Petrol - petroil ??

[Arthur Farrow]

In the next day or so going for my first Silk run.

Do any of you guys use Oil in the Petrol? Even a little bit? I have no reason to think the pump faulty and she is sweetly smoking with some 50 - 1 Petroil I drained out of my 28 Scott on the understanding that more oil especially in my running in phase is better than none.

I only had about a pint of that Petroil so before I go out I'm tempted to stick a gallon (4.55 Litres to the Imperially illiterate) of maybe 100 - 1 in it

I use Silkolene Comp 2

I'm rather hooping most of you will say just put 100% Petrol in it.

[hendred]

Petrol only for me.  I was using Morris semi syntheic oil and found it a bit smokey.  Came across some Morris full synthetic at a very good price. Runs well on it and hardly smokes at all now.  Need a drip tray under the exhaust now instead!

[Smokey_Paul]

I ran 100:1 with comp2 no problem at all, especially on a new engine worth a go

[Nick]

Where do you get your Morris oil?

[hendred]

Trago Mills near Liskeard or near Newton Abbott. Cheap because it is not in the current packaging.  When I run out I will get some oil from Smith & Allen.  They have a good reputation and are very competitive on price and have a huge range of oils, link to their synthetic 2 stroke:

https://www.smithandallan.com/products/transport-motorcycle/3477-smith-and-allan-powertech-pro-comp-2t---fully-synthetic-ester-2-stroke-oil/

[Nick]

I was told by a local motorcycle shop that Semi was best for bikes with ball bearing main bearings as the fully synthetic could make the balls slip.

But I don't know what the mains are on a Silk?

[hendred]

You will find the bearings in the technical section on the main site.  The main bearings are rolling element bearings.  The  problem of slip (if it really does happen) seems to be on 4 stroke engines with a more copious oil supply.  Plain bearing 2 strokes were made but as far as I'm aware a long time ago.  The synthetic oils mentioned here are designed for 2 stroke engines so I don't believe there will be a bearing slip problem using them.
The Silk engine has a plain bush little end and I believe the synthetic oil is beneficial here.  There have been problems with little end bearings and gudgeon pins wearing pistons - I have a pair with badly worn piston gudgeon pin holes.

Synthetic oils may not be recomended for initial running in as they have been know to make the bedding in of piston rings excessively long.

A search for engine oils on this site will bring up previous discussions.  I have used semi and fully synthetic oils with no problems and I know one Silk owner who has put 50,000 miles on his bike on mineral oil.  As always, pay your money and take your pick.

Hope this helps.

[Nick]

Thanks for the detailed reply Hendred, I am a life long motorcyclist but am struggling a bit with the Silk without a manual explaining details of the bike and full photos or drawings so you know what is inside the different engine cases!
My bike has a gas valve fitted down by the 2 stroke oil pump, that needs turning on before use.
do they leak past the pump or could it just be that when it was recommissioned in 2018 it was left to drip in like so Scotts do.

[hendred]

If you look in Technical/Downloads in the main site you will find the manuals supplied with the bikes.  If you look at the engine strip section it will give you some idea of the internals. There shouldn't be a tap in the oil line.  It will potentially cause a lot of damage if it is forgotten to be turned on.  My bike will sit all winter without a problem as it is a positive displacement pump.  If you have a leakage problem check the condition of the small O rings behind the oil pump cover.  They should be replaced if you remove the cover.  There are two more O rings between the pump body and crankcase and these should be replaced if the oil pump body is removed.  If you look in the manuals it will tell you which bolts remove the cover and which remove the pump from the crankcase.
Hope this helps.

[JJ]

Definitely petrol only in the tank, unless for some reason you want a smoke screen behind you and charred coating on the piston tops that will not help the gas flow.

[Smokey_Paul]

Petrol only for me now the engine is run in and pootling along happy
No to the tap have no idea why that has been fitted. Hendred hit that perfectly on the head