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Almost there, but bike gallops and stays there!
- inspirado
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It's been several years since I've posted but I got the bug again and am trying to get the bike back on the road (or really on the road for the first time I guess).
Anyways, I have pretty much stock 1983 KZ750 L3.
This is what I've done:
Opened and inspected carbs - they were all almost pristine inside. No need for cleaning.
Synched carbs - they were pretty badly out of synch, so I did so at around 5k RPM
Adjust float levels - they're now within spec.
Replaced engine-side boots with new from Jeff@Z1 (thanks!)
Replaced all vacuum plugs with new squishy ones!
With all that done the bike will start pretty well but it jumps in RPMs right away to 5k or so, even with the choke off. If I pull on the brake and release the clutch a bit to put load on the engine it will bog down to idle speeds and I can let up on the clutch and it will stay there. However, if I blip the throttle again the RPMs will jump back up to 5k and stay there. It also won't stay at idle for more than 30 seconds or so, it will generally start creeping back up to 5k.
I suspect a vacuum leak so I did the WD-40 check, but it's kind of inconclusive. I don't think the boots are the problem, but I think the throttle shaft might have a vacuum leak.
Is this galloping a typical symptom of a vacuum leak? If so, has anybody else had any problems with the throttle shaft? How do you fix that? I have access to a machine shop and can machine new brass bushings or put in new O-rings.
Please help if you have any advice! I've been so close with this bike for so long and I just want to get it on the road...
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- bountyhunter
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Are you sure you have all the vacuum fittings accounted for? Sometimes the one that runs the petcock gets overlooked.
Also: are the rubber seals around the pistons OK?
Binding on the throttle shaft won't cause the speed to creep up and runaway, it will just stick and stay at one place.
I think the vacuum leak is more likely. Maybe a PM to Wired George, he is the carburetor expert.
1979 KZ-750 Twin
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- tw..
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2-1976 KZ900 A4
1995 KZ1000 Police bike
1978 Z1R
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- inspirado
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Also, bountyhunter, I may have misspoke. I actually didn't mean that the throttle shaft is sticking,but that there MAY BE a vacuum leak around where it rotates in the carburetor body.
Thanks!
Dave
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- Grantl
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- KZRider is Da Bomb!!!
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Just one more thing to check out.
1981 KZ1000 CSR
1983 KZ750 Project Bike
1990 550 Zephyr
1994 KZ1000 P
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- inspirado
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- bountyhunter
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I suppose that could be the vacuum leak in question?Also, bountyhunter, I may have misspoke. I actually didn't mean that the throttle shaft is sticking,but that there is a vacuum leak around where it rotates in the carburetor body.
Thanks!
Dave
1979 KZ-750 Twin
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- wiredgeorge
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wiredgeorge Motorcycle Carburetors
Mico TX
www.wgcarbs.com
Too many bikes to list!
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- inspirado
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- inspirado
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