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Mikuni BS34 problem
- markovis07
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Bike is in stock, except for the L&W 4-1 exhaust. Stock airfilter also.
All jets are stock, main is 110.
Bike used to run well, and rev to the red zone with no problem.
I had a problem with choke, and removed float bowls, cleaned all circuits.
I discovered that float level was WAY high, and returned floats to 18,6mm (factory). Did not mess with mixture on any other adjustment.
Returned carbs on bike. Engine starts perfectly, choke working, but she won't rev over 5000 in any gear. Even in first. Works well until that, and then like it hits rev limiter. Tried to put petcock on prime, nothing. Replaced spark plugs, nothing. Tried to pull the choke, nothing. Tried to remove airfilter element, even worse!
Some people suggest me to put larger main jets. As i know main jet only affect from 3/4 of throttle to WOT. My problem starts to happen on only one third.
Also, if i put WOT, engine dies during driving. Putting throttle to half, returns me to "rev limiter", and on quarter bike works normally.
Help needed.
Maybe I should take up a cheaper hobby. Horse racing for example.
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- Steve1986
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1982 kz1000J
Miles-6700
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- Old Man Rock
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Maybe this will help you diagnose your symptoms....
Basic rule of thumb for 4-1, pods (I realize you're using air box), non stock configuration jetting etc....
Follow this link for BS 34 re-build/tuning... One of the best write ups w/images I've come across...
BS-34 Rebuild....
1976 KZ900-A4
MTC 1075cc.
Camshafts: Kawi GPZ-1100 .375 lift
Head: P&P via Larry Cavanaugh
ZX636 suspension
MIKUNI, RS-34'S...
Kerker 4-1, 1.5" comp baffle.
Dyna-S E.I.
Earls 10 row Oil Cooler
Acewell 2802 Series Speedo/Tach
Innovate LC1 Wideband 02 AFR meter
Phoenix, Az
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- markovis07
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Spark plugs looks okay. Dark brown.
Maybe I should take up a cheaper hobby. Horse racing for example.
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- Patton
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markovis07 wrote: ...discovered that float level was WAY high, and returned floats to 18,6mm (factory)....(
Would also perform the clear tube test on each carb to assure correct fuel levels.
"Float height" measured with carbs on the bench is not a reliable manner to assure correct fuel levels.
So long as fuel level is within specs, it doesn't really matter what the measured dry float height happens to be.
Good Fortune!
1973 Z1
KZ900 LTD
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- Old Man Rock
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Just because the 4-1 exhaust was on when purchased doesn't mean it was jetted correctly...
Case in point, float level was off thus extra fuel to compensate for the lean condition of the exhaust...
You adjusted float levels to spec now issues (more air than gas)....
1976 KZ900-A4
MTC 1075cc.
Camshafts: Kawi GPZ-1100 .375 lift
Head: P&P via Larry Cavanaugh
ZX636 suspension
MIKUNI, RS-34'S...
Kerker 4-1, 1.5" comp baffle.
Dyna-S E.I.
Earls 10 row Oil Cooler
Acewell 2802 Series Speedo/Tach
Innovate LC1 Wideband 02 AFR meter
Phoenix, Az
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- turboking
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Old Man Rock wrote: Key notes to LEAN condition..... "Bike used to run well, and rev to the red zone with no problem. " & " discovered that float level was WAY high"....
Maybe this will help you diagnose your symptoms....
Basic rule of thumb for 4-1, pods (I realize you're using air box), non stock configuration jetting etc....
Follow this link for BS 34 re-build/tuning... One of the best write ups w/images I've come across...
[url=http://kzrider.com/filebase/doc_download/508-mikunibs-
cvcarburetorrebuildtutorial]BS-34 Rebuild....[/url]
great rebuild/tuning article :side: thanks for the link
2005 Kawasaki mean streak
2000 325 H.P. mcXpress turbo Hayabusa
1979 kz 1000 mk II ATP turbo
1975 Z1 960 cc Mr. Turbo
1975 Z1 1428 big block ATP turbo
1976 Kz900 1103 cc ATP turbo
1985 GS 1150E
1983 GS 1100E
1997 Suzuki Bandit 1200S
2001 Kawasaki EX 500 Ninja
1972 Honda cb750 (836cc turbo)
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- mtkawboy
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78-KZ1000/1105, 80 KZ1000, 82 Kawasaki GPZ750, 95 Harley Fatboy, 80 Suzuki GS1100ET, 81 GS1100E parts bike, 83 GS1100SD Katana/1394,78 Yamaha XT500, 81 Yamaha XS650, 78 Yamaha XS650E, 48 Whizzer model J motorbike, 71 Honda CT70H, 71 Honda CT70, 81 IT 250 Yamaha,82 Honda XL100S owned
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- baldy110
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- markovis07
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I guess you're right, that the high fuel level compensated for the small main jet.
I've got good fuel flow, petcock works ok in all positions.
Maybe I should take up a cheaper hobby. Horse racing for example.
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- baldy110
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- 650ed
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1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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