1975 dt 250 restoration advice...and should i even do it?

Discussion in '2 smokers' started by davidb21, Jun 1, 2012.

  1. davidb21

    davidb21 Adventurer

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    Okay so this might be a little bit of an odd post but i could use some advise.

    My brother has a 1975 dt 250 thats been sitting in the back yard under a tarp for about a year now, the engine seems to be perfect, shocks seem okay, and for the most part the lights work. It was his daily commuter for about a year but he got sick of it flooding on him because it has a rusted tank.

    I dont really have any experience working on motorcycles and would like to learn, and think this could be a good project to learn on and it would really be a nice surprise for my brother. ( he doesnt live at home, doesnt have the time or money to fix it himself, and is currently stuck taking the bus to work 5 days a week )



    I think mainly what needs to be done is
    -de-rust the tank (then seal the tank? i read about some product your supposed to use after de-rusting, but dont really know)
    -clean the carb
    -re-upholster his seat
    -de-rust his exhaust which is pretty darn rusty
    -get the speckle rust off of just about every exposed metal part
    -and then replace whatever fluids might be old, dont care if they are or not just going to replace just to be safe


    I want to do this with out really spending any money, besides what i'll need to de-rust the tank. Im only working two days a week at the moment so until i land a new job i can make up what i lack in money and experience with time. I also have a couple buddies who wouldnt mind helping me out from time to time who have done some work on their own bikes, but are in no way mechanics haha.

    As far as tools/supplies go i believe i have everything i need to do all this, besides whatever i need to clean the tank.

    The main advise i need is on the cleaning of the tank, or if i should even attempt it not having any tank cleaning experience.

    What products or method would you guys suggest? Ive heard of a couple but am unsure of them.

    Like i said i really have no experience in this so it may sound like i kinda know what im talking about but im just going off of what little general knowledge of motorcycles i have and the research ive done on the internet so any and all advise is greatly appreciated.
    #1
  2. concours

    concours WFO for 44 years

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    Pics please... restore enough to ride and have fun on? Or restore to be very correct? If you like the idea of a two stroke dual sport (I do!) then do it! Cruise at 50mph all day, short bursts to 65 or 70.
    #2
  3. motomike14

    motomike14 Thumper Crusader

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    Assuming you have;

    1) compression in the motor
    2) spark from the motor
    and
    3) willingness to work at it

    Then, it can be a good project.

    Things you really need to be wary of though:

    If it's sat too long, bottom end seal could go. It that happens, you're in bad shape. Tell tale sign is if it bogs down and will not clear out with low RPMs. Bottom end seals are not too expensive on these, but do require a fair bit of work.

    Double check oil in the oil injector/the oil pump. Real easy for junk and rust to get inside the those tanks and create issues.

    If you de-rust the tank (whatever method you use), make sure to then run an external fuel filter afterwards. Rust will continue to appear for a long time, regardless of the method you use (always parts left).

    Since it sat outside, I'd spray some WD40 or similar lubricant down the spark plug hole into the cylinder. Even if the motor is not seized, that's a long time without oil going over that cylinder. Don't attempt to start it until you do that.

    They are great bikes with a huge cult following. I have a 75 as well that has been converted to a motocrosser. Reliable as anything else I own and definitely more fun to ride than most. Simple to work on and any parts you need are available.
    #3
  4. davidb21

    davidb21 Adventurer

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    Hey sorry for the slow response ive been a little busy, i want to get it to the point where it will be a reliable cruiser and also just make it look a little nicer by removing as much rust as i can, its not TOO bad but its got speckle rust pretty much everywhere.

    I'll post some pics up tomorrow
    #4
  5. davidb21

    davidb21 Adventurer

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    It was running a few months ago so it should still have spark, it definitely has compression.
    I dont think it boggs all the time i think its usually after its been run for a while which makes me think it might be rust breaking off and flooding it.

    We disconnected the oil pump when he first got it so he just premixes.

    How much wd40 should i use in there? and should i kick it a few times after spraying the wd 40 before trying to start it to get the wd 40 spread around?

    Thank you
    #5
  6. motomike14

    motomike14 Thumper Crusader

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    Just spray some in through the spark plug hole, kick it through a couple of times, just to make sure everything is still freed up. You could even drop a bit of pre-mix oil in there. If everything goes smoothly, throw a new plug in, clean the carb, get some premix, and away you go.
    #6
  7. Hunsta

    Hunsta Have guns will hunt

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    Yes Yes. Pics please.
    #7
  8. davidb21

    davidb21 Adventurer

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    Hey everyone sorry for the horrible lag in responding.
    Here are some pics (sorry if the quality isnt great they were taken on a friends phone, i'll edit this and replace the bad quality pics with better pics within the next couple days.)
    Ive been pretty busy and havent had any time to do anything with the bike yet but should have some time soon to start working on it.

    [​IMG]
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    #8
  9. vudu

    vudu Been here awhile

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    ...over here

    Tank cleaning

    Bunch of very knowledgeable enthusiasts.

    Good luck and keep us posted.
    #9
  10. anonny

    anonny What could go wrong?

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    Add change crank seals to list of things to do! :deal
    #10
  11. motomike14

    motomike14 Thumper Crusader

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    How crusty is the inside of the tank? For about $50.00, you can buy a product called Caswell, an epoxy tank sealent. It basically seals any rust in. If it's really bad, then forget it. If it's mostly surface rust with no heavy coating, you can just do a simple wash and use it. Use it on my DT racer and has been a great asset.

    http://www.caswellplating.com/restoration-aids/epoxy-gas-tank-sealer.html
    #11
  12. davidb21

    davidb21 Adventurer

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    Do you know how much the seals will cost me?
    #12
  13. davidb21

    davidb21 Adventurer

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    I think i might scrap the idea of cleaning the tank for now and come back to it after i get it running right, i found a clarke tank that will work that i think im going to get for it.
    #13
  14. FloridaSteve

    FloridaSteve Long timer

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    Well the answer is obviously Yes. Do it.:1drink
    #14
  15. anonny

    anonny What could go wrong?

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    Way less than if they leak and you take out the piston and crank :evil

    I don't but generally they are pretty cheap and good insurance for old 2 strokes.
    #15
  16. Cat Daddy

    Cat Daddy Been here awhile

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    Crank seals are cheap and still available through Yamaha parts channels.

    Yamaha part numbers

    93103-30150-00 OIL SEAL (38W) $10.49
    93103-40091-00 OIL SEAL $10.19
    #16
  17. Hunsta

    Hunsta Have guns will hunt

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    You guys in the US have a big source of parts, but the best source I found for my `76 was Yambits in the UK. They have everything.
    #17