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NOW FOR SOMETHING DIFFERENT

Discussion in 'Other Motorcycles' started by wizard, Jan 7, 2012.

  1. wizard

    wizard Active Member

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    1978 SR 500, bit of a mess, parts missing & no compression.
    I'm restoring this bike, stock as can be.[​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]
     
  2. Alive

    Alive Active Member

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    Looks like a good starting point
     
  3. Polock

    Polock Well-Known Member

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    look into the compression release mechanism, might be a easy fix
     
  4. Bushy

    Bushy Active Member

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  5. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    And I've got an original piece for you-- I still have the "grab handle" (standing handle?) from one of my SR's that got a luggage rack.

    It's all yours; plus if I can find it I have the Clymer manual for that bike somewhere.

    BOY, does that bring back memories; I had a '78 (like that one, with the disc rear brake) and after it got wrecked I replaced it with an '80 (drum rear brake.)

    I will PM you when I get a few with some boring details in regard to exhaust systems.
     
  6. Daplumma

    Daplumma Member

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    Very cool bike.I built this one from a Vintage class racer.
     

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  7. tskaz

    tskaz Active Member

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    Another project from Wiz, gotta know it's gonna turn out quite proper
     
  8. XJPilot

    XJPilot Member

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    Nothing like a good challenge eh Wiz! Can't wait to see the progress!
     
  9. wizard

    wizard Active Member

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    New sprockets & chain required & what to do about this, gear shift has been welded onto the shaft.[​IMG][​IMG][​IMG]
     
  10. MercuryMan

    MercuryMan Active Member

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    You don't see that everyday! Somebody with a heavy foot had a nice welding rig and some lazy bones. Or they had a tendency to lay it down.

    New shaft and lever after surgery to remove the old?

    Looking forward to this build, should be a nifty clean ride when done. At least you still have the sweet '500 single' side panels!
     
  11. mtnbikecrazy55

    mtnbikecrazy55 Active Member

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    I'll be watching this one!

    Holy shark finned teeth :O

    I'm looking forward to seeing what you do with it!
     
  12. JeffK

    JeffK Well-Known Member

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    A couple day project........

    I love small thumpers.......


    jeff
     
  13. mook1al

    mook1al Member

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    Those sprocket teeth are only slightly oblonged 8O
     
  14. wizard

    wizard Active Member

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    Comp test results:
    Dry 1 (one) psi
    Wet 35 psi.
    Will post pictures of the engine strip down & rebuild.
     
  15. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Would you like some good news?

    You know how I'm always cautioning folks about tearing an XJ down too far, because "since they weren't raced, things like oversized pistons are hard to come by."

    Well guess what motor is STILL, to this day, one of the most popular amongst club-level flattrackers here in the good ol' USA? (Parts a'plenty.)

    A picture is worth a thousand words-- I'm sure you'll recognize the mill.

    [​IMG]
     
  16. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    It's probably only a compression release or exhaust valve problem tho.
     
  17. wizard

    wizard Active Member

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    I pulled the decompressor out, so nothing is fouling the EX valve, it will need a top end service & maybe rings.
     
  18. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Cool. Widely available here, in all oversizes. I wasn't kidding about it being a popular flat-track motor, that picture isn't more than a year old or so. Michigan is BIG on flat track, TT/XT/SR500 "guts" are easy to come by. Let me know what you unearth, and I'll help you track down some innards.

    I was serious about the standing handle if you're going to lose that luggage rack; ditto on the manual but I haven't found it yet. I know it's here somewhere, I don't throw things like that away.

    I hope you jumped on the seat Bushy posted the link to; that stupid little tail piece is probably hard to come by. Boy am I sorry I sold my SR.
     
  19. wizard

    wizard Active Member

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    Thanks Fitz, I appreciate any help, I'm still trying to find my way around this thing, the on-line manual I have is half in French, I can't even find how to get TDC, comp' stroke to set the valves, I'm probably going mad, but the valve timing seems odd, any ideas, my manual talks about setting points, but this bike has CDI ignition, doesn't it ?
     
  20. MercuryMan

    MercuryMan Active Member

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    Parlez-vous français? Yikes no wonder your going mad! Those are the guys who built the Citron!

    Fitz if your like me you filed that manual under the 'it made sense when I put it there' system. Which only requires that you get back into that exact same frame of mind and voila it will appear. Oh damn another French word.

    . Wiz could you remove the plug and use a physical test for TDC? Using a compression tester w/the one-way valve removed, a clear tube that will fit it, some oil. If you create a loop with a small amount of oil it would be pushed up without draining out. The peak push would indicate TDC right? and the air moved by the piston would displace a lot of oil to make it easy to see.

    Singles are fun to ride! Nice predictable power curve and throaty exhaust
     
  21. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Unless it was messed with, there's a "cam position indicator" on the RH side of the top of the head. There's a little window, and a "flag" on the end of the camshaft. It's mainly there to help the unintiated start the bike. In use, you pull in the compression release until the flag shows in the window, then release it and kick. IIRC, TDC itself is when the flag JUST begins to appear in the little window.

    There are also the customary marks ("C" and "T") on the ignition rotor/flyweel, IIRC; the cam chain adjuster is manual and has a rather odd adjustment regimen.

    Yes, it has CDI ignition.

    When you finally get that far, the carb has an interesting feature as well: There's a little "button" on the side of the carb you push up; it only moves about a mm or two. It "cracks" the throttle a smaller amount than humanly possible, and provides the exact amount of throttle opening to start the bike. Once running, a "firm return" on the throttle one time pops it back down.

    I'm digging for the book. Thirty years is a long time.
     
  22. wizard

    wizard Active Member

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    I've got to make an extractor & pull the flywheel, it's so rusty I can't see the marks.[​IMG]
    Fitz, there is supposed to be a pointer on the crankcase, I can't find it.
     
  23. Polock

    Polock Well-Known Member

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    the TT model with points looks like this
     

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  24. wizard

    wizard Active Member

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    Look carefully at the picture of the flywheel, does that look like the remnants of the pointer ?
    Made the puller, removed the flywheel, the key has lost it's square edges & wasn't engaged to the flywheel, that's why I couldn't make sense of TDC.[​IMG][​IMG][​IMG][​IMG]
     
  25. Orange-n-Black

    Orange-n-Black Well-Known Member

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    Hopefully the weld on the shifter is only on the end of the shaft. If so, then you only have to grind a little past the weld and the shifter should come off. Any other welds on the shaft? If so your S-O-of-L. :roll:
     
  26. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Wiz, this qualifies as a "rescue" not a mere recommissioning. That poor bike. Good save.

    I can't tell if the remnants of the pointer as illustrated by Polock are there; but seeing his post brought back more memories. My SRs had a similar pointer, IIRC, and they were both CDI bikes. Also, I somehow dimly remember one of them having just a "vestige" of a pointer, to where I inscribed one after locating said remnant. Look on the inside of the casting where the pointer should be, (as in Polock's pic) and see if there's a cast-in ridge that just didn't get all the way to the edge.

    If not, don't assume I was right. Like I said, thirty years is a long time and very very many Labatt's. Although I can't imagine the location of the pointer changing, TDC didn't change.

    I WILL find the book; probably this weekend. I already found the standing handle; and I may have a couple of other bits, I just need to dig.

    DAMN you're making me sorry I sold my SR. I may have to flip the 650 and go track one down. I loved those bikes.
     
  27. RickCoMatic

    RickCoMatic Well-Known Member

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  28. wizard

    wizard Active Member

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    Yes I found that raised ridge & have made a 'nick' with a triangle file.
    The Woodruff Key was sheared in half, with one part in the flywheel key way & the other part in the shaft.
    Fitz, I've set the valve lash & hooked up the comp' gauge, what should it read ? I've kicked it up to 60 psi, if it had any more comp' I couldn't kick it at all.
     
  29. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Wiz, my friend, that's a good question.

    Unfortunately one I can't readily answer; when I had my SRs they were both bought new and I never ran a compression test on them.

    According to the SME's on the SR500 forum, the factory book lists 135~149PSI. Discussion on the same forum seems to indicate that most folks are happy to get 120 before they use up their right leg. Whatever you get from 4-5 stiff, rapid kicks is what you've got.

    Looky what I found "Googling about:" http://www.dropbears.com/y/yamaha/sr500info.htm

    SR500 forum: http://www.sr500forum.com/forum/index.p ... f6c9ec3834
     
  30. wizard

    wizard Active Member

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    Motor stripped down. Head & valves in good condition, just coked up.
    Bore is in very good nick, no ridges, gouges etc.
    Top ring, in the bore has 1/8" end gap, yes 1/8", middle ring has 0.85.
    I'm thinking hone & new rings.
     
  31. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Check your ring groove to ring gaps; be sure the piston is still good. If so, I gotta agree.

    Do you have any idea how many real miles are on this thing?

    How does the bore measure up; wear, "roundness" and taper-wise?

    Piston clearance gap?

    It's beginning to sound like this bike is more a victim of neglect and abuse than having had enough use to be worn out.
     
  32. wizard

    wizard Active Member

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    I'll do some more measuring in a minute, the ring grooves, you mean put the rings in the lands & see what gap there is, up & down, as it were ?
    Not a clue on the provenance of the bike / motor.
     
  33. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Yes sir; ring groove-to-ring clearance is a published spec, and an important clue to overall piston "health." I've seen them actually close up on an overheated piston; and 3X what they should be on old worn-out Triumphs.

    According to the specs I found online (hard to read, sorry; the columns don't collate properly) you're looking at:

    Top ring "side" clearance: .04 ~ .08 mm <.15 mm> (<allowable>)
    Second ring "side" clearance: .03 ~ .07 mm <.15 mm>
    The oil ring doesn't have a spec since it's an "assemblage" thickness-wise.

    If they're loose, the piston is worn. I'd try to stay in spec rather than live with the <allowable> side.

    What's the odo say? Or do you already have good evidence it's completely inaccurate?
     
  34. wizard

    wizard Active Member

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    Clock says 50 something klms, which would be 30k miles & would seem about right.
     
  35. wizard

    wizard Active Member

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    Head cleaned & valves lapped.[​IMG][​IMG]
     
  36. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    OOOH valve seat porn. That motor's a puppy; them's some sexy seats there, RL. Those are some nice meaty valves, you weren't kidding.

    TEXTBOOK. NICE professional job on the lapping, I'm jealous.

    Now get the rest of that old gasket off of there.
     
  37. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    I just went and looked at an XJ head.

    Am I the only one who's noticed how BIG those valves are in relation to the combustion chamber? It does look like a bloody V-8. That's a serious air pump (I never had mine apart that far.)
     
  38. wizard

    wizard Active Member

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    This is not what you want to see when you pull a case :cry: [​IMG]
     
  39. RangerG

    RangerG Member

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    Five out of six ain't bad!
     
  40. MercuryMan

    MercuryMan Active Member

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    Oops! PO must have been drinking vodka when he put that back together-proof that they often have a screw loose or in this case a bolt.

    Nice job on your valves Wiz, and I agree with BF those are big valves. I'll bet that single has a nice fat torque curve.
     
  41. wizard

    wizard Active Member

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    That post is sheared off, MM, had to order a replacement clutch. :eek:(
     
  42. wizard

    wizard Active Member

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    Got the cases all shined up, just need some bits for inside.[​IMG]
     
  43. wizard

    wizard Active Member

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    Don't tell Yamaha, full set of bearings & seals, for the rear wheel, $30.00.[​IMG]
     
  44. wizard

    wizard Active Member

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    I didn't think the 'hot & cold' method would work so well:
    Put the bearings in the freezer, overnight & heat up the hub, with the hot air gun. Sweet.
     
  45. wizard

    wizard Active Member

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    No one has been in here for a while.[​IMG]
     
  46. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    8O
     
  47. Ground-Hugger

    Ground-Hugger Member

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    Any spiders in there????
     
  48. LVSteve2011

    LVSteve2011 Member

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    Hey there's a Sidney funnel web SPIDER! Quigley and his sharps will rid you of that bugger!
     
  49. wizard

    wizard Active Member

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    It's not funny, I had a good poke around in there with a screwdriver, before I put my pinkies in there.
     
  50. Ground-Hugger

    Ground-Hugger Member

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    I know, I know, my wife has family in Australia. BUT its still funny!!!
     

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