NN203 - Flipbook - Page 11
They have an extensive collection of toys.
Alan9s Wrench
Alan Goldwater
INOAVicePresident
bout a year ago I
A
sold my MK3 to
a club member who
needed a left-shift
bike. He paid a good
price, with ongoing
advice
and
maintenance help as
part of the deal. So of
course as he put
more miles on the
bike than I had been
doing, things started
to fail.
First was oil weeping
around the front of the
cylinder head.During
some bench racing,
he
admitted
to
running the bike at
around 5k rpm or 80
mph on the freeway
as a regular thing. I reminded him that the plastic breather valve I
had installed only worked up to around 4k.
On my advice, he bought and installed the sump mounted
breather valve from JS Motorsport, which cured the oil leak from the
head. It9s not a cheap part ($310), but it seems to work well. A
similar part is also available from nycnorton.com (Ken Cummings)
for around the same price.
There were then lots of the usual minor issues, like a broken
rubber oil tank mount, but nothing serious went wrong until recently.
The primary started making noise, pretty clearly the chain hitting
the inside of the case. So off with the cover, and what a mess was
revealed! The automatic chain tensioner was collapsed and the
slack chain had left its mark on the case. There was aluminum
swarf all over the place. And worse, the sprag had failed, possibly
due to aluminum contamination so everything had to come off.
On examination, to my shock the upper chain tensioner plunger
was jammed in the bore, and once I pried it out the little spring
inside it was found shattered into many pieces. The ball check valve
Number 203
7
Norton News
