1150 gsa

My local Tescos is selling Castrol Power 1 10W-40 4T SL oil for £3.12 a litre, down from £12.47. My 1150 GSA currently uses Castrol 20W-50 Activo and burns the usual amount. My questions are: 1. Would the 10W-40 be okay? 2. Will the bike burn a lot more due to the thinner consistency? 3. Given...

My GSA has around 135,000 miles on it. The cam chain guide had disintegrated and there is a horrible low-level vibration from the bottom end of the engine. So I bought's a second hand 40,000 mile engine of eBay to do a swap. On the forums, I'd seen a thread where somebody had set up a DIY...