Motorcycle Repair: CBX 1000 Fuel and Oil, castrol valvemaster, wet clutches

Question
Hi Jan

My second question today! Here's hoping that's OK.

I'm trying, with amazing difficulty, to determine what fuel and oil a 1979 CBX 1000 Z should be 'fed'.

Fuel choice in the UK is from either (1) - unleaded or (2) - unleaded with lead substitute additive and octane booster (replacing leaded 4 star, Castrol Valvemaster Plus being what I use in my old classic car).

As for oil, an engine/gearbox oil suggested elsewhere is 'Castrol Act Evo 4T 10W/40 mineral'. Having read the description (e.g. at www.nielsencdg.co.uk) I'm not convinced - all the mention of additives worries me. I understand that motor car oil is unsuitable, because of all the additives. I've also read that anything other than mineral oil, such as semi or fully synthetic, will cause main clutch slip, maybe even starter clutch slip.

Here's hoping you can advise, please.

With Thanks and Regards
David  

Answer
I normally buy the better grade unleaded fuel for the CBX, lead substitute is not necessary, and the recommended oil is 10W40.  Synthetic oil is much thinner and can indeed cause undesirable effects such as clutch slip, although some of the CBX owners have good results with motorcycle synthetics made for wet clutches.  Bottom line is as long as you change your oil and filter regularly, you will be fine.  Don't forget the metal washer on the filter, between the filter and the spring.  It sticks to the filter when removed, and is amazing how often that ends up in the trash with the old filter!  Good luck,  Jan