Stumped Need Help


17 replies to this topic
  • marshaltex

Posted August 19, 2008 - 11:38 AM

#1

:worthy: Ok guys here's a head scratcher for you. My dad rides a 07 wr450 and he bought it about three months ago with less than twenty hours on it. The guy that we bought it from "said" that everything was perfect and practically brand new. From the looks of the bike it hadnt been ridden much.(no sidecase scratches, frame scratches, mud stains, ect.) From what we can see the Gytr Ais removal kit has been installed, and there was a GYTR Pipe and header on the bike. The bike ran really well and the seller told us that it had all of the "free mods" done. Snorkel pulled ,grey wire clipped, rejetted ect. by the dealer. When we started the bike however it required a cracked throttle to keep it running, minor adjustment i know but just for info. sake. So we bought the bike and brought her home. The pipe was for the wrong year model (so i claimed it and put it on my 03 LOL) and we put the stock system back on (derestricted). We know this b/c the bolt mount didn't match the hole and there was soot on the motor from the pipe being shoved to far forward and leaking.

My dad took it up to barnwell mountain ran it for about three hours total washed it and put it up running w/ battery maint. charger plugged in. Two weeks later the bike wont run, one time went down to the shop and it ran for maybe 6 seconds and then died. We change the oil, drain the carb, check the tank for debris, pull the jets to check for dirt, pull the plug check for spark, gap and burns, bike has good compression seems to be getting fuel, play with the idle, try to pull start it (behind our Ranger), check the fuses, check the battery connection...Nothing.

Where do i go? Ive read through the fix-it book and cant draw a conlclusion as to what is the problem is. This bike cant have more than 30hrs on it. I know i have spark, there fuel in the carb bowl, nothing to stop the air. fuel+air+spark=fire right? Ha :thumbsup: wrong in my case. Im down to the tough stuff thinking maybe a bad diaphram in the carb, maybe outta timing, i just dont know. None of these answer seems to make sense. PLEASE HELP

  • William1

Posted August 19, 2008 - 11:44 AM

#2

Try a fresh plug
Check the valve clearance
Get a new pilot jet
Increase the idle speed
Check the starter jet

  • Charles De Mar

Posted August 19, 2008 - 11:59 AM

#3

Try a fresh plug
Check the valve clearance
Get a new pilot jet
Increase the idle speed
Check the starter jet


what's that?

  • SJMC_DON

Posted August 19, 2008 - 12:40 PM

#4

Are you sure fuel is getting into the cylinder?

You stated you have spark.... if the cam timing was off you would atleast get a pop or back fire...

The e-start spins the motor right? (stupid question I know but just trying to rule out clutch / neutral switch, anything in the starter circuit)...

Might be that the auto decomp is stuck oir the plug for the old de-comp lever came out:excuseme:

  • AnimalDan

Posted August 19, 2008 - 03:22 PM

#5

To help narrow things down I like to put a shot of starter fluid into the air intake. If it fires and dies you know you have a fuel delivery problem. If it doesn't kick, then you can focus on the spark/timing side.

  • marshaltex

Posted August 19, 2008 - 06:07 PM

#6

thanks for the help guys. the motor does turn over witht the e-start and it is making compression. Im def. gonna give the starter fluid a try and see if that'll get her rollin'. ill update as soon as i do. any other help would still be greatly appreciated

  • marshaltex

Posted August 19, 2008 - 06:16 PM

#7

ucmc not sure what you mean when you say old de-comp lever. Are you refering to maybe a hole left in the case by the manufacturer for a manual decomp lever aftmarket?

  • SJMC_DON

Posted August 19, 2008 - 07:15 PM

#8

ucmc not sure what you mean when you say old de-comp lever. Are you refering to maybe a hole left in the case by the manufacturer for a manual decomp lever aftmarket?


disregard.... this would not apply to an 07':bonk:

I think the 06' maybe 04' and older were still using the same cyl. head from the good old manual de-comp days but Yamaha's plug for the de-comp actuator in the head would sometimes come out, leaving the bike (I think) with no compression. It was stab at your problem.

Keep us updated, hopefully it's something simple.

  • marshaltex

Posted August 22, 2008 - 11:23 AM

#9

well we put a couple shots of starter fluid in the air box and hit the e start and bike fired up like new(ran on the starting fluid) and then died. Hence we have a fuel delivery problem. So we pulled the carb went through the repair manual and checked every thing we could on the carb.(jets clean, fuel bowl height, diaphram in good shape, ect..) :thumbsup: Everything looks to be in superb shape, which it should be since the bike only has 30 hrs on it. Can you feel my frustration yet LOL?:worthy: I dont know what to do, im not he kinda person to say forget it it and take to a shop I wanna figure it out and fix it. Any ideas?

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  • Mtn-Track

Posted August 22, 2008 - 11:31 AM

#10

When you took the carb apart, was there any fuel in the bowl or was it dry?

  • marshaltex

Posted August 23, 2008 - 05:47 AM

#11

yea the bowl had fuel in it

  • Reedus

Posted August 23, 2008 - 03:49 PM

#12

Remove your pilot jet and hold it up to a light. If you can see day light your good to move on to another solution. If you can't, therein lies your problem. Clean it or just buy a new one.

  • Team_Oatmeal_Pie

Posted August 23, 2008 - 07:03 PM

#13

I would drain the gas tank completely and take a look inside with a flash light, if it sat for awhile it could be gummed up. I have seen brown sludge in tanks before and hence repeated clogged pilot jets/no idle/half throttle starts/runs for one ride and then no start next ride out

  • skintback426

Posted August 23, 2008 - 09:52 PM

#14

In my best slingblade voice... "It ain't got no gas in it."

You may have a partially clogged fuel line?

  • buggs bunny

Posted August 24, 2008 - 07:57 AM

#15

i cleaned and re oiled my air filter after a forty mile ride and put to much oil on the air filter so it caused a rich condition and wouldn't start, i thought more was better:bonk: .then re washed filter and tried to start again with no luck,with gas petcock turned to on and i herd gas in tank.so i changed sparkplug thinking i fouled it.then tried to start,no fire:foul: now im pissed,then for the heck of it i turned the petcock to reserve and it fired right up:applause: so moral of this story is it is always good to never give up + check the basics first.:thumbsup: :worthy:

  • marshaltex

Posted August 26, 2008 - 02:14 PM

#16

Well guys after the complete disassembly of the rear end of the bike, and taking apart the carb and cleaning it. We have realized that we skipped the first step that any good small motor mechanic would do on a motor that wont run.:worthy: Putting fresh gas in the tank::thumbsup: Yes i deserve a "you stupid idiot" from all you guys who have been helping me out. I really appreciate all the advice and time that you guys have given me.

But, what i did do right is gain unreplaceable know how on how the back half of this motor works. The easy way to get to the carb and how it works. Thanks again

Marshal:ride:

  • drtbk4ever

Posted August 27, 2008 - 08:54 AM

#17

Thanks for the update.

I like happy endings.

  • HappyG

Posted August 28, 2008 - 12:29 AM

#18

then for the heck of it i turned the petcock to reserve and it fired right up:applause: so moral of this story is it is always good to never give up + check the basics first.:thumbsup: :worthy:


yup ive seen the "reserve" position cure hard starting more than once.
youd be suprized how much fuel is left on reserve.




 
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