Two-stroke oil usage

**vamr** · 10th April 2007, 16:31

Also for reference...

Motul 710 smells better then TTS.

That is all.

**bumsex** · 16th April 2007, 12:55

Originally Posted by Racey Rider

Perhaps you would like to enlighten us as to why not, rather than just chuck out a statement like that!
and if we aren't to trust them,, what Are we to do,,, Not ride our bikes? Not ride further from home than half a tank of pre-mix?

Two stroke oil pumps have been a system working well for years.
Yes you occasionally hear of one 'packing up' and causing seizer, but then everything on any motorbike you might name has 'packed up' at least once, for someone, somewhere.

yes you are right of course and welcome to your opinion but the reason I say that is because when you are running an oil pump on a two stroke bike, you can never be sure of the exact ratio of oil to fuel at any one time.

I had a yam tzr that I would ride from hamilton to wairoa an back in my student days: it was pre mixed and I never had a problem with it.

**Motu** · 16th April 2007, 13:25

The other way around I think - with premix (or mix it yourself in the tank like in times of yore) at times the engine can be getting too much oil,others too little.The oil/fuel mixture is set to worse case scenario,in that it has enough oil for the most load it will ever have,in no load situations there is far too much oil.An oil pump regulates oil to speed and load,very much in the same way an ignition system supplies advance (with vacuum advance as well as cetrifugal)

I've taken oil pumps off 2 strokes,sometimes because of eliminating a possible fault that might happen,othertimes because of damage to the pump system.I prefer to leave it on,and for a road bike the pro's put the nay's into insignificance.

**imdying** · 16th April 2007, 13:54

Originally Posted by bumsex

the reason I say that is because when you are running an oil pump on a two stroke bike, you can never be sure of the exact ratio of oil to fuel at any one time.

But why does that even matter? When the bike needs more oil, the pump adds more, when the bike needs less, it adds less. What difference does knowing the exact ratio actually make to the rider?

**MrMelon** · 16th April 2007, 14:41

This is kinda relevant. I've got this kdx that's got an oil pump but the owner didnt know about it so has been running premix (admittedly he's only used 1 tank of gas since he's owned it) I'm pretty keen to run it using the oil pump. What should I do or check to make sure the oil pump's working fine so I can safely stop using premix. Should the oil tank be flushed, does it need to be primed to make sure the oil's flowing through or anything?

**Motu** · 16th April 2007, 14:54

There should be a bleed valve on the pump.Have a look inside the tank - if it looks clean I'd just put some oil in the tank,pull the hose off the pump and run a bit through with gravity.Hook up the hose and gravity bleed the pump.If the tank looks crappy,remove and flush.The pump will have a couple of marks on the arm the cable is on - the most important is wide open,this should line up with WOT,the carb will also have some mark on the slide too.Having a pump means you can ride anywhere,not be tied to your fuel can.

**MrMelon** · 16th April 2007, 15:17

Cheers I'll check that out tonight.

**Ixion** · 16th April 2007, 17:15

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)

**bumsex** · 16th April 2007, 17:22

Originally Posted by Motu

The other way around I think - with premix (or mix it yourself in the tank like in times of yore) at times the engine can be getting too much oil,others too little.The oil/fuel mixture is set to worse case scenario,in that it has enough oil for the most load it will ever have,in no load situations there is far too much oil.An oil pump regulates oil to speed and load,very much in the same way an ignition system supplies advance (with vacuum advance as well as cetrifugal)

I've taken oil pumps off 2 strokes,sometimes because of eliminating a possible fault that might happen,othertimes because of damage to the pump system.I prefer to leave it on,and for a road bike the pro's put the nay's into insignificance.

yeah what you have said here pretty much negates my argument. maybe I am just superstitious (about oil pumps failing)

**bumsex** · 16th April 2007, 17:24

Originally Posted by imdying

But why does that even matter? When the bike needs more oil, the pump adds more, when the bike needs less, it adds less. What difference does knowing the exact ratio actually make to the rider?

it matters because the pump can be calibrated or adjusted wrong and the engine then does not get the oil in the quantity required

**imdying** · 16th April 2007, 17:32

Originally Posted by bumsex

it matters because the pump can be calibrated or adjusted wrong and the engine then does not get the oil in the quantity required

But it you're running premix, then it's just as likely (if not more) that the engine is getting the wrong quantity of oil. Not to mention what happens if someone servicing it tops up the gas, or you get stuck without oil, or, or, or. Oil pumps have proven to be pretty reliable, humans, less so.

**Motu** · 16th April 2007, 17:53

Originally Posted by bumsex

maybe I am just superstitious (about oil pumps failing)

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.

**bumsex** · 17th April 2007, 07:18

yes, I remembersomeone writing above that four stroke oil pumps don't seem to fail that much (implying that 2 stroke ones shouldnt either), however the oil pumps on 4 stroke motors are very simple (the ones I have seen anyway) and all the two stroke oil pumps I have seen have a lot of things that can go wrong (are more complex). Cables breaking and more commonly with the bikes have worked on are the oil pump drive gears failing

**gammaguy** · 17th April 2007, 08:31

I have replaced a few failed oil pumps in the rotax engine fitted to the bmw F650 Bikes.They are driven by nylon gears and these can fail or sometimes bits of debris jam inside the pump.
and it makes more of a mess when they fail cos theres more bits inside to start with arent there?
four strokes more reliable?
pffffttt.