Are the Pods My Problem?
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Thread: Are the Pods My Problem?

  1. #1
    Junior Member trekker750's Avatar
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    Are the Pods My Problem?

    Greetings!
    I've got a CL450K3 that sat for 10+ years. I've got it running but not well. I replaced coils, condensers, points, wiring harness and spark plugs. I also cleaned and installed rebuild kits in the carbs. The stock airbox was missing and it had UNI oiled foam pod filters on the stock carbs. The bike will now start and idles beautifully but will not rev up. Opening the throttle even a tiny bit causes it to die. If I give it about 1/2 choke, and I carefully work the throttle, I can get it to rev up but not consistently. I double checked valve clearance, timing and float levels with no improvement. Running with pod filters off makes no difference. I did notice, with the filters off, that the slides do not rise when the throttle is opened.
    I read mixed things about the stock airbox and pod filters. Some reviews of the filters make them sound like they can work but the info I find on these forums counters that. Also wondering if I overlooked an air or fuel passage when I cleaned the carbs. Looking for some advice from folks that are more familiar with these than I am.
    Thanks in advance for your help!

  2. #2
    Senior Member WintrSol's Avatar
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    Many pod filters block direct air flow into the air jets, because the step in the rubber boot is too tall. This causes irregular fuel mix entering the air flow from the main and pilot jets, because there is not enough bubbling above the jets. There are a few with a smaller step from the sealing surface to the inner wall, so some do work.

    Now, running with the pods off and the CV pistons not rising is a different problem. Either the rpm don't rise enough to increase the airflow enough to lift the pistons, or you have some other blockage in the air passages, or just sticking pistons.
    Are the Pods My Problem?-carb_operation.jpg
    Rick

    Mine is a mostly 1970 CB450K3

  3. #3
    Senior Member JamesPal's Avatar
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    To add to what WintrSol said, there is a straw test to check if the floats are sticking. The video I linked below shows the idea. You can search for more infor by searching Honda CV carb straw test. On the DOHC carbs the principal is the same but the sensor hole is smaller and round. the slides must move freely. Some pods will block the sensor port.

    You did the right things for the ignition. New everything is the way to go.

    I'm not a fan of pod filters. My CB450K5 has the stock filters. I have replaced the paper with foam. The bike has stock exhaust. It runs great.

    Jim Palmer
    '85 GL1200I (Garage Find)
    '81 GL1100 STD (Project)
    CB450 K5 Done
    https://www.hondatwins.net/forums/1-...s-cb450k5.html
    What I learned from Restoring a CB450 K5
    Watch Mike and Jim Take on Mt Erie Washington State
    "If everything seems under control you are not going fast enough" Mario Andretti...

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  5. #4
    Junior Member trekker750's Avatar
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    Thanks! The diagram and video help, gives me a place to look for a problem. The slides move freely in the bores so I'm hoping for some blockage in that air passageway, that seem like an easy fix.

  6. #5
    Senior Member WintrSol's Avatar
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    After sitting that long, you could have spider webs in the air inlets, or other insect nesting stuff. Might be a good time to shine a light up the tailpipes, too; you never know.
    Rick

    Mine is a mostly 1970 CB450K3

  7. #6
    Junior Member trekker750's Avatar
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    Well, it's better but still has a long way to go. Thanks for the "straw test" tip! The air passages were clear but the vacuum slides wouldn't pass the straw test. I worked on them until they would, which improved the throttle response but it's still not running well. It dies as soon as you open the throttle the smallest amount. Giving it some choke helped and then I could rev it up but it wouldn't idle. Pods on or off did not seem to make a difference. I'm stumped at the moment so if anyone has a suggestion, please let me know.

  8. #7
    Senior Member TOOLS1's Avatar
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    You have a vacuum leak. Could be the rubber boots between the head and carbs, the rubber O-ring on the pilot screw, or the throttle seals. Get some starting fluid and spray around these places with the engine running and listen for RPM changes.
    TOOLS

  9. #8
    Junior Member trekker750's Avatar
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    Great suggestion, thanks. As soon as the snow stops I'll check it out.

  10. #9
    Junior Member trekker750's Avatar
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    Tested for a vacuum leak. It's likely I have a small leak around the throttle seals on the right hand carb. I got a pretty consistent rise in RPM when sprayed in that area. Strong mixed opinions on replacing the seals. I think I'll try to bring them back with some grease first. I'm going to tear the carbs down again searching for something else. it dies very abruptly with the smallest opening of the throttle. The vacuum leak seems minor and it's only on one carb, so i'm skeptical it's the only problem I've got.

  11. #10
    Supporting Member crazypj's Avatar
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    If you have the original pilot jets, clean them up and re-fit them. I have yet to see any kit where the pilot's match Kei-Hin spec. Youdid remove primary emulsion/discharge tubes as well as secondaries? The nylon seals under CV pistons the right way up? Uni's are normally easier to use than K&N filters on Kei-Hin 3 jet carbs although rarely will you get away without some modifications. You'll probably need at least 10% larger secondary main jets plus lower needles (shimming them is real bad idea), cheap pods are pretty worthless on almost all CV carbs and engines
    Last edited by crazypj; 05-13-2019 at 04:33 PM.
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