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Upper End Rebuild

Discussion in 'XJ Technical Chat' started by Jeromey Green, Dec 2, 2019.

  1. Jeromey Green

    Jeromey Green New Member

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    Hi Y'all, having finished the carburetor rebuild I'm onto the engine refresh now. I am doing an upper end rebuild because basically every seal is hemorrhaging oil up top including the upper head gasket. Oil just runs down the front of the engine and I'm sure its leaking from down on the lower end too. I am gathering components I will need, seeing as the upper head is coming off I'm thinking the lower head has to come off as the lower head gasket will be decompressed with the removal of the head bolts. I found piston rings for fairly cheap that I will order just in case, the compression is a hair low in one cylinder but I'm fairly certain it's just the old seals and crusty valves no longer sealing properly. I'll definitely do the obvious and clean/lap the valves, remove carbon buildup, replace the valve shims, hardware, etc. It's going to be a blast but any advice would be greatly appreciated, do y'all have any advice on how to extract the engine from the frame and disconnect the drive shaft? It will make everything exponentially easier if the engine just isn't crammed in the frame for this. This will be the most in depth engine work I've done so far, that being said I've done this on a car before so I'm thinking it will be similar.
     
  2. Jeromey Green

    Jeromey Green New Member

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    Ignore the cheap piston rings bit, after further research that's a bad idea all around. If these look toast or seem at all worn I'll measure for new ones and order them after the fact from XJ4ever
     
  3. Ryengoth

    Ryengoth Active Member

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    Two of the studs are in an oil channel up the side of the engine, those will require new donut seals at a minimum, which is where a lot of leaking could be from. A new head gasket will not be cheap so replace what you can before you torque it all down. You can often find used piston/ring sets from other bikes with low miles and they seal just fine if the cylinder bores are in-spec. New OE rings are also not cheap with most sets I've seen running 30-50 a piston set. When I rebuilt my 550 I ended up going with a used piston and ring set with less than 8k miles on it. I also had to swap the head due to galling in a cam cap so the whole valve re-shim ordeal was a PITA. I found a set of cams with 1k miles on them and sent them to WPC to get micro-peening for longevity.
     
  4. Jeromey Green

    Jeromey Green New Member

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    I am going to order the gasket kit, oil seals, hardware kit, etc. from XJ4ever. I will keep my eye out for low mileage oe piston rings then because this bike has 43k miles and slightly low compression in one cylinder and basically the minimum in the two others. There is a ton of carbon buildup in the exhaust ports which I'm sure isn't helping compression either so it could be just the valves no longer seal all that well. Do you have any ideas how to approach pulling the engine. I was thinking find something like a mattress and lay the bike onto it then unbolt the engine and lift it vertically out of the side of the frame. I don't have any of the proper tools so it's going to be me and another idiot doing this on our own.

    Also what is WPC which you mentioned?
     
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  5. Ryengoth

    Ryengoth Active Member

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    Remove the frame bolts and use a floor jack to lift it. You'll want to remove carbs, airbox, etc to make as much wiggle room as possible. I muscled mine in there but a small shop crane can help.
     
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  6. Jeromey Green

    Jeromey Green New Member

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    Well I don't have a crane so I guess it's maximum effort.
     
  7. tabaka45

    tabaka45 Well-Known Member

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    When I removed an engine from a XJ700 parts bike, after removing everything from the engine, I removed the mounting bolts and side bar, then leaned the bike over and pulled the engine out onto its side onto a wood pallet. I was surprised at how much the engine weighed.
     
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  8. Ryengoth

    Ryengoth Active Member

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    I personally would not risk a side drop. The side covers are thin. It's safer upright. I know from experience after dropping my 550 onto the oil pan corner and filter housing from 12". To help with removal off a center standed frame you can use some plastic totes turned upside down (or milk crates work) at the same height as the bottom rails. You can wiggle it over onto that and then use a hand truck or a helper to walk it around. Don't use straps to saddle and lift it unless you want to drop it like I did. :confused:
     
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  9. tabaka45

    tabaka45 Well-Known Member

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    When I removed it, it didn't "drop". The pallet was high enough that I was able to pull it out enough to rest the edge on the pallet and then just tilt it out. But I agree that you have to be careful not to let it hit hard when removing. Having enough folks to pick it up is probably the best solution.
     
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  10. Jetfixer

    Jetfixer Well-Known Member

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    One item I recommend ,get a cylinder hone (NAPA) ,with lots of lubricant (WD40) run the hone in a drill motor up and down cylinder till a good cross hatch pater in in the cylinder. This will help rings seat in . Cheers
     
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  11. Jeromey Green

    Jeromey Green New Member

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    Wow thanks for all the advice on pulling the motor guys, it's a huge help!

    Edit: well it will be Saturday I mean
     

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