ETZ 250 Oil Consumption

[Andy_C]

Can anyone tell me the ratio that the oil pump is set to deliver ?

Mine seems to get through a tankful of 2T oil pretty quickly - or perhaps I am just doing more miles than I think ?

Do these pumps ever over deliver ? Mine is set as per the manual.

Thanks.

[DAVID THOMPSON]

who made the pump
the one on my 1966 Yamaha ym1 305cc did great
bet it looked like an mz inside
dave

always check to see if its using some
careful changing oil brands or blends some have been known to clog up the oil lines
cause they do not like each other

[Andy_C]

David.

As far as I know it is the standard Mikuni item, and I always use the same semi synth oil.

One of my other bikes is a Kawa 2 stroke triple, and I am amazed that the MZ seems to use a lot more oil than the triple !!

[Blurredman]

I'm sure I saw it somewhere, but can't really find it now!

I do imagine though it is something like 75:1 at idle, and 30:1 full throttle.
Though that's guessing..

[Puffs]

Same here, can't find it either. I remember a story like 'the Mikuni pump can deliver down to ... ' and that the engine could do with less, or something along those lines. But I can't quite remember & can't find it back either.

The pump does not provide a constant oil flow (or a constant oil/fuel ratio, as you ask). The oil volume the pump provides, per revolution, depends on the position of the pulley. So the flow is RPM & pulley dependent.

I have always used the oil pump, but I cannot tell you how much it uses. I don't remember it as overly much though. Make sure the pulley adjustment is correct, it could over deliver if that adjustment is out. Or pre-mix.

[AlanJ]

Hi Guys,
Sorry this is a bit late but, I am just going to switch over to using my Saxon 301 instead of my TS 250/1 which of course uses premix 50:1, now, I was thinking about the Saxon and how long a tank full of TS oil will last when I read your posts. What I am about to say may be a lot of rubbish but, if I was designing a pump to take over the premix and because the engines have always run on 50:1, I would set the pump to deliver the same ratio ie as you open the throttle more fuel and therefore more oil, but, still at the same ratio, 50:1 because that's the setup for these engines. If what I am thinking is ok then as the oil tank takes about a Litre then if the petrol tank is 19L you can do 3 tanks full before you have to reload the oil. Please let me know if I am thinking a load of rubbish. Wish you all well Alan

[Puffs]

Hi Alan,

If you keep an accurate record of the volume of oil that you use vs. the volume of fuel you use, divide one by the other to get the average mixing ratio. It's just that to do it accurately, you'd have to do it over a long time, and very diligently, and I've never done that.

You may not be too far off: the pump provides more oil per revolution with an open throttle, just when it also uses more fuel. So maybe the ratio is indeed more or less constant. I don't know. It might also be richer at full throttle, when the load on the engine is higher; that's how I would prefer it. Something like what Blurredman says. But how they actually made it I don't know.

I'd keep an eye on the little watch glass in the oil tank & fill it up the moment you see an air bubble - or sooner, using the unreadable dipstick.

[AlanJ]

Hi Puffs,
Good on you, it's nice to know we are thinking on similar lines. Regarding the pump, I guess you would have to know how much fuel is used by the carb at full throttle and tick over, and as they are the boundaries and the throttle pull has to adjust the pump flow oil through those boundaries. Just a small thing though, the dip stick, I have put a little notch at 1L and 1/2L marks it saves screwing your eyes up. Wish you well Alan.