2008 yz450f need help! please!


11 replies to this topic
  • yz450rider7

Posted April 04, 2014 - 10:55 AM

#1

hey guys im new to the forum. I have a 2008 yz450f that i recently brought and the other day i was riding and when i stopped there was oil spillling out, it looked like it came from the bottom right or left of the engine in the front but it alot came out all over the frame and rear tire. It only leaks when running and i took the oil fill cap off when running and theres alot of postive pressure coming out. This is my first four stroke so i dont know much about the engines ive owned blasters and banshees before. any help would be great! i dont know if its something minor to fix or the top end/rings are shot also the bike still starts up in usually one or two kicks and no smoke out the exhaust or anything.

If someone could give me some advice on this it would be great paranoid.gif
thank you



  • Hoosier-Daddy

Posted April 04, 2014 - 01:54 PM

#2

Is the dipstick in tight? I have made the mistake of letting it run without the dipstick.

  • yz450rider7

Posted April 04, 2014 - 02:38 PM

#3

thanks but i was just in the middle of changing the oil and realized the bolt that goes into the crankcase on the side of the engine to drain the oil not the one underneath was stripped completey. not the bolt the actual block, the owner before me put some teflon tape on it so i guess it stopped the leak temporarly. so i guess thats were the oil was coming from so i guess i gotta get someone to tap or helicoil it for me.. im stil not sure about the high pressure in the crankcase



  • yz450rider7

Posted April 04, 2014 - 02:46 PM

#4

what the easiest way of fixing the stripped threads i know theres a couple methods timesert/helicoil ect... and is it something i can do myself or should i bring it to a shop i dont want any metal shavings to get into it



  • Doug the head

Posted April 04, 2014 - 02:49 PM

#5

what the easiest way of fixing the stripped threads i know theres a couple methods timesert/helicoil ect... and is it something i can do myself or should i bring it to a shop i dont want any metal shavings to get into it

Probably easiest and best to let a pro handle it.

  • yz450rider7

Posted April 04, 2014 - 03:05 PM

#6

yeah im gana see how much my local shop charges if its to much i will try myself i would like to learn how to do it... also anyone know anything about the high pressure in the crankcase my friend was telling me my rings are shot but idk if thats the case he said there should be no pressure in the crankcase.. im goin to do a compression test and check that out but my bike seems to be running good



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  • Doug the head

Posted April 04, 2014 - 03:10 PM

#7

yeah im gana see how much my local shop charges if its to much i will try myself i would like to learn how to do it... also anyone know anything about the high pressure in the crankcase my friend was telling me my rings are shot but idk if thats the case he said there should be no pressure in the crankcase.. im goin to do a compression test and check that out but my bike seems to be running good

Grayracer seems to be the yzf authority. Best bet would be do a summoning , and if you're lucky he will grace your thread with his presence. Good luck

  • Hoosier-Daddy

Posted April 04, 2014 - 03:18 PM

#8

Im pretty sure you cant do a compression test due to auto decompression on exhaust cam. Leak down test maybe..
As for the stripped hole, a wise older friend once told me it is always better to tighten something up again later than go too tight amd strip threads.

  • grayracer513

Posted April 04, 2014 - 03:37 PM

#9

... if you're lucky he will grace your thread with his presence. Good luck


A little early to be drinking, ain't it?

But here's the facts: the piston moves 450cc of air around on both the top AND the bottom, so what do you suppose happens when it goes down? (Stick your finger over the end of the breather hose one day while it's idling, you'll feel it suck back, too).

Your friend is correct if what he said was that there shouldn't be any NET positive pressure (the outflow should match the inflow) but under power, there is a little bit caused by the rings leaking combustion pressure.

  • Doug the head

Posted April 04, 2014 - 03:43 PM

#10

A little early to be drinking

Not exactly. Nearly seven pm . But I appreciate your concerns

  • yz450rider7

Posted April 04, 2014 - 03:44 PM

#11

thanks for all the info guys alot of help all my friends have 2 strokes so theres no one around here to help me



  • grayracer513

Posted April 04, 2014 - 04:58 PM

#12

Not exactly. Nearly seven pm . But I appreciate your concerns

Ahh. East coast time. Carry on, then.





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