My RC24 resurrection

Discussion in '1st & 2nd Generation 1983-1989' started by Wheezy, Sep 24, 2021.

  1. Thumbs

    Thumbs Member

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    It’s all pretty straight forward, the only one that is difficult to get to is the exhaust on #2
     
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  2. Wheezy

    Wheezy New Member

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    So worked on the valve clearances today. Found it difficult to get a consistent drag on the feeler gauges and it took me a few hours before I was happy, but got there in the end. You may recall that cylinder 4 still didn’t seem to be firing correctly. Well, both exhaust valve clearances were way out, so it might have been losing compression because of that. Hopefully, when I fire it back up next week, it will be a lot less clunky. Fingers crossed.

    [​IMG]


    Took the opportunity to tidy up the valve covers; the front one was particularly bad. Cleaned with emery paper, then primed and rattle can black finish. Don’t look too closely! But better than before.

    [​IMG]

    [​IMG]

    I also removed the radiator to make access to the front valves easier. The radiator is in a bad way. Loads of crap in the fins and a broken bottom mounting for the grill. I’m going to do my best to get it sorted but a new one from eBay might be the only option.

    [​IMG]

    [​IMG]


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  3. squirrelman

    squirrelman Member

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    something you'll learn about valve setting is that tightening the locknut will slightly change the clearance you've set so you're kinda chasing your tail.

    best to just try go/no-go method: for a clearance of .006", for example, a.005" will be too loose, and a .007" won't go in.

    rad fins need about 2-3 hours of work to fix. the rest looks grimey, they don't use salt on there do they ?
     
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  4. RogueRC24

    RogueRC24 Member

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    I just scrubbed my rad shield and sprayed black engine paint. Rad still silver/grey.
    I have the same knock after I did a valve adjust so I am not sure what the knock is. Maybe it is standard 700 running, but it doesn't sound great to me. I believe Capt80s mentioned his 700s had "noisier engines" than the 750s (?) but I am not sure.
     
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  5. Terry Smith

    Terry Smith Member

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    My 86 750 that I bought and sold recently sounded a bit rattly at low revs but smoothed out nicely under load and was super smooth when riding. So yes, I think these engines are just mechanically noisier, maybe due to the finger followers. I recall one of my original 700s had a fair bit of rattle from the gear drive, possibly the preloading springs in the split gears get a little weak over time and allow a bit more play.
     
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  6. Wheezy

    Wheezy New Member

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    Thanks all. I’m going to tackle the radiator this weekend. A few people on Facebook have recommended the Chinese replacements from eBay. I’d like to avoid them, if anything due to cost. Hopefully I can sort my one out.
    @squirrelman thanks for the tip. About halfway through doing it, I worked that out and I used the next feeler gauge up in my set as a no-go, which gave me a bit more confidence I was getting it right.


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  7. Thumbs

    Thumbs Member

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    The radiator bracket is one of the first things to corrode away, when you get a repair sorted don’t forget to use a big grommet and ensure the fixing bolt is not touching the alloy or it’ll corrode faster

    It’s worth seeing if there’s someone local who can weld a new one on

    Soak the radiator in a container full of warm water for a few days and treat with care

    There’s one on eBay uk that’s in rough condition, the same bracket you’re having a problem with is gone, corroded away
     
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  8. Wheezy

    Wheezy New Member

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    Is it worth putting some descaler into the radiator?


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  9. Thumbs

    Thumbs Member

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    Personally I don’t think so, see how it cleans up first
     
  10. RogueRC24

    RogueRC24 Member

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    Do you know anyone with a sandblast cabinet? I removed a lot of the corrosion on various hard parts including my rad rock shield. Fan bracket as well. They came out real nice. After that I used clear engine paint and just left the parts that alum color. My fan looks brand new ...almost. :) Scotchbrite might be the ticket as well. I hear that is good for corroded alum parts and not too harsh, but I haven't tried it yet (this weekend).

    ^^ I agree with the above. soak the rad in the sink or something with some dish soap. Not sure about the de-scaler, but I can't see how that would hurt. Def handle with care. :) You got this.
     
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  11. Wheezy

    Wheezy New Member

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    Bugger. This rad’s just too far gone. All 3 remaining mounting points for the mesh have sheared off. The aluminium was like chewing gum. [​IMG]
    Will order a new replacement.


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  12. Thumbs

    Thumbs Member

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    Get some alloy mesh off eBay and make a screen, zip tie the screen on, get it running then commit yourself ….
     
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  13. Wheezy

    Wheezy New Member

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    Yes. That seems sensible.


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  14. Thumbs

    Thumbs Member

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    You’re doing what I had to do to FK, so I can remember what I had to do ….it’s easy to run up big bills and you haven’t started on the cycle parts yet
     
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  15. Wheezy

    Wheezy New Member

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    Having one of those days. Just tried to bleed the brakes and air is being drawn into the lines from somewhere. So a full strip down needed here, too. Just as well it’s only a hobby.
    [​IMG]


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  16. RogueRC24

    RogueRC24 Member

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    I agree with Thumbs, it is ok not to 100% original at this point. Just try and get the bike up and running as cheap as possible first. SS lines are hard to destroy so maybe your crush washers need to be replaced. There are not a whole lot of options for pulling in air. I sometimes just flip the crush washers to see if I can cheat a trip to the store as well.
     
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  17. Thumbs

    Thumbs Member

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    If they’re copper you can anneal them back to soft by heating up until red then drop them into cold water …. I used to run lots of old British bikes, so reusing stuff is second nature

    This works with any non ferrous metal, so solid washers are salvageable, the strange ones used on the sump just crumple when they hit the water
     
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  18. Wheezy

    Wheezy New Member

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    I’ve realised that I was drawing in air via the bleed nipple screw thread, so I’ve put ptfe tape on them and that’s worked. So now drawing clear dot 4 through. But the callipers are siezed so still not getting pressure.

    One of those days so time for a beer. Hear you loud and clear re: radiator. I’ll clean up this one and just get the engine ticking over again. I want to see if my valve clearance work has made things better. Tbh, don’t have the cash atm to fork out on a new one. Thanks all. Learning loads and that’s the main thing.
    [​IMG]


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  19. Wheezy

    Wheezy New Member

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    Radiator in to soak for a couple of days.
    [​IMG]


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  20. Thumbs

    Thumbs Member

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    Nissin bleed nipples are longer than others, make sure you have the right ones, you might have sealed the thread for now with PTFE tape but it might blow under full pressure

    I’ve got a set of piston pullers you’re welcome to borrow, also some seals etc, my fingers don’t work like they used to and I couldn’t fit the seals, I’ll see what’s “left over”
     
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