Just had 1000KM on mine and filled it with Full Synthetic (Penrite).
Dealer today told me I should wait until at least 5000KM before going full synthetic, and told me to switch to semi synthetic.
He advised he has seen numerous bikes with glazing issue due to going full synthetic too early. I asked the dealer why this isn't mentioned in the manual, and he said it was common knowledge.
So today I removed the full synthetic and put in semi synthetic (Penrite).
Rang dealer and told him I put in semi synthetic as advised.
He told me I should have used Yamalube (semi) as it was designed especially for Yamaha bikes. Yamalube is also twice the price.
Last week I contacted Castrol to ask about running full synthetic in a motorbike after the 1000Km. Castrol advised me I will have engine issues (glazing) if going to synthetic too early. In fact he referred to the exact same issue (glazing due to going to full synthetic too early) with the Ford Falcon XR6 Turbo (BA) that is sold here in Australia. I rang Ford to check if this was true and Ford told me they never heard of such issue. Ford also advised me that Full Synthetic is now standard on most European cars.
Also rang Mobil and they told me that it's fine to use full synthetic (it's on their website).
I have had 3 previous motorcycles and 3 cars, all of them ran full synthetic from the beginning (whatever was on sale). My latest car (Toyota Avalon with 1MZFE, heads made by Yamaha) has over 300000KM on it. A mechanic recently advised me that the engine has hardly any worn parts and it looks brand new. He told me whatever I am doing keep it up.
Who the hell do I believe ??