Riggins
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| posted on 14/7/08 at 03:10 PM |
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ZX9R Poor performance at speed
No sooner have I introduced myself, I'm asking for help 
As some background I've only just purchased a Tiger B6 with a ZX9R (E) engine. This is my 1st kit car and although I have some basic mechanical
knowledge I have a lot to learn.
I took the car out for the 1st proper drive at the weekend and encountered a problem that I didn't notice on the test drive...
The car and engine performs fine throughout the rev range and when accelerating to high speed. However, when settling into a steady cruise of around
60+ mph after a couple of minute the engine starts to misfire/bog down.
I tried easing off the throttle and putting my foot down again but the problem continues. Changing gear makes no difference. Eventually the car lost
virtually all power and I was forced to pull over - at which point the engine stalled.
I left it turned off for around 10 seconds, restarted and it was running perfectly again. Pulled away, everything fine.
Got back up to the same sort of speed, travelled for another couple of minutes and the same problem again. Stopped - this time engine was still
running waited another 10 or seconds, blipped the throttle and all OK again.
I've tried looking using the search function for similar problems but I can't find an exact match.
Does anyone have any suggestions or can offer any help?
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YQUSTA
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| posted on 14/7/08 at 03:20 PM |
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i dont know what the problem is or how to fix it but there was another guy with the same problem
he put the fuel upto 8 psi on the regulator which seamed to fix the issue not sure if it should be that high though.
http://www.locostbuilders.co.uk/viewthread.php?tid=89015
YQUSTA
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simoto
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| posted on 14/7/08 at 03:22 PM |
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I too have much to learn but could be a choke/cold start enrichment prob or maybe coils/cdi breaking down with temperature.
striker/blade now complete, thanks to all on this site.
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worX
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| posted on 14/7/08 at 03:30 PM |
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Next time you take it out, take some tools out with you to do some investigating.
Next time it does it, whip out one of the plugs and see what the condition of them is - you prob already know this, but;
white = too lean
black = too rich
grey = correct ish fueling
wet = way too much fuel.
Now if they are wet (which is what I'd hope to see if I were you in that situation) then you will need to do some further investigations into
your fueling. So let us (the foum) know...
ATB
Steve
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JoelP
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| posted on 14/7/08 at 03:32 PM |
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i had a pinto once do that, was overheating or running rich IIRC (4 years ago now).
Get it jetted again, i would suspect its been diy jetted in the past and maybe a little rich.
chokes a good suggestion too.
[Edited on 14/7/08 by JoelP]
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progers
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| posted on 14/7/08 at 03:35 PM |
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Is the fuel tank vented properly?
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locoR1
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| posted on 14/7/08 at 03:37 PM |
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Sounds like it could be a vacuum forming in the fuel tank! blocked or no breather next time it does it try taking the fuel filler cap off if it makes
a sucking sound as you remove the cap you should be sorted!
 
Description
Check out my CB500T Cafe Racer build diary
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Riggins
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| posted on 14/7/08 at 03:40 PM |
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Thanks for the info.
I know that a Dynojet kit was fitted in between the test drive and when I collected the car. My immediate suspicion was that perhaps this has not been
set correctly or the wrong jets used.
It also has a Pipercross 'sausage' filter (sticking out the bonnet) and I wonder if perhaps at speed either too much air, or with the
turbulence, not enough is getting to the cabs?
[Edited on 14/7/08 by Riggins]
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jacko
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| posted on 14/7/08 at 03:57 PM |
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Try a u2u to roadruner on here he had similar problems with his car / engine
Jacko
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roadrunner
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| posted on 14/7/08 at 05:56 PM |
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Hi Matt, it sounds like you have different problem to the one i had, it sounds to me that the fueling is all wrong, it could be as already said,
jetting, fuel pressure or a vacuum on your tank, have you got a fuel pump fitted, i would try eliminating the problems one at a time.
Brad.
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will121
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| posted on 14/7/08 at 07:12 PM |
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another possibility that some kawasaki's suffered from is carbs icing up (sounds silly on summers day but happens) which sounds like the
symptoms you mentioned which is made worse if not running the standard airbox, when you either stopped or let it tick over the ice formed in the
venturi/jets melts and all is well again. some suggest fuel additives help but know dowt if others have experienced it they will advise or look on ZX9
web sites.
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Wadders
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| posted on 14/7/08 at 08:24 PM |
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Sounds like either fuel starvation, or possibly running mega rich on part throttle.
I'd suspect the former, possibly a blocked tank breather or faulty pump, as already suggested
The main jets only affect fuelling at full throttle
the needles affect midrange fuelling
Its deffo not:
Carb iceing or the sausage filter, choke is manual, so unless its sticking, you can rule that out as well.
Al.
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BenB
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| posted on 14/7/08 at 09:36 PM |
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I was going to suggest carb icing as well- I think the *at speed* is of interest here. If it was the state of tune it would more likely be when in a
high rev band.
Try taking a drive but not shifting up into top and keep the same revs as you're doing when the incident happens. If it still happens it's
to do with revs. If it doesn't happn carb icing is even more likely....
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Wadders
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| posted on 14/7/08 at 10:55 PM |
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No offence Ben, i know the weathers crap for July, but carb icing 
Al.
Originally posted by BenB
I was going to suggest carb icing as well- I think the *at speed* is of interest here. If it was the state of tune it would more likely be when in a
high rev band.
Try taking a drive but not shifting up into top and keep the same revs as you're doing when the incident happens. If it still happens it's
to do with revs. If it doesn't happn carb icing is even more likely....
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mackei23b
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| posted on 15/7/08 at 08:31 AM |
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Just to add to the debate, (though it does say that E engines did not seam to suffer from carb icing, assuming the heater circuit is plumbed in):
That said, I'd check the fuel supply issues first as mentioned and rule out first.
http://www.visordown.com/articles/view/used_review_kawasaki_zx9r_(b1__f2p)/4316.html
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Riggins
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| posted on 15/7/08 at 10:02 AM |
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Thanks for all the suggestions and feedback
It already feels like a great forum where people know what they are talking about and are happy to help and offer advice. Much better than some forums
I have used with previous cars!
Looks like I've got a few things to work through. I'll let you know how I get on - probably not going to be able to do anything until the
weekend though.
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cossiebri
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| posted on 15/7/08 at 06:29 PM |
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I suffered carb icing on my zx9 locost,it was early one morning(around 1:30am)even though it was the middle of Aug still bloomin cold, just used to
give it a bootful to clear it (me mates thought i kept wanting to race )
If it doesn't fit MODIFY it!!
Cheers BriF
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keith
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| posted on 15/7/08 at 09:25 PM |
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this sounds to obvious have you checked the fuel filter by the fuel pump
"aw right our kid"
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