@nottsbiker As @AndyYam used to say, the competition WR had those same bottles. They wouldn't restrict a competition bike.

@tdrnoob That should pick up a lot quicker than that.

This needs investigating for sure.

If it's running lean, then the plug will be plastered white.

It's hard to tell from that video, but that's where I'd start.

@nottsbiker It's not a silencer. It's Yamaha Energy Intake System and is used to as a resonance boost bottle.

I've explained it before, but probably poorly. Definitely research it.

@oldman It's just good we can still get them. Won't be long before they're discontinued.

@tdrgreg2 No it was worse than the RE engine lol.

It's all in that build thread.

It's a very special engine, it was an engine cast using motori minerelli stamps, indicating that it was a genuine Italian built engine.

But the casting is week, the cylinder is, well poor and it is in fact the SP you really want. Good luck getting one, it would be easier and cheaper to run another 125 super teen engine in the DT frame, like oh I don't know the Rotax 122 engine which can be had cheap and tuned better!

Can't find an example of the porting. but it's insane.

Until you look at the rotax engine, which again was mass produced, then you realise you're paying a lot of money for not much really.

@tdrgreg2 Super teen was a racing series for teenagers to enter. Due to their age and experience, the series was designed to race 125 two strokes.

Teens would predominately race Aprilia RS125's, Honda RS125's and the Occassional Yamaha TZR 125 RR

The engine in that bike is a direct fit into the Yamaha DT125R.

I fitted that into my DT.

@finnerz89 Mine don't lmao.

They have to send it away. But yes, they offer that service, but don't do it personally.

I used 200ml oil to a full tanks. Approx 10 litres.

Lovely little whistle to that engine too. Sounds great.

Who's building the engine? Them?

Basically, the engine should be built with lots of two stroke oil.

Bleeding the oil pump would happen naturally as its not a closed loop.

But if they are building the engine then you can't be certain of how much oil they've used.

So you best off filling the fuel tank up with fuel and premixing it with two stroke.

Probably best not to do a full tank, but enough to see you down the road.

As I have suggested to many, replace the line from the pump to the carburettor with a clear hose, that way you will see all the air being bled out and when the hose is full with oil, you know not to premix.