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Unknown Needle in Trottle Plate Area Kei Hin 34
- FaultedGeologist
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27 Sep 2014 10:19 - 27 Sep 2014 10:22 #648952
by FaultedGeologist
Clint
1980 KZ750 LTD H4
FSMaunual: kz.bike-night.com/media/GPz750-full.pdf
Stock except for:
New chain and sprocket (530?).
Dynatek Ignition
Manual tensioner on the way.
Buy JIS screwdrivers.
Unknown Needle in Trottle Plate Area Kei Hin 34 was created by FaultedGeologist
1981 KZ750 LTD H2 4cyl
While checking the throttle plates today, I noticed a needle sticking down on the #2 carb. It pokes out from the top and goes through one of three small holes in the top of the carb throttle side. I attached 3 pictures of it below. It has clearly dented the throttle plate just a bit. This is the only carb that has this feature, and it doesn't seem good. I can prop up the pin and the plate will shut enough that the pin will not come out, but only when the carb is on its side. This means when it is on my bike, the pin will always fall.
This is not in any diagram in my Clymer. What does this mystery hole do?
Thank you in advance...
The needle comes down exactly where the throttle plate crosses the top of the carb effluent.
On the top side under the rubber diaphragm is a capped off hole, as seen in dead center and just to the right of the air fuel mix screw.
A blow up of the holes in proximity to the throttle plate resting point.
While checking the throttle plates today, I noticed a needle sticking down on the #2 carb. It pokes out from the top and goes through one of three small holes in the top of the carb throttle side. I attached 3 pictures of it below. It has clearly dented the throttle plate just a bit. This is the only carb that has this feature, and it doesn't seem good. I can prop up the pin and the plate will shut enough that the pin will not come out, but only when the carb is on its side. This means when it is on my bike, the pin will always fall.
This is not in any diagram in my Clymer. What does this mystery hole do?
Thank you in advance...
Attachment keihin-carb-mystery-needle-throttle.jpg not found
The needle comes down exactly where the throttle plate crosses the top of the carb effluent.
Attachment keihin-carb-mystery-needle-top-diaphragm.jpg not found
On the top side under the rubber diaphragm is a capped off hole, as seen in dead center and just to the right of the air fuel mix screw.
Attachment keihin-carb-mystery-needle-drawing.jpg not found
A blow up of the holes in proximity to the throttle plate resting point.
Clint
1980 KZ750 LTD H4
FSMaunual: kz.bike-night.com/media/GPz750-full.pdf
Stock except for:
New chain and sprocket (530?).
Dynatek Ignition
Manual tensioner on the way.
Buy JIS screwdrivers.
Attachments:
Last edit: 27 Sep 2014 10:22 by FaultedGeologist. Reason: More detail, bad subject header...
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- JR
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27 Sep 2014 13:18 - 27 Sep 2014 13:21 #648959
by JR
1980 kz750E1, Delkevic exhaust
Replied by JR on topic Unknown Needle in Trottle Plate Area Kei Hin 34
That group of 3 small holes is where the gas from the pilot system exits the carb and enters the motor. They should be totally clear. No needles. The throttle flap/buterfly/plate when fully closed should close at or on those holes - see your other carbs.- without obstruction. Obstruction may make proper carb synchronization difficult
Can that needle tip be removed without damaging the hole? I dont think you want to enlarge the hole.
Is it possible it was left over from an attempt to clean by a previous owner ? I wonder if it might be the tip of a pilot screw (#1 in the diagram above) which a previous owner broke ? If it is small enough it might be possible to get it out by removing the pilot screw (with o ring, washer and spring) and by using compressed air and shaking.
Can that needle tip be removed without damaging the hole? I dont think you want to enlarge the hole.
Is it possible it was left over from an attempt to clean by a previous owner ? I wonder if it might be the tip of a pilot screw (#1 in the diagram above) which a previous owner broke ? If it is small enough it might be possible to get it out by removing the pilot screw (with o ring, washer and spring) and by using compressed air and shaking.
1980 kz750E1, Delkevic exhaust
Last edit: 27 Sep 2014 13:21 by JR.
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27 Sep 2014 14:24 #648964
by FaultedGeologist
Clint
1980 KZ750 LTD H4
FSMaunual: kz.bike-night.com/media/GPz750-full.pdf
Stock except for:
New chain and sprocket (530?).
Dynatek Ignition
Manual tensioner on the way.
Buy JIS screwdrivers.
Replied by FaultedGeologist on topic Unknown Needle in Trottle Plate Area Kei Hin 34
The pilot screw is ~5mm forward of this. The middle pic above has the top view. It is under the silver cap in the center of the pic. I do not have any replacement caps, so I didn't want to go popping this out.
There was one pilot screw that was missing the needle tip when I replaced the A/F fuel screws.
There was one pilot screw that was missing the needle tip when I replaced the A/F fuel screws.
Attachment keihin-carb-mystery-needle-drawingcopy.jpg not found
Clint
1980 KZ750 LTD H4
FSMaunual: kz.bike-night.com/media/GPz750-full.pdf
Stock except for:
New chain and sprocket (530?).
Dynatek Ignition
Manual tensioner on the way.
Buy JIS screwdrivers.
Attachments:
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- JR
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27 Sep 2014 14:44 - 27 Sep 2014 15:10 #648966
by JR
Yes
I totally understand where the pilot screw is located in relation to the 3 small holes (by pass outlet. #3 in the schematic in my post above). I have the same carbs. I am not suggesting that the needle in question is the tip of the pilot screw. My point was that previous owners have been known to bugger up pliot screws and possibly a pilot screw tip was broken at some point in time and became lodged 5mm or s back in one of the 3 holes. If the mystery needle was inserted from underneath where we can see it then it should come out that way. If it became lodged in the hole from the top then it becomes more difficult.
Regarding the "mystery cap" in your middle photograph in the first post I dont believe this is a "cap". I am guessing that it was a opening that was sealed after the various passageways and holes were drilled during manufacture.
I would not dare suggest that this be drilled out .
1980 kz750E1, Delkevic exhaust
Replied by JR on topic Unknown Needle in Trottle Plate Area Kei Hin 34
The pilot screw is ~5mm forward of this. The middle pic above has the top view. It is under the silver cap in the center of the pic. I do not have any replacement caps, so I didn't want to go popping this out.
There was one pilot screw that was missing the needle tip when I replaced the A/F fuel screws.
Yes
I totally understand where the pilot screw is located in relation to the 3 small holes (by pass outlet. #3 in the schematic in my post above). I have the same carbs. I am not suggesting that the needle in question is the tip of the pilot screw. My point was that previous owners have been known to bugger up pliot screws and possibly a pilot screw tip was broken at some point in time and became lodged 5mm or s back in one of the 3 holes. If the mystery needle was inserted from underneath where we can see it then it should come out that way. If it became lodged in the hole from the top then it becomes more difficult.
Regarding the "mystery cap" in your middle photograph in the first post I dont believe this is a "cap". I am guessing that it was a opening that was sealed after the various passageways and holes were drilled during manufacture.
I would not dare suggest that this be drilled out .
1980 kz750E1, Delkevic exhaust
Last edit: 27 Sep 2014 15:10 by JR.
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28 Sep 2014 02:19 #649009
by FaultedGeologist
Clint
1980 KZ750 LTD H4
FSMaunual: kz.bike-night.com/media/GPz750-full.pdf
Stock except for:
New chain and sprocket (530?).
Dynatek Ignition
Manual tensioner on the way.
Buy JIS screwdrivers.
Replied by FaultedGeologist on topic Unknown Needle in Trottle Plate Area Kei Hin 34
Could this be the a/f bypass outlet? Since I did find a broken a/f screw that was missing the needle (I took my readings on rotations of a/f screws very carefully) when I replaced them, it could be from the prev owner. Going to try taking out the a/f screw and shaking it back out the passageway. Okay, tried the shake around a/f and nothing came out. The needle that once appeared no longer appears, but I think that is due to having it shaken all around.
Clint
1980 KZ750 LTD H4
FSMaunual: kz.bike-night.com/media/GPz750-full.pdf
Stock except for:
New chain and sprocket (530?).
Dynatek Ignition
Manual tensioner on the way.
Buy JIS screwdrivers.
Please Log in or Create an account to join the conversation.