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KZ650 H1 Jerky wide open, choppy low rpm.
- agrestixrock
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17 Apr 2019 06:49 #802274
by agrestixrock
KZ650 H1 Jerky wide open, choppy low rpm. was created by agrestixrock
i recently installed a 4 to 1 header on my 81 KZ650 H1. i got this off of a 77 KZ650. both bikes have mikuni carbs. not sure on the #s though, the carbs on my 81 have the accelerator pump on the #2 bypassed because the person i got it from lost the cover so i put a different float bowl on it and capped the nipples that go between the carbs. before installing the header it ran pretty well from what i know. but now it shows signs of being both too rich and too lean. when it warms up it still wants half choke to run half decent. before i played with the choke i just set the idle higher to conpensate the rougher idle. when i was running it with no choke id get off and my boot would have oil all over the toe, my oil pan is leaking but since running it half choke there is little to no oil on my boot. i looked at the jets in both carbs and only the main jets were different. my 81 has 95 main jets and the bike i got the header off of had 110 mains. i checked my spark plugs and 2 were white which i know is lean, 1 was white but slightly the toasty brown so its close but still a little lean (this was the #2 the main carb), and the last one was black which is rich. last night riding home i tried to take off from a stop light quickly and when i hit full throttle it started jerking like i was riding a bull. im just thinking itd be easier to put the carbs off of the parts bike and putting them on because it was probably jetted for the exhaust im just sure
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- SWest
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17 Apr 2019 07:43 #802281
by SWest
Replied by SWest on topic KZ650 H1 Jerky wide open, choppy low rpm.
The pump was to compensate for a leaner setting on the later carbs. Often the slides have a leaner cutaway so the pump is needed. If you have earlier carbs they would be your best bet being they were setup for the exhaust. Pics would be helpful.
Steve
Steve
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- gd4now
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- Denco where did you go?
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17 Apr 2019 10:23 #802290
by gd4now
1977 KZ650 B1
Pods and Denco header
OLD KAW OWNERS SMILE ALOT
Replied by gd4now on topic KZ650 H1 Jerky wide open, choppy low rpm.
You do not mention if any changes have been made to air intake or not. If you are running the stock air box then I would think that the parts bike carbs with 110 mains would be somewhat rich.
1977 KZ650 B1
Pods and Denco header
OLD KAW OWNERS SMILE ALOT
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- agrestixrock
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13 May 2019 09:51 #803798
by agrestixrock
Replied by agrestixrock on topic KZ650 H1 Jerky wide open, choppy low rpm.
i will get some pics ASAP. i have not made any changes to the air intake. both bikes had pods when i got them. i think im going to take the old ones and put it on my bike to see what happens. the plugs are all different colors. #1 was dark brown, #2 was white, 3 was really dark and had build up, 4 whas white. still very choppy after i adjusted the air intake screws. this morning it ran fine after a week of sitting about halfway to work then it started jerking again.
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- Warren3200gt
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13 May 2019 10:34 #803806
by Warren3200gt
Replied by Warren3200gt on topic KZ650 H1 Jerky wide open, choppy low rpm.
If the plugs are all different colours maintainence has been serverly neglected. Get a manual and do EVERYTHING. You'll probably find most of your issues will disappear.
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- agrestixrock
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13 May 2019 16:15 #803832
by agrestixrock
Replied by agrestixrock on topic KZ650 H1 Jerky wide open, choppy low rpm.
i had it set up pretty well before i put the header on but since the exhaust was technically 2 pipes before and now everything is going into one its been a nightmare. i did have leaky carbs and it would still occasionally jerk at the top end probably because my accelerator pump was bypassed. when i got it it was a wreck and i downloaded the manual and have done almost everything i could. before i could ride all day on a hot day and not worry about it. but now its like a war inside my exhaust in the pictures, the first two are the current carbs with the "bypass" and the last one is a picture of the carbs that came off the bike i got the exhaust from. mines an 81 and the parts bike is a 77
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13 May 2019 19:42 #803841
by SWest
Replied by SWest on topic KZ650 H1 Jerky wide open, choppy low rpm.
Sounds lean to me.
Steve
Steve
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- Scirocco
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14 May 2019 13:03 #803868
by Scirocco
My 1975 Z 1 B 900 Project
www.kzrider.com/forum/11-projects/605133...ears-deep-sleep-mode
Replied by Scirocco on topic KZ650 H1 Jerky wide open, choppy low rpm.
Your carb bowls are leaking, fuel level is too high. Carbs need new bowl gaskets.
Old vaporised fuel covering the carb bowls and engine.
Have you check the fuel Level? Are your intake boots soft and not hard and brittle?
Old vaporised fuel covering the carb bowls and engine.
Have you check the fuel Level? Are your intake boots soft and not hard and brittle?
My 1975 Z 1 B 900 Project
www.kzrider.com/forum/11-projects/605133...ears-deep-sleep-mode
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- agrestixrock
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18 May 2019 10:45 #804089
by agrestixrock
Replied by agrestixrock on topic KZ650 H1 Jerky wide open, choppy low rpm.
i need new float bowl gaskets i know that the carbs from the donar bike have gaskets that look almost new. i cleaned them up and when i hooked them up they were pooring gas out. looked like from the passages between the carbs. it ran great but couldnt ride it because of how bad the fuel was leaking. anyone know any fixes for the rubber fuel rails? theyre just a metal tube wrapped in rubber that have bumps in them like o rings
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18 May 2019 12:51 #804095
by Scirocco
My 1975 Z 1 B 900 Project
www.kzrider.com/forum/11-projects/605133...ears-deep-sleep-mode
Replied by Scirocco on topic KZ650 H1 Jerky wide open, choppy low rpm.
I fix my rubber fuel rails (T-inlets) with electric wiring shrink tube.
My 1975 Z 1 B 900 Project
www.kzrider.com/forum/11-projects/605133...ears-deep-sleep-mode
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- agrestixrock
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18 May 2019 14:33 #804102
by agrestixrock
Replied by agrestixrock on topic KZ650 H1 Jerky wide open, choppy low rpm.
i did try that but it was slightly too big to cram into it but ill give it a shot with some different stuff
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21 May 2019 19:28 #804331
by agrestixrock
Replied by agrestixrock on topic KZ650 H1 Jerky wide open, choppy low rpm.
okay so i changed out the float bowl gaskets, applied a very thin layer of fuel lube to them to make sure they seal very well. doesnt leak anymore but now im having symptoms of a vacuum leak. guessing my carb boots because i bumped the carbs while it was idling and it died and wouldnt want to start. do i have to have the kawasaki carb boot clamps or will just cheap ones from the parts store work?
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