Carb cleaning help

[minig15]

Hi, just found this forum after recently buying a bandit 400

It's being a bit of a hassle to get the engine running right and I see a lot of people have similar problems.

I'm in the process of cleaning the carbs and have noticed that the bore between the idle and main jet is partially blocked, wondered if anyone had a way of cleaning this?

It has had compressed air through it and was thinking maybe bathing it in coke would do the job?

[ventYl]

I would try to use some not-so-thin wire bend to right angle. The main channel should be wide enough to get it there with some amount of luck.

How did you figure out that this bore is blocked? I am having constant problems with carbs (no ultrasound cleaner large enough to clean whole/half of rack in one step) and this passage is probably the last I wasn't giving much care.

[minig15]

Can't really find anything that's strong enough while being thin and checked it by blowing air through one jet into the other.

The bike only really starts without the rubber bungs in the idle jet, if anyone knows why they're there and what difference removing them makes.

[ventYl]

They are there probably mostly because the hole where pilot jet sits is too big for cylinder with so small displacement to produce enough drag at idle to reliable pull gas from float via it. If you remove them you'll get very rough idle (if it is able to idle normally with them).

You can try to use some carb pouring liquid. Given that the bore is in lower part of carb which can be made clean of any rubber parts possibly damaged by cleaner you can use even more aggressive ones if they don't harm aluminum and brass. While letting only lower part of carbs to sit in the liquid - IIRC there's no fuel line above horizontal axis of venturi except of choke line which can be blown by compressed air). One thing suggested elsewhere was to boil the carbs in either water or citric acid. Water will matte the carbs slightly, citric acid even more. Proper drying is necessary in such cases to prevent rust build-up on steel parts.

[Squishy]

I used compressed air.
Blocked all holes except the one I wanted to clean and forced air into it. You can use a piece of paper above the hole and you can see if the paper moves = air flow.

You have to disassemble the carb though, don't apply forced air with the diaphragm still in place.

[minig15]

Thanks, will try again and see if I can get any improvements.

After taking the plugs out I found the bike started more easily but the idle is a little bit rough and doesn't like to rev up unless you keep blipping it