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Discussion Starter · #1 ·
Hi out there; I've recently joined this forum, a little about myself and my bike. i'm a Brit living in Rio de Janeiro, Brazil. I bought a really run-down ZX7 L3 about 5 years ago as a project, and after 3 years of shipping parts into the country, stripping the WHOLE bike to the last nut & bolt, changing EVERY bearing, powder coating the frame, polishing the alloy and learning how to spray-paint (to reproduce the 1995 fairings colour scheme). I've finally got this bike back together & now both looking and running very well.
My only real ongoing "problem" is when I come to start her on choke from cold (ie every time as it's a real cold-blooded reptile). The choke appears to be more of an ON-OFF switch than a progressive devise, Is This Normal ?
As these are rare bikes down here, and as no spare parts ever seem to have accompanied the few imported bikes into Brazil I don't appear to be able to ask other local owners about "fine-tuning" things such as this ( they are happy if theirs starts at all!).
Also to add is that I brought into the country a set of extra carbs that had been "jetted" in the UK and possibly had been prepared for the race-track? and I also added a Micron (straight-through) race-can from a separate source (you can get away with running this on the roads here in Brazil, so I thought why the hell not?) This was both a looker and came with some nice SS headers (MOTAD) and was cheap.
So in summary; my bike runs exceptionally well it's fast and pulls like a train, there is no back-firing and no misfiring, but the damned choke on start-up is a devil to use to keep the engine in a sensible RPM range of a 1000-2500 warm-up idle, it just wants to REV or to die if you are not in there with a micrometer adjustment of the lever. I'm sure that this is not how the bike left the factory, have any of you out there any ideas as to why the choke should be so insensitive and ON -OFF ?
OH I forgot to add that I've restored ALL of the USA spec emissions system with the valve-cover reed valve breathers and the vacuum operated recycling to the inlet manifolds, so apart from carb Needles and the headers and end- can all the rest is standard. And I found that the choke plungers are made of Brass, so these should still be in good order?
Any ideas, or do all ZX7 Ninjas start this way????
 

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1993 Zx-7 L Model, 2006 ZX-10R
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What's your altitude and what is your fuel mixture screw set at?
 

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Discussion Starter · #3 ·
What's your altitude and what is your fuel mixture screw set at?
Thanks for the up-take. I'm at Sea-level and with 3 turns out on the "Pilot-air" screws. The only carb parts that I'm aware are NOT standard are the adjustable (5 position) needles, these have no markings but came mounted in this set of carbs. The optimum position has been found as 2 notches down and in fact any variation from this position (either side) just causes misfiring during normal running and a terrible flat spot from about 1250-2500 rpm. Richard
 

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Discussion Starter · #4 ·
Thanks for the up-take. I'm at Sea-level and with 3 turns out on the "Pilot-air" screws. The only carb parts that I'm aware are NOT standard are the adjustable (5 position) needles, these have no markings but came mounted in this set of carbs. The optimum position has been found as 2 notches down and in fact any variation from this position (either side) just causes misfiring during normal running and a terrible flat spot from about 1250-2500 rpm. Richard
I should add that standard needles (fixed ones) were not available (discontinued part) at the time I had these carbs set-up by a local (but good!) tuner. I've since sourced a set of standard ones but I'm very reluctant to loose the set-up that I've now got for normal running; it's just on start-up that this annoying over-revving occurs if you are not absolutely attentive on the microscopic choke adjustment required. R.
 

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Thanks for the up-take. I'm at Sea-level and with 3 turns out on the "Pilot-air" screws. The only carb parts that I'm aware are NOT standard are the adjustable (5 position) needles, these have no markings but came mounted in this set of carbs. The optimum position has been found as 2 notches down and in fact any variation from this position (either side) just causes misfiring during normal running and a terrible flat spot from about 1250-2500 rpm. Richard
I should add that standard needles (fixed ones) were not available (discontinued part) at the time I had these carbs set-up by a local (but good!) tuner. I've since sourced a set of standard ones but I'm very reluctant to loose the set-up that I've now got for normal running; it's just on start-up that this annoying over-revving occurs if you are not absolutely attentive on the microscopic choke adjustment required. R.
Were the carbs cleaned in an ultrasonic cleaner? Need to look at the choke circuit to figure out if it's sticky.

I know you just restored all the vacuum lines to USA spec. You should do the kleen air float bowl mod while you're in there. This won't effect your idle so no worries.
 

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Discussion Starter · #6 ·
Were the carbs cleaned in an ultrasonic cleaner? Need to look at the choke circuit to figure out if it's sticky.

I know you just restored all the vacuum lines to USA spec. You should do the kleen air float bowl mod while you're in there. This won't effect your idle so no worries.
Ok, it appears that the carbs were not ultra sonic cleaned but were dismantled/disassembled/separated for conventional cleaning. Is there a link for the Kleen-air float bowl mod that you can supply? Thanks again Richard
 
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