Re-assembling the XR’s engine bottom end

Time to clean up and put things back together!  No real surprises here, Honda made it fairly straight forward to re-assemble the bottom end.  The crankcase splits horizontally allowing one to assemble the transmission’s shift drum, forks & gears, balancer shafts, and crankshaft, and lay them  all down in the lower crankcase before closing everything with the upper crankcase.  Then install the clutch and align the front and rear balancers and things start looking promising.  Funny thing is that there is always a short moment of self-doubt were one wonders if every part was really in place and if something was forgotten.  Probably like a doctor counting all his tools after completing a surgery and making sure that he didn’t forget any instrument in the patient!  Nah, we’re good.

XR500 bottom end, left side.  Note the chain driven front balancer, shift plate and  shift spindle.

XR500 bottom end, right side.  From left to right: clutch, ignition advancer rotor, camshaft timing chain, front balancer weight.

The intend has been to rebuild the bottom end as an XR500.  I inserted though the neutral (gear) position indicator from the XL just in case I decide to use the XL left engine cover and its corresponding neutral switch sensor.  Then again, who needs a bright neutral light indicator on a dashboard?!

XL’s neutral gear position indicator.

Now that the bottom end is back together, let’s go crazy with paint!

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20 Responses to Re-assembling the XR’s engine bottom end

  1. Roland linder says:

    Glad to see that all is clean and coming together rapidly. By Spring time, it will be time to make the first test and have your first crash!
    Keep up the good work, it’s real cool to see the progrees

  2. Forrest says:

    I am a little confuse about the arrangement of its two balancer wheels. How it is positioned with respect to one another is a little confusing.

  3. Luci says:

    Hi,i have one Honda xr 500 pd02,I opened the engine, and do not know how to properly put balancer,I do not know the exact signs!Please help me with photo and explanations!Thanks and sorry for my bad english!

  4. Luci says:

    hei,please respon me

    • Mike says:

      There is more than just alignment involved to get the gears, shafts and balancers in place correctly. I would recommend that you get a copy of the Clymer service, repair and maintenance manual for the XR500 — steps are well explained and illustrated. You’ll also find tables with torque values. Here is a link to Clymer but the book is available from many other resellers and even your Honda dealer may carry copies.

      Clymer Honda XL/XR 500-600 1979-1990:

      • Luci says:

        I just need to signs, motor type is pd02! please help me :)! i dont buy manual, i am in Romania, not Shiping me! Thanks Mike

  5. Nic says:

    Good job Mike.

    Quick question : I have a XL500 engine that I’m rebuilding for a project. I’ve not seen any oil filter anywhere in the engine. Did I miss something or there is no oil filter in this mill ?

    • Mike says:

      There is no traditional oil filter on the XL/XR500 motor, but there is an oil screen. You access it by removing the right hand side engine cover (the cover which holds the oil dipstick), the screen will be at the bottom of the case. Remove, clean it and slide it back in place.

  6. jason says:

    hey mike, you seem to be a bit of an xl 500 expert. I have the manual and it says to mark a link on the balancer chain, line it up with the dot on the front balancer, then the ninth link to the dot on the crank sprocket and the twenty seventh to the dot on the rear balancer. the picture shows each balancer to be in a position lined up with an indicator on each side of the case. I’ve taken several physics classes and the math shouldn’t be that difficult, but with this link alignment my view doesn’t match the picture. what’s the trick to that and is it that crucial?

  7. Shaky Khan says:

    I need xr 500 r modle 1981 weight balancer timing chain diagram.

  8. Alejandro ortiz says:

    Hey mike can you tell me how did you puton the chain I need help I have the same XR50 and I don’t now how it goes and is a little loose

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