Fuel and Additive

[jonnierw]

Hi to all I've just signed up here.

I've only just started riding my 1977 Bonneville again. I was told the best fuel to run it on is the higher octane fuel (97). I've been told 2 things about using fuel additives. someone said they will help (the lead replacement additive from RedEx) and another person said don't use them at all.   What do you guys think?

Also the spark plugs get very blackened very quickly, even thought its not running rich.   Is it just burning a lot of oil or do I need to lean it out a bit more? also can i add anything to clean up the plugs?

Cheers

[Goldy]

Hi and welcome. If you look back through the pages of the forum you will find lots of discussuion on lead replacement additive. The general opinion is that if you run the engine at high revs and do high milage then you possibly need to use an additive. If you ride occasionally at medium revs, then dont worry about it. Enjoy riding it anyway.

[L.A.B.]

the spark plugs get very blackened very quickly, even thought its not running rich.   Is it just burning a lot of oil or do I need to lean it out a bit more?

Before you do anything it is important that you know how to tell the difference between an oiled plug, a plug that is too cold, and one that is showing signs of an over rich mixture.

http://www.spark-plugs.co.uk/pages/technical/diagnosis.htm

Also what plugs are you using?

As the standard NGK B8ES heat range plugs are considered by some owners (including myself) to be too cold, except for high speed running.
NGK B7ES are hotter plugs, so do not tend to foul as much.  
 

[jonnierw]

Thanks for help, I think I have sorted the problem. The plug I was running (NGK B7ES) was running a bit cold and the mixture was a bit rich.

I leaned out the mixture and after 100 miles so far the plugs seem to appear correct.

Thanks for the Spark Plug website L.A.B it was a big help.

The bike starts after a couple of kicks now as opposed to the 10-15 kicks it was taking (my right leg is now slightly bigger than my left!)

[dicky-yrrep]

I have started using castrol valvemaster plus,  lead and octane replacement for my super rocket at around £15 for 250 ml its twice the price of a decent bottle of whisky !! however it does convert 250 litres of fuel and is endorsed by the British Historic Vehicle Club. I obtained mine from Halfords although search ebay for a far better deal. Castrol also provide a technical advice line 01793 452 222

[Rex]

I'm sure it won't do any harm (other than to your wallet ) but will it do any good?
The A10 is a tough old bird, and not known to be prone to valve seat recession or other valve/ignition problems, especially after 50 years of use has it all hardened up nicely.

I'd save the money for a single malt..

[twolitre]

I have said many times that the fears of using unleaded fuel in older cars and bikes is largely unfounded.

I have run a 1968 2 litre Triumph car engine for over 80,000 miles on unleaded and I am still awaiting the dread after effects. Both my 1959 Triumph 5TA and my 1956 Triumph 5T run on unleaded and I am not expecting trouble for many thousands of miles if at all.

Anyway, if I do suffer valve seat recession (pocketing), the money I have saved by not buying additives will pay for valve seat inserts etc. many times over.

Save your money!