064 Help

[madhatte]

Doesn't smell like a ring end alignment issue to me; those transfer ducts were flat torn off. That's at least 45 degrees away from a ring problem. Notice also that both ducts were broken loose; it seems unlikely that a wayward wrist pin would walk first one direction and then the other. That leaves casting flaws or handling damage as my two guesses.

EDIT: *bridges... D'OH!

 

[blsnelling]

Very odd that both transfer bridges are broken.

 

[Tohya]

It looks like you lost the circlips that hold the piston wrist pin in place.

What does the piston look like?

 

[firefighter33]

Some more pics. I spend a lot of time with this to make sure things were right. i tapped the holes to 6mm and filed the bolt hole on the cylinder also.:bang::bang:

 

[firefighter33]

Both clips are still there.

 

[Jacob J.]

Did you rebuild the bottom end on that one? Looks like there were pieces from a blown main bearing or big end rod bearing floating around in there.

Never, ever just grab a used case and throw a new top end on it without a very thorough investigation and possible rebuild of the bottom end.

 

[firefighter33]

No JJ i did not touch the bottom end. so thats what happened??
i did flush the case out with fuel before i put the top end on.

 

[Jacob J.]

Flushing out the case is not a replacement for a rebuild. A main bearing can be blown and still 'look' intact to the naked eye. Then after you press it out of the case, it falls apart in your hand.

I always rebuild a used case, even if the previous owner tells me it was a low-hour saw. You save so much time and grief that way.

Also- if you're drilling and tapping cylinder mounts, this needs to be done with the case apart and with the crank bearings out of it. That way you run no risk of lodging debris in the mains or the big end rod bearing.

 

[firefighter33]

got it. that was a hard $120 mistake. but guess i wont do that again.

 

[Jacob J.]

got it. that was a hard $120 mistake. but guess i wont do that again.

Well, all isn't lost. That top end can actually be cleaned up and run. It won't be as crisp without the transfer bridges but I've seen landing 066s run for years without transfer bridges.

 

[firefighter33]

OK Thanks JJ. Guess i should have posted from the get go as i was doing the build. The 394 is getting bearings and seals. Did u get those pics of that cylinder JJ?

 

[firefighter33]

Well, all isn't lost. That top end can actually be cleaned up and run. It won't be as crisp without the transfer bridges but I've seen landing 066s run for years without transfer bridges.

Really? Cut the broken one out and just grind them smooth?

 

[Jacob J.]

Really? Cut the broken one out and just grind them smooth?

Yep, and carefully work the piston rings out of the grooves and file the grooves flat again...

A points file works well for cleaning ring grooves.

 

[firefighter33]

I can re use the piston also? Even with that chunk out of it?

 

[Jacob J.]

I can re use the piston also? Even with that chunk out of it?

The one picture is pretty blurry- but if it's not scored all the way up through both ring grooves and into the crown, you should be ok. Like I said, carefully work the rings out and then clean up the groove(s). If you can't get the one ring out without breaking it, go ahead and break it. The cost of a ring is still far cheaper than the cost of a top end.

 

[firefighter33]

The one picture is pretty blurry- but if it's not scored all the way up through both ring grooves and into the crown, you should be ok. Like I said, carefully work the rings out and then clean up the groove(s). If you can't get the one ring out without breaking it, go ahead and break it. The cost of a ring is still far cheaper than the cost of a top end.

Gotcha! I will pull it apart one of these days and post some better pics. Going to finish the 394 first. Maybe that will be easier than the 064?