pre-mix %

[hubbo1]

I have a s3 LI with a 185 kit, is 3% mix ok?

[Digger]

3% mix of what?

[hubbo1]

3% two stroke oil

[pacemaker]

if you are running the engine in I would say 4% oil to petrol for 500 miles.

[johnnyXS]

welcome to the forum Hubbo1

What Digger was asking is are you intending to use Mineral oil , part synthetic or fully synthetic oil ? The mix ratio that you use will be determined by the type of oil that you use.
Fully synthetic oil is a high performance low smoke oil which has significant burning and lubricating advantages over the traditional mineral oils so you could use a lower mix ratio .
Is has superior lubricating properties and low burning temperature means less carbon buildup in the engine and exhaust.
Here is a typical fully synthetic pre-mix oil for high performance scooter engines .
http://www.lambrettaspares.com/spares/bgm-parts/pro*race-fully-synthetic-2*-stroke-oil,-bgm/mbgm0446.html

If your engine is freshly rebuilt and not run in some engine builders recommend a 4% synthetic oil ratio for the initital 500 miles or so .
It is important to bear in mind that a higher ratio of oil means that your fuel ratio will be less and consequently weaker. A weak mix will tend to make your engine run hotter which is the last thing you want on a new build .
You'll need to rejet your carb to allow for the change in fuel oil ratio whilst running in to keep the mixture slightly rich rather than weak and rejet again when run in and using a 3% or less premix.

To avoid engine seizure its extremely important to make sure that your idle speed is not too low and the mixture is not too weak . When you deaccelerate from 50mph+ and shut off the throttle, the engine is still being driven at 5000rpm or whatever by the rear wheel but it now only has the very small amount of petrol and oil flowing through the idle jet to lubricate and cool the piston and rings . Thats the time you need to be particularly vigilant for signs of a seizing engine

[Digger]

What he said....

[hubbo1]

thanks very much.

the engine is just rebuilt and am running in, I am using fully synthetic.
should I still be using 4% then 3% after it is run in?

[johnnyXS]

well thats the 6 million dollar question isn't it !
There are as many opinions about that as there are makes of oil !.
There are some racers that use 2.5% and even 2% mix I've read.

Given the inexact way that most of us mix our oil and petrol I suspect that most of us are running our scoots on a continuously variable mix probably ranging from 2-4% anyway

If you are using fully synthetic then by most accounts the engine should be fine on a 3% mix after running in but a lot will depend on the type of riding you do ie pootling round town or long distance touring rallies etc.
If your engine was built with particularly tight tolerances as many seem to be today ,you might need an extended running in period of a further 250 miles or so until the rings and piston have less friction, there again there are some that can reduce the running in period to a few hundred miles or so by their driving technique and experience.

I would suggest you reassess when you get to 500+ miles and if you have not experienced any indications of seizing and the scoot starts and runs without issues then reduce to 3% . However if you were going on an extended high speed trip like a coast to coast etc then I would personally be tempted to use 4% for that journey on a new engine.

Hopefully others with more experience than me will add their experience to this thread.

[hubbo1]

I think I will stick to 4% until run in then try 3%-most of my mileage will be town and the occasional A road.
thanks for the info

[johnnyXS]

no worries I hope it was helpful.
I hope you'll come back and let us know how the running in goes.
If you have any pictures of your scoot you can post they are always of interest

[burnside]

I tend to put in approx 3% oil in all of mine (but 4% when running in). Semi-synth in iron barrel, fully synth in Nicasil. Never had any lubrication issues

Just make sure you jet according to the mixture, as said above using more oil will result in running slightly leaner.

[hubbo1]

10403013_10205262173329981_3616530222587202016_n.jpg

this is it
it looks blue in the pic, but it is Caribbean turquoise (an old ford colour)

[johnnyXS]

very nice , clean and uncluttered ...a modern classic look .
This is how I personally prefer them these days but I must admit I still have a soft spot for those with the 'Little Mod' look which is how many of us rode them back in the late 60's

[Gary Harwood]

I have two TVs that both have Nicasil top ends. I have always used nothing but fully synthetic oil. I ran them both in at 4% mix and following running in I reduced the mix to 3% plus a bit for good luck (so I guess I'm mixing at about 3.5%). One of the scooters has now done 13,500 miles, and the other one 5,000 miles, since the Nicasil top ends were fitted. I have had no problems with either of them.

[Loneranger]

I have never filled up my Lambretta at a petrol station, yet!
Since I built my TS1 225cc engine, I have used a 20 litre Jerry can, filled it with exactly 19 litres of unleaded Murco petrol and then taken it home.
I then have CAREFULLY measured and added the two stroke oil, mixed it thoroughly and then filled the fuel tank from the can.
During running-in I used 4% using Mineral to help the running in of the engine.
After 600 miles I changed to Rockoil fully synthetic at 3%.
Now using Rockoil fully synthetic for injector type system as I understand it mixes better.
Never had any running issues at all.

I believe that the correct ratio is very important and if mixed 'about right' at a filling station, that's when you might have an issue in the next few miles. Might just have opened a can of worms with that one!!!

Keep the faith and ENJOY being a Scooterist whatever your choice of scooter style that may be.

Ady

[burnside]

Wow over 600 miles and you've never had to refill whilst out?

You really don't need to be that precise, approximate is just fine. When I fill up I look in the tank, guess how much fuel I need then put in that amount of 2 stroke oil and then fill up (this way round it mixes it up). I never get it spot on, it's always a little over or a little under, as long as it's roughly right it'll be fine.

[Digger]

What he said but I always put my oil in last. The fact that it's a Lambretta will soon disperse the oil around the tank.