PLZ HELP 1990 Zxr400-H running incredibly rich

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fstarocka
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PLZ HELP 1990 Zxr400-H running incredibly rich

Post by fstarocka » Sun May 29, 2016 2:58 pm

Hi, this thing seems like it does not respond to anything I do.

Float height set at 11mm, mixture at 2 turns, cleaned 3 times now.. Floats not flooding, I have a filter before carbs.

Emulsion tubes look very good.. Air filter very non restrictive spandex thing..

No intake leaks.. Coils passed pri sec reading tests..



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jamesgoodfella
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Re: PLZ HELP 1990 Zxr400-H running incredibly rich

Post by jamesgoodfella » Wed Jun 01, 2016 3:37 pm

fstarocka,
saw your post on 400GB but I'll reply here as you said you had similar symptoms as me so I'll repeat what I said on there, here.
Try checking your fuel pump and relay if they are faulty.. I know carbs have a float valve to stop over filling but can't hurt to check.

Chapter 15 page 29 onwards, it will tell you how to diagnose if your fuel pump relay is gone or not(page 30).
http://www.zxrworld.co.uk/Manuals/H%20M ... r%2015.pdf
masterofinsanity wrote:or use a Duplo brick :smt002

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fstarocka
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Re: PLZ HELP 1990 Zxr400-H running incredibly rich

Post by fstarocka » Fri Jun 10, 2016 9:59 am

Hi thanks right now running on gravity feed, pump was toast when I got it..

Thanks will check anyway, and as for shims I did manage.. Have to mic the lot and order.

They are 7.48mm iirc..

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jamesgoodfella
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Re: PLZ HELP 1990 Zxr400-H running incredibly rich

Post by jamesgoodfella » Fri Jun 10, 2016 10:15 am

Did you test the fuel pump and the reply?
Just 2 wires from a battery to the pump, if it clicks on he pump is most likely okay. For the fuel pump relay, that's in the manual.
My new fuel pump was £19 off ebay and the relay was £17 from fowlers.
I've got some spare shims, happy to swap them . I'm sure others may have some to swap
2.25 - 2
2.30 - 1
2.35 - 3
2.40 - 1
2.60 - 1
2.80 - 2
2.85 - 4
2.90 - 1
masterofinsanity wrote:or use a Duplo brick :smt002

rccaulfield
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Re: PLZ HELP 1990 Zxr400-H running incredibly rich

Post by rccaulfield » Sat Jun 11, 2016 7:47 am

what size jets u running? Are needles standard?

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fstarocka
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Re: PLZ HELP 1990 Zxr400-H running incredibly rich

Post by fstarocka » Wed Oct 12, 2016 5:38 pm

hi guys - sorry for the delays and i appreciate the feedback.. was up country for a month for work.. back at the bike now -

im running everything stock, pilot jets 35, mains 98.. I did buy new plugs and installed a vac operated fuel pump that seems to be delivering quite alot of fuel.. so thats sorted.. I might have had a leaky needle - not sure..

pulled a plug today and it seemed nice and tan.. but i have to share that i really hacked things -

I couldnt really make out if my needle jets were worn or not.. but could possibly see a very slight bulge on the front sides.. so i went and drilled out the jets to 3.2mm, turned down a pop rivet alumimium jacket and drilled it out 2.5mm, obviously its a real hack and ive ordered brass tubes 4mmx2mm (going to turn down and drill out back to 2.5mm with carbide bits accurately and press the sleeves into needle jet holders) .. Ill make a write up if its successful :)

Anyway -the bike had great power, but one plug still fouled up - however it seemed after about 100miles open road it cleared and seemed to not run too rich.. i scrubbed the tailpipe and inspect after 100 miles on highway.. usually id have black powder on the inside indicating too rich..

dont have my tools here but when im back in the next few days ill be able to diagnose each plug..

very frustrating, this thing is so darn swift when it runs well.. just want to be done pulling the tank off every 3 days!

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