Need help!!! Asap!!!

Discussion in 'Motorized Bicycle General Discussion' started by runnermike, Jun 19, 2014.

  1. runnermike

    runnermike New Member

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    Can someone take a look at the pic and tell me if this is how it should be. I'm replacing my valve springs and upon getting ready to install the new ones, I noticed something did not look right. I was very careful when removing everything....

    20140619_090349.jpg

    The engine is a HF 79cc predator
     
  2. Davezilla

    Davezilla New Member

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    Looks to me like the intake side uses a steel spring seat and the exhaust side the spring sits directly on the head,even tho I can't imagine why they would let a spring sit directly on the aluminum like that.... Have you tried to install the springs and retainers yet?
    I'd assume that you'll notice right away something's wrong when you go to put the spring retainers back on because the exhaust side will feel excessively loose compared to the intake.

    I know it's too late for you to do this, but whenever I disassemble anything for the first time... take lots of pics from every angle etc so if the part has to sit in the garage for any length of time, the pics help me remember how it went back together or how things are supposed to be set up.

    Hopefully some of the Pred gurus in here can tell you if that's right or not pretty quickly, otherwise, just do a test fit to see how everything fits, you'll definitely be able to tell if it's wrong in the next step.
     
    #2 Davezilla, Jun 19, 2014
    Last edited: Jun 19, 2014
  3. runnermike

    runnermike New Member

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    I am getting ready to do it now. I am upgrading to 18lb valve springs, so they are about a 1/2" longer than stock....
     
  4. Davezilla

    Davezilla New Member

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    Test fit the stock springs first just to be sure... I think you're ok tho...
     
  5. runnermike

    runnermike New Member

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    We think alike....I just did the exhaust side with the stock spring and it was nice and tight. Besides that, everything looks good in there....I just wanted to be sure before I buttoned everything up.
     
  6. Davezilla

    Davezilla New Member

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    Cool... looks like you're ok... Glad it worked out
     
  7. runnermike

    runnermike New Member

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    Upon further inspection and research, I located my manual and it should, in fact, have 2 valve seats. There was only one in my engine. I am very meticulous when it comes to taking things apart and that is one of the first things I noticed. Just to be sure, I double checked my work area to see if maybe it was stuck to the spring when I pulled it out....found nothing.

    I'm assuming it was this way from day one. I have had no issues with it so I am hoping I don't now.....
     
  8. runnermike

    runnermike New Member

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    Is it possible it was this way from the factory? Are there any side effects, if any, from not having a valve seat on the exhaust side?

    If I do need to get one, where would I purchase one??

    Thanks
     
  9. Davezilla

    Davezilla New Member

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    It's possible it came that way from the factory, also on your manual, did it say valve seats or spring seats? The engine will definitely have 2 valve seats which is what the valves close on inside the cylinder, then there's spring seats that the springs sit on outside the cylinder.
    It's usually typical practice to have some kind of seat for the springs to sit on when installed on an aluminum head, most the time it's just a really thin washer that sits under the spring to prevent direct contact with the spring and the aluminum and it's put there to prevent abnormal wear. Without it you'd never know the difference and it could run for years trouble free or the spring could start to dig into the aluminum after a few thousand miles.

    It's possible it could have left the factory like that and it could run for years undetected but I'd keep asking around to see if anyone else knows more about this. as far as getting replacement parts, these engines are Honda clones so maybe look at a Honda small engine service catalog or look for some online shops that sell small engine parts since these engines are fairly common and the Honda parts should fit them.
     
  10. msrfan

    msrfan Active Member

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    That may be a seal on the intake, which is pretty common as the intake is the vacuum side. Keeps oil from being sucked through the guide and smoking.
     
  11. Davezilla

    Davezilla New Member

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    ^^^That's a good point as well...
     
  12. runnermike

    runnermike New Member

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    I went back and looked at the manual. It says there should be 2 valve spring seats...
     
  13. runnermike

    runnermike New Member

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    And upon further inspection, that does look to be a seal.....everything should be gravy....
     
  14. Davezilla

    Davezilla New Member

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    Yeah, if it calls for spring seats I'd definitely get one for it just to be safe, without it you'd be running the spring directly on the aluminum which isn't recommended, and if it's also a seal the engine may smoke from oil seeping into the cylinder and exhaust.
     
  15. crassius

    crassius Well-Known Member

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    doubt it's a seal as they're usually attached to the guide, but many times they also keep the spring vertical to the stem with a bit of lip at the bottom
     
  16. mapbike

    mapbike Active Member

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    Bingo....!

    You read my mind, a valve guide seal is only needed usually on the intake side.

    I think my old HF196cc engine build was the same way but its been a while so I cant be 100% on that statement.

    Map
     
  17. Davezilla

    Davezilla New Member

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    Same thing here, without it right in front of me I can just guess as to if it uses a seal on the exhaust side or not. Typically it really don't need one there, but on some engines they'll put a seal on both valves. Since there's a posative pressure at the valve guide it can't leak while running but some vertical cylinder engines may smoke a little just at startup if oil does seep past the guide after shutdown, but even if it does, the oil loss is very minimal like less than a drop each shutdown. Both statements above are right tho, it just depends on what the engineer decided to do there when he designed the engine.

    One thing for sure is there should be something there to prevent the direct contact between the spring and the aluminum, sometimes it's just a thin washer and other times it's machined to fit the spring perfectly and keep it centered over the valve spring land.
    Being that these engines are Honda clones it should be no problem getting a replacement part, and at the worst, it may take a call to Harbor Freight so they can order a new spring seat.
     

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