Last nite's trip with my kids seems to confirm that the TiiCo
vibration demons are gone. Did two things yesterday. Filled the
frame rails where the engine cradles attach with polyurethane
foam. Right and Left sides from forward of the firewall all the way
back, and accross the rear. There are lots of openings to
squirt into. Called Great Stuff (Minimal Expansion), it's used
mostly for insulation in houses. The idea was to deaden any vibe
transmission or "ringing" through these channels. Seems to
have made a big difference. If you try, WEAR
GLOVES! This stuff is VERY MESSY and does not come off skin.
It has to wear off.
I then dropped the shift linkage and "rebuilt" it without using new
parts. I figured that most with the TiiCo engine are reporting
shifter buzzing (including me), and that since the shifter is one of the
only direct connections between engine and body (no/little rubbrer
between) it would make sense that it's transmitting vibes. I knew that the
rear shift rod bushings (nearest the selector arm) were worn, so maybe
tightening them would interrupt the sympathetic vibes of the whole
rod. Removed the shifter rod from behind the gas tank to the
selector, put it on the bench and opened the clamshell steel mount that
holds the plastic bushing. Very worn and very dirty. Old
grease, grit and sand. Surprised the shifter moved at all. Looked
like the only way to remove the bushing was to drive out a drift pin on
the selector arm and remove it? Nah. That's asking for
trouble. Decided to cut the plastic bushing on the diagonal with a small
coping saw. Got it off, cleaned and removed more material from the
slot where it had been cut so that it could grip the shaft more
tightly. To get it to grip more tightly, I cut some rubber from and
old bicycle inner tube to place between the clamshell mount and the
bushing. When installed, it now closed the gap that I had created
where I cut it open. Reinstalled and found a nice change.
Besides the shifter being much more accurate and direct...no more
buzz.
After my crusade to kill the vibes, at around 4k rpm I can tell that
the engine is in it's vibration period, but nothing in the body resonates
with it. Now winding this engine up is really a pleasure.
Gary |
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