Primary Chain Deflection Measurement

Discussion in 'Transmission' started by Rocket J., Jun 9, 2015.

  1. Rocket J.

    Rocket J. Member

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    I've never learned a good easy way to measure my primary chain deflection. It looks easy in the manuals but that's because they have the primary opened up for easy visibility and access to the chain. Working through that little chain inspection window is not nearly as easy as the pictures show. I'm getting ready for fluid change and adjusting the primary chain and think I'll try using a long screw driver, making a sharpie mark where the screwdriver blade is at the bottom edge on the inspection window just touching the chain at the top middle; then pressing the screwdriver up until the chain is fully deflected and making another sharpie mark on the screwdriver blade at the bottom edge of the inspection window. The measurement between the two marks on the screwdriver is the chain deflection.

    Probably someone has an easier way to measure chain deflection and I'd appreciate knowing how they do it.
     
  2. Dan.1977P

    Dan.1977P Active Member

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    I cut down a yard stick so I could get it through and measure.
     
  3. Breeze3at

    Breeze3at Well-Known Member

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    I stick an open end wrench of the proper size (say 1/2") thru the hole. Move the chain up & down while holding the open end close. E-Z to see if you are tight or loose.
     
  4. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    Make sure when you take the measurements your doing it on a stone cold engine.

    Pete's wrench method does work well.:s
     
  5. Rocket J.

    Rocket J. Member

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    Yes, stone cold.
    Mine is an '05 Electra Glide and that inspection hole is about 4 inches square. On a lift just high enough to level the bike inside my garage it's also dark inside that hole. I used something similar to the cut-down yard stick and the open end wrench last time; a piece of plastic rod with marks to show 5/8 inch. I eye balled it to where I guessed it was between 5/8 and 7/8. I remembered that it wasn't easy to juggle the measurement device and a flashlight while pushing up on the chain and that it's still just an eye-ball judgement with no index marks to get a hard measurement. The screw driver with marks will give something to actually measure.
    Maybe I'm just being A retentive, but I'd also like some kind of dip stick arrangement to check for the level of primary oil, too. In fact I do use a plastic rod behind the adjusting shoe for determining my primary oil level. Just eye-balling the level to the bottom of the clutch can vary by many fluid ounces.
    Thanks for the come backs.
     
  6. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    32 oz and you're good to go, that will bring the level to the bottom of the clutch basket where it should be. Your manual should also reflect the amount as 32 oz.
     
  7. Rocket J.

    Rocket J. Member

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    Mine has always been a bit more than 32 ounces to get it to where it looks like the level comes to the bottom of the clutch basket. I've always cracked open another quart and added about 4 more ounces to get it to where I think it looks right.
     
  8. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    Strange, I have the same scoot and mine takes 32 oz to bring it to the correct level.

    Manual states, check it standing upright and the level must not be higher than the spring.
     
  9. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    Dont forget to roll it to a different spot and check it in multiple places...:s
     
  10. Rocket J.

    Rocket J. Member

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    Jeff, I suspect that the difference is in our eye and that if you got 4 or 5 people together to add primary oil you'd get 4 or 5 variations of how many ounces of fluid are needed to look right. 32 ounces is definitely below the clutch basket to my eye but to me the level with 32 ounces is still below instead of at (that's where I want it) and looks that way until 36 ounces.

    Yes, the book calls for measuring deflection at multiple locations along the chain run and adjusting from the tightest.