[ST] Removal of cylinder head and crankcase liners

["Dan Wallander" <triumph99@xxxxxxxxxxxxx>]

Hey all,

I ran into a bit of a problem with my '99 ST a couple of weeks ago.  First
time ever for being stranded and having to take any bike home in the back of
the truck.  Luckily, I was only an hour and a half from home.  Here's the
deal.  The number one spark plug decided to blow out of its hole.  Since I
was the last one in there, I know I tightened the spark plug down and did
not cross thread it or over torque the plug.  Looking down the hole, all of
the threads in the head are gone.  The last two threads on the spark plug
(what's left of it) are damaged, the rest are OK.

The cure is 'easy'.  Take the head off, have the thread repaired (have the
thread for the cam cover in the middle of the cam cap repaired at the same
time). Then reassemble everything.

I'm about halfway through the removal process and, having read the entire
procedure, I have a question.  The Triumph Service Manual (page 3.23) says
that the cylinder liners must be removed and resealed whenever the head is
removed.  This can be done with the engine in frame and the head removed and
really isn't all that difficult a procedure, but will take time and a
special liner removal tool.  However, I have never run into this before and
can't see how the sealer (which fits into a groove around the outside of the
liner about midpoint of the liner) would be affected by the removal of the
cylinder head.  I also know that I will never be able to line up the liner
in exactly the same place, so the rings and the liners may need to mate
again.

I don't have a dealer and am hoping the collective experience of this list
can help:

1. Triumph is emphatic about the replacement of this sealer, the liners are
reused.  Can anyone tell me why?  Do I dare blow off this part of the
procedure?
2. What is the sealer?  The manual only says silicone sealer, but does not
specify a part number or spec.
3. Is there anything else I should be looking at while I have my bike in
pieces?
4. Is there anything I should look at as a cause for the spark plug to blow
out like this?  (My experiences with other aluminum heads is that it just
happens sometimes, or someone damaged the threads at some point by
over-torqueing or cross threading.)
5. Does anyone have the liner removal tool that they would be willing to
sell or lend?  T3880315

I have a couple of photos on my website of the grenaded coil and spark plug.
http://www.danwallander.com/coilrepairtriumph.htm

Dan Wallander
'99ST (in pieces)
'74R90/6 (28 years and counting)
www.danwallander.com


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