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I'm hoping someone in the collective has a solution to this. Newish to me Kanguro, I've had to iron out several problems, electrics, stripped sparkplug etc.
The bike is back together and running but I don't think it's running well. Very high fuel consumption. I've stripped and untrasounded the carbs twice, new choke rubbers and new (white) floats. Even now, in winter, it doesn't need choke, in fact if I use it, it's likely to foul the plugs.

What am I missing?

3 possible things spring to mind.

1. Air filters - are they clean?
2. Float heights - have you checked them?
3. Chokes - are they sealing correctly when in the off position?

Just a few things that sprang to mind.

Thanks for the response Andy, all checked and correct.

You have checked the chokes- the piston tips perish. This causes permanent enrichment . If you remove the floatbowls you can double check for evidence of rubbing of the floats on the bowl. Bit of tubing on the choke jet then try blow/suck, should be sealed if off. I have resorted to removing choke jets and replacing with suitable fine screws to block off the choke circuit when investigating poor running.
What colour floats? White are known to fail or rub.
What are your jets- pilot, main , atomiser. Needle position?
What happens if you allow the bike to run with the fuel off?

It's been a while since I stripped my carbs, but I seem to remember it's possible to put the slide in the wrong way round?, it will start, but it will ruin extremely rich. Or am I thinking of another bike?
Alan.

Had a similar thing happen on my Ducati Pantah, tried all the things you tried & eventually fitted new emulsion tubes & needles in the carbs. Problem solved.

Hi there,
just a random question that springs to mind: have you checked they are the correct carbs for the bike?

I hope you don't have to go the whole wide world for a solution!
Cheers, Dom

RoryMunro wrote: ↑03 Jan 2026 12:29 Had a similar thing happen on my Ducati Pantah, tried all the things you tried & eventually fitted new emulsion tubes & needles in the carbs. Problem solved.

I once had a similar issue with a Gilera 98. On eventual close examination the needle jet was very worn to the extent that the orifice was oval. As a temporary work round for diagnosis I had actually purchased a very cheap new Chinese carb of the correct size for £10. Unfortunately most available are flange fitting. Even not correctly jetted for the bike it instantly started and ran better at low rpm. Thus encouraged, I acquired a new needle jet and needle for the Dellorto ME carb which solved the problem and sold the test one on Ebay.

That's the problem with twins. Double trouble and more faff to try a substitution test. Except, is it definitely affecting both cylinders (both plugs sooty)? If not, swap the carbs and see if it swaps the richness.

Thanks all for the replies, I'll work my way through the suggestioins.

On another note, does 230 Ohms with 54V at 'kickover' sound about right for the ignition coil? Volts seem lowish?

Daddy Dom wrote: ↑04 Jan 2026 21:35 I hope you don't have to go the whole wide world for a solution!
Cheers, Dom

[media]https://youtu.be/erOzZZ9jRkg?si=cxyGCT29GK7l7gDr[/media]

ericwwreckless wrote: ↑05 Jan 2026 22:57 Thanks all for the replies, I'll work my way through the suggestioins.

On another note, does 230 Ohms with 54V at 'kickover' sound about right for the ignition coil? Volts seem lowish?

230 ohms sounds good and I 'think' the voltage too. I'm sure 70-ish volts at idle speed was what's expected. Flywheel magnetism may be worth considering too. A number of people (including in the club) can give that a boost for you. It made a great difference along with a rewound source coil on my bikes.
Regarding your over rich problem. You mention having checked float heights I think. That is only one thing, the final check of what is going on in the float chamber is the fuel level. Either with a transparent float bowl (hard to find now, or a modified main jet holder drilled to allow a pipe attached to it. Then a short length of clear plastic tube positioned vertically, fuel switched on and you can see how high the fuel rises before the floats shut the needle valve. Like the float height there is a diagram or figure quoted with a +/- tolerance of about 1mm. I 'think' the figure is 5mm below the bowl/body joint. With mixed up floats (different weights etc) and all sorts of bending and needle swapping over the years, they can be a way out.

I've just done the plug caps off, how far will the spark jump test. Rear cylinder is 15+mm, front is barely 5, possibly less. Transducer?

Also, I'm revisiting float height, I made an adaptor so I can run a clear tube from the float bowl, let's see.

Ignition fault on one cylinder is most likely the transducer but it could be the 'pickup'.
A duff spark might well mean poor combustion on the affected cylinder and so unburnt fuel.