Carb throat balance when tuning now a rebuild saga !, those with Zenith carbs can learn from my bad fortune ? |
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Carb throat balance when tuning now a rebuild saga !, those with Zenith carbs can learn from my bad fortune ? |
porschetub |
Aug 29 2023, 11:25 PM
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#1
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Advanced Member Group: Members Posts: 4,703 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
Doing a tune on my Zeniths ,cant find an exact rpm range and done a ton of research ;
Bruce Anderson mentioned 1800 in his book, Factory says 1000 in the gary.suggate site factory manual, Haynes manual tells us 1000. So far I have tuned throats @ idle ,1000rpm ,1400 and 1800 on hand throttle and strangely I get the same balance any way ?. Now thinking its not an issue but would appreciate feedback from 6yl guys with carbs,TIA,cheers |
porschetub |
Sep 4 2023, 05:55 PM
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#2
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Advanced Member Group: Members Posts: 4,703 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
Thanks for the reply Tony,my carbs are euro spec so no overun system which appears to be a blessing as this system is rather hard to dial in if fitted and to delete requires other work.
I repaired my rollers and they work a lot better ,alfa1750 now sells these but as whole assemblies but not when I was sorting mine . I made the same mistake as you did with fuel so I will run my carbs out of fuel then drain whats left in the bowls via the main jets,strange thing is the RH side carb has the degraded parts from the old fuel other side not so ,all my pump discharge noozles orings are now leaking and the mixture screw ones the same,they just fell apart when I screwed them out. Fuel hose to each carb were in " soon to fail mode " 2 quality brands used 1 was hard and starting to crack and the other was like mush ,all rubber hoses changed for Gates 50 psi carb hose. Looks like I will order 2 complete base rebuilt kits and take an offer to use a mates ultrasonic cleaner...I don't want to be doing this again as its a right PITA to get the carbs on and off. Thanks for the input from all keep it up,cheers. |
porschetub |
Sep 9 2023, 01:35 PM
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#3
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Advanced Member Group: Members Posts: 4,703 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
Thanks for the reply Tony,my carbs are euro spec so no overun system which appears to be a blessing as this system is rather hard to dial in if fitted and to delete requires other work. I repaired my rollers and they work a lot better ,alfa1750 now sells these but as whole assemblies but not when I was sorting mine . I made the same mistake as you did with fuel so I will run my carbs out of fuel then drain whats left in the bowls via the main jets,strange thing is the RH side carb has the degraded parts from the old fuel other side not so ,all my pump discharge noozles orings are now leaking and the mixture screw ones the same,they just fell apart when I screwed them out. Fuel hose to each carb were in " soon to fail mode " 2 quality brands used 1 was hard and starting to crack and the other was like mush ,all rubber hoses changed for Gates 50 psi carb hose. Looks like I will order 2 complete base rebuilt kits and take an offer to use a mates ultrasonic cleaner...I don't want to be doing this again as its a right PITA to get the carbs on and off. Thanks for the input from all keep it up,cheers. Checked all the float levels with my PMO gauge (which I finally found ) and all levels exactly even in the middle of the two lower marks as per Zenith setting so happy with that but knew they were ok but good to check. Can't run the engine anymore as have to many leaks from bad seals ,RH is now leaking fuel and fouling plugs due to leaking pump noozles. Kinda pissed me of because I had it running real nice for a short time until this,any way when my kits arrive it will be fine,cheers. |
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