Saving a '81 KZ750-E

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13 Nov 2021 10:56 #857884 by Skidmark
Replied by Skidmark on topic Saving a '81 KZ750-E
I went back and checked the Dynojet instructions.  I actually used the stage 3 kit.  136 main jets.  Mixture screws 3.5 turns out.  Dynojet needles, e-clip on the fourth groove from the top.  Slide lift holes drilled out with the drill provided in the kit.

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'81 KZ-750 E2
'87 Suzuki Savage 650 Street Tracker (lost in the shop fire)

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13 Nov 2021 12:25 #857888 by Nessism
Replied by Nessism on topic Saving a '81 KZ750-E

I went back and checked the Dynojet instructions.  I actually used the stage 3 kit.  136 main jets.  Mixture screws 3.5 turns out.  Dynojet needles, e-clip on the fourth groove from the top.  Slide lift holes drilled out with the drill provided in the kit.

Hum.  I have no idea if those jets are ideal or what.  Simple experiment is to tape off a portion of your pods and see if that helps.  If so, the mixture is too lean.
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13 Nov 2021 14:22 #857893 by DoctoRot
Replied by DoctoRot on topic Saving a '81 KZ750-E
I has a similar stumble on a KZ750E. was a pinhole in one of the diaphragms. easy to miss.
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13 Nov 2021 15:10 - 13 Nov 2021 15:17 #857894 by 750 R1
Replied by 750 R1 on topic Saving a '81 KZ750-E
I have a stage 3 dynojet kit too {2303} , the jets that came with it were bigger than 136. I don't have the kit here but i can check tomorrow for you if that helps ...   Dynojet, Mikuni and Keihin all use different sizing on their jets, a 120 in a mikuni isn't the same in Keihin or dynojet, and 120 in a dynojet is different to both of the others...  Makes things confusing...

PS, I just checked dynojets site and the jets are listed as 180 and 185....

www.dynojet.com/amfile/file/download/file/777/product/3472/

Another thing, I'm keeping my old jets just in case i need something slightly smaller, we will drill out my old jets and re mark them to give more options..
 
Last edit: 13 Nov 2021 15:17 by 750 R1.

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14 Nov 2021 15:24 #857937 by Skidmark
Replied by Skidmark on topic Saving a '81 KZ750-E
That is a different bike.  Here the correct kit for mine.

Wouldn't partially closing the choke achieve the same thing as partially taping off the pods?

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'81 KZ-750 E2
'87 Suzuki Savage 650 Street Tracker (lost in the shop fire)

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14 Nov 2021 15:33 #857938 by Skidmark
Replied by Skidmark on topic Saving a '81 KZ750-E
The main jets that came out of the carbs were 125's (just for reference).

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'81 KZ-750 E2
'87 Suzuki Savage 650 Street Tracker (lost in the shop fire)

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14 Nov 2021 16:18 - 14 Nov 2021 16:18 #857939 by DOHC
Replied by DOHC on topic Saving a '81 KZ750-E

Wouldn't partially closing the choke achieve the same thing as partially taping off the pods? 
I'm not sure how the CV carbs work, but my impression of the VM carbs is that the choke circuit is pretty crude.  It isn't venturi based and is not well metered.  It's just a bypass that dumps fuel in at high vacuum.  

It seems like restricting the air intake would more closely approximate changing jets, especially with larger throttle openings where the main circuit dominates.  

'78 Z1-R in blue , '78 Z1-R in black, '78 Z1-R in pieces
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Last edit: 14 Nov 2021 16:18 by DOHC.
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15 Nov 2021 04:12 #857954 by 750 R1
Replied by 750 R1 on topic Saving a '81 KZ750-E
What carbs are you running ?  those jets are pretty small, no air correctors either...
My carbs are BS34's

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15 Nov 2021 07:56 - 15 Nov 2021 08:05 #857958 by Skidmark
Replied by Skidmark on topic Saving a '81 KZ750-E
Keihin CV34's.

I am going to start by removing the carb bank and rechecking my float levels.  Then I will get them back on and recheck the carb sync.  Then I will redo the air mixture screw tuning per the Dynojet instructions.  This will all be done on the lift while the front end is apart for the fork seal replacement.  I just got the new kick stand welded on the street tracker, so she is ready to get off the lift and park on her own.  Getting the green monster back onto the lift will give me the opportunity to modify my old racing stand to fit the Kawasaki frame (it was for my Suzuki GS750e).  That way I can have the front end raised without removing the header.

Retired gearhead
'81 KZ-750 E2
'87 Suzuki Savage 650 Street Tracker (lost in the shop fire)
Last edit: 15 Nov 2021 08:05 by Skidmark.

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15 Nov 2021 08:01 #857959 by Nessism
Replied by Nessism on topic Saving a '81 KZ750-E
Now that you mention it yes, applying the choke should work to check lean conditions.  The choke is an actual choke on thoese carbs

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20 Nov 2021 14:07 #858118 by Skidmark
Replied by Skidmark on topic Saving a '81 KZ750-E
Back on the lift and back apart.  While I have the forks off for a rebuild, I will pull the tach and see if the squeal can be fixed without opening the gage up.  Before the forks and front wheel are back on I will remove the carbs and verify the float levels are still where I set them.  In the picture you can see the run of oil down each caliper mount bracket on the forks.

 
 

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'81 KZ-750 E2
'87 Suzuki Savage 650 Street Tracker (lost in the shop fire)

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20 Nov 2021 14:24 - 20 Nov 2021 14:25 #858119 by DOHC
Replied by DOHC on topic Saving a '81 KZ750-E
That floor jack and board look a bit precarious with no front end.  I bought a small scissor jack to use with my motorcycle lift.  It has movable saddles that rest on the frame rails.  I think it works very well.  The bike is very stable.

www.amazon.com/gp/product/B076CSCLBY/

Edit: Hmm..  It was only $54 when I bought it.  Maybe there is a cheaper option.

'78 Z1-R in blue , '78 Z1-R in black, '78 Z1-R in pieces
My dad's '74 Z1
'00 ZRX1100
Last edit: 20 Nov 2021 14:25 by DOHC.

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