Hitchcocks Forum

Hi folks, I have an issue with my Super Meteor.

Actually broke down the way home following a club run. Have traced it down to not charging and not being enough power for the electronic ignition.

The bike has been converted to 12V, has a two wire rotor and is fitted with a Zenor diode. It also has a boyer power box and contactless ignition fitted by the previous owner.

If I run the bike off a battery charger (with battery still connected) it runs fine, as soon as I drop the battery charger it will not rev and eventually stops. Have connected a voltmeter across the two wires from the rotor and I'm getting 14-16v (is this about right?), across the battery without the charger is 12V which drops when revved (then she splutters and cuts out).

The zenor diode on its' mounting plate is getting very hot, even too hot to touch after less than 10 mins.

The rectifier seems to be kicking out the right Dc voltage.

Should the zenor get that hot so quickly? Where else can I check?

Any ideas?


Many thanks

Dave

Dave, I think you'll find the rotor has no wires at all! The stator, yes...



How come it has a Boyer Powerbox AND a separate rectifier and zener diode fitted, unless that's the TCI black box for the ignition?



Assuming it's the classic 12V rectifier and zener diode which are actually responsible for your regulated DC supply, and your post rather suggests they are, we might be looking at a failing zener which has over-charged the battery. Zener diodes do run hot, did the previous owner fit the thing on a decent sized finned alloy heatsink and mount it where it gets plenty of breeze? Have you also checked that your battery can still hold a decent charge?



I'd replace the separate rectifier and zener with a modern single-phase rectifier/regulator (these need a decent airflow too), this will let you simplfy the electrics while you're about it.



A.

Hi Adrian, thanks for the reply again, yes I meant the stator, too hot to think clearly at the moment LOL

The boyer box is purely linked to the electronic ignition which is a Kirby mk8 and is not a power box (my bad!)
.
The zener is mounted on a heatsink under the headlight but was too hot to touch very quickly, and it gets plenty of airflow there. The battery was ok but I've stuck it on a slow charger and will have a look.

I'll look into replacing the zener and rectifier with a combined unit .
Any come out as favourite on these bikes? is it worth going for the Boyer Powerbox?


Cheers

Dave

The Power box is probably one of the dearest, it has a built-in capacitor which you might not need. For alternatives, try Al Osborne/Paul Goff/Max's Speed Shop/Tri-Supply (Andy Gregory).



A.

Thanks Adrian.

For an update: years ago I bought a box of crusader bits which included a full kit to convert to 12v which I've never bothered to use. I had a feeling there was a rec/reg in there so had a rummage and found it is actually a used power box!

Fitted it this evening, disconnected the zener and bike fires up happily. Still blooming hot in the man cave so only jury rigged it

Not sure if this episode has taken the battery out as I had the battery on charge for a while and when I stuck the lights on it drained the battery very quickly and voltage dropped massively.

I've put the battery on a trickle over night but might need a battery. Can now get shot of the zener and sort the wiring out properly.

Many thanks for your help.


Dave

I'm afraid your battery is cooked or some such word !

Glad you have it sorted. Not relevant now but I dimly recall some mates with classic bikes saying one of the best things to do with a zennor was to bolt it to the back of an alloy numberplate for heat sinking purposes.



Also worth pointing out there is no reason you can't use a reg/rec off a Japanese bike on a 12v Enfield. This gives the option of getting one of the more modern mosfet / switch-mode ones which are highly effective and unlikely to fail. Most Japanese bikes have three coil stators but you can just leave the redundant phase disconnected. I have a ZX6R reg/rec on my bullet.

That's a good point about using a 3 phase reg/rectifier, they can be had very cheaply on ebay. However, if that Boyer Powerbox is still OK then I'd use it, though possibly with an oriental unit to hand as a back-up.



I'd not heard of the Kirby Mk8 ignition until now, a quick search reveals it is one of Kirby Rowbotham's Boyer-based ignition kits:



http://www.techeng.force9.co.uk/info~mk8.htm



One of the advertised features of the Boyer Power Box is that it will let you run your bike battery-less, but if you're going to give this a try, pray that Mr Rowbotham has used a Mk4 Boyer ignition on yours and not a Mk3! If you're just going to fit a new battery (and it looks like you'll have to), don't worry.



A.

Thanks guys, for the cost of the battery, I'll order a new gel one.

At least it should last a few years (as long as it doesn't cook again!)

Back number plate would be a great mounting point, better than the front on the forks where mine was, doesn't look great, just functional.

I'll wire the boyer powerbox in properly and give it a go.


Dave

Might be a bit vulnerable to road muck in that position, for my Super Meteor-framed AVL hybrid I stuck the reg/rectifier on an alloy plate in front of the left-hand rear shock absorber, it seems OK there.



A.