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Checking needle and seats for leaks
- skooterbum4real
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He states that he bench tests his snowmobile carbs with the tool, by placing the carbs in an upside down position, so the floats are pressing the needles into the seats. He then attaches the tool to the carbs with a piece of hose running from the end of the tool to the fuel inlet of the carbs. He then applies 5 to 7 lbs. of air pressure to the carbs, then cuts off the air supply, and lets them set for x amount of time. If the air doesn't bleed off, then the needle and seats are sealing as they should.
Has anyone tried this method before, and was it an acceptable way of checking the needle and seats ??
1978 KZ650B 8,500 miles
1976 KZ750 Twin
SPECIAL CONSTRUCTION V-TWIN CHOP
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- bountyhunter
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skooterbum4real wrote: I was talking with my auto mechanic yesterday about the carbs on my kz650. I mentioned that I'm going to rebuild them due to fuel filling the air box. He showed me a little tool he made up years back with black pipe, an air regulator, and a pressure gauge.
He states that he bench tests his snowmobile carbs with the tool, by placing the carbs in an upside down position, so the floats are pressing the needles into the seats. He then attaches the tool to the carbs with a piece of hose running from the end of the tool to the fuel inlet of the carbs. He then applies 5 to 7 lbs. of air pressure to the carbs, then cuts off the air supply, and lets them set for x amount of time. If the air doesn't bleed off, then the needle and seats are sealing as they should.
Has anyone tried this method before, and was it an acceptable way of checking the needle and seats ??
I did the same thing minus the fancy test tools: take the brass seat and needle out (very easy) insert the needle in the seat and apply lips to back of the seat and create suction and see if air goes through.
1979 KZ-750 Twin
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- skooterbum4real
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bountyhunter wrote:
skooterbum4real wrote: I was talking with my auto mechanic yesterday about the carbs on my kz650. I mentioned that I'm going to rebuild them due to fuel filling the air box. He showed me a little tool he made up years back with black pipe, an air regulator, and a pressure gauge.
He states that he bench tests his snowmobile carbs with the tool, by placing the carbs in an upside down position, so the floats are pressing the needles into the seats. He then attaches the tool to the carbs with a piece of hose running from the end of the tool to the fuel inlet of the carbs. He then applies 5 to 7 lbs. of air pressure to the carbs, then cuts off the air supply, and lets them set for x amount of time. If the air doesn't bleed off, then the needle and seats are sealing as they should.
Has anyone tried this method before, and was it an acceptable way of checking the needle and seats ??
I did the same thing minus the fancy test tools: take the brass seat and needle out (very easy) insert the needle in the seat and apply lips to back of the seat and create suction and see if air goes through.
:woohoo: I would end up swallowing the needle and seat trying that... :laugh: Not sure how well I would digest the parts !!
1978 KZ650B 8,500 miles
1976 KZ750 Twin
SPECIAL CONSTRUCTION V-TWIN CHOP
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- martin_csr
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Inspect the brass parts for wear or pitting. The 81 manual has a drawing showing how a wear ring can form. Mine looked good, but I went ahead & polished them with brass wool. Some guys use a q-tip & chrome polish. If they're worn or pitted, get new. Also, the seats should have washers on them.
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- JR
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skooterbum4real wrote: I was talking with my auto mechanic yesterday about the carbs on my kz650. I mentioned that I'm going to rebuild them due to fuel filling the air box. He showed me a little tool he made up years back with black pipe, an air regulator, and a pressure gauge.
He states that he bench tests his snowmobile carbs with the tool, by placing the carbs in an upside down position, so the floats are pressing the needles into the seats. He then attaches the tool to the carbs with a piece of hose running from the end of the tool to the fuel inlet of the carbs. He then applies 5 to 7 lbs. of air pressure to the carbs, then cuts off the air supply, and lets them set for x amount of time. If the air doesn't bleed off, then the needle and seats are sealing as they should.
Has anyone tried this method before, and was it an acceptable way of checking the needle and seats ??
my similar method
carbs off the bike. Bowls off. Carbs upside down. Blow into the fuel line or a clean new piece of fuel line. If the needle are not seating you will know pretty quickly. I don't think i can blow hard enough to left a properly seated float
his method seems more precise but mine doesn't require special tools
1980 kz750E1, Delkevic exhaust
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- SWest
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- 10 22 2014
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Steve
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- ffltstn
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Ken
'82 KZ1000
'95 Voyager XII
'98 Vulcan 750
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- skooterbum4real
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Good info !! Thanks guys !!
1978 KZ650B 8,500 miles
1976 KZ750 Twin
SPECIAL CONSTRUCTION V-TWIN CHOP
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- missionkz
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They really looked good so I threw the new replacement ones in a bag and reinstalled the 38 year old ones!!
Even with a high float level, no leaks from those needles and seats... ugh... my old ass bowl gaskets leaked a bit when I'd tip the bike on the center stand.
And the new gaskets did too... they took at least a week to swell up and stop dripping.
Then I reset the float level with the clear tube method and it's all a moot point now.
Bruce
1977 KZ1000A1
2016 Triumph T120 Bonneville
Far North East Metro Denver Colorado
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- SWest
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- 10 22 2014
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Steve
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