Re: Sand in center cylinder

Chuck. It is possible for send to enter the combustion chamber during
stuffing cycle of the exhaust  system if water injected in to header has
small particles of sand in it. To avoid this problem you have to install
quality water filter. You need to maintain to frequently because if it gets
plugged up you risking catastrophic engine failure due to over heating. With
out examining piston crown and cylinder head its impossible to evaluate your
problem. On some water craft engines cylinder damage described in your post
has nothing to do with sand. As carbon deposits increase in the header area
of the exhaust system it become hard and sand like material which can easily
end up inside the cylinder during cylinder staffing cycle. This type of
cylinder failure is not restricted to water craft only, it happens to all
two stroke engines, specially when modified unit is working at high cylinder
temperature and carburetion is set on the lean side. I have seen brand new
engines with pistons looking like they have bin sand blasted on piston top
and exhaust port window area. Preventative maintenance is the key to stay
away from expensive engine failure. Highly polished exhaust port and pipe
header area helps prevent carbon deposits from possible cylinder failure.
Ask your service person if carbon was removed from your tuned system, if not
then possibility of another cylinder failure is just around corner.

George Ski
HPT Sport USA
www.hpt-sport.com
270-898-2617
"Chuck" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> I have a '99 Yamaha 1200XL Ltd.
>
> What are the possible ways that sand could get into the center cylinder
> other than directly through the spark plug hole?  I had to have the center
> cylinder rebuilt and the diagnosis was sand in the cylinder.  I'm curious
as
> to the possible reasons.
>
>