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How much will a ^$@^&& rebuild cost me?

Discussion in 'XJ Technical Chat' started by phorce1, Aug 13, 2008.

  1. phorce1

    phorce1 Member

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    Location:
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    XJ650G Compression

    ----DRY - WET
    1 -- 100 120
    2 -- 130 180
    3 -- 110 210
    4 -- - 80 130

    What's up with the 180 and 210 wet readings? How high would a freshly rebuilt cylinder read with a squirt of oil in it?

    I've done a top end rebuild on a VW before. New cylinders/pistons/rings. So I should be able to handle the work.

    Do the readings above generally indicate full top end rebuild with +1 pistons or possibly just re-ringing?

    Thanks all.
     
  2. RickCoMatic

    RickCoMatic Well-Known Member

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    Since you have to take the Head off the bike, anyway ... you might as well have (or do) a Valve Job with new Valve Seals.

    Since all your numbers "Came-up" Wet ... you might need to just Lap the Valves after wire brushing all the crud off the Valve Stems.
    No problem.

    The Block.
    Depending on what you find when you determine why the 4-Hole's number is so low ... you might possibly need Machine work. Time will tell.

    Do new Rings on all the Holes and be prepared to need a set of Oversized Rings for the 4-Hole.
    Maybe it's just cracked Rings without a whole lot of Cylinder Wall scoring that can be Honed-out rather than needing to be Bored.

    I hope that its a simple fix.
    I hope you dont need the Hole "Punched" and a Oversized Piston.
     
  3. phorce1

    phorce1 Member

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    I'll trailer the bike to may garage and get cleaned up enough to pull the engine next week.

    What about the high wet readings? How high is "WTF ?!?"

    And now ... the REST of the story.

    First, the bike has only been over 30 MPH once since I got it, and only for a few seconds.

    When I got the bike it was running on 3 and I didn't realize it at first. That was a bad plug. Still "ran funny" after replacing the plugs so I took it to a "shop" to have them clean and sync the carbs, set the valves, and put a POR15 kit in the tank because I could see crud in the filter -- I figured that's what was causing the problems.

    At the time I did not own a working compression tester (I owned one but it kept giving me different readings every run)

    I got the bike back and NOW, after they "fixed it" it was suddenly "cold natured". It had to warm up GOOD before I could even get it past 2000 rpm. I could feel it hit all 4 though.

    then I went away for a couple of weeks and parked the bike. When I got back it was running like crap again. I'm a new rider and I won't take a vehicle on the road unless I know it works right.

    Looked in the tank and there was crap peeling off. Great, they screwed up the POR15 job so it's not getting fuel and running bad.

    They gave me a replacement "complete" kit (with the stripper to get the old stuff out) and I said I'd do the tank work myself. Yep, the stripper broke loose the actual problem. Looks like they didn't let the tank dry and ended up pooling the POR15. That tank is destroyed. There are big CHUNKS of POR15 inside that are too large to remove through any of the existing openings and it would take LOTS of the POR15 stripper to dissolve hem down. I had the tank acid boiled at a radiator shop and all that did was get rid of the surface rust and turn the tank into a lawn sprinkler. Pinholes around the seams (which is what the POR15 was going to fix).

    I still haven't talked to the shop owner about that. He's out of town.

    Also discovered the aftermarket coils onboard were bad after warming up. I have the numbers around here somewhere, but they were definitely bad. Replaced those with a new set of Dyna's from chacal.

    Got another clean tank. Still ran like crap. Can't get it to hit on all 4. Won't go above 2000 rpm easily. If I ease it into 2nd and let it "coast" up to 15 or so mph then downshift to kick the RPM's up over 2000 I can then KEEP it there but still feels like it's not hitting on all 4.

    That's the point where I took it over 30 for the first (and only) time. If I stayed in the throttle to keep it over 2000 I could "go fast". But if I let it drop to idle it won't come back up unless I use engine braking to get the rpms up.

    Talked to the mechanic that worked on the bike and he suggested crap from the tank had gotten in the carbs so they weren't pumping at lower vacuum. I took the carbs apart just to the "good cleaning" stage without messing with any adjustments. the bowls looked good but at least one float needle was not working right. I have a set of parts carbs so I went through and replaced the main and pilot jets with the best of the bunch and picked out 4 working float valves.

    Same behavior from the bike after reinstall. I used ether to test for intake leaks.

    Looks like 1 and 2 aren't firing. With the plug removed and grounded I see a bright white spark. But after starting the bike those plugs are wet with fuel.

    With the bike running at idle pulling those 2 plug wires causes a BARELY noticeable "blip" in rpm. Pulling off either 3 or 4 kills the bike.

    I swapped plug wires from left to right (keeping them on the correct coil) and got the same behavior so it's not the coils.

    I bought the new compression tester and it indicates that #4 should be having problems, not 1 & 2..

    Yes, this is a long rant about me not checking the bike closely enough before buying it.

    Ideas.
     
  4. RickCoMatic

    RickCoMatic Well-Known Member

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    It's like the old story about the guy walking from town to town.
    When he passes this old farm there's a swayback horse tied-up to stake in the the pasture.
    It looks tired and on its last legs.
    There's a sign that says: "For Sale Cheap", nailed to a post by the horse.

    The guy knows better than buying a horse that old; so he just keeps on walking by.
    That's when the horse calls-out to the guy and says: "Just offer the farmer
    fifty bucks cash and tell him to throw-in a saddle. We'll be galloping away from this god-forsaken place - quick!"

    The guy can't believe he has come across a talking horse, so he asks the horse if it has the strength to make it to the next town without going lame.

    The horse says: "Sure. No problem. Get me the hell out of here."

    The guy starts seeing dollar signs. A talking horse. That's something people are going to pay some good money to see.
    So, he goes up to the farm house, rings the bell, does his best to get the farmer to sell him the horse and a saddle for the 50 bucks the horse told him the old man would take.

    Cash on the barrel head.
    Saddle on the swayback.
    Before he kicks the horse and gallops into town, he figures he ought to let the farmer know how bad the old geezer just got screwed!

    "Hey, old man! You just sold me a talking horse. I'm going to be rich!"

    It's the farmer who's standing there with the big grin on his face, though.
    Then he yells back at the guy trying to get the horse moving toward town.

    "Get that oat-burning, glue-factory nag off my property, pal. I don't ever want to see it again. I hope it didn't tell you he was going to win The Derby!"
     

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