Hi all, bought 2001 929 in Feb with 15000mls up. Feels like a solid bike very happy. Doing a bit of a service and flushing the radiator, but when i start putting coolant back in it only takes about 2 ltrs whereas the haynes manual say it should take 3.5? Any ideas? I gave the system three good flushes so dont understand. Also the radiator is covered in white crap? As an aside when bought, the chain was tight so went to loosen, but couldnt get wheel straight, took off rear wheel and it was missing a spacer- SCARY
I had the same problem as you, got 4liters of coolant and only opened 2 bottles. I was bleeding the system for ages, thinking I'd done something wrong. After many hours of head scratching, I came to the conclusion it was because of the outlet position on the radiator itself!!! I had drained the usual way at the water pump, that will drain all the pipes and the radiator but only down to the outlet height. So the bottom half of the rad still had coolant in, the only way to full drain is to remove the rad. The outlet is halfway up the rad on the fan side!!!!! I think the white stuff on the rad is corrosion, the paint on mine just fell off, leaving it white sort of chalky feel, I rubbed it down best I could, an Hammerited it, in situ.
Thanks appreciate info that is most likely what has happened but wont be removing rad too much trouble cheers