OS50hyper cilinder

[maxime]

Hi,

yesterday I broke my engine bearing for the first time, and I think it sucked a ball of the bearing to the combustion room, and scored my piston :( . Had an OK flight in the backyard, installed my new muffler(sb50hp JK) and tried to start it, but started was having rough time starting. first I thought it was the fan that came up...

so the piston is scored on the head, head was a little damaged, but I sanded it off a little bit, and is OK now.

so will order a new piston+ring.

but do I have to change the cilinder? there are a few hairline scratches in it(Can see it a tiny bit if I hold the cilinder in a bright light). in a normal illuminated room you don't really see the "scratches". will this have an effect on performance?

Someone at my flying field told me it was ok, but would like to double check with you guys

if I keep this cilinder, should I sand the side of the cilinder slightly like in new motorcycle cilinders, so that the ring settles better(600 waterproof or something??)?

[WayneBrown]

The cylinder is likely okay. If there is no visable defects such as a crack or gouge, LIGHTLY sand it with 800 or 1200 grit paper and install the new piston and ring.
Do not use the 600 grit, it's too coarse.

[maxime]

I've read that these bearing failures on the hyper 50 are quite common, but that this type of bearing failure(bearing completely broke down in parts, and balls of the bearing went to the combustion room) are maybe still under warranty? Could anyone fill me in on this?

I'm using cool power 15%, and engine was definitaly NOT running lean!

I looked over on Hobby Services, but they only treat stuff in the US :? .

anyone know of a Hobby Services or something like this in Europe? Or where can I turn in my hyper for possible warranty?

It's about the same as this persons blown out .50(not a hyper, but same result)
http://www.helifreak.com/viewtopic.php?t=7957&highlight=liner

[Laurens]

www.rcheliparts.nl sells engine spares, just like www.rchelistore.com.