OIl seal

[Suzukidave]

Geez .. i will never look at a oil seal the same again

[tz375]

Thanks Dave. That's enough to make a head spin. And worst of all that is just one of many seal shapes

[Vintageman]

Important piece for a 2 stroke engine no doubt. I bet mcuh has been learned over the years

I always thought the seal lip is directional ( like that one pic). We test cyclinder for leak down, when in fact the Suz cranks use crank case oil the pushes from the other side in some cases. These bikes will smoke from oil leak that way, but still seam to hold OK from Crank Case side. Both direction need to be tested/ Maybe the seal can handle both ways. If not is should

[tz375]

Crank seals are usually double lipped so that they seal in both directions.

[Vintageman]

Tz375,

I have to go through my pile of seals but I am pretty sure this was not the case on T350/GT250 single center bearing. I paypal you over a beer if wrong. I owe you few now but still confident on this one

I was having problems and look at that specifically once I undestood how it was used
Trans oil is pushed into center seal by on of gear teath like a pump. The inlet holes is as big if not bigger than outlet in case halve so I am sure there is pressure that side . There is a pick on T20 race site somewhere but you need both hales to understand inlet hole.

[Vintageman]

Tz375,

You are technically correct. Two lips where required. Owe you that beer

Note however, the inner (crank oil side) has no tension spring like the rod side.

You see a lot of these bikes run fine, but burn crank oil (some nor ethan others.
I think that design proved to be a short coming, with time longer than they were designed for.

I may be getting one of these. I don't typically change seals if not needed...

But on this crank I am planning to change the inners

http://www.ebay.com/itm/Suzuki-GT250-T2 ... 42&vxp=mtr" onclick="window.open(this.href);return false;

[tz375]

Funny thing is that over the last few days I have been researching an oil pump seal and going through catalogs of seals plus on line searches and there are dozens of seal designs and materials.

And that's just shaft seals for rotating shafts. High pressure are different to low pressure and operating temperatures make a big difference as does the solvent nature of the material being sealed in/out.

The issue for us is that we have no idea what the old crank seals were made of and if they are alcohol resistant or not.