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mixture help !! cv34 carbs.
- malvernmart
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hi,i have been on all your forums about my cv34 carbs and still cant get it right !! :ohmy:
bike-- kz 750 ltd - 1980
carbs-- 4 x cv34
exhaust-- motad 4 into 1
air filters-- 4 k&n ( oval shape)
prim main-- 68(stock 62)
second main-- 135 (stock 125)
ok here is the problem -- the bike had standard air box and the motad exhaust on it when i got it,however it always run a bit rough...
i decided to drop the k&n filters on and try to get it 100% right..
this is the list of things i have done in stages----
had bike set up on rolling road inluding dynamic testing to get best power etc..
it run worst AFTER than before !! ( he had put a 116 second jet in ).
took it back and they put a 120 jet in..
i then decided to set it myself ( waste of £100)
stripped carbs completely..full clean/degrease and air line jet.. all holes clear
changed jets to above table..
full carb rebuild including 4 new fuel/mixture screws ( including washers and seals)
reset float heights ..
new plugs/leads etc etc
now for the dilemma:angry: --
bike fires up straight away with a little choke,knock it off and she purrs like a kitten at 1000 rpm..
ihave full power and super smooth running straight through all revs and gears !!
the bike does tend to run slightly faster at 1750 rpm when warm. (not a problem though )
why am i on here you are thinking ??
3 OF MY PLUGS ARE SUPER SOOTY !! number 2 cylinder that feeds vaccum fuel tap is fine ..
number 4 cylinder gets thick soot within 2 miles :huh:
i also get a slight popping when de accelerating ..
i have tried all the different mixture settings including having screws out 1/4 turn only .. i have checked all over for air leaks etc and all ok ..
i have even run bike with no filters on to see if they were the problem. all carb vaccums have new rubber caps on too.
do i just not worrie and ride it as it is ( if it aint broke dont fix it ..) or does anyone have any ideas ( i have done everythink that has been on this forum ) :S
thanks in advance from over here in england ..
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- baldy110
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- Patton
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malvernmart wrote: ...
reset float heights ....
Would also perform the clear tube test to assure proper fuel level.
Good Fortune!
1973 Z1
KZ900 LTD
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- OldSchoolZ
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So many bikes that are carbed and running rich have totally worn out needle jets, not to be confused with jet needles. The needle jet is the basically female part of the neddle assymbly. These needles wear out the needle jet and it wears oblonged. Once that happens, they run rich and never can be correct until they are replaced. Beyond that Im guessing your float levels are slightly off or lowspeed screws are too rich. Back in the day I diagnosed sooty conditions on these guys sooo much that if flat vales and lowspeed couldnt help, I'd simply replace them, and almost always they ran better. The needle jets are hard to see into as well. They start wearing bad around25k-over miles from constant moving of the jet needles up and down.
Remember, don't work on your bike so much you never ride it.
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- Patton
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And also visually examine spark quality with plugs removed, which should be fat blue sparks (not weak orange sparks).
Good Fortune!
1973 Z1
KZ900 LTD
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- malvernmart
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i did do that as well
i set the heights to the same level as number 2 cylinder ( the good plug )
this was one of the last things i did ( after trying everything else ) .
this action made the bike run and tick over super smooth
the whole thing is a puzzle :blink: -- especialy number 4 plug-- i will clean it with wire brush and check it within 1 or 2 miles , and it is thick with soot ( dry , not wet from bad rings etc )
has enyone else hjad or got this problem
cheers again...
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- malvernmart
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i looked at the needles and they do look ok, however the bike has 34000 miles on the clock , so that could be the problem -- you have given me an idea now -- il change number 2 needle ( good plug ) over to number 4 and see if that does the trick !!
i will post back soon ..
on a sad note however i have looked for needles before ( no 1a ) and can not find any at all -- guess no one produces pattern needles ?? ( unlike jets )..
cheers again though - this imput from you all has given me a next step approach
martin
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- Patton
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Assure valve clearances within specs;
Lube pivot points on ignition advancer;
Assure pilot jet plugs and their o'rings are fitted and serviceable;
Assure pilot air jet is clean and clear.
Good Fortune!
1973 Z1
KZ900 LTD
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- rcook52459
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For reference, turning a/f screw "out" enrichens, and turning "in" leans.
If meaning only turned out 1 turn from seated, that should be plenty lean.
The enrichener circuit (as opposed to a true choke) is designed to operate when the throttle remains fully closed.
When starting a cold engine, it's best to not touch the throttle.
"Pumping" the throttle largely disables the enrichener circuit.
Good Fortune!
1983 750 spectre,all stock almost 16,000 on it on 1980 Suzuki gs1000l
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- Patton
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Good Fortune!
1973 Z1
KZ900 LTD
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- rcook52459
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1983 750 spectre,all stock almost 16,000 on it on 1980 Suzuki gs1000l
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- TexasKZ
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malvernmart wrote: cheers oldschoolz..
i looked at the needles and they do look ok, however the bike has 34000 miles on the clock , so that could be the problem -- you have given me an idea now -- il change number 2 needle ( good plug ) over to number 4 and see if that does the trick !!
i will post back soon ..
on a sad note however i have looked for needles before ( no 1a ) and can not find any at all -- guess no one produces pattern needles ?? ( unlike jets )..
cheers again though - this imput from you all has given me a next step approach
martin
OldschoolZ is not talking about the needle, he is talking about the jet that the needle goes in and out of.
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
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