ZXR750 L3 wont rev past 7-8000???

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jwdg298
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ZXR750 L3 wont rev past 7-8000???

Post by jwdg298 » Sun Sep 14, 2014 6:08 pm

Hi all,

Long story short but I stripped my ZXR down to check the valve clearances, then unfortunately went away for some time before I got her completely put back together. Nothing dramatic and I got her rebuilt ok on my return (or so I thought :roll: )

I got her running lovely, changed oil and filters etc then proceeded to Cadwell for a trackday..... I then discovered the running problem. She wont rev past about 7-8000rpm, slightly variable depending on gear but this is throttle fully wound on.

She feels like she is juddering at these revs, but then occasionally she will let go when you least expect it and rocket you off at light speed. Not a pleasant feeling which caused an involuntary wheelie over the mountain :shock:

I was wondering what may be causing this issue? Is it most likely a fuel or vacuum issue? Is it crap in the carbs? The problem only seems to occur when riding and she idles lovely. I'm not 100% sure the vacuum pipework is connected properly under the airbox. The ones that connect carb and tank etc. as the Haynes book is a bit vague on this matter (and I didn't label them....) Anyone got any pictures of the connections?

Or is it possible that my fuel pump is kaput after too long sitting dry? Any suggestions or pointers would be greatly appreciated.

Thanks

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Steve-TC1
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Post by Steve-TC1 » Mon Sep 15, 2014 11:17 am

Sounds like a small ram air pressure equaliser tube isn't connected


Find 32151 on top of the carbs and follow it forwards towards the front of the bike , I think it will be off somewhere along the line

http://www.ronayers.com/Air-Cleaner12-C376155.aspx

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yorkie
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Post by yorkie » Mon Sep 15, 2014 12:02 pm

If its not the ram air, I have heard of a similar problem that turned out to be the ECU at fault.
Just got yourself a ZX-9R, then do yourself and your bike a favour, read this thread the sticky post in General Technical viewtopic.php?f=21&t=28097

Please will forum members put their bike model letter, & 1 or 2 after their Profile Location. eg: Your Town & B1,2,3,4 C1,2 E1,2 F1,2
As all zx9's are all slightly different, and I get fed up having to ask which model & number, as a year may not be accurate.
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jwdg298
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Post by jwdg298 » Mon Sep 15, 2014 1:07 pm

Oh, thanks and I hope its as simple as a pipe disconnected. Don't like your suggestion so much Yorkie ;) i'll let you know what I find.

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ZX-9RE1Nick
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Post by ZX-9RE1Nick » Mon Sep 15, 2014 8:45 pm

Had a similar problem with my H***a FireBlade.... Turned out to be a dodgy coil , might be worth looking into fella.
PREVIOUS RIDES:
'76 FS1E (78 mph!)
'81 Fantic Caballero 125
'83 DT125LC
'89 GSX 550ES
'95 Fireblade RRS (Sorry, I soon realised the error of my ways!)
'96 ZX-9R B3
'99 R6
'04 ZX-636R B1
CURRENT RIDE:
'00 ZX-9R E1
Gotta love a mean green ninja machine - even if it's blue!

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