600cc Comet Carbie?

BigEd

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I have found a couple of instances where starting became hard with the new BTH mags, the one I struck was on a customers Black Shadow that has always been a good starter. Though I do know he keeps the bike in a shed where moisture is not uncommon. When he brought the bike to me last, he complained of hard starting which surprised me a little, so I gave it a go, and true enough it would not start. After a small amount of brain scratching, I decided to remove the end cover off the BTH (the instructions tell you not to do this, but that never stopped me before) anyway what I found was the two pole pieces which form the primary part of what is basically like a CDI unit where lightly covered in rust .......!!!....Out with the Dremel and a small wire brush, I polished the ends of the pole pieces, wiped them with a clean rag, and refitted the end cover. The bike started first kick, and again, and again, no problem. So the slight build up caused enough resistance to create a descent spark at kicking speed.................. Now there's a lesson for you all............;)
The instructions say this because some people can't leave well alone. You looked and did some gentle cleaning, all that was required in your case. People who venture further will start taking bits off which is when they are likely to get more problems. A simple instance being that if they loosen or take off the rotor arm it is unlikely that they get it back on in the correct position. This can cause the angle between the two firing points to change amongst other things.
 

greg brillus

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Most all people with bikes and anything electrical scares them a bit especially magnetos.........But I spent several months working with probably the best magneto/generator repairman here in Australia. The previous one of these BTH mags I had seen with the same problem, was a member down in Victoria with a very nice rapide who rides rain hail or shine, who had removed the cover off his and emailed me some pictures, the pole pieces and the arm/shaft were very rusty, more than just a light coat too........I don't know what his outcome was as he had been in several discussions with the original owner/manufacturer of these mags. I contacted the chap from BTH and explained the issue, and I suggested that perhaps better sealing of the units might help, but that was some time ago now. I think it is quite safe to carry out what I described, so long as you don't disturb anything else. I have never had a bad word to say about these mags and I have installed quite a few of them, with good success, but occasionally something like this can crop up.
 

chankly bore

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Thanks Dave. Yes you helped me a lot with your ignition timing advice for a twin spark head. To this day it's the biggest power gain I've had, and the cheapest.

My plugs are always wet when I pull them out when it won't start. It seems to me that I aren't able to kick it over fast enough. I have to give it one almighty swift kick with everything I've got behind it if I have any hope of starting it. I have seen seasoned pros start my bike easier than I do so I do think it's a lot to do with my technique, or lack of. I'm getting better, but my bike seems crowd shy.

When I used to run a 48 rear sprocket I found 1st gear a bit pointless and the bike was very vibey? I could never pull top with 46, 4400rpm was about it.

I am running Terry's mk ll cams. I still have my standard ones somewhere, I don't know what profile they are, nothing too sporty I suspect because my dad was a plodder.

Back to the shed.

Thanks again David
A thought. Have you checked that the choke plunger on the Dellorto is bottoming and sealing correctly?
 

Dave Hulstone

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Crikey, was all that 3yrs ago? I ended up fitting a Grosset ignition designed for a twin spark, set at 24/2 and an Alton electric start. I Still have the Dellorto 36mm fitted. I have recently put back on the original, loud, straight through silencer from Armors? while my VOC spiral one is being welded and have had to increase my main jet size from a 145 to a 160 and my pumper jet up a size to keep it happy. It is noticably quicker but anoyingly loud.
Life is good in Vincent world.
 

Martyn Goodwin

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Crikey, was all that 3yrs ago? I ended up fitting a Grosset ignition designed for a twin spark, set at 24/2 and an Alton electric start. I Still have the Dellorto 36mm fitted. I have recently put back on the original, loud, straight through silencer from Armors? while my VOC spiral one is being welded and have had to increase my main jet size from a 145 to a 160 and my pumper jet up a size to keep it happy. It is noticably quicker but anoyingly loud.
Life is good in Vincent world.
Ear Plugs ??????????
 

Bill Thomas

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I wonder what a 2" down pipe with a one off Big Armours Silencer would sound like,
Would it be louder or more Mellow ? :) , I haven't seen my old Race Pipe for many years,
It might be rusted through, I bent it myself in 1980, And it had a few wrinkles, But I liked that it looked home made.
 

vibrac

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my 2" pipe and billet silencer got just under the 105Db limit. but dont construe that as a vote for 2" pipes in real performance I think they are not the best
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