You have an open center hydraulic system. The pump volume is adequate to run a loader. One good way to tap into the system is to cut the smaller (pressure) line coming off the pump and install a compression fitting and run that line up to the loader valve. Come out of the valve back down to the tractor line that you cut and connect with another compression fitting. This makes a "loop" where the pressure runs through the valve, and when the valve is activated, it diverts flow to the appropriate ram. You can also use 3 lines and a power-beyond, but this is simple and works with the correct valve.
Warnings: If you hook it up wrong and deadhead the pump, it will ruin the pump in about 2 seconds. Sometimes you get lucky and only shear a key.
This tractor will be unstable with a loader. You will have to ballast the rear a lot. If it is a 2wd (no "D"), you will notice a loss of traction because of the weigh on the front and consequently transferred off the rear.
I have 2 really nice YM1401's in stock and I will not install loaders on them for safety reasons. Perhaps if you got a real light loader and sized the rams down, or regulated the pressure to keep the maximum lift down you would be ok. On a short wheelbase narrow tractor, you must really watch the rollover potential. The tractor weighs about 1100lbs, a decent loader like a Koyker 110 weighs about 600 with brackets and bucket, so we have a total of about 1700 lbs, most forward. The bucket will lift nearly 1000lbs. If you have it lifted high and get on a small slope or drop a tire into a rut, you are going to roll. Be careful!
