Yamaha dt250 - strange battery ?

Discussion in '2 smokers' started by jordan325ic, Apr 20, 2010.

  1. jordan325ic

    jordan325ic Been here awhile

    Joined:
    Mar 21, 2010
    Oddometer:
    271
    Location:
    Dakar, Senegal
    Hello everyone. I just finished my MSF course last week and am currently on the hunt for my first bike.

    I've got a friend who has a barely-running 1976 Yamaha DT250, which he offered to let me ride in the meantime if I can get it going. The battery was dead, so I tried to jump start it. However, once I lifted up the seat I did not find a battery I recognized.

    The battery I saw looked like this:
    [​IMG]

    BUT it had no terminals and no threaded holes. The only thing it had was a red wire going in, black wire going out and those little yellow knobs. There was not any visible metal at the battery or anywhere down the wire to attach the jumper cables.

    How do you jump a battery with no terminals?

    Also, quick bonus question: The air filter is in very poor shape (disintegrating). I have (with some difficulty) tracked down an OEM air filter, but I'm wondering if I should go with an aftermarket K&N filter which can be cleaned/re-used? What does adv think?
    #1
  2. gvthnks

    gvthnks Been here awhile

    Joined:
    Nov 15, 2008
    Oddometer:
    578
    Location:
    Actionville NC
    That's a 6v battery. Don't jump it. The DT250 will run without the battery but you shouldn't.

    I'd use a foam type stock filter.
    #2
  3. dan-c

    dan-c Back

    Joined:
    Aug 19, 2005
    Oddometer:
    13,769
    Location:
    SATX
    It won't hurt a yammie enduro to run without the battery. The battery basically supplements the lighting, i.e. blinkers are better, tail light lights without the engine, stuff like that.

    Better batteries are the sealed agm ones that are used for back-up power for home alarm systems. Just take the battery to your local Batteries Plus store or the like and get one. No worrying about acid eating up the seat and battery box and the damn drains that never seem to get routed correctly.

    I use a UNI filter on my yamaha's they come with the cage and sleeve that are just like stock except better.
    #3
  4. jordan325ic

    jordan325ic Been here awhile

    Joined:
    Mar 21, 2010
    Oddometer:
    271
    Location:
    Dakar, Senegal
    So the battery will not effect the bike's ability to start?

    I guess I'll start looking elsewhere for the reason why it won't start. I tried kick-starting it many times, tried to pop the clutch with the bike rolling. It sounded like it wanted to start but never did catch and actually run. I guess I'll replace the air filter and go from there. This is my first time working on anything with a carb, so it will be a learning experience.
    #4
  5. dan-c

    dan-c Back

    Joined:
    Aug 19, 2005
    Oddometer:
    13,769
    Location:
    SATX
    No it get's all the power from the magneto (and coil).

    If it's been sitting pull the plug, ground it to the head and see if you are getting spark (should be a decent fat spark, not weak looking), never hurts to change the plug while you're at it.
    If you have spark, you may want to pull the carb and rebuild it. It is pretty easy to do.
    #5
  6. capeklr

    capeklr Been here awhile

    Joined:
    Dec 28, 2009
    Oddometer:
    333
    Location:
    Cape Town
    Check that you are getting fuel through the fuel tap and into the carb. there must be fuel in the carb bowl or float chamber.
    Remember also to check that there is 2 stroke oil in the bottle and that the pump works or it won't run for long.
    #6
  7. Inane Cathode

    Inane Cathode Cheated Anion

    Joined:
    Jan 7, 2008
    Oddometer:
    4,608
    Location:
    Arvada, CO
    New plug right now. Take the carb off, clean it out, put a filter on the fuel line, rinse the tank out with fresh gas, give it a spritz of ether in the intake it should fire up.
    #7
  8. baloneyskin daddy

    baloneyskin daddy bikaholic

    Joined:
    Oct 21, 2009
    Oddometer:
    2,177
    Location:
    southcentral PA.
    Ether eats the hell out of 2stoke crank seals.
    #8
  9. Inane Cathode

    Inane Cathode Cheated Anion

    Joined:
    Jan 7, 2008
    Oddometer:
    4,608
    Location:
    Arvada, CO
    Not any more than they already are, and just a spritz you're not plumbing the stuff into the carb. If it wont fire on ether it wont fire on anything and it indicates a major problem.
    #9
  10. Beezer

    Beezer Long timer

    Joined:
    Oct 26, 2004
    Oddometer:
    6,005
    Location:
    Anchorage, formerly Spenard (hub of the universe)
    JC Whitney has all those batteries. an ya, pour some gas in the sparkplug hole it should kick off if you have spark.
    #10
  11. jordan325ic

    jordan325ic Been here awhile

    Joined:
    Mar 21, 2010
    Oddometer:
    271
    Location:
    Dakar, Senegal
    Hmm. It just dawned on me that he may not even realize his bike is a two stroke. He told me the oil filter is probably clogged, but that it's OK if you put some oil in the gas tank. Now I have never had any experience with 2-strokes, but a few minutes of googling indicates that 2 strokes don't have oil filters and there is a pretty specific ratio of gas to oil that needs to be upheld.

    Anyway, I recall the bike being pretty smokey when it last ran. I think he may be putting the wrong amount of oil. What ratio of gas to oil do ya'll use?

    And what could be damaged by running the wrong ratio of gas to oil?
    #11
  12. CoolioRZ

    CoolioRZ Adventurer

    Joined:
    Nov 7, 2008
    Oddometer:
    35
    The bike should have an "oil filter" screen at the bottom of the injector reservoir. Maybe your friend was referring to that?

    As far as a pre-mix ration goes, 32:1 will suffice.
    Damage from the wrong ratio could be as simple as fouled plugs and too much smoke. Running too rich will also quickly carbonize your top end.
    Running to leaning will quickly wear out rings, seize your top end and maybe the bottom end.
    If you go the pre-mix route, I'd definitely recommend using a ratio-rite.

    Excess smoke can also be a symptom of a bad clutch side crank seal.

    What year is your DT? Is it a reed valve model?
    #12
  13. jordan325ic

    jordan325ic Been here awhile

    Joined:
    Mar 21, 2010
    Oddometer:
    271
    Location:
    Dakar, Senegal
    Well, I found out the problem. He was mixing in 4 stroke oil instead of 2 stroke, so the plug was fouled. Replaced the plug, cleaned the carb, replaced the air filter, put new gas in, and she started right up.

    Got to ride her around, and she is fast! Now there's either a throttle issue or an idle issue, because when I'm not in gear (clutch in or in neutral) she revs very high. Tach is broken, but it's way wrong. He thinks it's the throttle sticking. Also, that headlight SUCKS. Need to upgrade that if I'm every going to ride at night again.
    #13
  14. RodT

    RodT Been here awhile

    Joined:
    Sep 20, 2008
    Oddometer:
    352
    Location:
    Westwood, CA.
    The throttle issue might be an air leak. If the bike sat for a long time, and just because of age, the main seals could be bad. The seal under the mag, might be sucking air. That can cause an eratic throttle. If it is an air leak, do not run it, it will seize the piston. If the other side is leaking, it can suck oil out of the trans. and cause it to smoke really bad. You can do a pressure test to see if the seals are bad. Rod
    #14
  15. jordan325ic

    jordan325ic Been here awhile

    Joined:
    Mar 21, 2010
    Oddometer:
    271
    Location:
    Dakar, Senegal
    I'm sorry, I'm new. What's a mag? Where are the "main" seals and what do they seal?
    #15
  16. truck6driver

    truck6driver The Fireman

    Joined:
    Sep 23, 2007
    Oddometer:
    7,577
    Location:
    Hope Mills, N.C.
    Batteries plus can get those batteries.
    If I remember correctly there is a conversion kit for it too that will change it over to 12 volt but you will need to swap all the light bulbs out for 12 volt ones. If you plan to ride it alot I would look into that.

    Ray
    #16
  17. pclem12

    pclem12 Adventurer

    Joined:
    Aug 25, 2009
    Oddometer:
    78
    all the time at idle, or only after having given it throttle?
    #17
  18. jordan325ic

    jordan325ic Been here awhile

    Joined:
    Mar 21, 2010
    Oddometer:
    271
    Location:
    Dakar, Senegal
    I only rode it for a few minutes, but it appears to only happen after giving it throttle.

    I did disconnect the throttle cable when I cleaned the carb. I suppose it's possible I re-connected it wrong, but he said there was a "sticky throttle" problem before I touched it. He says that giving the throttle a twist or two fixes it.
    #18
  19. jordan325ic

    jordan325ic Been here awhile

    Joined:
    Mar 21, 2010
    Oddometer:
    271
    Location:
    Dakar, Senegal
    Well, maybe it's not a throttle issue?

    Today I rode the bike and twice I was coming to a stop with the clutch in and the bike started revving very high. Gave it a few tugs of the throttle and it just kept on revving, if anything it seemed to go higher (tach is dead so not sure exactly how high it was revving). So I hit the kill switch, it kept running like I hadn't done anything. I turned the key to the "off" position. Still kept revving. The only way I could turn it off was to stall it out by releasing the clutch suddenly.

    Not really sure what's going on with that. Any suggestions?
    #19
  20. rightone1974

    rightone1974 Adventurer

    Joined:
    Aug 17, 2012
    Oddometer:
    19
    Location:
    Saint Maries, Idaho
    I had the same problem with my dt250 and it wound up being the float level if not that it is your timing. mine would not idle because the jet was clogged then it would not get full throttle so i replaced the needle and seat then it ran great. they are good reliable bikes and durable and quick
    #20