Subject: [TR] Cracked Head

From: "Greg Lemon" <[email-masked]>
Date: Sat, 13 Dec 2014 00:23:56 -0600

About a year ago I worked on a spare head I had for my TR250, I called it my
"special experimental test head" because I was going to bump up compression
slightly more than I had with my current head, and also was going to clean up
the narrow spots by the valve guides and such to improve flow.

I dismantled the head myself, using a stepped valve guide removal tool, and
then I did the port work on the head with a dremel and a carbide bit and
grinding stone.

When I took the head in to the machine shop for the final work they
magnafluxed it and determined it had multiple cracks.

I put it down to a learning experience, but I have one more head and I may
start working again, sorry for all the background, but now we get to my
question.

I had originally assumed that the head was cracked when I started, but as I am
thinking about it, I am wondering if I cracked it myself either in grinding it
out or removing the guides (which I did using a purpose made commercial valve
guide removal tool or drift, and a hammer, as I recall they came out
reasonably easy, took more than a light tap, but I didn't have to wale away
with a sledge or anything).

I had not heard the TR6 head to be especially prone to cracking, but have no
idea of the history of the motor, it turned free when I got it that is all I
know.

Anyway, cracked before I started, cracked by me when I worked on it? no way to
really know or venture an educated guess at this point?

Greg Lemon

** [email-masked] **

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