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Discussion Starter #1
Ursula started running rough again today on the way to work. Running rich and bogging down when taking off from a dead stop.
I read in the verses that the "coasting enricher gasket" which I interpreted to read as the air cut diaphram as it's in the location described, could develop pin holes. Both front and rear carb air cut diaphrams have the dreaded pin holes so I ordered a pair of them. Boy, are they expensive!!! $36.61 each at Ayers. Car carb parts aren't anywhere near this much, at least in my experience.
Hope this fixes the problem once and for all.
 

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I wish a guy could just throw on a Holley 2-barrel and be done with it, hell for that matter plain old old TBI setup would probably be cheaper.
 

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yeah, someone could rig up a TBI or maybe even a direct port for the cost of rebuilding some of these carbs..... all you would need is a machine shop, a computer and some mid line engine knowledge... in 10 years when i am rich (right?) i plan to do cam, direct port injection and tuned header pipes. I wanna see if i can pull 70-80 hp outta this motor. he he. anyone have any ideas how to go to belt?
 

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and the Adventure Cycle
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If it's for something that'll bring a smile to your face, it's expensive, no doubt !!
Hope that fix gets your bike running good again Jim !
 

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"I read in the verses that the "coasting enricher gasket" which I interpreted to read as the air cut diaphram as it's in the location described, could develop pin holes. Both front and rear carb air cut diaphrams have the dreaded pin holes so I ordered a pair of them."

Not following you on what part this is that you have pinholes in. Can you describe it in more detail? Just want to learn...
 

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and the Adventure Cycle
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Check out this part # (43028-1053 DIAPHRAGM,AIR CUT VAL) on the 'Carb Parts' page at Ayers.
(down at the bottom, middle)
 

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Discussion Starter #9 (Edited)
Silicone disolves in gasoline so it won't work to heal a rubber diaphram in the carbs.
Just to update, pulled the carbs today as the intermittant stuttering and misfiring continues. Disassembled the floats and both valves appeared clean. Pulled the jets and they too appeared clean. Blew everything out with air just in case. Both front and rear carbs were jetted identically. 38/132. The main diaphrams look good and have no pin holes that I could see. Float tested the floats and found no leaks. Valves look good. There is a shiny area where the valve meets the seat but the valve is all symetrical with no concave wear spot as per the Clymer's.
I did find that the carbs have been disassembled before as there was some damage to the screws that hold the float bowls onto the carbs and the cotter keys that hold the throttle linkages together were non standard. (Wire with a z bend vice a cotter key).
I also discovered that the carb boots were reversed. Front on rear and vice versa. Since I had to pull both off the cylinder and therefore lost my reference boot, it's been a pain trying to get the carbs back on. I finally gave up for the night and will reattempt on Monday since I have it off.
I am also dreading putting the intake ducts back into the surge tank and then back on the carbs. They were a major pain to get out and I figure they will be a pain to get back in.
I really hope this solves the problem. I am also going to check the petcock and see if it is clogged or otherwise fouled with crud. The fuel that drained from the carb was kind of dirty but none of the jets were clogged that I could see. I took some pics for any who might be interested and will attempt to post them once the job is complete.
 

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Discussion Starter #10
Final update.
Ursula is back together and running great. I don't know if the carb tear down helped anything or not but the experience was worth it. The intake ducts were indeed a pain but not as hard as I expected. I'm just glad all the gaskets and O rings resealed. I did notice that once I replaced the air cut diaphrams that my decel popping is almost non existant. I readjusted the mixture needles to about 2 turns out on both carbs. If you experience excessing popping, check those air cut diaphrams. Mine were paper thin in some areas and had many pin holes causing the bad decel popping. The nice thing about these is you don't need to pull the carbs to replace them.
The petcock was clean, so who knows?
 

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