On the phenomenon of gradually diminishing performance...

As those of us in our mid-years are aware, a slow, gradual change is often
difficult to observe. Sometimes it's only when the easy deceleration becomes
a full stop that any real problem is actually recognised and not just put
down to old age or explained away in a fleeting "It'll sort itself out"
manner, that the thought "something must be done" forces its way to the top
of the things-to-do list.

No, kind reader, my cock has not malfunctioned, but the Virago has been
showing signs of all not being well. It's not a racing machine by any means
but the acceleration had become leisurely even for a 21 year old 535cc
V-twin, the mid-rev range was extremely hesitant, and the popping and
farting on the overrun had got quite embarrassing and old-lady-scaring.

The "something must be done" moment came yesterday when it was backfiring at
idle. On the days/weeks prior to this the plugs had been carefully cleaned
and gapped and the mixture screws had been synchronised and altered to weak,
then rich, and everything in-between. All these efforts only had a
temporary, and probably psychological, benefit so it was decided yesterday
that the carbs must come off and be deep cleaned.

Fortunately this job is only mildly difficult and after a bit of a minor
struggle the pair of Mikunis were sitting on the bench in one of the sheds.
I like taking carbs apart; their precision pleases me, and soon the bench
was covered with tiny brass and plastic parts, all of which were carefully
inspected, cleaned, lightly oiled, and eventually reassembled. I had
suspected the diaphragms previously because they're original and as baggy as
your granny's flaps but as they're ~£70 a piece they can keep working until
they fall to pieces. After removing the cover of one carb I noticed... a
complete lack of diaphragm. Such was my surprise that the bike ran at all
without a diaphragm, followed swiftly by the wondering "Where the **** did
it go??" that it took a fair few seconds to realise it had just come adrift
from the rest of its assembly and was stuck to the back of the cover. The
diaphragm was carefully prised away from the cover and again took its
rightful place together with the slide and needle.

After almost destroying the inlet manifold gasket by forcing the carbs
between the cylinders with nary a thought for the thin bit of rubber's well
being, all was reassembled and it started properly and sounded ok. The test
run this morning revealed actual proper acceleration again! I'd forgotten
what that felt like and realised that it'd been poorly for months, just
because the diaphragm assembly was coming to bits. All sorted and back to
normal. What a shame we can't be rejuvenated in a similar fashion. I likes
bikes, me

As an aside, on the way out I saw a fellow bikey chap having a bit of a lie
down in the gutter, a long way from his ER-6 (I think), and surrounded by
concerned-looking people. My first thought as I pootled up the outside of
all the traffic, was "clumsy ****". Thanks UKRM.

 

The magik of the internet will see someone of a honey-smelling nature
pop up in a minute with the web addy I've completely forgotten/misplaced
of the people who make/supply diaphragms for fraction of that price.

No probs. It's a relief to not know the **** - we don't have to care,
then.

 

sorry, been away.

you mean these folks...

http://www.nrp-carbs.co.uk/index.htm
--
Adie
(replace spam with nickname to reply)

UKRM FAQ: http://www.ukrm.info/faq/

YZF-R1 : FZ1 : GPz 750 turbo
keeper of the FAQ for my sins
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