carb balance zx400g

[quaidpinder]

hello all hope you all had a good christmas ... just been reading the carb balancing guide from the site but my carbs are different to the ones in the pictures i think they are 30mm carbs and dont have the rubber connections on the bottom for the vacumn pipes i will post some pictires later all i have is some clear rubber tabs with screws in on the reverse of the carb was just wondering if anyone knows where id have to connect the tubing on these carbs for balancing .. am just in the process of cleaning them up so any further hints or tips would be most welcome .. thanks very much !!

[masterofinsanity]

if you only have the holes with screws in them then you will need the adaptors, some come with the gauges.

[quaidpinder]

ok thanks very much .. hoping to have the bike ready for spring this year ... next will be new coils and leads as the old ht leads have gone brittle and dont seem to make contact very well on the top of the plugs..
Have never done a carb balance before so should be interesting ,, was reading a thread somewhere where a chap had stripped down his carbs and boiled the whole lot in a pot of water used wd40 to disperse the water and let them dry,, or for the ultimate clean use lemon juice !! bizzare ?!

[RedexRobB]

if you want to go that far i think you can pick up small seismic cleaners for less than 40 quid, seen em edvertised in Aldi once.

[Neosophist]

The ZX400G is basically an Early ZXR400H if it's the model i'm thinking of.. same engine too as I went to look at one before I got my ZXR...

You dont' connect the vaccumn gauges to the carbs, instead you connect them to the inlet manifolds.

If you look at the rubbers where the carburettors clamp onto you'll see a metal pipe stub just below this. It might be blanked off or linked to another cylinder (cyl# 1 -> 4, 2 -> 3 if their linked) this is where the gauges attatch to.

You can boil carbs in lemon juice / vinegar etc if the carbs are really bad, however remove all rubber, use a weak solution, dont' boil for longer than 20 - 30 mins and always clean off with distilled water straight away.

Ususally removing all the jets and cleaning with paraffin and proper carb cleaner, combined with blowing compressed air through will suffice.

[quaidpinder]

ok thanks i will have a look , as i mentioned in another post i have pulled the carbs apart and noticed the rubber diaphrams apear to be the wrong ones in the carb as they are to big to go back in perfectly , when i removed the cover they were not perfectly round or all sitting in the lip they were crikckled up to get the black cap on properly , when i tried to put them back in i found it very difficult to get them to sit in their housing so putting the outer cap back on was only possible if the diaphrams were partially pinched cant be good .... i am going to try again but dont think i will manage it very well ... this is turning into a nightmare ... !!!! :smt013 anyhow next i am trying a new set of plugs ....

[stuzx4r]

If the diaphragms don't fit properly into the top of your carbs then your bike will NOT run as it should, it’s the air pressure at the base of the rubber that lifts the slide, when the throttle is opened. no lift no acceleration!

I would suggest a second hand set of carbs may be your best solution.

Good luck.

[Neosophist]

ok thanks i will have a look , as i mentioned in another post i have pulled the carbs apart and noticed the rubber diaphrams apear to be the wrong ones in the carb as they are to big to go back in perfectly , when i removed the cover they were not perfectly round or all sitting in the lip they were crikckled up to get the black cap on properly , when i tried to put them back in i found it very difficult to get them to sit in their housing so putting the outer cap back on was only possible if the diaphrams were partially pinched cant be good .... i am going to try again but dont think i will manage it very well ... this is turning into a nightmare ... !!!! :smt013 anyhow next i am trying a new set of plugs ....

lol seen this before!

Have you or somebody else cleaned them with carb cleaners / solvents?

They swell up if you do and dont' fit properly again >.<

You may be lucky.. take them out and clean them with fresh water and let them dry overnight somewhere warm (like an airing cupboard) and see if they've returned to their original size.

I dropped one of mine into some carb cleaner by accident and it swelled up loads, wouldn't fit, but after a good washing and letting it dry out it returned to its proper size.

The will appear to be a bit crinkled as you put it but should fit properly around the edge, i'll take you a picture if your still struggling.

[quaidpinder]

ok well got the diaphrams back in ok and cleaned the plugs up and cleaned all the connections up and guess what ? .BROOM first turn !! Got a new throtle cable on the way as the lower linkage was broke so im gonna fit that then balance the carbs ,, . I did however notice that when i gave the bike a litlte throttle it seemes to be over fueling as it will rev right through the range steadily but if i ring its neck it splutters and doesnt rev past 4 k anyone got any thoughts ? ..

[Neosophist]

ok well got the diaphrams back in ok and cleaned the plugs up and cleaned all the connections up and guess what ? .BROOM first turn !! Got a new throtle cable on the way as the lower linkage was broke so im gonna fit that then balance the carbs ,, . I did however notice that when i gave the bike a litlte throttle it seemes to be over fueling as it will rev right through the range steadily but if i ring its neck it splutters and doesnt rev past 4 k anyone got any thoughts ? ..

It might not be too rich.. did you allow the bike time to fully warm up? A cold bike will bog down to some extent when cold.

[quaidpinder]

yeah i let it tick over and warm up properly .. it doesnt have the airbox attached however so maybe it pulling in to much air sounds like a mixture issue to me , either over fueling or not enough one or other , may renew the inlet rubbers to discount an airleak but im not really sure whats up with it ....

[Neosophist]

yeah i let it tick over and warm up properly .. it doesnt have the airbox attached however so maybe it pulling in to much air sounds like a mixture issue to me , either over fueling or not enough one or other , may renew the inlet rubbers to discount an airleak but im not really sure whats up with it ....

These bikes will run AWFUL without the airbox

[quaidpinder]

ok thanks for all the help ... !