honda305.com Forum

Hi,

You can also use two teaspoons to get the needles off, it works !

Jensen

Jensen

Great idea. I'll try that next time.

G

I used the "screwdrivers and cardboard" method, teaspoons would have been just as nice, and the needles popped right off. They landed within sight, too. A brief search turned them up!

Sorry to be late to the party... but... I'd have taped a piece of string to the needle to limit its range.

Not that I'm all that smart. I needed to clear the diesel from my cylinders to make room for the acetone+atf mix, so I used compressed air. Didn't block the spark plug hole nearly well enough, got soaked in diesel. At least I had a tarp down to catch the excess.

Spent the better of today removing the engine from my old girl and pulling the head and barrel off. As I suspected, it had broken rings. Not just in one cylinder, either, the top compression ring in both cylinders was broken. Also, the left cylinder piston was badly scuffed. It looks like it was the one that seized on me that day so long ago.

I've attached more photos, and I would really appreciate thoughts on where to go next. The liners look good, maybe a hone will be enough. I'm quite sure I should replace both pistons, and most definitely a ring set is in order.



This is what I found when the barrel was slid off:



This is the scuffed piston:



The head looks okay.



As does the barrel.





The cam chain tensioner roller looks a bit worn.



I did a little light (yes, light) cleaning on the case - it's going to come up nicely!



Things don't look at all bad here, either.



The old girl sans propulsion unit...



Thoughts?

I'm trying to decide why my engine would have stuck a piston the way it did. To me, that indicates a possible oiling problem, and I will have a look at the oil pump as well as the oil galleries on that side of the engine. The engine looks so freakin' healthy inside - clean, little signs of wear, certainly nothing excessive, that the notion that one cylinder locked up is a bit of anachronism. Perhaps it overheated? The combustion chamber on that cylinder looks to me like it was running leaner than the other, maybe too lean?

I still need to clean the barrel and have a close look at the liners. Then again, why did the top compression rings in both cylinders break? Did that happen first and then it seized? Oh, who knows.

I hope, I hope I don't need to have the thing bored and have to replace both pistons. I've been looking at prices for 305 pistons and rings, and you'd think they were made of Unobtanium. Yikes...

Well, the rebuild goes on!

Interesting that your left hand piston has seize marks at the side as well as back/front. There should be more clearance at the side of the piston, whereas the back / front skirts will be in more intimate contact with the liner.

Jensen / Ed are good judges of what the root cause might be but I would definitely want to replace the pistons after that much trauma. If you decide to do that, getting the barrels re-bored to match oversized pistons is a minor expense that will give you peace of mind if nothing else.

As you have already suggested, you should check all oil ways and take a look at the oil pump and filter.

Seizure is a 'chicken and egg' situation with too much heat - too little oil escalating each other until you get the result you have here.

G