Two-stroke oil usage

[MrMelon]

Main thing is you need to bleed the pump and lines. Like Mr Motu says, there'll be a bleed valve on the pump. That will bleed the pump, but odds are you may need to bleed the lines also. You can (usually) see any air bubbles in the line, so slacken off the banjo bolts at athe end and run the engine with the oil pump manually held full open until there are no more air bubbles (it makes a shit of a mess, but)

Ok so just to clarify this, I should take the hose off at the oil pump that comes from the oil tank and let a little oil run out then hook it up to the pump again, then could I run the engine for a few minutes to get this oil sucked through the pump, and through the hose to where it's added to the fuel mix just after the carb? There's still a bit of premix in the tank so I shouldn't have any problems with lack of oil running it like that for a bit.
Or will that be a bad idea? I couldn't easily see any bleed valve on the oil pump.

[Ixion]

Yes. If there's no bleed valve (not all pumps have one), just slacken the banjo bolts , one section at a time , and let oil run out until there's no more air. What you're basically doing is making sure you don't get an air lock. Once oil is flowing without bubbles or froth, tighten that bolt and move to the next one.

On the far side of the pump you'll have to have the engine running (otherwise no oil flow). Hold the lever that the cable operates in the "full throtte" position (ie max oil flow), to make the job quicker and also ensure that the engine gets enough oil. It only takes a couple of minutes, though it makes a right mess.

[MrMelon]

Ah yep I think I should be able to sort it. Didn't see a lever there which changes the flow rate but i'll have a better look when I get into it tonight.

Cheers.

[Ixion]

Just follow the cable that goes to the pump, it's whatever it hooks onto. Twist the grip to full throttle and see what moves.

[MrMelon]

Ok this has got me. I went to top the oil tank up but it started overflowing pretty much straight away. I've had a closer look at the oil line that comes out form the oil pump and joins on after the carb and it looks like it might be full of oil. Is there any way I can tell for sure whether there's oil in the oil tank without pulling the whole thing apart? Riding it without premix to see if it seizes or not isn't the answer I'm after either.

Cheers

[Mr. Peanut]

I worry,because I've had a cable break.I remember smugly thinking - ''At least my bike doesn't smoke like those Spanish bikes,and I just love this nice light throttle....'' When things are going just a little tooooo well is the time I get suspicious.Actual oil pump failure is very rare - Ixion will tell you how old his pumps are.

My pump floods the engine with oil if the cable breaks. Had it come off after a bin, and got quite a shock!

[Motu]

Normaly,on Mikuni and Yamaha pumps...the arm is spring loaded against the pull of the cable,so it goes to the low delivery position on cable failure.That's why everyone worries about cable breakage.Dunno what you have to make it do that.

[Mr. Peanut]

Normaly,on Mikuni and Yamaha pumps...the arm is spring loaded against the pull of the cable,so it goes to the low delivery position on cable failure.That's why everyone worries about cable breakage.Dunno what you have to make it do that.

I've been wrong before! Engine was totally flooded with oil, and wouldn't rev out.

Noticed the cable was off the pump (lucky I didn't ride it home, engine just rebuilt!!) reattached and it slowly improved.

Cable could have slipped half off and held the pump open though.

[gammaguy]

not always.

My TDR 250 oil pump cable frayed and jammed the pump on full.(which was nicer than the alternative!)

[Motu]

A common one is for the outer cable to be pulled up on the boot,then they over oil.When working on a 2 stroke I always make sure the cables are fully seated.

[Ixion]

Ok this has got me. I went to top the oil tank up but it started overflowing pretty much straight away. I've had a closer look at the oil line that comes out form the oil pump and joins on after the carb and it looks like it might be full of oil. Is there any way I can tell for sure whether there's oil in the oil tank without pulling the whole thing apart? Riding it without premix to see if it seizes or not isn't the answer I'm after either.

Cheers

Just stick a dipstick down it?

But for safeties sake, loosen the banjos where the pipes go to the motor (or inlet manifold) and check that oil comes pissing out when the motor runs .

[Ixion]

A common one is for the outer cable to be pulled up on the boot,then they over oil.When working on a 2 stroke I always make sure the cables are fully seated.

Yeah, I've had that happen. With Suzukis quite often when the cables correctly adjusted there's actually quite a lot of slack on a fully closed throttle. And sometimes the outer can jump out of the socket on the adjuster thingy and catch on the top of it. So on large throttle openings its pumping far too much oil. Much smoke.

I also have a habit of reaching down and giving the cable a tug if I'm working the motor hard, to give an extra squirt of oil, just like giving an extra squirt on the old petrol tank mounted lubricators (shit, that's going back a bit!).Or, just if I want to check the cable hasn't broken!

[MrMelon]

Just stick a dipstick down it?

But for safeties sake, loosen the banjos where the pipes go to the motor (or inlet manifold) and check that oil comes pissing out when the motor runs .

The arrangement makes it pretty impossible to get a dipstick down there but I managed to pull the oil line off where it connects after the carb and it seems to dribble out a bit of oil whenever I give it a rev. Filled the tank up with 91 today and went for a blast. Done 40k's so far and it hasn't seized so I guess that's a good sign. Was smoking cars the cars behind me out hardcore down the motorway while it used the last of the premix up though heh heh. Cheers for the advice

[kippy]

i get about 4tanks petrol on a full tank 2stroke dono how much that is..and i get about 180km petrol on a tank and if i feel like riding i get 120 to 140km on a tank