idle problem

[shoryzo]

Hello,

i have a problem with my zx400l from'96
symptoms:

- cold start with choke 100% - starts and speeds up to about 4000 rpm
- keep the choke on about 1-2 min (until the temp rises above the blue mark)
- cut the choke half way - idle drops to about 1.500 rpm then stalls
- start again whith full choke (it doesn't start otherwise)
- turn the idle screw half turn - goes to abot 3000 rpm
- cut the choke - idle around 2000-2500 rpm
- give a little gas rev around 4000 rpm then drops under 1000 rpm and stalls
- tryed to stabilize the idle speed from screw(when hot- temp half way between cod and hot) to 1700 rpm - not a chance (idles a little bit but then stalls)

I've took it to a mechanic, he tryed to balance the carbs (could only do it at around 4000 rpm.....all 4 carbs syncronized, but no idle at 1700 rpm -stalls)

What could it be the problem ?

Low compresion rate?
Carbs need to be cleaned and the the pins replaced?

I am in desperate need of a hint, at least what are the steps that i have to take to identify the problem.

Best regards
A.

[RedexRobB]

If it sounds anything like this then it could be your plugs. It certainly sounds like the problem i had.



Failing that, whip the carbs off for a clean.

[CaNsA]

What are the carb rubbers like?

Seated correctly, nice and tight with no leaks?

[shoryzo]

@RedexRobB

Yes this sounds like my problem too. Indeed i have a bad sparkplug cap (i didn't thought that might be a problem. Indeed i had a problem with that early in spring. The bike woun't start cause that sparkplugcap that was bustet(cracked), but i thought that i fixed the problem sience the motor starts).

I'll change all the the whires and the sparkplug caps. Can you tell me a part no for that? I looked it up in NGK catalogue but didn't find one.

@CaNsA

The rubbers on my carbs are moist and elastic, seated correctly, nice and tight with no leaks. No rupture or damage what so ever. Think they work fine.



Thanks!

[RedexRobB]

Im refering more to the plugs themselves rather than the caps and HT leads, as you can see in my video my bike starts and runs but wont idle, change of plugs cured it. The correct plugs are NGK CR9EK. You can apparently use the NGK CR9E without any bother, it just has a single ground electrode compared with the two on the EK.

Having read your other post is this the same mechanic as the one who told you about low compression? Becuse i now wonder about his competence with the balancing, why bother if it doesnt idle?

[shoryzo]

Yes ofcourse is the same guy. I don't know why he does this, maybe my money are no good for him, i dunno....
(and the shop it is KAWAMOTORS - suplyer for kawa parts)
I ve got back my bike, still has idle problems ( idle around 3.5k just to run on a standstill - red light for example) but otherwise it runs just fine.
I'll change the plugs and then i ll try to clean the carbs and balance them again.

Thanks again!

Best regards,
A.

[shoryzo]

Hey guys, got back whith a video:

http://www.youtube.com/watch?v=fk8HRmZq ... e=youtu.be

just today i've started the bike (full choke), strted imediately.
but this is how it idle.

could it be a sparkplug problem? ( i know you all said that i should get new spark plugs, but they will arrive on friday and until then , maybe i can check something else...carbs or somethin)


Thanks alot!

(ignore the other sounds...one is from clutch basket and one from valve or came shaft....so i've been told)

[RedexRobB]

I would wait for the plugs and see. Its sods law that you start looking and adjusting other bits and bobs and you create other problems. Hopefully plugs will sort it, it sounds like its a slight misfire to me.

[shoryzo]

UPDATE:
today i ve changed the spark plugs, the caps and the whires.
starts nice (even without choke - Bucharest temp today 37 C) , idles smooth at any rpm ( set it at 1.7 k) but i still have e problem
when i accelerate climbs rapidly (which is normal) , but descends very slow. (can be seen in my video above)
(throtle cable had been cleaned and greased works perfect....)

carb balancing is the next step? or it could be something else

Thanks!

[shoryzo]

UPDATE 2

went to a mechanic and balanced my carbs but the problem still persists.
he also took my compresion rate and it was 6 KgF/cm2 (1 st cyl); 6 KgF/cm2 (2 nd cyl); 7 KgF/cm2 (3 rd cyl); 6 KgF/cm2 (4 th cyl)

this drives me crazy and i can't ride my bike. It idles @ 2.5 - 3 k and because it is very hot outside the water level rises quick when standing still.

what should i do?
Thank!