Mk1 Concentric bad starting from warm

Bill Thomas

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Years ago as a Car Mechanic, I used to go on breakdowns To find mostly women had the choke out, Because they always start it with the choke out !!.
Reminds me of my Dad, Went to the doctors, The Doc' says this is to stop your headache ,Dad said, I don't have headaches, Doc says you will after you take these other pills.
They are putting so much junk in this Petrol, And we all know it's not good for us, We were better off with a bit of lead. Cheers Bill.
 

Len Matthews

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The thing is Greg, I have only been out the once, This year, And with me giving it a good flood, I can't fault it,
YET !. If it would only stop peeing oil from where the Macdougleator goes in, It would be Perfect !.
Gave it a good clean up and it looks Super.
Now Comet time, Cleaned it up last night and it's looking the Bizz.
I wonder if it's going to be good this year ?.
Might try and get out later.
Have Fun, Bill.
Bill, in your post you mentioned McDougalater. I had a spate of starting problems until I ditched the car alternator I had used for years. As you know car type alternators need battery input to start charging.Mine was robbing power from my ignition coil hence the starting problems.I'm now using an Alton which requires no battery input.
 

greg brillus

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I put small insulator spacers between the cylinder head and manifolds, but I don't think it did much. Perhaps the spacers need to be quite thick to have more affect. I think this is an offshoot of the modern fuels, where it appears that the top end volatile properties of the fuel boil off quickly. This explains Steven's comment about the need to enrichen the mixture on a hot engine, something that was not needed with leaded fuel. The experimenting to get it right can drive you nuts at times, and can cause havoc with your right leg too.
 

Bill Thomas

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I have them on the l/ning, And my special with Dellortos has a nylon sleve where they fit over, Always thought the carb was too cold !,Very strange. Cheers Bill.
 

Normski

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It may be as Greg says, heat from the head transferring into the carb body and vaporising the fuel. Tickling would put a fresh lot of cool petrol in to counteract this. That would explain the contradiction of flooding helping a hot engine to start. Triumph specified a thicker o ring than the Amal one for the carb to manifold fitting which along with some stepped studs and rubber bits meant that there was no metal to metal contact between manifold and carb. Even after a good thrashing you could feel the heat difference either side of this with the carb being cool - set up like this there was never the fear that a quick stop would lead to starting troubles. On my Egli I've monoblocs with 1/4" Tufnol spacers but there is still some slight metal to metal contact through the mounting studs, it's on the job list to insulate those too. As an aside I've never had carb icing with a Brit bike but it has plagued some oriental ones.
 

Bill Thomas

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Morning Norm, I have had icing with my E.I. flat slide carbs from USA, Only at slow running, I guess it's when the air speed is so high though a small gap, They were on Rubber mounts like Amal Mk2.
I think Amal said you have to run richer with this new petrol, But I have found you have to lean the carbs off or it fouls the plugs, I might have got that wrong !!.
I wish I had not sold my T.T. carbs, They just needed leaning off, But I didn't understand what was going on !.
Glad Steven and Norm are backing me up, I thought I was going Mad, Why has this not been in print before.
Cheers Bill.
 

macvette

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I thought you might like this Bill, it's from the blue'un in 1956 20180425_073249.jpg
 

Normski

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Is the engine using any oil Bill? Could you be leaning it off to make the plugs hot enough to keep them clean of oil? ( I think you mentioned that possibility in a post above) What happens with the next grade hotter plug?
 

Bill Thomas

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I thought you might like this Bill, it's from the blue'un in 1956View attachment 21971
Thank's Mac, They were good times, I think we have all drunk a bit of that, When getting petrol out of a tank !.
It was still good in the late 70s, I ran my Special with 12 to 1 pistons on the road and track, Was doing 110 mph over the finish line of 1/4 mile standing start 12.5 seconds.
I have had a taste of this new stuff !, They say I should be Dead.
Cheers Bill.
 
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