Fuel selection and additive

Not open for further replies.
Dec 5, 2007
1970 commando 750 S . Hi in Australia (and elswhere) i guess we now have no leaded fuel available. The best I can get is unleaded 95octane. Do i need to add a lead replacement to the fuel to protect the valve seats? i have an old mustang that i need to do this to but not sure if its required for the bike

The valve seats and the valves are made from the same material. There is no need to replace the seats and no worry about unleaded fuel. So if you have a shop recommend this run don't walk away.
If you are very lucky you can find a shop that does good head work. Good head work is when the fit in between the valve guide and the valve stem does not exceed .0008 and the valves are dead concentric with the seats. Good valve guides are made from Alum/bronze like Amco 50 it is hard to machine and hard to wear out. Map cycle and Rowe do the best guides. Most people use Black Diamond valves that have a super hard and thin coating on the stems.

I agree with Norbsa, no need to replace valve seats.

But I would recommend an additive, I use Morris (superclean zero lead) with good results in all my classics.
Contact morrislubricantsonline.co.uk.
It treats 6 litres petrol to 20ml additive and I get no pinking and ride my Commando's hard.

Castrol also do an additive ,Castrol valvemaster which is popular in UK.

I would stay clear of the Fuel Cat,which you drop in the tank,once only treatment.
I tried this on two of my Commando's + other halfs Triumph Thunderbird & her daughters Triumph 3TA with the same result they all run Rough!!
It was a good job I placed some wire around the gauze as I could fish them out of the tanks easily & throw them as far away as possible.

Good luck.
Not open for further replies.