Replacing the stock fuel tank and filter (chinese vtwin)

[iron_monkey]

I was surprised to find that 3 pipes run from the engine to the fuel tank, instead of one. 2 of those pipes (one from each cylinder) are called "return oil pipes" in the manual. So im guessing the fuel tank also has an oil tank?

This is not a dry sump engine, and those pipes seem tiny for oil feed pipe. What do they do? Are those pipes redundant? How do a deal with them when I remove the fuel tank?

Can someone direct me to the kind of fitting I put on the intake manifold so that I can use an aftermarket filter?

[gilburton]

Fuel return pipes.You'll need to return them to the fuel tank or possibly this solution??https://www.dieselbikeforum.com/view ... f=33&t=240
They will be from the injector pump and/or they might be from the fuel tap or filter??
They aren't under any pressure so normal fuel pipe using a "Y" or "T" type fitting to get a single return to the tank will suffice.
If you look how some petrol bikes have a tank breather something similar could be added to your chosen tank for the return.
When it says oil it means DIESEL oil!
These engines don't seem to be available in the UK but there is plenty of info on this site from the rest of the world!

[sbrumby]

These pipes are called leak off pipes. All diesel engines have them. When the injector pump forces high pressure diesel to the injector it unseats a piston in the injector held in place with a very strong spring. When the pump ceases the piston reseats but a very small amount of fuel leaks past the piston this just trickles back to tank. Some people just feed this into the line from tank to pump others just run a separate return to tank.On a twin these can be pipes 2 into 1, on a car it is 4 into 1.

[coachgeo]

Study your engines system to see how it bleeds air. Unlike a petrol engine........ air in the fuel system will STOP a diesel engine. Somewhere in there is a way to bleed the air out that makes its way in there. Often this air is fed back to the tank via the return line.

Do these small engines ALSO have an Injection pump (IP) return line? This line is not a trickle but a flow of fuel. On engines I'm familiar with the injector return lines actually get dumped into the IP to tank return line.

If you loop the return lines right back to the IP then eventually you'll have an air issue. There is ways around it. Some just put in a air line valve and occasionaly bleed air out of it. It does take a while to have an air issue....... IFFF you dont have an air leak??