Sig change: Am I mad ?

BOL recieved with thanks.
The electrics are now fettled, cleaned up the connections, replaced flasher
and 3 bulbs. Shiny new Varta battery, Total spent so far UKP 40.95.

There is a mild clunking from the chaincase/gearbox area due to
slight uneven running at tickover, it goes away at around 1800 rpm.
A set of new plugs made little difference so my crystal ball is cackling
at me showing amusing images of an oldfart getting frustrated at the
carbs. I just HATE trying to balance four inaccessible carbs.

Probably a good idea to check the compressions, points etc and wave a timing
light at it before tinkering with the carbs though.

The saga continues .....

 

That sounds like typical Honda clutch/primary chain chunter and it goes
away when the carbs are balanced.

*Could* be knackered primary chain, but only at very high mileage. And
that tends to be a deeper knocking sound that goes away as the revs
rise, anyway.

Balancing 400 Four carbs is surprisingly easy, as long as you've got the
gauges. The nice thing is that there is always enough fuel left in the
lines and carb bowls for bloody ages - seriously, they'll run for an
amazing distance with the tap closed - so you don't need to rig up a
fuel supply.

And yes, always do the timing and tappets before doing the carbs.

 

I dont have vacuum guages so I will try my tried & tested method of
presetting the carbs to be identical, set the tickover adjuster so that
the pistons are JUST lifted, tweak to the same resistance to blowing
through each in turn, refit carbs, then measure the rpm drop when
disconnecting each plug in turn with the nice digital tacho on my
ancient SnapOn timing light and tweak to get the rev drops the same.

In theory this method should be just as accurate, I have used it on
V8 cars and the GS500 in the past.
There is probably a cheap set of vacuum testers available somewhere
but why spend cash if I can avoid it.

 

Pah, call that easy? I've just balanced the throttle bodies on the MV.
Attach Carbtune hoses to the four ports on the side of the bike (2 on
each side), twiddle air bypass screws (which point out the sides & are
really easy to get to), job done. Took about 3 minutes.

 

I've only ever balanced carbs on two bikes: an H1, and the Wing.

Special tools for the H1: three teaspoons.

Vac gauge for the Wing, one screwdriver, and an afternoon's plastics
removal time.

 

Looks like I dont need to balance the carbs, the timing was out by a
country mile, sorted that one and the noise has gone.
OTOH, it was not possible to get the points gap right and the timing within
the adjustment range at the same time. Either the points or the
unobtainium advance mechanism must be worn. Closing up the points a tad
gives just enough retard to reach the F timing marks.
Just a tiny amount of timing chain noise now, not enough to justify a
major engine strip to fix.

 

Not when there's a work-around involving sticking a screwdriver down the
tensioner tunnel.

 

Don't bank on it. 400F carbs are horribly finicky.

I bet they didn't have four carbs.

And I know these don't.

Don't be a pikey. Buy the gauges. Once you have 'em, you have 'em for
life, and they're hyper-useful.

 

Gawd, those wheels look gash in black.

I have several sets of good order silver s/dream wheels (and tyres) if
you want 'em.

Paul.

 

What do you suggest ?.

 

That said, my dial gauges have seen me in good stead for 20 years.

 

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember (The
Older Gentleman) saying something like:

The Morgan Carbtune, in its various incarnations, has been very good.
Amazingly simple and dead reliable.

Ditto. One thing I make a point of doing is zero them to a common carb
before I start, if they haven't been used for ages. They never drift out
much anyway, and the real knack is to damp them properly.

 

Ordered.
I suppose one can never have too many tools.

 

I've been using a twin[1] gauge type for years - damping's never a
problem and the few times I've tried swapping them oves as a check,
the difference has been negligible. Damping's never been a problem.

I bought a twin one I *think* because that's all I had at the time and
I was too broke/pikey to pay for a four-cylinder version.


[1] yes, fours too. It just involves swapping over the hoses &
blanking plugs a couple of times.

 

Bad form and all - did I mention that damping's never been a problem?

 

You may have. But enough of that - was damping ever a problem?