Author Topic: De coke  (Read 619 times)

Offline Goldy

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De coke
« on: 12.01. 2012 19:12 »
I have taken the head off the A10 to do some jobs over the winter. I am amazed at the amount of carbon on the piston tops and in the combustion chamber, it,s only 1500 miles since I put it all back together. I have been using valvemaster in the petrol, could this be the cause. Any thoughts.
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56 A10 Golden Flash - Restore, ride, relive.                                          
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Online bikerbob

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Re: De coke
« Reply #1 on: 13.01. 2012 16:38 »
Hi there
I have been using Castrol Valvemaster since it first came on the market a good few years ago and I had the head off my A10 Gold Flash last year and the amount of carbon on the head and pistons was what I expected for the mileage done  nothing out of the ordinary. If you have excessive carbon build up I would be looking elsewhere for the cause maybe you are running to rich.
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Offline BSA_54A10

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Re: De coke
« Reply #2 on: 14.01. 2012 15:33 »
Have a good look at the inlet valve stem.
If there is a heavish deposit on the stem they you have excessive clearence.
Other then that then you are looking at poorly seated rings
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Offline Goldy

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Re: De coke
« Reply #3 on: 15.01. 2012 13:44 »
i think the mixture might be slightly rich but not far out the valve guides were replaced but not looked at the piston rings, thanks Goldy
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56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing