oil to petrol ratioI have an ES250

[djhaughey]

I have an ES 250 which runs at 33:1 and is consequently very smokey. The TS 250 runs at 50:1 and yet is a very similar engine The only differences I see is that the ES has a channel to supply the right-hand main bearing with gearbox oil while the left-hand one must get its oil from the primary drive/gearbox oil.On the TS,where the seals are outside the bearings ,the lubrication must come from the 50:1 mix. Is it feasible to run an ES ,with modern bearings, at 50:1 or would that spell disaster? It seems to me that, since the ES bearings are not touched by the petroil mix, the engine could run a lower oil mix? Am I correct----any advice or experience of trying it would be welcome.
Dessie

[arry_b]

Don't do it!

The small end on the ES is a plain bush, rather than a needle roller. That's the bearing that signifies whether you can run at 33:1 (bushed small ends) or 50:1 (needle rollers). Unlike the main bearings, the small end only gets lubricated from petroil mist and there isn't enough oil in there at 50:1 to get enough to stop the bush wearing.

If excessive smoking's your problem, you may have worn rings, or it may be down to the oil are you using? Some are far smokier than others.

[djhaughey]

Good point. I had forgotten about the small end. So, if the small end was changed to a needle roller the bike could run on 50:1 ; or are there any other drawbacks or things to consider? Thanks for that reply as it may have stopped me doing something daft
Dessie

[stogadog]

Just to throw a spanner in the works - I've been running my ES on 40:1 for the two years that I have had it and it has been fine. I do agree with the last point though that the smoke may be something else, rings, oil type etc rather than ratio.

[djhaughey]

Hi,
Thanks for your comments. By the way the rings etc are fine.It's just that not having seen it run for 35 or so years I had forgotten how smokey it could be. when it was running every day 40 years ago there were lots of two strokes , so it wasn't as noticeable. Anyway, just to sum up and be clear about ratios, running an ES at 40.1 would do no harm, but, if the small end were to be changed to a roller bearing it could be run at 50.1 . I assume they are interchangeable, since very little on MZs changed without a definite purpose in mind.
Dessie

[DAVID THOMPSON]

if it set for 40 years the rings may have died by loss of the tension
as there made out of round and compressed into a circle
in the cylinder
run it for a while and see what it does
dave