Drinking problem Z650 B1

[Zebedee]

Help
My little zeds drink problem continues.

Ive refurbed the carbs ( a couplke of times) and had the cjhocke plungers done by Rob (thanks Rob) I havent fitted teh air corrector screws because quite frankly its not too much air thats the problem.

fitting the reworked choke plungers upped the MOG from 15-18 to abot 32 mpg.
But the exhaust pipe is black and sooty. plugs too.

air screws are out 1 and about 13/16ths I tried 1 and 3/4 and have been leaning it off by a 16th ever since.

Its running an after market pipe (just went and looked and its got black okay rusty headers a 4into1 and a chrome silencer {MACH Asuya No Id never heard of it either?} but stock air box apart from someone ( a previous owner?) having cut the centre tube out?

It pulls like a train and doesnt suffer from any mid range hesitation.

Oh and its running 102.5 main jets (as per clymer manual) but I cant help thinking that the American market version had all sorts of strangulation devices on it that would contermand the increased jet size.

Now I have some 100 jets ( standard according to the Haynes manual) but should I try those?

Also how practical is it to do without removing the carbs by just dropping the bowls off? Fortunately Ive only just put them back on with new gaskets, new screws and slight smear of copper on the screw threads.

Thoughts please? are 100's too lean?
Anything else you can suggest?
Ive tried colourtune but my colour sight just isnt good enough! Although I can see black sooty plugs no problem. I now have several sets of those!

[warren3200gt]

Unless you doing mostly motorway miles at 70+ your going to be on pilot jet range probably 70% of the time.
What size pilots have you got? 15 is stock for a standard Vm24 equipped UK bike.
To give you an idea, the difference between 15 & 17.5 is 17%. As the pilot system is continually in use from 0 to full throttle that alone could get you upto about 40mpg.
You don't need to increase pilot size from stock even if running no filter at all.

Additionally think about final drive gearing and which rear tyre you are using.

[Zebedee]

Thanks Warren Im going to go off and check the pilot jets as I bought a kit well 4 actually and changed the pilots and gaskets etc, but without checking the sizes?

[warren3200gt]

When it comes to jets only use genuine or kyster.
Ebay jets are all over the place quality wise and virtually never flow at the size stated. They cause more issues than they solve.

[Zebedee]

ah I think you've hot the nail on the head.

I checked and the pilots are 15 according to the blurb. Although cant see any numbering on either the new or old pilots.

I mainly do a couple of miles of bimble 50-60 on country roads before turning on to a designated european 'Freight Route' with variously 30. 50 30 limits and then duall carriageway 70 before finally turning onto the A34 dual which is 50 mostly for my route then short distances of 30 and 20.

So most mileage is actually at full throttle on the dual carriage way between roundabouts.

I think the cheap ebay jets are to blame.

Zebedee (David)