Eng. Miss RS34 carbs

Mark1200 · L Plate Warrior Joined: 13 Aug 2022 Karma :

Hi guys. i need some help to get rid of a miss in my KZ900 eng. im sure it is the carbs and not electrical. i have switched coils and wires and the miss stayed in the same cyl.
i have cleaned the RS34 carbs a few times and the miss has moved to dif, cyls. after cleaning.
During the last cleaning i discovered the pilot screw O rings have degraded and some bits may have gone into the pilot circuit? I replaced them with new.
i will clean them again and focus here.
i have been testing where the miss is by using a temp gauge on the header .i can tell which cyl is running hot or cool, so i can know which cyl is missing/starving for fuel.
what i just noticed just now is that if i hold my hand lightly in front of the carbs bell mouth(air filters removed) i can feel a slight air pulse on Home , a very strong pulse in Blogs almost like its spitting back, and no pulse on 2 and 4?? At the header, the temps are like this, 1= 300* 2=215* 3=255* 4=175* don't pay attention to the low temps its not completely warmed. just not that #1 is running best and 2,4 are worst. they should all be a similar temp.
What is this difference in pulsing telling me??

compression and valve clearance is good is good.
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76 KZ900, cams, RS34's

jeffyjeff · World Chat Champion Joined: 02 May 2020 Karma :

When you cleaned the carbs, did you check and adjust the float levels equally?
Are you sure that there are no restrictions in the fuel supply to each carburetor?
Are you sure the carburetors are accurately synchronized?
Does the engine miss under load, or just at idle? Exhaust temp readings immediately after the engine has run under load may give you a better idea of discrepancies between cylinders.
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History shows again and again how nature points out the folly of men - BOC

jaffa90 · World Chat Champion Joined: 06 Apr 2016 Karma :

Does it have an inline fuel filter in between the the fuel tap and carbs just in case the fuel tap is breaking up or the tank?

Mark1200 · L Plate Warrior Joined: 13 Aug 2022 Karma :

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

You can test for inlet air leaks using any form of flammable vapour. An unlit bolwlamp would work, as does a spray of EZ start or even WD40. If you spray it on the inlet rubbers with the engine idling and the idle speed increases, it must be sucking extra fuel through the leak.

Another way is to get it somewhere very still and use a smoke machine to see if it's drawing in smoke.

Or just change them. You can pick up a set of new ones for £20-ish.
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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.