This is my style ( if you disagree, simply don't follow ).

First, I remove the glowplug and pour few drops of engine oil into the hole.

Secondly, without the glowplug on the engine ....... I turn the flywheel anti clockwise and I try to feel the piston's upward movement to TDC.

If it feels smooth or quite smooth then I consider the break in process is done .

( If I fell stuckness or pointy ..... it means the break in process is not yet completed ).

When you can barely feel any metal pinch at all with the glowplug IN cold, is when the engine is getting to the fully broken-in spot. That metal pinch will not be there when the engine is hot. I find the engine will want to load up more when they are this spot, since the cold pinch affects it more. When warmed up, they idle more consistently and run fine.

Well, that "metal" pinch is there even when the engine is hot, so it tells us that there is a long way for it to be fully broken in, right? It has run less than 1/4 gallon so far.

Thanks for the reply, I checked this and there is a lot of stuckness... these Plus engines will be a lot harder to break in than my Picco motors:sneaky:

When you still have the metal pinch when it's hot it's defiantly not broken in yet. But you will notice that the engine wants to go faster and faster on a point, around then the worst pinch is gone and you can start leaning the engine. Then i always keep driving it fairly rich until it get's a stable tune and doesn't richen itself while on the track.

The metal pinch when cold could stay for a long time if you have a good engine.
For example, one of my current JP engines still has tremendous metal pinch after 5 liter of fuel. But when it's warm the metal feel is gone and it is running perfectly.

A quart of fuel is nothing. At 3/4 to 1 gallon is when that motor should start to feel good. I would just run it now in the car at a good pace. As it breaks in more, it wil start running too rich, so you will have to lean it. Once it gets to a consistent tune, it will most likely broken-in at that point.

When you say the metal pinch, means it locks up when its TDC when cold?

Yes, when cold. The engine will have a tight bind (metal pinch) feeling before TDC. When you barely feely any bind or none at all, just smooth good compression, the engine should be fully race ready and broken-in.

Yes, at between 3/4 to 1 gallon (just like ezveedub said) the engine IS FULLY break in. From this point, the engine will be in highest performance. This superiority will last usually only 2 races. After that point, the engine's performance is going downward.

So, competitively speaking, it only last 5 races huh :lol:

Actually, the engine will run for a while, provided you get a nice carbon ring around and down the piston skirt. This carbon layer will fill in the areas where there is no metal contact, forming a nice compression seal. Leakdown is the killer of any engine. I find some engines have nice compression, but slowly leakdown to TDC. Thats the sign of a worn or bad motor, and they usually can't keep the idle going for long.

Thats enough for me:) I run about 3litres of fuel per race(3 days), so 5 races would be 15lts of fuel.

I used my 12-3SCT at the Motonica GP race this past weekend. This is my first Novarossi engine.

I put a quart of Trinity break-in fuel through it first (a few tanks at idle then running it on the track very rich). Between tanks I let it cool. By the end of the day I switched to my race fuel which is Werks 30%.

I got advice from Novarossi USA and Garen at the track that it's OK to not add shims for 30% unless I lose plugs (which I have not). So I didn't...

Day 2 and 3, the engine ran great. It never stalled, always started easily, and I ran it around 210. It felt a bit rich and I knew I could lean it but I want a long life from this engine so I'm taking it easy. Even at these settings, the engine was strong and well worth my money.

Does anybody know how many original shimm are in the 353 09 engine

1 single piece aluminum shim that measures 0.30mm

In theory that does not work. The piston and sleeve are form different materials and you have to do with expansion of both. An engine can have a lot of pinch in cold conditions but the fitting at operating temperature could be just right.