XL500R Seized at TDC?

Discussion in 'Thumpers' started by GravvyTrain, Jan 5, 2012.

  1. GravvyTrain

    GravvyTrain Adventurer

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    This is my first rebuild and it looks like I got a seized piston. I want to take off the head/jug but the timing chain needs to come out first. I want know what is the timing for this bike so I won't worry too much about running into any more problems if/when I get to putting it back together..
    From what I can tell- the piston is either at TDC or very close to it. The cams are down and the top sprocket has one bolt up, but the timing mark on the main shaft sprocket is at about 5 o'clock?
    Also, anyone know if it is necessary to remove the clutch pressure plate and/or chain tensioner?
    I'm worried about getting the camshaft sprocket off because of the stuck piston- I won't be able to turn 180 degrees to remove other stud.

    Any ideas? =]
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  2. GravvyTrain

    GravvyTrain Adventurer

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    YES the piston is stuck no more after moving the top cam chain sprocket !
    I could put it all back together now, but I want to see about this cylinders condition.
    Probably need rings/seals and I'll be riding again. Will update when I remove the head.
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  3. GravvyTrain

    GravvyTrain Adventurer

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    OK guys I am getting a manual, but until then... AM I MISSING A CHAIN?? down there behind the clutch cover?
    Looks like on the bikebandit schematic, there is supposed to be a spring that lets the front balancer move back and forth :huh
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  4. Switchblade315

    Switchblade315 Long timer

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    You are missing a bolt to hold the balancer adjuster in place. and yeah I think there is a spring missing as well should be on there to pull the adjuster back and up.

    the chain for it is on the other side of the motor.

    oh and the spring is not meant to let it move it is meant to adjust the balancer when you loosen the bolt that is missing.

    did the motor move when you turned it backwards? it may be something broke on the other side of the crank case that had it locked up.

    and these motors are easy to time. get it top dead center and just line the marks up on the cam sprocket. should be two marks on there, they line up with the top of the head.

    There's a lot of info on here for those bikes and most of us that own one have been through the motor.. ask for help and you will get it.
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  5. GravvyTrain

    GravvyTrain Adventurer

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    Yeah it moved when I put a wrench on the cam sprocket and tugged it a bit. I will take off the other side cover as soon as the rain goes away..
    Its a mystery how the engine could have burnt that much oil that quickly- I changed the oil after I purchased the bike, and had been riding it for about a week. There wasn't any oil puddles or anything like that either. I went to run around town and then it 'seized' . When I had tried to break it loose by riding a hill in 4th and 5th but no luck so I had to dismantle and go from there. I drained the oil and to my surprise there was basically no oil to drain :cry.
    My plan is to take off the head and find out whats really going on in there.
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  6. Switchblade315

    Switchblade315 Long timer

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    they hold all but 2 quarts. mine used a quart in 40 miles on the last ride I did before I rebuilt it. And it wasn't smoking enough to even see it. Someone had put a set of .25 over rings on a stock piston with the same old used up oil ring that it came with in 82. they had to grind the over bore rings to get them to go in the stock bore cylinder.

    i've done a lot of work to mine and I've got to go back and fix a few things i should of fixed the first time. I sent you my number in a PM, and i trully meant give me a call so i can give you the heads up on what to look at fixing the first time, and the problems i created with what i did. I'm normally free to talk any time during the day.

    i love my Old XL. and with all the Mods I've done to it it's making one hell of a bike. I'm in working on putting a XR400 muffler on it right now. it's not as easy a mod as I first thought but it's getting there.
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  7. GravvyTrain

    GravvyTrain Adventurer

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    Wow now I could believe how much oil it burnt through. These old bikes need TLC .
    And how do you fit OS rings with stock jug??
    That is a great build you got on your xl - i like what you did with the headlight looks good.

    I have taken the head off, jug off .
    Looking at getting a piston [OEM or other?] & Set of rings
    The jug/cylinder looks like it has deposits of melted residual ring material that has stuck to the surface. So I assume the shop will tell me whether I can just keep it at stock size or bore over.

    PICTURES

    HERE ARE THE VALVES.
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    PISTON/JUG
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    Now I know what was making the tapping noise when running- it was this balance shaft flange hitting the chain guide because it wasn't bolted in place(it is now).
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  8. GravvyTrain

    GravvyTrain Adventurer

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    Hey this seems like a good deal I found on ebay listed as "79-81 XR500 XL500 CYLINDER&PISTON".
    $74 including shipping...I'm pretty sure that will fit with my motor :huh

    #8
  9. GravvyTrain

    GravvyTrain Adventurer

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    So apparently all of the bikes from 79-82 are just about the same, and the jug is interchangeable.
    This thread says it all:
    http://www.thumpertalk.com/forum/archive/index.php/t-806655.html

    I will order a gasket kit and an OEM piston w/ rings. Might be able to take my cylinder to the shop - they can hone it for $35 instead of buying another one.
    Hope to get her running next week , stay tuned..
    #9
  10. Switchblade315

    Switchblade315 Long timer

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    that might clean up with a honeing if not go with the first over bore. I think it's a .25 stock compreshion piston. You can't hardly find a new stock bore stock compreshion piston. I stayed stock bore but i went up to a 10.5/1 compreshion piston. I now have a labor knock. But I think I know why. I did not replace the old warn timeing chain and I think my cam timming is off just enough to cause the knock. So here's my advice to you. PUT A NEW TIMMING CHAIN IN THAT THING!!!!! you are there and you just have to remove the clutch and maybe the drive gear for the chain. Trust me do it now wile you have the motor apart.

    with that said the stock bore 10.5/1 compresion piston does make more power and it doesn't make the bike harder to kick, well it didn't mine but my auto decomp is still working. Do not go to the 12/1 comp. piston. you'ed have to mod the hell out of the motor to run that thing.

    and if you are wondering they are 8.5/1 comp. stock.

    now as to how they got the over sized rings in a stock bore. they filed the gap bigger the rings egg shaped to go in there. I don't know why it was done or how I'm just glad it wasn't ran much with it that way.

    And 82 is a basterd year. the bike used thing from the older 500s and it had things that the newer bikes had but it's the only year that was built like it was. the 82 does not have a reed valve motor like some of the other 500s. so make sure the one you are looking at on Ebay isn't a reed valve model. And I just looked at them on Bikebandit and all the gaskets are the same on a 80 as they are on a 82 so that should be fine. but a one size over bore woult hurt a thing oun yours if it needs it. and after a honeing if it's still in spec. run it. it's going to use a little oil if you get over 65 regardless.

    mine uses a pint to every two or three tanks of gas. well it also leaks a few places so it would be a little less. probly would go to 5 tanks of gas before needing any. and I get 120 miles to a tank. So it's really not to bad.

    But trully get a new timeing chain.
    #10
  11. GravvyTrain

    GravvyTrain Adventurer

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    #11
  12. GravvyTrain

    GravvyTrain Adventurer

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    Well I received the cylinder/piston I ordered from Ebay today , and it showed up on my doorstep in a wet, torn box - with the top fin exposed and broken. :huh

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  13. GravvyTrain

    GravvyTrain Adventurer

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    After looking at the piston again, I've found a crack in the skirt..THAT wasn't in the ebay description! Talked to the seller and now it looks like USPS threw my parts around like they didn't care about the neon orange sticker that says FRAGILE . Might just have to get INSURANCE next time :1drink
    I'm fortunate to have spotted this before slapping it in there ~

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  14. Airvent

    Airvent Been here awhile

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    Bummer about the shipping damages. I'd be pissed at the seller for cramming it in a flat rate box without adequate packing.
    #14
  15. Switchblade315

    Switchblade315 Long timer

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    Yeah that is the sellers fault for not packing it better. I use to work for UPS and a sticker on the box mean nothing. you want something to not get broken you pack it well, News paper is cheep. Anyway the broke fin wont hurt anything other then look bad and it's on the back side and will never be seen. I bet you could hone your old one ... ether way that piston was shot so a new new piston and rings is needed.

    And I'ed get a good chain. you don't want that to brake.
    #15
  16. redprimo

    redprimo Been here awhile

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    Iv'e got a 80 xl500 that I have been draging my feet on putting back together. I had it bored 1st over and I have a new piston and rings and a gasket set and that is where it sits, all ready to go back together. Mind if I jump in on your rebuild party?
    #16
  17. GravvyTrain

    GravvyTrain Adventurer

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    Sure you're welcome by me :freaky

    I've ordered another piston and a YBN cam chain. Should be here this week along with the various other OEM parts that should be arriving today [nuts, bolts, air filter, exhaust collars & gaskets, and head gaskets]

    While I wait for the parts to come I'll put some black primer on the 'new' cylinder I've got to make it match with the rest of the engine.
    #17
  18. Ivanych

    Ivanych Ivanych

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    OH! OH!
    I received a package from the USA to Russia in the same box 2 months ago.
    It was the hub of the rear wheel for my XR500r. The box was ripped off as well, but the hub is to stand the beatings.
    I think that they play in football these our boxes.:dog
    HOLD ON!
    #18
  19. Switchblade315

    Switchblade315 Long timer

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    When i worked for UPS, every year I would do a post on a site for your local UPS Box Basher. It was on how to ship thing at Christmas time with out anything getting broken. Yes they throw, kick, and drop your package. and by now everyone should know it.

    paper packing is the best thing you can use. peanuts will fall out. foam will not protect you stuff, and you can never use to much. I always told them pack it and then shake it. if something inside moves add more packing, shake it again is if moves add more, shake again if it doesn't move add more packing. now tape the hell out of it. use 4 times as much as you think you need, tape every edge. and go around the box completely with tape not just across one side and then the other.

    if you do this then anything you ship will make it. also double boxing helps.:lol3
    #19
  20. redprimo

    redprimo Been here awhile

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    Since my bike is an 80 XL500s The engine is unpainted. Don't confuse no paint with being an easier task to rebuild. My bike spent the last 30 years within a couple of miles of the Pacific Ocean so the unpainted aluminum had a thick coating of oxidation that made it look more like concrete than metal. I cleaned up the case with a wire wheel on a dremel type grinder, not a fun task, but not as tedious as it sounds. It looks ok, not suitable for a restoration, but just fine for a daily ride.
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    The manual says to make sure to oil restricter orifice is clear and show a pic of it out of the case but dosent say how it is removed (it is that little dot between the two studes closest to the timing chain) Mine looks cleat but I would have like to pull it out to get a better look.

    As I was cleaning up the bottom of the cylinder I nearly missed the O ring between the sleave and the casting, The new one is red in the pic. Any guess as to what purpose it serves?
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    I am much more experianced with 2 strokes (big chain saws :evil) and on those I don't use any gasket sealant. Right now I have my cylinder sitting on a dry gasket but it has yet to be bolted down. The Clymer manual I have makes not refrence to using any sealant, what do most guys with engines that don't leak do?
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