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1979 KZ650 - Accelerator Pump & Rod

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11 Jan 2022 15:31 #860428 by CMcAuliffe
1979 KZ650 - Accelerator Pump & Rod was created by CMcAuliffe
The last carb to get stripped and get dunked is my #2, which has the accelerator pump. There are a couple things wonky with it, and I'm wondering if anyone has any experience.

The pump lever has surface rust and is slightly bent towards the front of the bike. No biggie - I plan on carefully bending it back, hitting it with brass wire brush and some enamel.

Attached to that is the pump rod. I've read in the manual (and on this forum) to not mess with it. However, it is crusty and a little bent. I'm coming up empty searching for a replacement. I may go to the local hardware store and see if I can cobble together an acceptable substitute. Anyone done it before? I'm not a machinist, so whipping one up on a lathe is out of my league.

After stripping the bowl, I still hear a rattling from within. I'd already removed the ball check valve from the edge of the bowl. My manual, which includes a 1979 supplement, does not indicate any other check valves. I found a post on this forum:  #786976 , which shows an "older service manual." The image on that post indicates two additional check valves in the center of the bowl under the vacuum sensor. I'm guessing this is what I'm hearing, but apparently they were sealed by the factory? I'm not in danger of losing anything in my dip tank, am I?
 

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11 Jan 2022 15:34 #860429 by CMcAuliffe
Replied by CMcAuliffe on topic 1979 KZ650 - Accelerator Pump & Rod
Stolen from martin_csr post from 2018. The "older" service manual. My 1979 Supplement in my Service Manual does not indicate any other check valve than the one on the side of the bowl.

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11 Jan 2022 17:26 #860435 by Nessism
Replied by Nessism on topic 1979 KZ650 - Accelerator Pump & Rod

The last carb to get stripped and get dunked is my #2, which has the accelerator pump. There are a couple things wonky with it, and I'm wondering if anyone has any experience.

The pump lever has surface rust and is slightly bent towards the front of the bike. No biggie - I plan on carefully bending it back, hitting it with brass wire brush and some enamel.

Attached to that is the pump rod. I've read in the manual (and on this forum) to not mess with it. However, it is crusty and a little bent. I'm coming up empty searching for a replacement. I may go to the local hardware store and see if I can cobble together an acceptable substitute. Anyone done it before? I'm not a machinist, so whipping one up on a lathe is out of my league.

After stripping the bowl, I still hear a rattling from within. I'd already removed the ball check valve from the edge of the bowl. My manual, which includes a 1979 supplement, does not indicate any other check valves. I found a post on this forum:  #786976 , which shows an "older service manual." The image on that post indicates two additional check valves in the center of the bowl under the vacuum sensor. I'm guessing this is what I'm hearing, but apparently they were sealed by the factory? I'm not in danger of losing anything in my dip tank, am I?

 


Your accelerator pump cover lever is supposed to be bent; it's that way so the angle of the pump rod has clearance around the center feed fuel Tee.
The pump rod can be taken apart.  The upper eyelet is screwed into the aluminum body.  You can remove the eyelet, extract the rod, straighten it, then reassemble with some lube inside.

The carbs with the vacuum diaphragm are problematic.  There was a thread posted here recently that describes what to do to disable the 2nd diaphragm.  You can choose your own path, but I'd disable the vacuum diaphragm.  
 
The following user(s) said Thank You: CMcAuliffe

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12 Jan 2022 11:09 - 13 Jan 2022 09:16 #860456 by kevski
Replied by kevski on topic 1979 KZ650 - Accelerator Pump & Rod
Plus one on what Nessism says, i deleted the vacuum diaphragm on my thou and the carbs are much better behaved.
Last edit: 13 Jan 2022 09:16 by kevski.

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12 Jan 2022 18:54 #860466 by CMcAuliffe
Replied by CMcAuliffe on topic 1979 KZ650 - Accelerator Pump & Rod
I'll keep it in mind. I've yet to get the bike started, so I'm hesitant to mess with something without a baseline.

I can see how that pump system gets messed up. The deeper fuel bowl and both pump surfaces were covered in crusty crud.

I managed to disassemble the pump rod without damage or parts loss, and it cleaned up nicely.

Thanks for the help..

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13 Jan 2022 09:18 #860481 by kevski
Replied by kevski on topic 1979 KZ650 - Accelerator Pump & Rod
Deleting the lower diaphragm will not disturb base line settings, it will improve the base line.

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13 Jan 2022 13:54 - 13 Jan 2022 14:03 #860488 by zed1015
Replied by zed1015 on topic 1979 KZ650 - Accelerator Pump & Rod

Stolen from martin_csr post from 2018. The "older" service manual. My 1979 Supplement in my Service Manual does not indicate any other check valve than the one on the side of the bowl.

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Yes! There are three check valves in the pumper system of your carbs that utilises the sense diaphragm 3 - 5 and 15.
This carb was for one or two years only after which the sense diaphragm was deleted and only the actual accelerator pump with check valve 15 remained on the later versions hence them not being show in the later manual.
The sense check valves govern the accelerator pumps fuel supply in relation to intake vacuum and was a flawed system which is why it was disabled on the later model..
Removing the triangular diaphragm and rectifying the associated check valves and passages so that the accelerator pump has fuel on demand at all times not only vastly improves it's function but is also what Kawasaki did to cure their issues and on the later version you will still see the triangular casting but it is unmachined with no cap, diaphragm or drilled passages.

 

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Last edit: 13 Jan 2022 14:03 by zed1015.

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