ET: Engine (Twin) Seeking Ignition Suggestions For Twin - Can't Get The ATD Fitted
- Thread starter CarlHungness
- Start date
I copied and pasted and DID get it to open..thanks so much. If you click on the link it gives us the Security Risk notice and won't load.
I was able to print out the whole Lucas Workshop Instructions, so thanks so much.
I didn't even think of using the de-comp..I jumped to the conclusion of using the clutch. If I ever have to push it to start it your suggestion is a good one.
I've said it previously, your post really has me turned upside down. I can SEE sparks from the B-TH, much less resorting to having it burn a lil' hole in a piece of paper. I DID get it running again with the B-TH but was rough as could be so went to the Lucas. And the Lucas fired it for 60 seconds and died. Have re-installed the B-TH twice with no results and the spark does NOT seem to go forward from the electrode but backwards..sometimes. I'm causing a lot of consternation among the membership and have to apologize for doing so, and really appreciate all the help I've been getting. I feel a bit ham-fisted for acts I've previously done successfully, so I'm talking to meself now.
To make myself feel better after reading your burn-thru-the-paper experiment, I just popped $84 USA dollars
out of my sock and sent my B-TH back to the UK to be tested. I told them to give me a price if they can fix,
if in fact it is duff. Or, if it can't be, keep it and don't send it back, I'm donating it to you. If it can be fixed I
don't need no stinkin' ATD. Or if nothing's wrong with it I'll let out a primal scream you'll be able to hear
from Indiana to London.
I hesitate to join this discussion as I am no engineer and barely a mechanic. I have been riding Vincents for 60 years, both Comets and a Rapide. In that time, I have had a few problems with ATDs, namely stripped fibre pinions (once notably on a burn up with George Lazenby in Park Lane), sheered advance stop ears and broken springs. I have also had this problem of the ATD stuck at full advance. All my replacement ATDS were second hand and I admit I have never lapped in the tapers on any of them. The ATD in question would stick at full advance whenever it was tightened up on the magneto. I suspected it was binding on the crankcase. I stuck some plasticene on the back side and screwed it on. This quickly showed that it was, in fact, binding on the crankcase. At some time in its previous life the taper had been enthusiastically lapped in on the magneto shaft, probably more than once, thus taking up all the necessary clearance and was therefore useless. Incidentally, although I have never lapped in any of the ATDs, none of the ones that I have used has ever slipped.
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I think Carl is chasing shadows (if you will excuse the pun) surely two of the problems that have been suggested are extremely easy to check and either confirm your suspicions, or rule out completely, if the ATD is slipping on the taper, then once set at say 34 degrees advance, kick the engine over a few times, and then check it again, if it has moved it would immediately be apparent, the same goes for cams slipping on camshafts.
BT-H magnetos do not throw off big fat blue sparks, but they certainly work, they are not just made for Vincents, but all the British Bikes that used Lucas type magnetos, if they did not work I am certain they would have been exposed as charlatans a long time ago, I have been very happy with my BT-Hs barely perceptible sparks for the past 18 years, only the condensers let me down once.
Vincents will run very well, even when in appalling mechanical condition, as I can testify as recently as last year at the Far Far North Rally, front big end disintegrated, thrown debris up into the front cylinder bore taking the piston and liner with it, and it was running very well indeed, two up.
I think the most likely outcome will be a fuel problem, but I think I would have given up long ago, and sought the help of a second pair of eyes and hands.
And in reply to Hugo, I agree with his comments, but having said that, I have lapped, but only with the finest grade paste, and just until you can see that you have full contact of the taper with a fine grey finish, we are not talking lapping in heads and barrels here, or valves.
BT-H magnetos do not throw off big fat blue sparks, but they certainly work, they are not just made for Vincents, but all the British Bikes that used Lucas type magnetos, if they did not work I am certain they would have been exposed as charlatans a long time ago, I have been very happy with my BT-Hs barely perceptible sparks for the past 18 years, only the condensers let me down once.
Vincents will run very well, even when in appalling mechanical condition, as I can testify as recently as last year at the Far Far North Rally, front big end disintegrated, thrown debris up into the front cylinder bore taking the piston and liner with it, and it was running very well indeed, two up.
I think the most likely outcome will be a fuel problem, but I think I would have given up long ago, and sought the help of a second pair of eyes and hands.
And in reply to Hugo, I agree with his comments, but having said that, I have lapped, but only with the finest grade paste, and just until you can see that you have full contact of the taper with a fine grey finish, we are not talking lapping in heads and barrels here, or valves.
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I have noted that my BTH on the Rapide produces such a strong final spark it is not in any circumstance visible to the naked eye.
The use of a spark revealer inline cap is an essential bit of cheap kit.
Buy two, turn the lights off in the garage start the bike and crank up Radio 2.
I can testify there is certainly enough power generated via the BTH to knock you on your arse!
Al
The use of a spark revealer inline cap is an essential bit of cheap kit.
Buy two, turn the lights off in the garage start the bike and crank up Radio 2.
I can testify there is certainly enough power generated via the BTH to knock you on your arse!
Al
One other B-TH point you dont need a large plug gap
A quote from the B-TH web site
N.B A local Dyno expert who has tuned many race winning vintage machines has found that a plug gap as low as 0.007" (Seven thousandths of an inch) does not reduce the power output registered on the dynamomete.
A quote from the B-TH web site
N.B A local Dyno expert who has tuned many race winning vintage machines has found that a plug gap as low as 0.007" (Seven thousandths of an inch) does not reduce the power output registered on the dynamomete.