The coolant volume is very variable, depending on the model, type of radiator, (Full-width core or a slot up the middle, honeycomb or film core, size, etc..) I think that most Scotts will come to the boil after 10 minutes or so not moving ! The old honeycomb cores are very efficient, and if you come to the boil in traffic, they will come off the boil after you have only gone a few yards. I’ve said this before, but when filling your radiator you should always ‘burp’ the trapped air out of the top shoulder on the opposite side to the filler. Fill up to the level of the breather pipe, then lean the bike well over to the side opposite to the cap, and you will hear a glug-glug-glug sound as the trapped air goes over to the filler side and then escapes. Then top up again. If you think about a bit of schoolboy physics, gases expand a lot on heating, while water expands very little in comparison. So, any trapped air expands a lot as the coolant heats up, and immediately increases the level of the coolant, which promptly escapes down the overflow pipe, leaving you with a low coolant level and far more prone to overheating. Please also check that your overflow pipe isn’t blocked.
Brian
