Mk1 Concentric bad starting from warm

Bill Thomas

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I never liked the Mk1 s, but she runs so good at the moment.
I have just bought a pair of second hand Mk2 s, To me they are a Proper Carb' with Proper Chokes,
I am very pleased with the one I have on the Comet now, Just need to get Manifolds etc, Might get Ron to get them on Open Day at the Factory. If they make the twin go better, 30mm !!, Not sure I will be able to handle
all the Power! Cheers Bill.
 

erik

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flooding when engine is warm shood be contraprductive.what is about the ignition?if the magneto is weak this poor warm starting is a symptom.mostly the capacitor is behind his best days.regards Erik
 

Bill Thomas

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I know what you mean Eric, Which is why I have never done it before.
I have been a Car and Motorcycle Mechanic for many years.
The Ignition is Rita electronic, Not a Mag'.
Nobody was more surprised than me when it started and it did it again half an hour later.
I agree with Greg, That the weak slide may be some of the trouble, But I have tried slightly richer and it wets the plugs, So I had to try something else, I have also tried altering the float level.
Maybe a better Carb' I hope the Mk2 Amal, May fix it, But for now it seems to work. Cheers Bill.
 

Bill Thomas

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Now you have me !, I know nothing about electrics, I don't think the systems made for Vin's are very good.
If they were good, I think you would be able to run bigger plug gaps, Like cars.
When I needed an ignition for my ex L/ning, The only thing on the market was Rita, I hate it but untill it packs up it will have to do.
I now have a spare "D" Distributor, For next time !.
I have the same fault with my Special, With "D" distributor, But with 36mm Dellortos, I have a proper choke.
None of my Bikes Spit back when cold, So I don't think the slides are too weak.
Same on that Bike, If I go richer, Plugs foul in short time.
I think we all agree that the pilot setting on Mk1 concentrics are not good, Some like jets some not.
Brother Ron's won't work with them, Mine won't work without !!.
Cheers Bill.
 

erik

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my opinion is:if you have a weak spark,and you will have it all over the range ,you can Forget carb Tuning.the first thing to check is the ignition.under compression and heat the spark is different from if you screw out the plug and look at it.and when the ignition works perfect and the Timing is correct,then you start Tuning the carb.best regards Erik
 

Bill Thomas

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It's only when it's been standing for a short time after a run, The bike goes too well apart from then.
I have tried 12v twin coil, But it's now back to 2x 6v, It seems to prefer that, Rita told me to try a Twin coil 12v.
If it's still in trouble when I am 90, I will have to sell it !. Cheers Bill.
 

greg brillus

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I'm not sure you are alone there Bill, I've found my bike start straight away after a fuel stop. But if you stop for say 20 to 30 minutes, then you can have trouble. I think it is the heat soak from the engine that Percolates the fuel in the carb. So is it rich or lean for the next start................:rolleyes:..............Cheers............Greg.
 

Bill Thomas

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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.
 

ClassicBiker

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Bill,
I know it seems counter productive to flood a warm engine but my '72 Triumph Daytona has always required a good flooding to start when hot. It has run RITA since the early '80s. In fact it ran the original 12 volt coils until last year. When it started to exhibit what Erik is referring too. I think Greg is correct it is heat soak vaporizing the fuel. I had a '66 Triumph TR4A that would not restart when hot unless I made the mixture extremely rich. I cured that problem by having the radiator re-cored. That brought the temperature right down.
Steven
 
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