The story so far

[Dorset shortwing]

Hi all , bought an L model a few weeks ago that had been stood since 09 so obviously ran like a pig so i replaced plugs, completely checked , stripped and cleaned carbs drained old fuel and now runs much better but is still a pig when you open the throttle from idle and will cut out and will only rev and pull cleanly under power with the choke half open so my question is do you think this top end lack of drive with choke off can be cured with pilot screw adjustment ?

[banner001]

probably not, the pilot has its greatest influence up to 1/8-1/4 throttle...after that its needle and then main jet.

sounds like you need to give the carb a good clean - or fit bigger main jets, maybe richen the needle, what air filter/exhaust you running?

[KwakKwak]

Mine came running really erratically, very rich - 110 jets, imagine. Cleaned the carbs and set them back to the settings handed down by wise old Mr Kawasaki, replaced filters, gaskets and seals etc etc and hey presto, revs to red without a hitch. Kawasaki were right after all. Standard settings are the place to start and if you're lucky finish.

Having said that I've a sneak that mine may prefer 98 jets due to the exhaust system, but it's really very close to almost running nearly quite perfect .
Balance those clean carbs too, it's the happy ending, if you like.

[Dorset shortwing]

It's running the standard air filter and exhaust. ....in fact the bike is totaly standard and only done a genuine 7.800 miles and is not a grey import.
Also I have balanced the carbs.

[KwakKwak]

If the bike has sat for years especially with petrol in it, then you will have quite a list of O rings and gaskets to replace.
I replaced all fuel pipes and filter, tap packing and O rings too.
Check out an old post by an old man, "flatside and cvs too......a problem solved" If you have dealt with this then you have defo cleaned the carbs properly, if not, reboot.
Your bike is showing all the classic signs of being a ZXR400. Most important thing to remember is it will without a doubt be a simple fix

[Dorset shortwing]

Any idea where i can get the carb and fuel tap O ring set ?

[KwakKwak]

Any idea where i can get the carb and fuel tap O ring set ?

This question is NOT to be asked here, you will be systematically hunted down and be on the end of a damned good telling off, for the fuel tap go OEM, the non OEM kits come with bolts that ain't long enough, I used the viton kit available here through Maelstrom, I think thats right, for the carbs, loads of O rings with it, and good value, takes a while in the post though, worth the wait, or do the very obvious, they're extremely brilliant and speedy you know.

[Dorset shortwing]

Any idea where i can get the carb and fuel tap O ring set ?

This question is NOT to be asked here, you will be systematically hunted down and be on the end of a damned good telling off, for the fuel tap go OEM, the non OEM kits come with bolts that ain't long enough, I used the viton kit available here through Maelstrom, I think thats right, for the carbs, loads of O rings with it, and good value, takes a while in the post though, worth the wait, or do the very obvious, they're extremely brilliant and speedy you know.

Yep,,, you have now lost me

[KwakKwak]

Search "Viton" here on the forum, it's a kit for the carbs, float bowl O rings etc.
Or order from Cradley Kawasaki, I singlehandedly keep them in business, bottom of my, and other nice chaps posts they are very very efficient and helpful, nice website to order from.
DO NOT ask for their web address, it could bring the forum crashing down

[Dorset shortwing]

okay ,,anyway here is a pic of the bike , i have to use it for work next week and have sussed the blip the throttle at junctions technique (ZX4 was the same) and for warp speed open the choke half way

[Dorset shortwing]

Hmmm photobucket have lobbed the front off :wanker

[Dorset shortwing]

See if this one works

[KwakKwak]

Bike looking really good. If you're replacing O rings and gaskets, check airbox and carb holders too. Viton kit has one set of these O rings, damned if I can remember which though.

Black wheels always look best, FACT, unbiased view of course.

[banner001]

what main jets are you running? needing choke means that you are not getting enough fuel in that particular part of the throttle range, if it starts to bog before you get to half throttle (and a bit of choke sorts it somewhat) get some small M3 washers from ebay and raise your jet needles with 1-3 washers each, combine this with a slightly larger main jet and see if the bike pulls without needing choke.

it can also be caused by a blockage/slowing of fuel through the openings in the carb...this can also be sorted by using the techniques above, although these will only be a stop-gap and can get worse over time.

if you take it to a dyno place they will charge you £20-30, you will get an air-fuel trace that will show you how the bike is fuelling.

[Dorset shortwing]

what main jets are you running? needing choke means that you are not getting enough fuel in that particular part of the throttle range, if it starts to bog before you get to half throttle (and a bit of choke sorts it somewhat) get some small M3 washers from ebay and raise your jet needles with 1-3 washers each, combine this with a slightly larger main jet and see if the bike pulls without needing choke.

it can also be caused by a blockage/slowing of fuel through the openings in the carb...this can also be sorted by using the techniques above, although these will only be a stop-gap and can get worse over time.

if you take it to a dyno place they will charge you £20-30, you will get an air-fuel trace that will show you how the bike is fuelling.

Thank's, i did not take note of the main jet size when i stripped them but i have just ordered the Viton o ring kit so will live with the problem until the o ring's come then look but to be honest the bike is totally standard so far even down to original tool kit so expect to find original items. Also once above 2000 rpm it pulls fine right up to about 8000 rpm then needs half choke to scream up to the red line so it's the initial throttle form idle and the top end of the rev range that it suffers.