www.zxrworld.co.uk

balancing carbs.
Hi guys i am currently in the process of trying to balance my carbs. I have seen the liuttle how to do page on here, which I found through previous forum pages.
I am finding it difficult to get the reading the manual says ( eg 2cm/200mm vaccuum). as there are only 3 screws to do this. my gague reads up to 20 inches.
I did initially balance them all as they were, but all the same, which was at about 150mm vaccuum, but then the tickover would go below 4000 revs at all, no matter what I did so i feel this must be wrong. any advice on how to do this best?
air box on or off?
what reading to go for?
and which to start with of the three screws ( why the f :smt013 k has it only gt 3 screws?)
please help me

the 1st screw balances carbs 1 & 2 the 3rd screw balances carbs 3 & 4 the middle screw is used to sync the 2 pairs together. i'm assuming this is the how to you are referring to? http://www.zxrworld.co.uk/zxr400/balancing.html

I see you have read the manual but not properly! Thats 2cm Hg or less DIFFERENCE between two cylinders, not the actual reading the vaccum pressure needs to be. What that means is that it doesnt actually matter what the vaccuum pressure is as long as they are the same.

My write up that Baz there has posted should fill you in with all the info you need. Use it, and if you want id love to hear some feedback on how easy you found balancing your carbs with that to hand.

That should be all you need know, if you really get stuck, ask away.

HTH

RobB

I balanced my carbs using your gudie Rob, simply as pie

Glad to hear it Oli

I need to update it a bit actually, because i found a way to stop the carbs opening up when you push on the screws to turn them when balancing; push on the throttle twist where the cables join the carbs

as i say, I initially did it exactly to you " how to" page, but theynhe tick over rocketed. when I turned the tick over screw down ( being the black tisty knob thing lol), the throttle body ( where the cables connect to the end of the butterfyls) stayed open, floating in the air. the cabels were slackened off and this did nothing. if I push it with my finger It will go down, but then when opened again, it raises and stays high
any ideas

Thats odd, what i would do is clean, and then work some oil into the return springs on the carbs by putting a drop of oil on them and working it in by opening the throttle fully and closing it, theres one right behind the throttle twist and another in the middle i think. Be a good idea to unscrew the throttle stop adjuster all the way for this, then screw back in.

What might be worth doing is once you have oiled the springs is to take the cables off completely to stop them interfering with the adjustments and also to see if it is actually them causing the problem of opening the throttle. You can still blip the throttle if need be while adjusting by turning the thottle twist by hand.

ok, carbs are balanced, and the springs are clean. The engine tickover is much better, I have also changed the vaccuum tues under the carbs. The bike fires up really well and runs nicely, but still, after about 30 mins of riding, hasa tendency to cut out on me and can be a little bit of a bugger to start. I may ned to check the fuel micture again, as I have now balanced the carbs, but any other ideas?

What are the mixture screws set at the moment? Standard is 2 and 1/4 turns out from fully in. Thats assuming you have standard jets and exhaust.

It could be your inlet rubbers leaking thats causing it to stop. Spray some carb cleaner round the inlet rubbers while the engine is running, if the revs hange in anyway then they are probably leaking.

m gonna wack some sealer around the nlets, to seal them up dead good, and re set the mixtur eon the carbs, I will also get one of those mixture things that shows the spark, and when it goes blue the mixture is sweet!
stay tuned
steve

I Found your how to guide simply brilliant rob as I done mine a couple of weeks ago and i'm a complete nerd. But then you know this as there your gauges i have got

steve87 wrote:m gonna wack some sealer around the nlets, to seal them up dead good, and re set the mixtur eon the carbs, I will also get one of those mixture things that shows the spark, and when it goes blue the mixture is sweet!
stay tuned
steve

Thatll be a colour tune! Not used one of those yet, look good tho!

Mark, when you cleaning the carbs? Ill pick em up when im round to help.

Saturday afternoon mate as i have to work on sunday :smt013

Hmm, not sure if ill make suturday afternoon. Ill let you know