1982

And after a bit of a run the engine had little inclination to
settle down to a calm tick-over.

It would stick at 1500 revs and sometimes up to 2000.

I could pull it back (at stand-still) by braking and letting out
the clutch, but it would go back up to 1500.

Carbs have recently been o'hauled and properly balanced, I'm
loathe to change those settings.

Ideas please regarding what might be causing this.

 

1982 SOB perchance?

Air leaks downstream of the carbs, maybe induced when the carbs were
fettled?

Sticky throttle/choke cable?

You've failed to reset the ignition timing to GMT this year?

 

Sticking throttle cable(s)?

Wrong pilot jet settings (whatever you may think to the contrary!)?

 

The Older Gentleman was seen penning the following ode to ... whatever:

Probably the cable splitter under the tank, actually...

Hmm. I think the OP has a ShiteOldBoxer, and they don't tend to rev
that madly with the pilot jet being wrong.

Makes me wonder if he checked the state of the carb diaphragms.

 

Hmmmm.... in my experience with fecked diaphragms, the bike runs
perfectly, but just lacks all top end power (the diaphragms can't lift
more than half way because of the holes).

 

A relative youngster! not done 40K yet

This sounds interesting. Downstream meaning the engine side of
the carb?

If it were that ^^ , the engine speed would stay down once I had
lowered it, shirley?

It's an import ^^!

 

(see next of mine)
I've no idea about the jet settings, that could be another chapter.

Would a symptom be lumpy take up from low revs?

Diaphragms are both good, new as of earlier this year.

 

Howard was seen penning the following ode to ... whatever:

R100RT? You serious? They all do that, sir...

Nevertheless, get a set of proper jets from Moto-Bins or
Motorworks. Make sure the carbs are clean inside - corrosion doesn't
do them any good, and I've seen some serious fscked ones.

Another thought - the screws that close off the vaccuum take-off
points for balancing haven't fallen out, by any chance?

Other problems I've encountered were sticky throttle butterflies,
usually due to dirt on the outside more than anything. Clean and lube
a bit, that may make all the difference.

Not snagged and no airleaks?

 

Having looked at cables, settings and whatever I could find in
the fine detail, I had missed the massively obvious.

The carb was practically hanging free, with air gaps fore and aft!

Test run tomorrow.

 

Check that you have tightened the wheel spindles, fork clamps and brake
unions as well then!

'Hog

 

That'll happen soon. New brake lines for the front and new cast
disc for the rear.

Forks?

 

<chortle>