1984 Kawasaki KZ750 high speed issues.

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Going at it for a for a few minutes and then it has a wobble definitely sounds like the float bowl(s) emptying

I recall on the Z1000 we had similar problems. Fuel flow from the tank was fine and in the end we left the carbs in-situ and took the bowls off. Fuel pissed out of half the carbs but dribbled out the other two. Turned out someone previously had used PTFE tape on the T-pipes between paired carbs and done a piss-poor job of it.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[mentalboy]

Thinking in reverse here. My zzr1100 came with a carb top that restricted it, the common bypass was to fit the carb tops from a z750. Could it be that yours has restricted carb tops possibly similar to the 1100, mebbe to meet Canadian/US laws?

Easy to tell, the unrestricted top is flat across its top, the restricted one has a bevel set into it to stop the slide from its full range of travel.
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Make mine a Corona.

[tatters]

I finally got around to working on this again. Took the carbs off and tested the flow out of each when the floats are in the down postion, fuel flow was good.

Installed the carbs back in the bike and took it for a run and still runing like crap at high speed. I then took the carbs off the bike again and installed main jets that were a size larger than stock.

Took the bike for another ride and it is now x1000 better can now pulls to 110mph.

Its odd that the main jet size increase would correct the issue as the bikes exhaust/airbox etc is completey stock and l am quite sure the top end engine has never been messed with such as a 810cc big bore kit etc.



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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650 Present:G650XC,C12,KZ750,1190ADV

[stinkwheel]

It's possible the old jets were worn or ovalled. Small damage can often only be seen with a loupe but can seriously affect a performance engine.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

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