hi I have a 88 fs1 I am currently restoring I have checked the piston and barrel and it is 43.00 mm not standard 40 so nice and tight I have changed the carb a mishumi 16sch which does have a slight sticking float problem so occasionally drips out of overflow I have fitted a early fizzy exhaust wadding taken off baffles points good timing not checked yet and new spark plug I no it is a restricted model but when I accelerate I can get it up to 40 mph in 3rd gear soon as I put it in to 4th the speed drops right back to 30 so frustrated any one out there no about these bikes please