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Thread: 1985 yamaha 225dx primary clutch noise only at idle normal??

  1. #1
    Join Date
    Feb 2020
    Location
    ms
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    13

    1985 yamaha 225dx primary clutch noise only at idle normal??

    Hello this is my first post. I recently purchased a 225dx. I have had one of everthing honda has this is mt first Yamaha tricycle. anyways it runs great and shifts fine all drive functions work, there is a annoying rattle or clattering noise coming from right lower end of engine. only does it at idle if you raise the rpms just enough to fully enguage the centrifugal clutch it stops. does it in gear or in nuteral. I pulled that case cover off to investigate. I did not find any slack in anything.clutch nut was tight.drum and shoes not worn bad at all. shoes would move a tiny bit but dident seem to be my cause , any ideas on this? I did a forum search but really dident find anything useful, thanks in advance

  2. #2
    Join Date
    Apr 2011
    Location
    Mexico
    --
    9,003
    You mentioned that the clutch nut was tight. Are you referring to the one that holds the outer hub in place? You would have had to have removed the pressure plate from the secondary clutch in order to access the nut I’m talking about.

    If that is in fact not that you checked, did you also grab that outer hub and try to rock it?

  3. #3
    Join Date
    Feb 2020
    Location
    ms
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    13
    thanks for the reply. I only checked the primary or centrifugal clutch nut. I did grab that drum and tried to rock it. I dident mess wit what I call the shift clutches at all due to the nature of the problem not changing tones or frequency when pulling up on gearshift or letting it down into gear. however if the nut your speaking of could cause excessive lash or mesh I will order another gasket and inspect again

  4. #4
    Join Date
    Apr 2011
    Location
    Mexico
    --
    9,003
    There’s a lot going on in that trike’s drive train. Gears, bushings, bolts, springs etc.

    I’d pull that secondary clutch apart and take a good look at it.

    I’ve worn out a primary clutch and there were no noises that accompanied its demise, it just started needing more and more rpm’s to engage and it would hit hard instead of locking up smoothly.

    There should be cushioning springs, or plastic inserts in the back of you secondary hub. Those can get beat out and cause a loose hub that makes noise when it’s not under load.

    If that’s what you find You might be able to fix it with the punch and , post some pictures up and I’ll give you some ideas. There is a very low possibility that it would come apart on you on an engine like yours.

  5. #5
    Join Date
    Feb 2020
    Location
    ms
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    13
    Thanks for advice. I just ordered another clutch cover gasket. I plan on ripping back in the soon. I will check the things you mentioned. It makes the noise with the bike in gear idling and nothing transmission or secondary(gear shift clutch) at least should not be moving any with no throttle applied. I did however see there’s a counter balanced drive gear on that side of the crank and behind the primary clutch. It does have springs and pins as u mentioned and it’s always spinning regardless of gear or throttle. Might check that out too

  6. #6
    Join Date
    Apr 2011
    Location
    Mexico
    --
    9,003
    Good point. I know mine has a counter balancer, but I’ve never looked closely at it. If the motor is running it’s moving, but I don’t know if they can start making noise from wear.

  7. #7
    Join Date
    Feb 2020
    Location
    ms
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    Well I have a update. I pulled clutch cover again and inspected everything real well. Every thing looked fine no slack in anything clutches like new. I was still wondering what the noise was so with the primary and secondary clutch off the machine and on the ground I slipped cover bk on with a few bolts and it still made the same noise plain as day. Only thing left on that side turning is counter balancer and oil pump. It still sounds like it’s coming from the balancer. The drive gear for it has a spring loaded buffer similar to a automotive clutch disc. I can get some slack to show in it but I don’t know if it’s my noise. I have some pics and video if I can figure out how to post them.

  8. #8
    Join Date
    Feb 2020
    Location
    ms
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    13

  9. #9
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    Feb 2020
    Location
    ms
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  10. #10
    Join Date
    Feb 2020
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    ms
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    The first video shows how fast it does it after first started. So give it a few seconds and it will start making noise

  11. #11
    Join Date
    Apr 2011
    Location
    Mexico
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    9,003
    Given that that knock was without an drive train connected I'd and find the problem.

    But before you do that you can grab a wooden broom handle, or a hockey stick and press one end against your ear and the other in various places around the engine to try and hone in on the source of the knock.

    It's really had to tell just from the video, but defiantly sounds like it's coming from the bottom of the engine. When you rev it up in the video is sounds like it goes away, but it could also just be changing the knock to a higher more frequent sound that is harder to hear. You'd detect it with the wood handle though.

    Could just have something to do with your balancer, but it could also be crank bearings, either end of the connecting rod, or a loose or broken piston. You can either drive it till it tells you what the problem is ten miles from home, or pull it apart and find the problem in your shop. The latter being the preferred and cheaper way.

  12. #12
    Join Date
    Feb 2020
    Location
    ms
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    Yes I’m going to disable the balancer and throw the cover bk on temparily and if it still does it then she’s coming out for tear down. Thanks for your reply

  13. #13
    Join Date
    Apr 2011
    Location
    Mexico
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    9,003
    Keep us posted

  14. #14
    Join Date
    Feb 2020
    Location
    ms
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    Isolated the balancer. Threw covers bk on with only oil pump turning. Still had same noise. Decided to tear engine down to inspect. I found the most clearance I’ve ever seen between piston and cylinder bore. With the rings off and piston in the cylinder I could hold it up and see around it. No gouges top of cylinder measures standard bore and piston says Yamaha on underside. So I wondered how could it have that much clearance and not smoke. So I looked back in the history folder that came with it and seen where engine was rebuilt back in1995. Come to think of it back then people sometimes put oversized rings on or just rings alone. So long story short my noise was definitely piston slap. Rod and crank are in specs and look good. I’m gonna get cylinder bored and new piston and probably a new timing chain. I’ll post more updates as they come. Thanks

  15. #15
    Join Date
    Apr 2014
    Location
    Edmond, KS
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    2,531
    I'm glad to hear that you found the issue. At least it doesn't need to have anything done to the bottom end.

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