2 Stroke help please.

Not sure if anyone knows about 2 strokes but my son has a 50cc 2 stroke Derbi Senda X-Treme SM, for the moment we are using pre-mix as I am not convinced the oil pump is working properly for the 2t oil.
The oil pump is on the side of the engine and is controlled by the throttle cable (comes from the throttle and then splits into two, one cable goes to the carb and the other to the oil pump).
To prime the oil line you let the engine tick over and manually operate the cable, you can see the oil going up the tube to the carb a little bit at a time which is fine , you do this until it is all the way to the carb. Problem is that when you come back to it a couple of days later it needs priming again which is not so good. I can not see any oil leaks, any ideas?

no idea at all just a complete gess is there an air lock in the tube? try bleeding it and see what happens soory not a lot of use bin a long long time since I had a 2 stroke lol RD125 what a bike  

Hi Andrew, after starting the bike, how long does it take for the oil to reach the end of the pipe after it's rested a couple of days?, Things to check are..Oil hose blocked or kinked? release it and see if oil flows freely, air hole in oil cap blocked causing a vacume? try it with cap released to allow air in the tank , Have you bled the pump properly till all air bubbles have gone? Is there a bleed screw on the pump as well as letting it pump out of the end of the pipe?

simbo wrote:

Hi Andrew, after starting the bike, how long does it take for the oil to reach the end of the pipe after it's rested a couple of days?, Things to check are..Oil hose blocked or kinked? release it and see if oil flows freely, air hole in oil cap blocked causing a vacume? try it with cap released to allow air in the tank , Have you bled the pump properly till all air bubbles have gone? Is there a bleed screw on the pump as well as letting it pump out of the end of the pipe?

It takes about 5 min to fill the tube, I have ordered some new pipe and found a secondhand pump on ebay (I can keep it as a spare or whack it back on ebay if I get it sorted), Its off the road at the moment as the water pump srung a leak, which is now fixed.
Pulled the pump oil feed and it flows freely, bleed screw was removed etc and the pump primed.
Good shout re oil tank cap, I will have to check that, I have had that on a petrol cap before, but it was obvious when you undone the cap as it started hissing!!

Keep us informed     It's nearly30 yrs since I had my grubby little fingers on an auto lube system  

Stick a malossi cylinder kit on it and keep mixing in the tank ....I always disconnected the auto lube systems on all my 2/strokes ...had one fail on a vespa and never trusted them since... always use a quality oil like silkolene and not that castrol rubbish ....