Sodding back bearing on OS50

[Mslater]

Just changed the back bearing on my OS50, first time on this engine got 44 flights out of the original bearing.

No great shakes bearing came out, new one in - used the oven again.

Then it gets to the bit where you've gotta put the liner back and keep the ring in the correct position.

I BROKE THE RING - ARGHHHHHHH even more annoying coz I can't get to the shop until Saturday.

There has to be a technique to putting the liner back in - any tips/tricks would be appreciated (I've seen the finless vid)

[inferno]

Time for an os55??

[Mslater]

Time for an os55??

Can I have my logo back ? I only had to oil that !!!!!!!!!!!

[Paulice]

so did you have opti flavored potatoes again?

[Spanner]

not seen the vid, but you are making sure the ring locates on the little locating pin on the piston?

[pgkevet]

Some days those liners just don't want to go in easily
I oil everything thoroughly to make it easier and I also use a soft pencil to mark an arrow on the crown where the ring pin is located so it's easier to check nothing has moved between 'fiddles'

[machasm]

I like the idea of marking the crown with a pencil. When I do mine I am never sure if the ring has spun round or not until its in.
Gonna use this tip next time.
Cheers.

[Aidi]

Try this

[Mslater]

not seen the vid, but you are making sure the ring locates on the little locating pin on the piston?

Yep, but it moved as I put the liner in, then got caught. Didn't take much to snap it after that.

[Bruinbear]

As you ease the liner over the piston ring try and compress the ring gap side slightly before the rest of the ring at a slight angle. The chamfer on the bottom inner edge of the liner should guide the rest of the ring to fully compress.
Just take it easy, gently does it and you should be good to go !
Mike.

[Aidi]

The important factor which everyone seems to be missing is the gap on the piston ring must be lined up with the small pin on the piston head before attempting to slide the liner on. If the ring and pin are not lined up, the ring will not compress enough to allow the liner to slip over the piston.

[Paulice]

Just changed the back bearing on my OS50, first time on this engine got 44 flights out of the original bearing.

Did we not change that one in July?

[Steve]

Drop your fuel nitro to 20% and you'll be changing bearings no more than once every two years......




maybe?

[Mslater]

Drop your fuel nitro to 20% and you'll be changing bearings no more than once every two years......




maybe?

I'm running 20% !!! Always pull the fuel tube off and let run dry. Then glow on and turn the engine over to burn off the rest (Usually fires once or twice). Hand turn starter to close the exhaust post, put bung in the exhaust.


PAUL - this is the new OS50 July would be correct.

[Mslater]

Got a ring !!!

Fitted tonight and all ok, think I've got it sorted now ended up quite easy.

1. Insert the piston and hook up the crank - Set at TDC
2. Line up the ring
3. Hold gently with some tweesers
4. line up liner and slide on gently at a slight angle, push down gently over the ring.

Dead easy, I actually took it apart again it was so smooth I thought the ring had dropped out.

Thanks for the help.