please help with my pyle of yz!

the bike is a 2004 we go a few weeks ago my bike started being hard to start warm......first clue valves ..the clearances were right on...but upon further inspection sure enough the valve faces and seats were whipped so i had the seats r cut and put stainless valves in with the heavier springs and bases and er all back togther and ran perfect for about ten rides or so at about an hour or two each so to be safe maybe 25 hours.....25 easy hours i never take it past 3/4 throttle and always change oil and filters as th book says....all of a sudden yesterday as i pullled back in my driveway it stalled....while riding i was fiddling with my pilot screw and idle trying to fine tune it...needless to say i kicked and kicked and kicked until i threw a fit and cussed it out home from work today and kicked some more plus put fresh plug in.....still no results .....i reset the pilot to where it was to begin with and no results so for the heck of it i pulled the hot start and kicked few more times .. it finally started up but WILL NOT stay running unless i have the hot start pulled as soon as i release it it dies...i removed the seat and when it is running i can here a faint chirping sound from the air this normal?.....and tomorrow i plan to do some investigating.....but does this seem like another valve issue or a carb issue??? this is my first yamaha and was fairly impressed with it until now in wich my whole leg hurts and there is a hole in my shoe from kicking...please some one point me in any helpful direction before i say screw it and my garbage man gets a sweet bonus i have alot invested in it but the way its going thats where its heading ....cause if it wont run then its no use to me at this point im about to cut my losses and go back to a honda...thanks in advance to any of the yamabeleivers

The chirping sound is normal for an fcr. I believe the hot start lets more air in. I would say its probably carb related.

kinda my thoughts but my re check clearances for like the 20th time while im at it i thought hondas were finicky lol...also can you possibly give a base setting for my pilot screw to my knowledge it has factory jetting....also im baffled as why it would just all of a sudden do this even after running flawless with the same settings...

Gray is really good at YZ troubleshoots. He may chime in later.

In general, if you have to leave the hot start pulled for the bike to run it is an indication that the combustion mixture is too rich. Pulling the hot start allows more air into the mixture.

Sounds like the carb is flooding, or a jet fell out, something like that.  Have a look at the vacuum release plate on the slide, too.  Could be cracked or have a missing corner.  Might check the cam timing while you're at it.

cool thanks guys all f the above are all ideas  I thought just needed a conformation lol after work today I plan on starting by checking the timing and valve clearance...maybe it jumped a tooth or something... ive never had to get into one of these carbs but if the valves are still good that will be my next step also still kind of baffled as why it just all of a sudden started this but ill check it all out and let you guys know what I find hopefully something...very frustrated lol

so heres an update came home and checked timing...dead on....valve clarances still right where i left i moved on to double checking all wiring connections ect. found nothing so finally got the nerve to tear into the carb right off the bat i noticed some blackish dust stuff in the filter side of carb....ah haa i thought so i disassembled and cleaned everything ...put back together and with a little tuning of the pilot screw she once again runs.....point being gray was right on it was flooding due to the pilot air jet being plugged by this black dust happy it runs now but the mystery of the dust??? thought and thought finally gave up and just enjoyed hearing it idle but decided id clean my filter while the seat was off and BAM found a tear in the seam of the filter.....not sure how it got there but couldnt have been there long as i just cleaned it a week ago.....point being like a ass i chased around alll kinds of issues when it was just a dirty carb.....thinking when i washed it maybe the soap i used made it brittle or something but no more re using filters for me its worth the 20bux to get a no toil pre oiled!! thanks again guys and happy trails untilthe next yama- crisis!

Keep water away from the air filter when washing, not because it can harm the filter in any way, but because the foam filter stops water about as well as a tennis racquet.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By yz480doinwork
      Brand new, still in the packaging Lexx end cap fits the stock muffler of 2006 & 2007 YZ450f and 06-13 YZ250f. Comes with a forest service approved spark arrestor and two different size tips. Don't spend hundreds of dollars on a slip on, this tip can be quiet and forest legal or loud and make power! Also a note for WR450 guys: get this tip and find a used 06/07 YZ muffler, fits directly on 09-15 WR450. $80 shipped free to the lower 48. PM, call or text 406-223-8789
    • By Woody Oakson
      So I have a 2008 yz450f and I would like to add some LED lights to it to make it street legal. Mainly just a headlight and a tail light and turn signals if I need to (which where I live hand signals work).
      So where I need help is getting power from the stator to a battery. Wiring from a battery to anything else I got and understand and don't need help with (but recommendations are welcome). So my questions are.
      What type of power is coming from the stator. AC or DC? Will I need a regulator or rectifier? How do I wire something from the stator to charge a battery? What would that wiring look like? Would this stator work? Anything else I should know? Any help would be appreciated. Thank you.
    • By Samx22x
      Alright so I’m new to the site so maybe this question has already been asked. I have a 2002 Yz426f and I want a new exhaust, it has the stock header and silencer and sounds amazing but I’d like a little more from it, I know I want the fmf power bomb header and am kind of undecided on the silencer, I see on fmf’s website that their silencer will add low end and slightly take from top end and the other way around but I’m looking for increases throughout rpm range. I do a lot of trail, hill climbs, jumps, and wheelies so kind of need good performance everywhere in the rpms. My question is what silencer I should get and the jetting I should get for the carb. Thanks
    • By Zack Ailing
      hey guys just picked up a new project bike. Its a 2008 Yz450f with a big bore kit and a stroker crank. The total cc of the engine is now 499. It runs on race gas and will be an absolute monster when shes ready to rip. I will continue to make more videos on the bike so stay tuned Link to the video: 
    • By High On Octane
      2005 YZ450F, Athena Big Bore, Power Bomb, Q4.
      Ok.  Last fall after a decently hot day at the track, I noticed coolant leaking from the weep hole on my water pump after pulling into the pits.  Ordered an Athena re-seal kit, put it all back together and didn't really get a chance to ride it.  3 weeks ago, went out to the track, and after about 20 laps, it started leaking again.  Kept filling it with water to get thru the day, never ran anywhere close to dry or empty, jut a cup or 2 low.  Ordered a Hot Rods re-seal kit with bearing and also ordered a new w/p shaft.  Did it all again and got it back together, ran it, and as soon as it got to temp, it was leaking out of the weep hole again.
      So, what the heck am I missing?  I'm totally stumped on this one.  Is something wrong with my case cover?  Do I need to replace the w/p itself?  I'm feeling like I should've just ponied up for the Boysen in the first place, and now it's biting me in the butt.  Any help or suggestions is greatly appreciated.  Thanks!