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Hesitation: But ONLY at WOT Gear Shift
- bountyhunter
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If I crank it up hard in a low gear with WOT, then let off the throttle to shift gears at maybe 5000 - 6000RPM, then when I crank the throttle back wide open there is a definite hesitation and then the power hits on hard.
The fuel levels are right, there is never any hesitation when I hammer the throttle under any other condition, it's just when I am winding it up, let off fully to shift, and snap the throttle back open.
Otherwise it pulls very strong at just about any condition where I snap the htrottle open.
The only thing not stock is I have put in different carb vacuum pistons (slides) because the rubbers on the originals were shot. The new ones are off a newer year and slightly different than stock, but I am using the stock needles (which are adjustable) set to the same height below the flat surface of the piston.
1979 KZ-750 Twin
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- MFolks
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Sparkplugs and wires good?
1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
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- bountyhunter
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1979 KZ-750 Twin
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- TeK9iNe
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In your case, it might be something with the slides, like the cutaway, or sticking or something...
My advise is don't close the throttle.
You only need to blip the throttle back some to shift up without touching the clutch.
You certainly don't have to close the throttle, then slam it back open.
Add some fuel to your pilot circuit via the mixture screws, and see if that helps.
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79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
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- gane
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[img][/img] 1977 KZ1000A1
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- guitargeek
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1980 KZ750-H1 (slightly altered)
1987 KZ1000-P6 "Ponch"
1979 GS1000 "Dadzuki"
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- bountyhunter
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Hmm, good ideas. The pilots are pretty much dead on, I actually have tried different jets and settings. I am using the stock 45's right now, 47.5 ran a shade rich.I've seen that happen on more than one bike.
In your case, it might be something with the slides, like the cutaway, or sticking or something...
My advise is don't close the throttle.
You only need to blip the throttle back some to shift up without touching the clutch.
You certainly don't have to close the throttle, then slam it back open.
Add some fuel to your pilot circuit via the mixture screws, and see if that helps.
1979 KZ-750 Twin
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- bountyhunter
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Bountyhunter, just a shot in the dark, But, c/v carb pistons have a vacumn control orifice located in the vicinity of needle jet hole. It's diameter controls slide rate & speed. (that's why some jet kits use different springs, & require drilling/restricting .) In some cases, diaphrams can be swapped. & may be an option. luck G
I was suspecting there might be a subtle difference between the slides. I don't want to try swapping the diaphragms because I am sure I would tear them. Screwing with 30 year old rubber is not for me.....
1979 KZ-750 Twin
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- bountyhunter
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I have actually played around with needle height, my needles have five slots and I think I am on the one that runs best.Raise your needles.
1979 KZ-750 Twin
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- guitargeek
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1980 KZ750-H1 (slightly altered)
1987 KZ1000-P6 "Ponch"
1979 GS1000 "Dadzuki"
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- bountyhunter
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1979 KZ-750 Twin
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- riverroad
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I hate them. They are THE most persnickity carbs I've ever messed with. Mostly because of the bizzare single throttle cable that splits into two, one for each carb. To synch them, your supposed to slowly turn the throttle, watching for each slide to start moving at the same time, then adjust the cables until they do start opening at the same exact time.
I've done that, but I still have similar symptoms as you do. And I think the reason for that is the diaphram springs might be slightly different from each other, so they're probably not really synched at all.
Do you have any kind of vacuum ports you can hook some guages up to them to see what's really happening?
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