Bike is a 2008 ZX14, It's been sitting for nearly a year and a half with very rare use. Now that I have a long commute again I've started using it a lot more. I noticed the last time I rode it when moving house the front brakes were very soft. I bled the lines and all was good on the next ride. It sat again and during this time got soft again. I replaced all the fluid in the front rear and clutch system and bled everything. Clutch and rear are fine but the front fluid has gone murky again and within a week is spongy again.
I am thinking that something has corroded while it's been sitting. My question is what should I be trying first? Lines, calipers or master cylinder?