following on from my nightmare trackday at mallory a few weeks ago i have purchased a decend battery. (odyssey)
i put my meter across it and it was showing 12.2volts. connected it up,tried to start car a couple of times and nothing. tested again and had 11.8 volts. put it on charge for 15 mins had 12.6 volts and it started first time instantly.i ran the car for a bit but only had 12.1 volts at idle, so turned ignition off had 12.1 volts.tried to start it again and nothing!
what voltage should i be getting at idle? as im worried the reg/rec may be faulty and every time i try to start it i lose around 0.2 volts.cheers

A battery below 12.5v is a flat battery. It sounds like yours is not charging have you put the tester across the battery with the engine running as it should show around 14v when you rev it. It could be the generator or just the reg/rec which is a common fault on Blades.

idle voltage should be high13/ low 14 i think.

i should have everything to do with the charging system on a 919 spare in my garage if you want to try them.

thanks for the offer. ill try the new reg/rec ive bought next weekend, and if still having issues ill give you a buzz! cheers

Almost certainly the re/rec.
But also check the three yellow altrernator wires. If they have any other joints before they reach the reg/rec, these are also susceptible to failure

thanks mate. i checked the 3x yellow wires and all was fine. the reg/rec is mounted on the front bulkhead,so only about 12" away in total!

[Edited on 2/6/13 by daniel mason]

you really need 12.75 to mid 13 looks like you have a charging problem what voltage are you getting from the 3 yellow wires from the stator
what year is it as ones around 200 burned the stator out if it has gone i have a number of some one that will rewind it for about £50 and he is top notch

dan i've remembered that i have a 919 engine minus its gears, starter and carbs that has been sat in my garage for the last few years.
haven't a clue what condition its now in, i replaced it when the gearbox failed. also have a spare head.

none of its any use to me now so if you want it you can come and pick it up. its in windermere.

i'm moving out of my garage before much longer and if its still there it will just be getting binned.

I've had two blade regulators fail, one stopped charging and the other fried the battery.

The field windings are also a weak point in the alternator, get a multimeter and check the resistance between pairs of yellow wires, I cannot remember the value but any two should have very similar values and should not measure anything to earth.

The standard fireblade regulator is on the edge when on the bike, it sits up under the rear seat in an area with good airflow, in a BeC they tend to be placed on the bulkhead so very quickly overheat, I placed mine under the radiator so it gets a decent cold airflow. If yours is exposed to heat and not well ventilated it will quickly fail!

Any bike 12v regulator will do, have a look on eBay and get one with big heat sinks if you want to avoid further issues, when you add 2 x head lights, tail lights, brake lights etc in a BEC you are really going beyond the standard items limits.

Regards Mark

thanks guys. ill take the bits if you dont want them mate cheers.
mark. my reg is on the bulkhead but has its own fan mounted to it. my new one has extra cooling fins so i will try it next weekend! cheers

i have been trying to sort this again today and think its the alternator windings. i stripped bace the 3 x yellow wires to find they had melted themselves together causing a dead short.
i removed the alternator and checked continuity across the yellow wires and i had very low ohm readings between all of them. the fireblade haynes manual states the reading should be infinity between these conductors so it seems its fried itself!

i'll u2u you my number