Simon
I had a spare alt so put it on the bike i tested the old one and i dont think it was up to speck. i know what you are saying with the wiring but i tried to fiddle around for ages all to no avail, i am still looking at the wiring but i seem to be running out of ideas.
i think the cdi as you suggested is of a later bike i have seen one for about £50 do you think i should go for it ? its bloody annoying i havent ridden in over a month and i am missing the wind in the air,if i had any that is.
Dave

What's the markings on your existing CDI? If it's a later model, I should be able to scrounge up an electrical diagram and confirm what the connections should be for it to work. Although, as it sometimes works, I'd guess they are actually correct, but there's no harm in knowing exactly what you're playing with.

50 quid seems a good enough price for a CDI (cheapest I've seen was around a ton USD) and if it doesn't fix the problem, at least it will get you back to "stock" (and you can sell on your existing one to cover the cost, I guess, consider it a loan to your bike .

It's an intermittent "sometimes it will, sometimes it won't" thing, isn't it? God, those are annoying.

If you've got a new alternator on, and it tests OK, the issue is unlikely to be the alternator side wiring (it would seem unlikely that you get identical symptoms from 2 separate pieces of gear), and if it works sometimes at least, you know the rotor side of the pulser is good, which leaves CDI connection, CDI, CDI-Coil connection, CD earthing, loom / switchgear issues, coil earthing, coil, HT lead and plug cap

Have you checked where the HT lead comes out of the coil? Apparently the HT lead cracks and sparks to earth there, mine has a shitload of bathroom silicone sealant on it (for exactly that reason, I think). I found a link showing how to redo these coils with a completely new HT lead, but frankly the silicone approach seems a reasonable bodge.

Double-check and clean the CDI - alternator connections. Again, I'm sure, and don't forget the pulser 3-way connector

A new, stock, CDI would eliminate the existing CDI from the equation entirely, which leaves the loom, coil earth connection, and the plug cap. Certainly worth a shot if you're relatively sure the coil and HT side are good, gets you back to stock, and is unlikely to leave you far out of pocket if it turns out to be the same.

If you think the coil or HT lead is toast, cheapest replacement might be a C-90 stepthrough coil. But don't quote me on that.

Simon

Simon,
i am chasing my tail here. i have re checked the alternator ands there is an open circuit between the red and brown wires so i guess that will need a rewind if i can find someone in Essex to do it! the original alt was out of spec as well i did try to cut the wires back(to see if the wires were broke) but it didnt make a difference. so now i am changing my opinion and thinking may be the cdi dose work. the cdi colours are as follows:red,brown,black,black/white,orange,white,green,green,red/brown,blue/yelllow.i know what you mean with the coil i did change the ht but decided to buy a new coil anyway. there is a light blue and dark blue wires that have been cut off at the cdi box. i know i will get there in the end but

cheers
Dave

Open circuit? As in "zero resistance"? That's probably be a short between red and brown between the coil connections in the alt itself, and the loom connection (especially if there's no path to earth from either the red or the brown). You can verify this by pulling the sidecover (*again*, I know, I know), and measuring resistance between the red and brown solder points on the coils themselves, see if those are in spec.

If the coils are in spec, you can avoid a full rewind and just do a rewire. Short term, you might be able to make it all sorta work by individually wrapping red and brown in electrical tape, then re-taping the whole lot being careful to keep the 2 wires away from one another, although failures of this type generally occur at the exit through the casing. I'll whip the sidecover off mine (my gaskets are already ****ed beyond all recognition, so once more won't hurt), get a photo to show the points you wanna look at, if you like.

Simon

Come on Guys!
This is making very painful reading, will be of no help to anyone else in a similar situation and is surely limiting any help people may be prepared to offer!!!

Dave has just said that he has an OPEN circuit, ie. INFINITE resistance. This is the exact opposite of a SHORT circuit or ZERO resistance!
These two states prove different conditions and require different solutions.
The CDI unit wiring is;
Orange = low-tension feed to HT coil
Black = earth
Black/White = ignition switch & kill switch short to earth
Red = 12v battery feed (or the Red & Brown wires may be the ignition source coil - a continuity test will tell)
Red/White & Green/White for the pulser coil
I can't help with any others, as reading back through the previous threads, there are too many guesses and variations to be of any use.
State clearly what you have and more help will follow.....

Oh, DUH! Brainfart on my part there. Blame it on lack of caffeine

Still, I am almost certain it's nothing to do with the CDI, and that the problem lies either in the wires to the generator or in the generator itself. As it's an intermittent problem, and it showed up when Dave untaped and retaped the wires from CDI to generator, I suspect a break in one of those wires. Pulling the alternator and continuity testing the coil from the tap points, and the red and brown wires to the tap points, will show where the fault is. If it's in one of the wires (as I suspect), then it's only a case of replacing at least one of (but if I was doing it I'd do both of, if not the entire set) those wires. If it's in the ignition source coil, then it's rewind time.

All correct apart from the bit I bolded - on a CDI, the battery plays no part whatsoever. Brown and red are the ignition source coil, there's no "may" about it

FWIW, there's 2 red wires on these bikes. One from the genny to the CDI, and one from the battery to the main contact switch (via the fuse, and with a feed from the reg/rect). Difficult to mix them up, but if you did the results would be - erm - "bad".

The CDI Dave has is not from a 500, far as I can tell, and it's been "bodged" to work with the 550's electrics (2 wires left floating at the CDI would strongly indicate that), but apart from the possibility that one of the connections is going intermittent, I can't see that it's anything to do with the problem anyway.

I haven't managed to find a CDI with the exact set of wires Dave's has, it could be an aftermarket replacement - Dave, what's it got marked on it, just out of interest?

Simon

Hi guys,
Thanks for the responses very helpfull. i have been lacking in the caffine department as well. i will let you know the outcome. i am going to try the re-wire first as when i double checked/moved the wires i got the reading i should have(fingers crossed!)
Simon as for the cdi i am afraid it has not got any markings on it,but i would guess its an after market item as it hasn't any lugs on it for attaching to the bike
cheers
Dave

Any joy, Dave?

hi Simon,
no not as yet,just not had the time which is bloody getting on my nerves.
waiting on a cdi .will keep you posted
cheers
Dave

Simon,
i have checked the wires from the alternator and all appear to be within the tolerances that they should be. the old one had lots of dodgey wires the other one that i replaced it with did need some new connections etc,so i am fairly confident that my cdi is playing silly buggars.
i have just got to try and find one as i missed out on the one that i was after!
Dave

I can't get a spark, I've changed the plug, and all of my ohms are in spec. I noticed above that Tufty says the red and brown wires coming from the alternator shouldn't have any connectivity between the wire and ground. both do have around 300 ohms of resistance when I test them with the multimeter.
what would this mean? is the coil grounded? I can see no visible contact points or stripped wires. Any advice would be greatly appreciated.

btw this has had me grounded from riding through some very nice weather; I'd love to be back on the road!

Anyone know IF the stator from a 1st gen. XT6 will work on a 550?
Got a friend that's facing this problem currently.....seems that IF a 550 stator can be found....it's Astronomically priced!
Was hoping a stator from an early XT6 could work....as they seem a bit easier to find.

ANY input on this would be GREATLY appreciated!