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I'm new to mechanics and I'm taking apart my engine!

Discussion in 'XJ Technical Chat' started by Ben Babuski, Nov 26, 2019.

  1. Ben Babuski

    Ben Babuski New Member

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    I have a 1982 Yamaha XJ650 Maxim that I bought for dirt cheap from a guy off of eBay. I got the bike because I wanted to learn how to work on bike engines, and I do not know a single mechanic so I am just trying to figure it out as I go (I have the Hayne's manual, but it hasn't proved to be very useful yet). I currently have my engine halfway apart, the pistons are out in the open, the clutch basket is exposed and the left crankcase cover is off. I am trying to get to the starter clutch, but I also want to replace everything else that is broken or worn badly in the process. I have no idea what I am doing and I need someone to give me a checklist of things to inspect, it would be greatly appreciated! Also, I plan on using this thread to update my progress with you guys, let me know if you want pictures.
     
  2. Kickaha

    Kickaha Active Member Premium Member

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    Why did you take the engine apart ? was it running? did you compression or leak down test it prior?
     
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  3. jayrodoh

    jayrodoh YimYam Premium Member

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  4. kerriskandiesinc

    kerriskandiesinc Active Member

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    Yes, please get a service manual, Clymer, Haynes as a last resort...although Haynes can sometimes have little stupid mistakes in them
     
  5. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    The Yamaha service manual is still availble direct from Yamaha as PDF.

    You have taken on an advanced project for someone who has never had an engine apart, but the fellas here will get you through it.

    For future reference, an engine shold not be taken apart without doing some diagnostic work beforehand, so you have an idea of what needs to be done to it.
    My advice is to take a short break from that project and sign up for a small engine repair course in order to get some familiarity with the process and what to look for as you work.
     
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  6. Ben Babuski

    Ben Babuski New Member

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    Yeah sorry, I wasn't very thorough in my first post, the engine was running before, good compression, good spark, but the fuel tank needs replacing or a very good cleaning. However, when I tried starting it, the starter clutch would only sometimes catch but mostly it would just grind. I tried new oil and refurbished the starter motor but neither of those fixed the problem. I also know the carburetors need to be synched and the oil seals for the forks need to be replaced. I'm only taking this engine apart because I want to learn how to work on them and no shop around me is hiring apprentices. I got the bike for dirt cheap and it is not a big deal if I screw anything up. I have a pretty good concept of how everything works in an engine, and I am hoping that getting a hands-on experience will help me to understand it more.
     
  7. Ben Babuski

    Ben Babuski New Member

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    Also, is it normal to have some heat scarring on the side of the pistons, it's equal on all four pistons and it's just about halfway down the height of the piston.
     
  8. tabaka45

    tabaka45 Well-Known Member

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    If it makes you feel better, I got my start at age 14 by tearing into a Cushman engine and clutch. No where near as complicated as what you are doing, but I suspect at age 14 I was no where near as capable as you now are. My suggestion is to take a lot of pictures, label everything, keep everything absolutely clean, get a service manual, make sure you have the correct tools and a good place to work, go slow, and ask the guys for help. You should be able to get a service manual on a disk or by pdf off of Ebay for less than $20. I think I paid $10.99 for mine. It's a lot better than Haynes, especially for what you are doing. I'll be interested in following your progress.
     
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  9. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Post pics please.
     
  10. Ben Babuski

    Ben Babuski New Member

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    When I try to upload an image it says "Error- The uploaded file was not an image as expected".
    I tried .JPEG, .PNG, and .HEIC and none of them worked and when I tried converting it into a PDF it says that the file is too big
     
  11. Jetfixer

    Jetfixer Well-Known Member

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    Couple of items , only use plastic scrapers on mating surfaces , a razor blade can leave scratches that can lead to leaks , as to sealants Yamabond or Permatex RTV high temp ..either one use only light application ( to much can squish into the inside of engine, this can break off plugging oil passage) . A good quality gasket set ( go to xj4ever on upper right corner of page) be aware you will need rings again xj4ever. A hone is needed to put a cross hatch in the cylinders with lots of spray lube, you work this up and down with the hone chucked in drill. I recommend , if you have a NAPA that still has a machine shop have them check the cylinder taper and have the head checked for evenness , they might have to mill head . They should be able to check the crank as well . I have rebuilt several engines these are a few items that should be looked at. Expect to spend around 500$ to 1000$ = in parts, machine work if required, a few tools ( hone, ring compressor, inch pound torque wrench click type Harbor freight carrie's these) a rebuilt engine will give you the satisfaction that you accomplished this . Good luck.
     
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