Best Oil for 350 Engine

robinh44 · Post by **robinh44** » 03 Apr 2007 19:29

Hi,

Wondered what people in the group would recommend as the best oil for the Morini 350 engine, I know the top end relies on oil mist for its lubrication, just wondered if some types of oil 'mist' better than others?. Thanks in advance.

Regards

Robin

Jem · Post by **Jem** » 25 Apr 2007 19:36

over here in Bristol many of us use Morris semi-synthetic. I don't know about "misting" qualities (you probably need to ask a chemist from the oil companies) but I guess that lighter oils - 10W/40 - will mist better than the traditional 20W/50.
My own belief is that having too small a bore for the rocker cover breather pipes restricts the flow of air/oil to the valve gear so make that breather breathe.

robinh44 · Post by **robinh44** » 25 Apr 2007 21:09

Jem

Thanks for the info, I realised how important the vent pipes are on the valve covers so have replaced the old hard plastic tubes with some good quality rubber hose.

Regards

Robin

3narf · Post by **3narf** » 30 Apr 2007 11:58

I seem to remember NLM advising me not to use fully synthetic as the gear type oil pump shreds the polymers.

I use mineral-based Silkolene stuff, Comp-4 I think it's called...

You can use any motorcycle-specific oil (you need the EP additive for the gearbox) as long as you change it in timely fashion. Don't spend too much for oil for a Morini.

robinh44 · Post by **robinh44** » 30 Apr 2007 13:06

Hi,

Yes it makes sense, when running old engines use oil types that are friendly to the older types of rubber & plastic in use in them. Halfords still stock a mineral oil for older engines as well.

Regards

Robin

EVguru · Post by **EVguru** » 30 Apr 2007 14:57

The oil NLM normally recommend is 10W40 semi-synthetic.

Morini themselves specified Agip SINT 2000 on the late bikes.

Fully synthetic would be fine, but not really justified on cost.

The better synthetics are effectively monogrades, but with such a high viscocity index that they behave like a multigrade. Polymers that ravel up or unravel with temperature to maintain viscocity are mostly added to mineral oil. The 'supermarket' oils tend to have a high polymer content added to a low quality base oil (poor viscosity index) and break down quite fast. Fine on a bike that does 1000 miles a year and has a pumped rocker feed, but not the best for a Morini.

Most oil pumps are gear type, or at least trochoid, rather than vane and don't degrade the polymers faster than the oil gets contaminated. It's roller bearing crankshafts (like my Tornado) that can 'chop' the polymer chains up.

I use a semi syhth and change it whenever I can see it on the dipstick. Synthetic oil 'clings' and keeps the valve gear lubricated when the bike is layed up for a while.

If you want to stick to a multigrade, you can still get Duckams Q 20W50 from Halfords and through the A1 motor factors chain. I hate the stuff; The trademark green colour is actually designed to rapidly turn black making your oil look dirty.

robinh44 · Post by **robinh44** » 30 Apr 2007 15:29

Paul

Thanks for the excellent advice, maybe I will stick to the Comma semi-synth I put in all my other vehicles.

Robin