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hart

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About hart

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  1. It should run with anything over about 100 PSI compression but if fluid is running straight through the intake with no lobe of the cam touching the lifter you won't get any compression. I usually pour gas in a head that is out of the engine upside down and see if it can hold the gas in it for 5 min or so.. sounds like yours would leak right out because you have done the same thing from the other side of the valves. I vote like stated above that the valves are bent but that's just a guess.. I believe it has to come apart.
  2. Yes, your cams define the compression stroke because the piston has a top dead center on the power stroke and at the end of the exhaust stroke. If your valves are bent or shot you should be able to see light through them when you pull off the head, if your hand got blown off the intake side when you cycled the engine then its obvious there is major damage to the valve surfaces, they are bent or you don't have the cams timed right. If you pulled off the head and couldn't clearly see the problem,, you better check you cam timing process. Good Luck!
  3. had a friend do the same thing to his bike because he was running it wide open on a highway and the oil was not synthetic and old oil too... dyno oil + old oil + wide open on road = blown rod almost every time.
  4. Your not troubleshooting the problem,, You could have a lot of money flowing if you don't get systematic. If you have good compression there is no valve or piston problem. Seems to me you don't know if you have good compression. You have some compression.. Usually if your valves leak or the piston rings are bad,,etc you can push start it. you could still have a spark problem or a spark timing problem,, a fuel/air problem,, and of course a compression problem,, do you have a compression tester? have you checked valve clearance?
  5. hart

    2014 YZ/WR 250f

    After what you have said about terrain I would change my advice. That 450 is still too big IMHO but a new yzf may not buy you much compared to an older one, you sure don't need the power.. an 07 in good shape with a recluse would do you just fine I think. Good Luck!
  6. hart

    2014 YZ/WR 250f

    Man, I cant imagine anyone knocking your plan! I'm right with you, I don't believe those 2 bikes will end up anywhere near 20lbs different. I've rode those big lugs in the woods and endure and its a world of difference. I really like the Yamaha reliability and straight line stability so that's my dream too. The recluse will take away all the value of e-start IMHO If you can afford to take the loss is the big question. I sure see folks buy up their dreams and then 2 years later sell it out with 20 hours on it for a 3000+ loss.
  7. hart

    09 yz 250 athena 290 big bore

    what controls how far the valves move is the lobes on the cam not the length of the valves. so don't worry about setting the shims. thats a different deal. If you are using the wrong TDC mark on the crank this exact situation will happen. also if the piston is backwards or wrong. You say that your sure the cam timing is correct but have you verified it with a manual process? other than looking at the marks.. there is a way to do this. If the crank key is out of place this will happen and you will be "positive" its timed correctly but you will be wrong.
  8. hart

    09 yz 250 athena 290 big bore

    Be patient,, this is a great opportunity to learn. A few of the obvious things I would do in order are:: 1. cams out of time,, you can prove this by taking the cam chain and cams off and while the valves are closed hold the chain up with fingers and turn over the engine,,(dont let the chain bind) if no interference its the cam timing. Do not set the valve clearance trying to avoid interference! Look for different ways to identify the dots on the exhaust cam, it can be confusing. Always top dead center on the non power stroke,, the intake and exhaust valves should be cracked open evenly so the piston doesn't hit 2. rod too long,, cyl too short,, etc.. you won't be able to prove this without taking off the head and trying to turn it over with the head on and then off 3. other interference,, parts over the piston like a dowel,, bad crank, parts blocking the crank/flywheel.,,parts in the gears on the clutch side,, etc. you cant prove this without tearing everything down good luck!
  9. hart

    Racer X's 250F Shootout "Verdict"

    Or they could just slowly move away from it like the 5 valve head,, Interesting days though and I love Yamaha taking chances like this,, To be fair KTM has taken many more risks than any of these others and they aren't always winning because of it.
  10. hart

    2006yz250f rear shock spring id

    a lot of times its on the end of the spring,, that is covered by the adjuster so you probably cant see it unless you loosen it up and try to sneak a view from one side or just pull off the shock
  11. hart

    High compression piston kit vs. Big bore kit

    most big bores are higher compression too so you will see quite a bump in power with bb
  12. hart

    YZ250F woods bike

    I wouldn't go nuts to your dealer,, The WR is designed to be the woods version so don't be pissed if they tell you so. the wr is detuned,,so it won't be real abrupt on the throttle at low speeds. it also has softer suspension for stepping over roots and obstacles. The wr also has a catch bottle for antifreeze in case it gets hot. The wr has larger radiators on certain years maybe all. The oil thing is probably wrong and a yz250f cools pretty well so i wouldn't listen to them but they are right about the purpose of the bikes.
  13. don't expect worlds of difference with the airbox and exhaust mods. They make maybe a little more difference than on any other bike. with a yoshi and powercommander and airbox mods mine would still get beat by a stock drz400. the problem most people have with the wrr is you have to rev it like a 2 stroke to get the power you want. most of the real world dyno's show the stock wrr at about 24 hp,, exhaust/programmer/airbox about 27-28 and big bore/exhaust/programmer about 31-32 for the money leaving it stock is as good as anything,, if you have to mod it its hard to stop because it gets noticably more fun with exhaust/programmer,, and at least as much more with the big bore. now your talking about a 7500 dollar bike,, good luck
  14. hart

    JD jetting kit for WR250

    Just did a jd jet kit.. I'm telling you that it will really help with the bog. the jet kit comes with the accelerator pump mod, including the leak jet change recommended. plus the normal jetting changes.. really transformed the bike. they really respond to questions about recommendations too. I really think your looking in the right direction with JD.
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