C15 Unleaded Petrol Cylinder head mod

[Steve C15]

Hi does anyone have any info about how to best convert a C15 cylinder head to run on unleaded petrol please ?

Or know a company that does the required work to the head ?

Steve

[Mike Farmer]

 

Run it with REDEX in the fuel

Mike

[DAVE BRADY]

Hi Steve,

If the seats are in reasonable order then have the seats ground rather than cut and they should be good for many thousands of miles.  The seat inserts used by BSA where of good quality unlike those of the motor industry of the same period.
I have run an A65 for many thousands of miles on the original seats with no excessive seat recession.  Unleaded from the pump with no additives.

Dave.

[Colin SS90]

I was also worried that my SS90 hadn't been modified to run unleaded, but after reading various articles about the high mileages that need to be covered to damage valves and seats I decided to just run it on straight unleaded, although I now add some Castrol R to the petrol (about 100/1 mix) just for a bit of peace of mind and a classic exhaust smell. I also worry about the oil settling in the bottom of the tank, so I give the bike a good shake before turning on the fuel.
As another added precaution I check the valve clearances quite often, they don't change so that's another good indication that unleaded fuel is not detrimental to the engine.

[Steve C15]

Thanks for the info lads.

I like the R40 trick.

I will give it a try.