Bogging down in certain conditions

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25 Apr 2022 21:06 #866166 by TexasKZ
Replied by TexasKZ on topic Bogging down in certain conditions
Well, I am going to circle back to the low speed circuit in the carbs, particularly the tiny passages that the pilot jets feed. Will not idle as low as it is supposed to and bogs when opening the throttle from small throttle openings suggests that some of those passageways are clogged, thus not providing enough fuel. Raising the idle speed can mask part of that problem by forcing the carbs to the main jets to make up for the super lean condition. Opening the throttle makes it worse until the main jet overtakes the pilot system.
Surging and idle mixture screws having no effect also suggest clogged pilot passages. Sometimes the only way to be sure is to run something like an E string from a guitar through each tiny passage.

1982 KZ1000 LTD parts donor
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26 Apr 2022 03:51 - 26 Apr 2022 04:58 #866169 by Csr75095
Replied by Csr75095 on topic Bogging down in certain conditions
Okay I should address the idle issue. It will idle lower. When it's cold I put the choke on till it will run on half choke then I turn the choke off when it will idle on its own. When it's cold before it's totally warm up, it will idle at like 750 rpm and once it warms up, it has no problem idling at 1000 rpm flat. I set the idle at abt 1200 because the bogging seemed to be mitigated with higher idle but it absolutely will idle just fine at 1000 rpm. Now when I tore apart and cleaned the carburetors, I did not use a guitar string to clean out the jets but I did soak them then blew them out with air. If you still think it's a jet issue then I'll take your word for it and give it a try because the pilot mixture screws do very very little to help and the bogging is specifically in the low circuit. Now i have torn apart, cleaned and tuned many different carbs, not saying I'm a master mechanic but I know how to work on motors but i am not totally certain which jet is the low rpm circuit jet. Can you tell me which one it is?
Edit: I re-read what you said. You're saying the passages in the carburetor itself, not the pilot jet could be clogged. I hadn't considered that. As long as the bike sat, I suppose that's entirely possible. My dad plays guitar so ill get a few sizes off of him. 
Last edit: 26 Apr 2022 04:58 by Csr75095.

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26 Apr 2022 12:04 - 26 Apr 2022 12:13 #866193 by howardhb
Replied by howardhb on topic Bogging down in certain conditions
Attached is a pretty comprehensive diagnostic procedure...

H.

 

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  • Last edit: 26 Apr 2022 12:13 by howardhb.

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    26 Apr 2022 16:42 #866200 by Csr75095
    Replied by Csr75095 on topic Bogging down in certain conditions
    I reviewed that pdf and it certainly seems like my pilot circuit has an issue. I took my carb apart and re cleaned it. I also accidentally broke one of the o rings on one of my pilot adjustment screws. So I ordered a few of those and we'll see how it runs after. 

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    02 May 2022 07:52 #866531 by Csr75095
    Replied by Csr75095 on topic Bogging down in certain conditions
    For anyone following this thread, I tore my carbs back apart and re-cleaned everything. I made sure everything I could get to was free, clean and clear then put it all back together with a new 2.5mmX1.5mm o ring for each pilot mixture screw since I ruined the one. Since that, it's been running pretty damn good but still not perfect. Not sure what else to try but I'm tired of messing with it. It's running pretty damn good and that's good enough for now. Thanks for the help everyone contributed and if nothing else, I learned about the mechanical timing advancer which was very interesting. 

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