Rehabilitating main bearings

andrethegiant70 · Mar 25, 2007

Hi, folks! I have a 266xp case that I'm condsidering salvaging for a new project. It had obviously sat for a long time and was locked up pretty good but after a bit of prodding and alternate washings/soaking of fuel mix and straight 2-stroke oil its spinning pretty nicely. My question is, has anyone had good luck rehabilitating bottom ends ths way or am I wasting my time? Thanks in advance....

Crofter · Mar 25, 2007

Rust tends to pit the bearing balls and races and needle and pins at the points of contact. You can free them up but the marred surfaces will not last long. If it is strictly gummed fuel with no rust you might be OK.

Tzed250 · Mar 25, 2007

The bearings will self destuct if there is damage to the races. Don't risk good parts with something as cheap as a set of crank bearings.

oldsaw · Mar 25, 2007

Tzed250 said:
The bearings will self destuct if there is damage to the races. Don't risk good parts with something as cheap as a set of crank bearings.

Spoken like a true master. Bearings are cheap on the front end, not so much on the back side of a repair.

Mark

mattinky · Mar 25, 2007

I have to agree - replace them, I don't have much experience with saws yet but I've worked on 2-stroke dirt bikes for years. Time after time I've seen people get an old bike running, rebuilding the top end and not the bottom trying to save a few bucks. They usually last about an hour before either the bottom end rod bearing or crank bearings sieze or the piston siezes from a lean condition caused by leaking crank seals. A lot of people just don't understand the whole concept of crankshaft seals on 2-stroke engines - they absolutely must be leak free for the engine to perform properly. If your crank bearings have the slightest amount of slop it will cause the seals to leak. If you want a trouble free saw replace the crank bearings and seals and make dam* sure the bottom end rod bearing is in useable condition - no rust/pitting/slop. Matt

andrethegiant70 · Mar 26, 2007

What I was hoping to hear was "Yeah! As long as they feel pretty smooth you should give it a try!" The truth can be hard to hear....

Highclimber OR · Mar 26, 2007

Gotta agree. I would not risk it with questionable parts, especially when it could do more damage than the value of the questionable bearings. I'de ere on the side of caution on this one if I was you.