I am getting closer to starting my old 1994 2 stroke 400cc, but we have monsoon/cyclone season here at moment and bike lives under a tarp so dont get long to work before I have to replace tarp

so far I have cleaned every part of spark system and I do have a spark [but maybe not great] but alas did not start

so pulled off carby and instead of petrol it is full of the green 2 stroke oil

not yet tried it with petrol as rain came again but just a question on why it would fill with oil. Bike has been sitting for 3 months with front a few inches higher than back so it seems whatever mechanism [check valve?] is used to stop oil entering engine [and flowing back to carby] is not working, and yes the oil tank was essentially empty [and yes the low oil light was working for first time ever having cleaned up all those little bulbs etc in console].

anyone had this happen before or could give any suggestions?

I am really thinking it will start tomorrow but I expect a huge cloud of smoke as I am thinking the cylinder must be full of oil for it to flow back to carbie

 

Before starting the engine remove the sparkplug and crank it over several times to make sure the cylinder is not full of oil.
A Hydraulick lock can and or will rupture a piston.
also if there is a crankcase drain plug remove it and see how much oil is settled into the crankcase.

 

anyone had this happen before or could give any suggestions?

It will and does happen on 2-strokers with oil injection. Usually it IS a faulty oil line check valve. As stated, turn the engine over S-L-O-W-L-Y at first to make sure you don't have a build-up of oil in the crankcase. If you do, the oil will come up through the transfer ports and get on the top of the piston and cause hydrolock, which usually ends up in a bent connecting rod. If you can, remove the carb, attach a small hose to a turkey baster, get the piston up in the cylinder and thread the hose under the piston and down into the crankcase and suck as much of that oil out as possible. then put about a teaspoon of raw gas down in there to dilute the oil, turn it over slowly a few times more, then siphon out that stuff. Then progressively kick it over faster and faster until no more "mist" comes out of the sparkplug hole, then put in plug and try to start it. Don't rush this process and good luck.

 

thanks for the words of caution, for some reason my email notification did not happen and I was about to try to start the vehicle.

Could someone perhaps explain the "reed valve" part to which the carby connects [I have never had a 2 stroke engine in my life so don't fully understand how it all works without valves]

EDIT - not to worry, I just found a good tutorial so now understand

I am thinking more and more that after 15 years this may be good time to lift the head and clean out combustion chamber etc

 

decided to keep going in rain so removed head under umbrella, and very clean in fact

reed valves were gunked up with about 1/8 inch gap at top but after clean up they actually "snap" shut if displaced, so I am hoping that will help matters

in line filter for oil was fairly much blocked so gave reverse flush, as I did to the check valve as well. Hard to see how any oil was getting through, especially without engine going

did the turkey baste trick as suggested and got a small amount of gunk out

head gasket looks fine and I cleaned up both surfaces on head/block so will put back together tomorrow

thanks for all the tips

 

Ya hey You are doing it right.Sounds like You have got a fine machine there,now for a little TLC.
Post as to how it all turns out.

 

well sorry for so many questions but 2 more

1. anyone have the torque setting for the head nuts on this 400 cc 2 stroke?

2. I am trying to make sure oil injector pump is working fine while I can still sort of get to it [before replacing fuel tank].

because I have cleaned out tank, filter etc it looks like I need to bleed system and have located cover plate, removed it, undone bleed screw and oil flows

I then expected by turning over engine with starter motor I would get oil coming from the check valve/banjo fitting [disconnected from manifold] but nothing

book says " Start the engine and rotate the oil pump lever to its full open position. With the
engine at idle, hold the lever up for thirty seconds to make sure all air is out of
the system."

I have located this lever but what is fully open posn and is "up" the same as "fully open" and why do I need to "hold the lever"?

so is there a reason I can't do this just using starter motor?

 

The oil injection pump is opened by a cable Y`d off from the throttle cable.If You observe the oil pump lever while running the throttle to WOT{wide open throttle}it should move the lever.release the throttle and manually rotate the oil pump lever in the same direction until it stops.This would probably be up according to what I read from Your post.
If the oil pump lever does not move with the throttle then it may be run from some other source or it could be a broken pump cable.
I would think that cranking the engine over with the starter should give You the same affect.
I have never worked on a Polaris 2 stroke so My opinion may not be worth much and it has been probably 30 yrs since I`ve worked on a 2 stroke motorcycle.
I do not have a clue as to what the torque should be on the head bolts.

 

well I neglected to say that I did have the throttle at WOT while turning engine over and I observed that the other end of the cable did rotate in the oil pump [but I did not observe what the lever did]. But I was thinking that using WOT would give exactly same effect.

Anyway, the sun is out this morning so I will try it out this morning