 12.5V with a standard digital multimeter.

NB: the Ninja charging voltage is 14 ~ 15V.

[vifferman]

Golly 15.3 seems pretty high, I guess if it is kept no higher than that with the light off then the regulator must still be working. What about with light off? No higher I would hope.

It used to be they were reigned in at about 13.7 & if they went higher then they were kafunk. I was surprised my RF sits at 14.5, so maybe they have bumped them to 15.3 but I’d expect the battery to get a hard time at that voltage & the occasional bulb to blow. Incidentally the high wattage bulb in a bike with a relatively puny alternator is a bit tasking on the system. On an 80s Suzuki that would prove certain doom to the alternator which would take the battery & rectifier with it, with the rectifier gone the voltage would spike up high enough to kill the ignition. Oh joy.

While it sounds like a lot, it's not uncommon. My VFR with a new battery and brand-new, rewired heavy-duty R/R put out that much. And the high-wattage bulbs make things better, as they suck current that the R/R doesn't have to bleed off as heat (through the resistors). Just make sure the connectors to the bulb are good, and that it's using a relay, as any corrosion in connectors, thin wires in the circuit etc. will cause too much heat due to the current flow, and things could melt and/or burn.

thepilot's suggestion about checking the earth(s) is a very good one, anda not uncommon source of electrical problems.

[Devil]

I had similar problems a while ago and they were centered around the starter solenoid. Bad connections made the tacho read way too high, then made the bike gurgle and eventually die. Check out the connections around there, assuming thats where your main fuse is.

[F5 Dave]

High wattage bulbs in a bike that has a grunty alternator ok. In a small bike I would be concerned.

On my RF it was losing ~ 0.8V between the battery & the (std wattage but 50% brighter type) bulb. With a relay it got the whole lot.

[vifferman]

High wattage bulbs in a bike that has a grunty alternator ok. In a small bike I would be concerned.

On my RF it was losing ~ 0.8V between the battery & the (std wattage but 50% brighter type) bulb. With a relay it got the whole lot.

True - I forgot it was a 250.
However, I ran a 130/90W headlamp in my VF500 (not a huge alternator, I bet) for several years, and had no electrical problems (apart from some idiot leaving the ignition in "P" instead of "OFF"). I had the same battery in it from July 1994 to when I sold it (early 2000?) But like you, I ran a relay, with large gauge wires to the battery. Incidentally, using a realy for the horn(s) makes a HUGE difference to their effectiveness. Bikes have wiring that is way too light.

[louisb]

Ok. current situation. Last night i tested everything i could find. pulse generators, alternator, regulator, charging voltage, coil and spark lead resistance... I even re-soldered all joints in the CDI!

Still going like a dog, and seems to be missing now!

Next thing to do is change the headlight back to the original and try and find all earth points, clean and retighten...

I was going to buy a replacement CDI but at $150 i am a little reluctant as it could be anything.

[louisb]

After re-checking everything on the bike again, including reconnecting and checking the earths, i've decided that it can either be the CDI or the coils.

So does anyone know where i can get a replacement CDI for the spada?

Buckets n Bits (welly) are not answering there phone.

[F5 Dave]

Try after lunch, sometimes goes out in mornings.

[louisb]

Thanks Dave.

[louisb]

After replacing the CDI unit $150 later... Still exactly the same.

Only just idles and when you rev it it takes ages to speed up and has virtually only enough power to move the bike while reving the shit out of it and riding the clutch.

Next thing to replace is the coils... this could get expensive.

If anyone has any other ideas... i'll take em.

[F5 Dave]

So do both pipes get hot at the same time from cold, or does one take longer to get hot?

[Motu]

Throwing parts at it is not a good diagnostic proceedure - find the fault and fix that,much cheaper.