Well what a disastrous rebuild this has been

[bikerboy]

I am going for the mag I cant think of anything else 

Muskrat, it could be tappets but its not and when I have known that in the past the exhausts normally glow a nice red colour 

I am going to email Priory Dynamos, that guy is pretty on the ball and very reasonably priced and see what he thinks. Another month without riding the damned thing

[bikerboy]

Topdad

The filters on the taps are good (both taps are new) the tanks is as clean as can be inside. When it does stop it tickles up immediately.

When I check for spark when it is hot and wont go there is a spark there but its pretty weak. It has twin carbs so IMO if it was fuel based then its likely only one cylinder would be affected.

All I have to do is sit next to it reading my kindle for 45 minutes to an hour then it will burst back into life and go for another 20 miles or so. I give the distance at 20 miles but the 3 times it has happened cruising at 55 ish its been fine, when I have slowed down to a stop as I come off the motorway then bang it stops dead. I suspect it would carry on quite happily if I did not dethrottle.

Mind you the good thing is I have read nearly all the books I got for my birthday while I have waited for it 

[Topdad]

Given all that I'd get the mag off asap and get it sorted. Whilst laid up check the tappets as per Musky ,just to be on the safe side and when back ,enjoy. Ask the mag wizard to treat it as urgent, man can't life by books alone!! That'll sort it best wishes BobH.

[bikerboy]

E-Mailed Andy at Priory Dynamos and mags and in his words "this is classic magneto failure".

To be honest he has quoted me £100-£150 to replace the armature and capacitor and to rebuild the mag and test etc. Which I don't think is a bad price at all.

In fact common sense tells me that as I was willing to spend over £250 on exhausts and silencers which are purely cosmetic that a £100 or so on a recon magneto can hardly be grumbled about.

Mind you I will grumble about it anyway 

[fido]

Topdad

All I have to do is sit next to it reading my kindle for 45 minutes to an hour then it will burst back into life and go for another 20 miles or so. I give the distance at 20 miles but the 3 times it has happened cruising at 55 ish its been fine, when I have slowed down to a stop as I come off the motorway then bang it stops dead. I suspect it would carry on quite happily if I did not dethrottle.

That is exactly how my A7 was when the magneto was on its way out. If you didn't have to slow down for a junction or a 30mph section of road it would keep going but as soon as the revs dropped it would die and stay dead until it cooled down.

[A10Boy]

God bless Joe....

[bikerboy]

fido

That's good to hear at least it means I am not wasting £100 or so

[sparx]

Spot-on symptoms for a failing capacitor in the maggy. It's not the easiest of jobs to fit a new one, so if you are not confident doing the job yourself £100 to £150 would be money well spent. The armature is probably ok but peace of mind is worth a small fortune.....

[a10 gf]

capacitor in the maggy

About the Brightspark alternative > http://www.a7a10.net/forum/index.php?topic=5359.0

[fido]

Spot-on symptoms for a failing capacitor in the maggy. It's not the easiest of jobs to fit a new one, so if you are not confident doing the job yourself £100 to £150 would be money well spent. The armature is probably ok but peace of mind is worth a small fortune.....

In my case I had already renewed the capacitor. I then had the magneto reconditioned and a new armature was fitted, they sent my old armature back in the parcel with the completed mag.

[mayes]

I had some problems on my bike starting after checking spark was good then poor,I would like to say by skill but more by chance I found the earth cut out was  shorting out and gave hit and miss spark discon the earth cut out and try - John

[bikerboy]

Mayes

I had actually already changed the cut out earth for a lucas push on pull of type just in case so I could get it off easily. It was definitely not that.

To be honest I could possibly have got away with the brightspark capacitor but hey I have spent about 2 grand on the engine so far I might as well go the whole way and get it right after all being 57 years old it should be the last time I ever rebuild it. So a nice new armature and capacitor saves me worrying about it.

[RichardL]

A nice new armature will deal with any shorts developing between windings. As for the cap, I would have been inclined to just forego the cap buried in the armature and gone straight for the EasyCap. Be sure that your rebuild includes remagnetization.

Ken or Groily at BrightSpark might chime in on the benefits of just going with the EasyCap. (We'll promise not to accuse them of self-promotion.)

Richard L.

[A10Boy]

Given that mag problems which cause poor hot starting are more likely to be a capacitor failing than an armature failing, its worth trying an easycap. I fitted one on my AJ and it cured the starting problems without further ado. You still have to disconnect the old capacitor unless it has failed open circuit, but its easy enough to do. If the maggy is otherwise good, the easycap is the way to go in my view.

BTW, no connection.

[bikerboy]

manosound, a10boy

I know what you are saying as those easycaps are supposed to be pretty good but I am happy with the cost of the mag work and now at least I know that its not going to let me down (hopefully anyway)